ZH^j
 
 THE ANATOMY AND PATHOLOGY 
 OF THE TEETH. 
 
 BY 
 
 C. F. W, BODECKER, D.D.S., M.D.S. 
 
 With Three Hundred and Twenty-five Illustrations. 
 
 Adopted by the Natioxat, Association of Dental Faculties 
 AS a Text-Book imjk Dental Students. 
 
 PHILADELPHIA: 
 
 THE S. S. WHITK DENTAJ. MANrFACTTKING CO. 
 
 1894.
 
 Copyright. 1894, by C. F. W. Bodecker.
 
 
 TO HIS 
 HIGHLY ESTEEMED TEACHER AND FRIEND, 
 
 Carl Heitzmann, M.D., 
 
 THIS BOOK IS DEDICATED BY THE 
 AUTHOR.
 
 PREFACE. 
 
 WHEN, nearly eighteen years ago, I lirst entered the hibora- 
 tory of Dr. Carl Heitzmann and listened to his lectures 
 on general histology, I became so thoroughly imbued witli tlie 
 conviction of the correctness of his views that I resolved to study 
 the tissues building up the teeth in tlie light of the novel doc- 
 trine. Ever since I have been a faithful attendant at his labora- 
 ti^ry. Besides myself, hundreds of dentists have attended 
 that institution, largely owing to the enthusiastic impulse of 
 my much-lamented friend, the late Dr. William H. Atkinson. 
 As a consequence, a number of these gentlemen, including 
 Professor Frank Abbott, Dr. William H. Atkinson, Dr. John 
 I. Hart, and Dr. F. A. Roy, have enriched dental literature with 
 the results of original investigations, made in the same labora- 
 tory, all of which wdl be found embodied in this book. 
 
 So long as the cell-theory holds sway over the minds of the 
 majority of microscopists, the views here laid down cannot meet 
 with general acceptance. As early as 1859 no less a man than 
 Thomas H. Huxley declared that the history of the develop- 
 ment of the teeth was not intelligible upon tlie grounds of the 
 cell-theory. We to-day can state that neither the normal nor 
 the morbid anatomy of the tissues is explicable on the basis 
 of that theory. How long it will be before the novel views 
 advanced by l^r. Carl Heitzmann, and which are directly antag- 
 onistic to the cell-theory, will gain a tinal victory it is impossible 
 to foretell. In our time discoveries are made in rapid succession : 
 some are at once accepted, to be discarded later upon more 
 critical investigation ; others, which meet with incredulity or
 
 VUl PREFACE. 
 
 open denial at first, prevail in the long run, as they must do if 
 verified by honest observations and facts. It is gratifying to 
 my highly-esteemed friend and teacher to know that already a 
 number of independent observers have indorsed his views. It 
 is true lie has not escaped the criticism, even enmity, which 
 appear to be the lot of every daring original investigator; but 
 while opposition may delay the acknowledgment of these newly- 
 interpreted facts, it will not be able to prevent their ultimate 
 acceptance. 
 
 I cheerfully acknowledge the great assistance rendered me by 
 Dr. Carl Heitzmann in the preparation of this book. To him 
 I am indebted not only for the artistic illustrations, which were 
 all made by him, but also for aid in the microscopical researches, 
 both those previously published and those here set forth for the 
 first time. 
 
 While the minds of the majority of American dentists are 
 largely directed toward so-called practical topics, I yet hope 
 that no intelligent dental practitioner — and this work has been 
 written only for such — will lay aside the book, after its con- 
 scientious perusal, without feeling that he has gained some 
 additional knowledge from it. I ask only unlnased, conscientious 
 reading. I know that our profession is not lacking in students 
 competent and willing to give this, and to them I trust the 
 verdict as to the value of my labors. 
 
 This book may help in demonstrating that scientific investi- 
 gations are not neglected in our country. Its preparation has 
 cost all my leisure time during almost a decade ; but if its publi- 
 cation shall prove of service to my profession, I shall feel more 
 
 than repaid. 
 
 Carl F. W. Bodeckbr. 
 
 New York, July, 1894
 
 CONTENTS. 
 
 PAGE 
 
 CHAPTER 1. 
 The Superior Maxillary Bones 1 
 
 CHAPTER II. 
 The Inferior Maxillary Bone 9 
 
 CHAPTER III. 
 The Teeth . . . ' 18 
 
 CHAPTER IV. 
 Individual Characteristics of the Teeth 24 
 
 CHAPTER V. 
 
 The Pulp-Chambers of the Teeth 28 
 
 CHAPTER VI. 
 The Articulation of the Teeth 84 
 
 CHAPTER VII. 
 General Anatomy of the Human Teeth 39 
 
 CHAPTER VIII. 
 General Histology 46 
 
 CHAPTER IX. 
 
 Development of Connective Tissue 68 
 
 CHAPTER X. 
 The Minute Structure of Dentine 69 
 
 CHAPTER XI. 
 
 The Minute Structure of Enamel 90 
 
 CHAPTER XII. 
 The Minute Structure of Cementum 101 
 
 CHAPTER XIII. 
 Synopsis of the Development of the Teeth 124 
 
 CHAPTER XIV. 
 Development of Dentin k 120
 
 X CONTENTS. 
 
 * 
 
 GHAPTEE XV. page 
 Deyelopmext of the Enamel 148 
 
 C H A P T E R X V I. 
 Faulty Development 194 
 
 CHAPTER XVII. 
 Development of Cementum .227 
 
 CHAPTER XVIII. 
 The Development of Teeth in Embkyos affected with Rhachitis 232 
 
 CHAPTER XIX. 
 The Dental Pulp 244 
 
 CHAPTER XX. 
 The Perice.mentum 256 
 
 CHAPTER XXI. 
 Eruption of the Teeth 261 
 
 CHAPTER XXII. 
 Absorption of Temporary Teeth 264 
 
 CHAPTER XXIII. 
 Physiology' of the Hard Dental Tissues 270 
 
 CHAPTER XXIV. 
 General Diagnosis of the Diseases of the Teeth .... 274 
 
 CHAPTER XXV. 
 Irritation and Keav Formations of Dental Tissue .... 288 
 
 CHAPTER XXVI. 
 Secondary Dentine 292 
 
 CHAPTER XXVII. 
 Mechanical Abrasion 309 
 
 CHAPTER XXVIII. 
 Erosion 316 
 
 CHAPTER XXIX. 
 The Reaction of the Dentine upon Fillings 320 
 
 CHAPTER XXX. 
 Hyperostosis of Roots of Teeth 329 
 
 CHAPTER XXXI. 
 Inflammation 348 
 
 CHAPTER XXXII. 
 Inflammation of the Gums, — Ulitls 363
 
 CONTENTS. XI 
 
 C H A P T E 11 A X X T 1 1. ,.^„^. 
 
 Inflammation ok Dkntink, — Ehuknitis ....... 370 
 
 CHAPTER XXX IV. 
 Pulpitis in its Clinical Aspects 380 
 
 CHAPTER XXXV. 
 MoKBii) Anatomy ok Pulpitis 397 
 
 CHAPTER XXXVI. 
 Dkcenekations and Atkophies of the Pulp ...... 412 
 
 CHAPTER XXXVII. 
 Morbid Anatomy of Atrophies and Degenerations of the Pulp . 420 
 
 CHAPTER XXXVIII. 
 
 Pericementitis in its Clinical Aspect 432 
 
 CHAPTER XXXIX. 
 Morbid Anatomy of Pericementitis 462 
 
 CHAPTER XL. 
 Caries of the Teeth 488 
 
 CHAPTER XL I. 
 The Effects of Arsenic Dioxide and Metallic Arsenic upon the 
 
 Pulps of the Teeth, — So-Called Coagulation-Necrosis . . 518 
 
 CHAPTER X L 1 1. 
 Necrosis of the Jaw-Bones 584 
 
 CHAPTER XLIII. 
 Empyema of the Antrum 642 
 
 CHAPTER XLIV. 
 
 The Clinical and Anatomical Features of Tumors in General . 546 
 
 CHAPTER XLV. 
 Tumors of the Teeth 553 
 
 CHAPTER XLVI. 
 Cysts in the Oral Cavity 569 
 
 CHAPTER XLVI I. 
 Tumors of the Jaws 673 
 
 CHAPTER XLVIII. 
 Malformations and Malpositions of the Teeth 609 
 
 LITERATURE 614 
 
 INDEX 669
 
 The Anatomy and Pathology of the Teeth. 
 
 CHAPTER I. 
 
 THE SUPERIOR MAXILLARY BONES. 
 
 To the dental practitioner these bones, together with the lower 
 jaw-hone, are the most important ones of the human bod}'. 
 They occupy the central region of the face, on either side of 
 tlie nasal cavities, and each of them, in a normal condition, 
 is mounted with eight teeth. In connection with the other 
 facial and cranial bones, they constitute the frame-work of the 
 upper and greater part of the face. Each superior maxillary 
 contributes to the formation of the roof of the mouth ; to the 
 floor and outer walls of the nasal cavities, as well as to the floors 
 of the orbits. Aside from the Ixxhi, which is somewliat cuboidal 
 in shape, we distinguish four processes, — z.e., the inalar, the nasal, 
 the palatine, and the alveolar ]>rocess. The body of this bone con- 
 tains a large cavity, the anlnun of Wf/hmore, obviously for the 
 purpose of minimizing the Aveight of the bone, and at the same 
 time of increasing it^^ pro[)ortionate strength. 
 
 The external or facial surface (Fig. 1) shows above the incisor 
 teeth a slight depression, called the incisive fossa. Outward from 
 this is another depression, the canine fossa, which is deeper than 
 the incisive, and sejiarated from it by a vertical ridge, the canine 
 eminence, corresponding to the socket of the canine or cuspid 
 tooth. At the upper portion of the canine fossa we observe the 
 infra-orhifal foramen, through which pass the infra-orbital nerve 
 and artery. 
 
 The posterior or zygomatic surface is pierced by several aper- 
 tures, tlie orifices of the jxtsUrior (hnfal canals, for the transmis- 
 sion of the posterior dental vessels and nerves. The lower part 
 
 2 1
 
 2 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 of the zygomatic surface gradually develops into the maxillary 
 tuberosity, which is most conspicuous after the eruption of the 
 wisdom or third molar tooth. 
 
 The superior or orbital surface is made up of a thin triangular 
 plate of bone. It is traversed by the ii'fra-orbital groore, carrying 
 the infra-orbital nerve and artery. This groove terminates in a 
 canal, dividing into two branches ; one of which, the infra-orbital, 
 opens below the border of the orbit, while the other, which is 
 smaller, pierces the anterior wall of the antrum, and bears the 
 name of anterior dented ceuial, transmitting the anterior dental 
 vessels and nerve to the front teeth. 
 
 Fig. 1. 
 
 External or Faciai, Surface of the Right Superior Maxillary Bosk. 
 
 7, Incisive fossa : C canine fossa : E, canine eminence ; F, infra-orbital foramen : P, posterior 
 dental canals : G, infra-orbital groove ; .1/, malar process. 
 
 The malar process is a prominent rough eminence serving for 
 the articulation with the malar bone. The descending ridge 
 constitutes the boundary between the facial and z^'gomatic sur- 
 faces.' From this ridge a small portion of the masseter muscle 
 takes its origin. 
 
 The nasal process, directed upward, has a concave external sur- 
 face. The anterior border of this process articulates with the 
 nasal bones ; the posterior is hollowed out by a groove in which 
 the lachrymal duct lodges. This groove is converted into a
 
 THE SUPEKIOR MAXILLARY BONES. 3 
 
 canal by the lachrymal and a part of the inferior turbinated 
 bones. 
 
 The palate process (see Fig. 2) is a strong piece of bone project- 
 ing horizontally from the inner surface of the superior maxilla. 
 It is especially thick anteriorly, the upper surface forming a large 
 portion of the floor of the nasal cavity, while the lower surface 
 makes up the greater portion of the roof of the oral cavity. 
 The lower surface is slightly concave, and is channeled at the 
 posterior part of its alveolar border for the passage of the pos- 
 terior palatine vessels and the anterior and external palatine 
 
 Fig. 2. 
 
 Inferior Surface ok the RniHT Superior Maxillary Bonk. 
 
 P. palate process; S, anterior nasal spino ; ^1, opening of antrum; .1/, lower meatus of 
 nasal cavity ; L, lachrymal groove. 
 
 nerves. The two palate processes assist in forming an orifice 
 in the median line, the 'anterior i>cdatiiie cuital. This canal is 
 divided into four compartments, two of which run laterally to 
 the right and left nasal fosste, while the anterior and posterior 
 compartments run along the median line. The anterior one 
 serves for the transmission of the anterior branch of the descend- 
 ing palatine arteries. The anterior and the posterior c^mjart- 
 ments transmitthe naso-palatine nerves, the left running through 
 the anterior, the right through the posterior canals. The roof 
 of the mouth is pierced by a number of small cijnals which
 
 4 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 cany the vessels for the nutrition of the bone. The upper sur- 
 face of the palate process is concave and smooth, exhibiting the 
 openings of the canals above mentioned. The inner border of 
 the palate process is raised into a central ridge which supplies a 
 space of attachment to the vomer. Anteriorly, this process pro- 
 duces a sharp prolongation, the aidcrior nasal spine. The pos- 
 terior border serves for articulation with the palate l)one. The 
 upper portion of this surface shows a large, irregular opening, 
 that of the antrum. The upper border of the opening is par- 
 tially closed by the cellular cavities of the ethmoid bone. 
 Below this opening a smooth concave surface presents itself, 
 the hirer meatus of the nasal cariti/. Behind the opening we 
 notice a rough surface that articulates with the perpendicular 
 
 Fig. 3. 
 
 The Alveolar Pkocess of the Right Superior Maxillaky Bone. Xiew from Below 
 
 IN Natural Size. 
 
 plate of the palate bone, being traversed by a groove which, 
 with a corresponding portion of the adjacent palate bone, forms 
 the posterior palatine canal, directed obliquely downward and for- 
 ward. In front of the opening of the antrum a groove is seen, 
 which with the lachrymal and inferior turbinated bones consti- 
 tutes the lachrymal or nasal duct. At the base of the nasal pro- 
 cess is. the horizontal or inferior turbinated crest for the articulation 
 of this process with the inferior turbinated bone. The wall of 
 the inferior meatus of the nasal cavity is perforated by numer- 
 ous small foramina, which serve as carriers of nutrient vessels. 
 The alreola.r proc(:-<s is the portion of the jaw which holds the 
 teeth. It contains eight excavations or sockets for this purpose 
 (Fig. 3). The deepest of these excavations is the socket of the
 
 THE SUPERIOR MAXILLARY RONES. 5 
 
 canine or cuspid tooth ; the sockets of the molars are the widest, 
 and are usuall>- subdivided into three smaller cavities, corre- 
 sponding in number with the roots of the teeth. The socket 
 of the third molar is usually single, while that of the iirst 
 bicuspid exhibits two cavities, and that of the second bicuspid 
 usually but one. The sockets for the incisors are always single. 
 They are of roundish form for the central, but for the lateral 
 incisors the sides of the receptacles are somewhat compressed. 
 
 The <inf flint is the largest of the so-called pneumatic spaces 
 of the skull. It is a cavity of four surfaces, — tlie upper or orhital 
 surface ; the poMefior surface, produced by the maxillary tuber- 
 osity ; the anterior or facial surface, which is slightly depressed 
 by the canine fossa; and the inmrr or nasal surface. When 
 regularly formed, the antrum has the shape of a triangular 
 pyramid, and either the upper orbital or the inner nasal sur- 
 face may be considered the base of the pyramid. The inner 
 wall of the antrum is divided by the articulation of the turbi- 
 nated bone into an upper and a lower half {pars supra- and pars 
 infra-tarbinalis). The lower half is made up anteriorly by the 
 superior maxillary, and posteriorly by the vertical lamella of the 
 pahite bone. The upper half is supplied with several openings, 
 which are quite large in the skeleton, but much smaller in the 
 vital state, in which condition the l)ones are covered by their 
 lining membrane. If the mucous covering closes these gaps, 
 such membranous portions Zuckerkandl* terms fort fan tiles. Of 
 these, he designates one as anterior and one as posterior. There 
 is left only a longitudinal opening, the ostium maxillare, within 
 the unciform process of the ethmoid bone, and one ethmoidal 
 cell, invested by a mucous membrane, communicating with the 
 frontal sinus and the nasal cavity. The lower surface or floor 
 of the antrum is formed by a thin bony plate. Between this 
 and the alveoli of the teeth is a layer of spongy bone. The 
 latter substance, as a rule, is thinnest over the roots of the molar 
 teeth. The roots of the incisor teeth are not within the boundary 
 of the antrum. The canine and the Iirst bicuspid, though near 
 the floor of the antrum, do not quite reach it, the floor being 
 overlaid by a bulky osseous structure. The apices of the roots 
 of the second bicuspid and the buccal roots of the molars are 
 in contact with the floor of the antrum. The second bicuspid 
 
 *Normal<' uml P;itholn<risclic Aiiiituniii' dor Njisciiholc. Widi, 1882.
 
 b THE ANATOMY AXD PATHOLOGY OF THE TEETH. 
 
 and the first molar, as a rule, correspond to the deepest portion 
 of the antrum. 
 
 Variations in the Size of Antra. — The difference in size of 
 the upper jaws of various individuals is not great, but of the 
 antra the shapes and sizes vary considerably ; nay, sometimes 
 there are marked differences in the two antra of the same head. 
 
 Zuckerkandl publishes the following table of variations in 
 the size of antra, some of the figures of this table being quoted 
 from C. Reschreiters : 
 
 Heights of 
 Upper Jaw?. 
 
 Heights Breadths Depths 
 of Antra given in Millimeter?. 
 
 64 
 
 19 
 
 25 
 
 21 
 
 64 
 
 29 
 
 25 
 
 21 
 
 64 
 
 32 
 
 28 
 
 33 
 
 64 
 
 32 
 
 25 
 
 34 
 
 64 
 
 32 
 
 24 
 
 32 
 
 64 
 
 33 
 
 22 
 
 34 
 
 64 
 
 39 
 
 25 
 
 £0 
 
 55 
 
 13 
 
 15 
 
 14 
 
 59 
 
 37 
 
 29 
 
 18 
 
 Communication between the Antrum and the Nasal Cavity. — 
 
 The opening termed ust'ami maxlUart is situated in the middle 
 meatus of the nose. It leads into the hiatus semilunaris in com- 
 pany with the ostium frontale, which communicates with the 
 frontal sinus (see Fig. 4). The latter is situated superficially in 
 the frontal portion, while the ostium maxillare lodges backward 
 and is somewhat hidden in the infundilndum. The best view 
 of the ostium maxillare is ol)tained from the antrum (see Fig. 
 5, Ji), where we observe it a little below the orbital surface, 
 on the upper border of the nasal surface of the antrum. Its 
 shape is irregular, most frequently semilunar, but often oval, 
 and sometimes round. According to Zuckerkandl, this opening 
 varies from three to nineteen millimeters in length, and from 
 three to five millimeters in breadth. Sometimes there exists, 
 between the antrum and the nose, an accessory communication, 
 which is usually small and round (see Fig. 5, A). This acces- 
 sory opening generally is situated in the posterior fontanelle, 
 somewhat lower than the ostium maxillare. In rare instances 
 the communication between the antrum and the nasal cavity is 
 closed, the result either of a chronic intlammatory process or 
 of a malformation during development.
 
 THE SUPERIOR MAXILLARY RONES. 7 
 
 The Lining Membrane of the Antrum has a double function, 
 — /.t,, it serves as a periosteal cover, supplying the nutritive 
 vessels to the bony walls of the cavity, and at the same time 
 secretes mucus. It is continuous with the mucous lining of the 
 nasal cavity, and is closely adapted to the depressions and eleva- 
 tions in the bony wall of this cavity. According to Sappey, the 
 mucosa of the antrum is supplied with glands, which in appear- 
 ance are much like the Meibomian glands of the eyelids. They 
 
 Sagittal Section THuorcai the ^'asai. and Okal Cavitiks, partly after Zuckkr- 
 
 kandl. 
 /^. semilunar hiatus; L'. upper lip, the ethmoiilal bulla ; /,, low^r lip. the unciform process; 
 M. insertion of middle turljinatod l)one ; T, lower turbinated bone; A', mouth of Eustachian 
 tube. 
 
 are irregularly distributed, and much scantier than those of other 
 mucous membranes. 
 
 The antrum is supplied with blood-vessels, principally derived 
 from the mucous mcml)rane of the nasal cavity, although some 
 of the smaller branches arise from the posterior dental arteries 
 through the alveoli.
 
 8 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 Development. — The superior maxilla is one of the earliest 
 bony formations, and, as anatomists suppose, it starts from four 
 centers of calcification, namely : the prcmaxiUari/, the palatine, 
 the maxillan/, and the malar portions. With the exception of the 
 maxillary portion, all these develop from and around hyaline 
 cartilage. The premaxilla, to the presence of which the great 
 
 Left Superior Maxillary Bone, exhibiting the Comsiumcations between Antrum 
 AND Nasal Cavity. (After Zuckerkandl.) 
 
 0, orbital cavity ; //, maxillary cavity or antrum of Highmore ; M. slit-like opening or 
 ostium masillare ; A, accessory opening between antrum and nasal cavity. 
 
 German philosopher and poet, Goethe, tirst drew attention, holds 
 the two incisor teeth on each side. In young subjects its articu- 
 lation with the palatine portion is still visible. In the con- 
 genital malformation of the upper jaw termed deft palate, .this 
 portion is separated from the remainder of the maxillary bone 
 by a single or double fissure, usually associated with a corre- 
 sponding fissure of the upper lip, called Jiare-lip.
 
 THE INFEKIOR MAXILLARY BOXE. 9 
 
 The RDtrum begins to develop in the maxillary portion of the 
 bone at about the fourth month of fcetal life. 
 
 Involution.^ — By this term is indicated a retrograde change 
 leading to a partial or complete disappearance of tissues and 
 organs. It is of frequent occurrence in embryonal develop- 
 ment, the same as in senile reduction of the size of organs, 
 especially that of the skeleton, whereby bone-tissue is brought 
 back to librous and myxomatous tissue preceding absorption. 
 
 The studies of the authors herein named were made on the 
 upper jaw of a woman who died when seventy-tive years of age. 
 The thickness of this jaw, between the oral and the nasal cavi- 
 ties, was not more than from four to five millimeters. The sur- 
 face of the oral cavity was perfectly smooth, without a trace of 
 a tooth or socket. The bone was present only in thin ledges, 
 arranged in an irregular line, and without distinction between 
 the compact and the cancellous structures. Xumerous pieces 
 of hyaline cartilage were present in the same stratum with the 
 bony tissue, which proves that the cartilage grows from a pre- 
 vious bony structure, and that it replaces the latter. 
 
 CHAPTER II. 
 
 THE INFERIOR MAXILLARY BOXE. 
 
 This is the largest bone, and the only movable one, of all the 
 facial bones. It consists of a horizontal bo(/>/ and (iro perpendicu- 
 lar projfrfions, the ra/ni, arising from the body nearly at right 
 angles to it. 
 
 The body presents for examination two surfaces, the external 
 and the interned ; and two borders, the alreeJar and the inferior. 
 The external surface (see Fig. 6) is convex from the median line 
 to the ramus, and slightly concave from above downward. In 
 the middle line we observe a shallow vertical ridge, indicative of 
 the junction of the two pieces of bone from which the body de- 
 velops. The ridge terminates below in a protrusion termed the 
 mental process. Outward of this central ridge is a slight depres- 
 sion, the incisive fossa. Farther backward we find the large 
 
 * ' ' Senile Atrophy of the Upper .Jaw. ' ' By Carl Heitzmann and Frank Abbott. 
 
 DcnM r'o.v/»o.s' • 1892.
 
 10 
 
 THE ANATOMY AND PATHOLOGY OP THE TEETH, 
 
 mental foramen for the transmission of the mental nerve and 
 artery. The location of this foramen corresponds with the in- 
 terstice between the roots of the first and second bicuspid teeth. 
 Posterior to this foramen begins a curved ridge, the external 
 oblique line, which runs backward and upward, being continuous 
 with the anterior border of the ramus. 
 
 The alveolar process is more massive posteriorly than in its 
 anterior portion. It is pierced by sixteen sockets for the recep- 
 tion of the teeth. 
 
 The inferior border of the body is rounded and quite massive 
 anteriorly; posteriorly it becomes more narrow. In the vicinity 
 
 Fig. 6. 
 
 The Inferior Maxillary Bone— External Surface of the Right Side. 
 
 M, mental process ; /, incisive fossa ; F, mental foramen ; Z, external oblique line ; G, groove 
 for facial artery ; A, anterior or coronoid process ; P, posterior or condyloid process. 
 
 of the rami this border exhibits a shalloio groove, in which the 
 facial artery is located.- 
 
 The internal surface of the body is markedly concave from 
 the median line to the ramus, and slightly convex from above 
 downward. (See Fig. 7.) In the central line we observe four 
 tubercles, two above and two below, the r/enial tuhercles, which 
 vary greatly in size and arrangement in different individuals. 
 Laterally to the tubercles we notice a shallow depression, tlie 
 sublingual fossa, in which the sublingual gland rests. Posterior
 
 THE INFERIOR MAXILLARY BONE. 
 
 11 
 
 to this depression is the begimiiiio; of the internal oblique line 
 or /lu/lo-hj/oid rid'/i', which becomes more distinct as it passes up- 
 ward and backward. The portion above this Une is smooth 
 and covered by the oral mucous membrane, whereas the portion 
 below shows a shallow depression, tlie sahmaxillarii f<)!<sa, corre- 
 sponding to the site of the submaxillary gland. 
 
 The perpendicular projections, or rami, have a more or less 
 quadrilateral shape, each ramus presenting two surfaces, four 
 borders, and two offshoots. The external surface is ridged, and 
 serves for the attachment of the masseter muscle. The internal 
 
 Fig. 7. 
 
 The Inferior Maxillary Boxe— Isteusal Surface or the Right .Side. 
 
 G, genial tubercles: .1/, mylo-hyoid ridge; 0, opening of the inferior dental canal; //, 
 mylo-hyoid groove ; A, anterior or coronoid process ; P, posterior or condyloid process. 
 
 surface is pierced about its center by an oblique aperture, the 
 opening of the inferior dental canal. Anteriorly this aperture is 
 surmounted by a ridge terminating in a sharp spine, which at its 
 lower part shows a notch leading to the n))/lo-}i'/nid groove, for the 
 mylo-hyoid vessels and nerve. The lower border of the ramus 
 exhibits a large rough surface for the attachment of the internal 
 pterygoid muscles. 
 
 The inferior dental canal takes an oblique course downward 
 and forward in the ramus, and a horizontal one in the body. 
 This canal is located underneath the sockets of the teeth, with
 
 12 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 which it communicates by small openings. At a point about 
 level with the first bicuspid tooth it ends in the mental foramen. 
 In the posterior two-thirds of the bone the inferior dental canal 
 runs near the internal surface, while in the anterior third it is 
 near the external surface. This canal holds the inferior dental 
 vessels and nerve, from which small branches pass to the apices 
 of the roots of the teeth through the small openings at the bases 
 of the alveoli referred to above. 
 
 The upper border of the ramus is thin, and shows two pro- 
 cesses, the aiiicrior or eoronoid, and the posterior or condyloid. 
 Situated between these processes is a deep depression, the sig- 
 moid notch. The coronoid process is a thin piece of bone serving 
 mainly for the attachment of the temporal muscle, and — at its 
 outer surface — for the attachment of the masseter muscle. 
 The condyloid process is more massive than the coronoid, and 
 terminates in the cond3de, which is covered with hyaline carti- 
 lage. The condyle, placed upon a constricted portion of the 
 neck, is of an oblong shape. Its long axis is set obliquely upon 
 the neck, the outer extremity being higher and directed more 
 forward than the inner. Its surface is convex both antero-pos- 
 teriorly and from side to side. 
 
 The lower border of the ramus is thick and continuous with 
 the body of the bone. At the angle of the jaw it is marked by 
 oblique ridges on each side, for the attachment of the masseter 
 and internal pterygoid muscles. 
 
 The posterior border of the ramus is covered by the parotid 
 gland. 
 
 Development and Involution. — The lower jaw, one of the 
 first-formed bones of the embr3'0, is developed principally from 
 a hyaline cartilage, which, in honor to its discoverer, is termed 
 31crkel's cartUaf/c. The formation of osseous tissue begins about 
 the sixth week of intra-uterine life. (See Fig. 8.) 
 
 Meckel's cartilage, invested by perichondrium, — which at this 
 stage is not as yet fibrous, but made up of spindle-shaped proto- 
 plasmic bodies, — forms a ledge, from and around which ossifica- 
 tion takes place. The perichondrium plays as great a part in 
 the production of bone-tissue as the cartilage itself. The first 
 step toward the development of bone is the calcification of the 
 basis-substance around the cartilage-corpuscles. Xext a reap- 
 pearance of protoplasm takes place in the non-calcified portion 
 of the basis-substance, whereby the entire territory of the car-
 
 THE INFERIOR MAXILLARY BONE. 
 
 13 
 
 tilage-corpusclc is rendered granular. An increase in the size 
 of the granules results in an augmentation of the nuclei, and at 
 last the entire cartilage-corpuscle is transformed into a cluster 
 of medullary or emhryonal corpuscles, which furnish the mate- 
 rial for bone-production. A preliminary stage of ossitication is 
 
 Fig. 8. 
 
 First Formed Trahecul.k ok Bonk, in Lowku .Jaw of IIi'max Embryo, Six 
 
 Weeks Old. 
 
 II. hyalino, or primordial, or Meckel's cartilage: N, non-calcified ba;!i?-siibstanee around the 
 torritoriosof hyaline cartilage ; //.calcified basis-substanceof territories of cartilage-corpuscles; 
 B. cartilage broken up to embryonal or medullary corpuscles; '/, coarsely granular cartilage- 
 corpuscles; 6'. calcified embryonal corpuscles; T, trabeouUv of bone-tissue with territories; 
 M. M, M. my.xomatous or medullary connective tissue. Magnified 200 diameters. 
 
 a deposition of lime-salts in a number of embryonal corpuscles, 
 derived either from the hyaline cartilage or the perichondrium. 
 By the coalescence of a number of such bodies territories of 
 globular shape are formed, the center of the globules being
 
 14 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 Fid. 9. 
 
 Inferior Maxilla 
 OF AN Embryo in the 
 Secosd Half of the 
 Third Month. 
 
 occupied by bone-corpuscles, while the peripheral portion is 
 transformed into glue-yielding basis-substance, saturated with 
 lime-salts. This change does not alter the structure of the pro- 
 toplasm. The trabeculce of bone are originally small and irreg- 
 ular ; later they unite into cancellous tissue, incloshig medullary 
 spaces tilled with protoplasmic bodies and carrying blood-vessels. 
 In the second half of the third month the 
 maxilla is as yet a minute ledge of bone, but 
 with indications of future sockets, and of the 
 coronoid and condyloid processes. (See Fig. 9.) 
 In the j&rst half of the seventh month the 
 future sockets of the teeth are wide and irreg- 
 ular excavations. Both the coronoid and 
 condyloid processes are plainly seen, the latter being almost 
 horizontal. The mental foramen is already established. (See 
 Fig. 10.) 
 
 At the time of birth the lo\ver jaw is made up of two pieces, 
 articulating in the center line. The upper border of these pieces 
 is grooved, without being subdivided into sockets. The cortical 
 portion is imperfect and pierced by numerous medullary spaces, 
 especially near the central symphysis and in the region of the 
 rami. The coronoid is more advanced in size than the condyloid, 
 which latter retains a nearly horizontal position. (See Fig. 11.) 
 In the sixth year of life the inferior maxillary bone has at- 
 tained a considerable size, and the condyloid process is inserted 
 Of the teeth we observe on either side of 
 
 at an obtuse angle. 
 Fig. 10. 
 
 Fig. 11, 
 
 Inferior Maxilla of a Fiktis in 
 THE First Half of the Seventh 
 Month. 
 
 Inferior Maxilla at the Time of Birth. 
 
 the jaw the two temporary incisors, the cuspid, and three 
 molars, — two temporary and one (the sixth-year) permanent. 
 (See Fig. 12.) In the adult the condyloid process is conspicuous 
 by its almost rectangular junction with the ramus, whereas with 
 advancing age this process appears inserted again at an obtuse 
 angle. 
 
 In old age the lower jaw gradually returns to its embryonal
 
 THE INFERIOR MAXILLARY BONE. 
 
 15 
 
 shape. (See Fig. 13.) After the teeth are lost, the sockets become 
 obliterated, and are replaced bv small pits and grooves, the points 
 at which the conversion of the bone into medullary tissue begins. 
 The mental foramen is now seen to be near the previous alveolar 
 surface, and to be considerably widened. The body, as well as 
 
 Fig. 12. 
 
 Inferiou Maxilla of a Boy Six Yeaks Old. 
 Fui. 13. 
 
 IxFKiiiou Maxilla i.\ Sentle Acje. 
 
 the ramus, is reduced to a thin ledge of bone, mostly smooth at 
 the surface. The laws of development, as well as of senile 
 involution, are not as yet fully understood. It is certain, how- 
 ever, that all changes take place by juxtaposition, and not by 
 interstitial growth. All phenomena become intelligible, if we 
 admit the fact that not only are the bone-corpuscles endowed 
 with properties of life, but so also is the basis-substance, and 
 thus both are enabled to be reconverted into protoplasm, and 
 airain to o'ive rise to connective tissue.
 
 16 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 CHAPTEli III. 
 
 THE TEETH. 
 
 The tooth, macroscopically considered, consists of a crown, a 
 neck, and a root. The crown of a tooth is that portion which 
 is covered with enamel, and, when the tooth is fully erupted, is 
 exposed above the margin of the gum. The neck is the part 
 that is covered by the gum. It begins at the border of the 
 enamel and extends to the alveolar process. The root, in its 
 normal condition, is entirely inclosed l)y the alveolar process. 
 
 The Right Tekth of ax Adult Tvv-enty-two Years Old. External View. Labial 
 
 (Bi'ccal) Surfaces.* 
 
 Between the neck and the root of a tooth we observe no distinct 
 macroscopical boundary, but for descriptive purposes and for 
 practical convenience we employ differentiating terms. 
 
 The dental formula that represents the permanent teeth of the 
 human mouth is noted as follows: 
 
 If; Ci; Bf; M f = 32 
 
 (See Figs. 14 and 15.) 
 
 *The teeth Nos. 9, 10. 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, and 24, 
 in shape correspond with their fellows of the opposite side of the dental arch, 
 except that the general shape of their crowns is reversed, and it has therefore 
 heen deemed unnecessarv to illustrate tlieni.
 
 THE TEETH. 
 
 17 
 
 Upon examining the crown of a tooth, we observe on it five 
 surfaces. First, the outer surface in regard to all teeth, called 
 the " labial" surfiice of the front teeth, and the " buccal" surface 
 of the bicuspids and molars. Second, the inner surface, in con- 
 tact with the tongue, and therefore called " lingual." Third,, 
 the "grinding-surfaces" and the "cutting-edges," the former 
 name being applied to the under surfaces of the upper bicuspids 
 and molars and the corresponding grinding-surfaces of the lower 
 bicuspids and molars, while the second term is given to the 
 similarly opposed edges of the front teeth. The two surfaces of 
 each tooth still to be named are those that are in contact with the 
 neighboring teeth. The surface of each tooth directed toward. 
 
 25 26 27^1 28 29 
 
 The Right Teeth of an Adult Twenty-two Years Old. Internal View. Lingual 
 
 Surface. 
 
 the center of the jaw is called " mesial"; that toward the poster- 
 ior portion of the dental arch is known as the " distal." There 
 are four incisors in the upper and four in the lower jaw. The 
 two middle ones are termed " central incisors" ; the two outer, 
 "laterals." Their cutting-edges, when the teeth are erupted, 
 usually exhibit three protuberances, which, in use, soon become 
 smooth through wear. The upper incisors, especially the 
 centrals, are much larger than the lower ones, and in normal 
 articulation overlap the latter. The upper incisors are inclined 
 toward the median line, rendering the mesial surfaces somewhat 
 longer than their corresponding distal surfaces. The incisors 
 are wedge-shaped, thinning from the base at the gum toward 
 
 3
 
 18 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 the cutting-edges. These edges, in adult teeth, viewed anteriorly, 
 represent a straight line. The general shape of an incisor thus 
 anteriorly seen is, approximately, that of a square, though it 
 narrows toward the neck. The mesial angle of the cutting-edge 
 always inclines more than the distal. From this tapering of the 
 crowns of the teeth toward their necks result more or less V- 
 shaped spaces, which vary in diiierent mouths. In some 
 instances we meet with teeth of which the crowns are almost 
 square, in which case the intervening spaces at the necks are 
 quite small ; while between teeth which exhibit broad cutting- 
 edges and narrow necks we observe large V-shaped spaces. 
 
 The upper incisors usually have single roots, which are more 
 or less conical toward tlie apices. 
 
 The. labial surfaces of the upper incisors, especially in young 
 subjects, are mostly marked by slight longitudinal depressions 
 and elevations, which, through wear, gradually disappear with 
 advancing age. In adults the labial surfaces are more or less 
 smooth and slightly convex. In some instances we meet with 
 transverse furrows or pits in these surfaces, which, however, 
 must be regarded as abnormalities. The enamel at the gingival 
 border of the labial surface terminates in a curved, somewhat 
 elevated ridge. The lingual surfaces are irregularly concave. 
 The periphery is bounded by a more or less prominent ridge of 
 enamel, which, toward the margin of the gum, forms what is 
 known as the Ixisal rvhj( or cim/'ihrnt. This basal ridge is 
 frequently found to be divided by a deep groove or pit, which, 
 in the majority of such cases, soon becomes the seat of caries. 
 The boundary line of the enamel on the lingual surface is curved 
 similarly to that of the labial surface. These ridges, as the}' turn 
 into the mesial and distal surfaces of the incisors, take a down- 
 ward course, following the festoons of the gum, and meet with 
 the enamel ridge of the labial surface, producing a Y-shaped 
 appearance in both the mesial and distal surfaces of the teeth. 
 
 The iqyper central incisors (Xos. 8 and 9) occupy the center in 
 the dental arch, being the broadest of the incisor teeth. Their 
 roots are almost cylindrical, and gradually taper from the neck 
 toward the apex. 
 
 The upper lateral iiicisors (Xos. 7 and 10) are smaller than the 
 centrals. The mesial angle of their cutting-edge usually over- 
 hangs more than that of the central incisors, in consequence of 
 which their distal angles appear more rounded. Their roots
 
 THE TEETH. 19 
 
 are compressed laterally, and taper from crown to apex, corre- 
 sjDonding in length to those of the central incisors. 
 
 The hnrer central incisors (Xos. 24 and 25) are the smallest teeth 
 in the dental arch. They are even smaller than the upper lat- 
 erals. Their general outline is the same as that of the upper 
 laterals, but the angle of their mesial surfaces is much less over- 
 hanging. Their lingual surface is usually smooth and but 
 slightly concave. The roots of these teeth are more compressed 
 laterally than those of the upper laterals. 
 
 The lower lateral incisors (Xos. 23 and 26) are somewhat wider 
 than the centrals of the lower jaw, yet in every other respect 
 their appearance is the same as that of the central incisors, 
 although their roots are a little lono;er and heavier. 
 
 The upper canines, eye-teeth, or cuspids (Nos. 6 and 11) oecu|>y a 
 prominent position on either side of the incisor teeth. They 
 form the corners of the dental arch, and are in every respect 
 more stoutly built than the incisors. The crown terminates in 
 a more or less blunt point, from either side of which a rounded 
 cutting-edge slopes away and becomes continuous with the 
 mesial or distal surface. The cutting-edge of the mesial surface 
 is somewhat shorter than that of the distal surface. By this 
 difference in the length of the cutting-edges we are enabled to 
 distinguish the teeth belonging to the right from those of the 
 left side of the mouth. Upon the labial surface of an upper 
 cuspid tooth we observe a somewhat prominent ridge, which 
 extends from the summit of the cusp to the neck. This ridge 
 renders the surfiee more convex than the corresponding labial 
 surface of an incisor tooth. In the median line of the lingual 
 surface of an upper cuspid w^e also observe a ridge, the direction 
 of which is identical with that of the labial surtace. In some 
 instances, where this ridge joins the cingulum, it develops into 
 a regular small cusp, which in shape is not unlike that of a 
 lower first bicuspid tooth. The mesial and distal surfaces are 
 of a triangular form, similar to those of the incisor teeth ; but 
 their base is much broader. The roots of the upper cuspid 
 teeth are much stouter and longer than those of the incisors, 
 and are usually somewhat compressed laterally. The position 
 of these roots in tlie mouth can easily be determined, since they 
 are marked by a prominent ridge upon the external surface of 
 the nuixillary bones, the canine eminences. 
 
 The shape of the lower cuspids (Xos. 22 and 27) does not differ
 
 20 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 much from that of the upper ones, although they are smaller in 
 every respect. The ridges upon their lingual surfaces are not so 
 prominently developed, and their roots are shorter. 
 
 The jrremolars or bicuspids, eight in number (Xos. 4, 5, 12, 
 13, 20, 21, 28, and 29), are arranged in pairs, both in the upper 
 and lower jaws, posterior to the cuspids. Their crowns are 
 quadrilateral ; but the buccal portion of the crown is larger 
 than its lingual half, as is especially noticeable in the first bi- 
 cuspids. The shape of the buccal surface of a bicuspid is similar 
 to that of the cuspid of the same side of the mouth ; the ridge, 
 however, extending from the summit of the cusp to the margin 
 of the gum, is not so strongly marked. The grinding-surface 
 of a bicuspid, as the name implies, exhibits two cusps, of which 
 the buccal is the largest. These cusps are separated, from each 
 other by a furrow which, in some teeth, is quite deep, and often 
 becomes the seat of caries. The mesial and distal portions of 
 this furrow are bounded by a small ridge of enamel, continuous 
 with the sloping lingual and buccal edges of the cusps. The 
 cuttin£r-edo;es are similar to those of the cuspid of the same side 
 of the dental arch. 
 
 The upper bicusjnds (Nos. 4, 5, 12, and 13) are somewhat 
 larger than those of the lower jaw, and their lingual cusps are 
 more developed. The lingual portion of the crown of the first 
 upper bicuspid is narrower antero-posteriorly than its buccal 
 half. The shape of the crown of the second bicuspid is more 
 nearly square, and the entire tooth a little stouter than the first. 
 The root of the first upper bicuspid always is much compressed 
 lateralis', and, as a rule, contains two pulp-canals. Sometimes 
 its root is bifurcated, while the upper second bicuspid seldom 
 has more than one root, or one pulp-canal. 
 
 The lower bicuspids (iN'os. 20, 21, 28, and 29) are smaller than 
 those of the upper jaw. Their crowns are roundish and some- 
 what bent inward. Their roots are conical. The first lower 
 bicuspid is the smallest of the bicuspids. Its outer cusp is much 
 higher than the inner one, which is but slightly developed. 
 From the buccal to the lingual cusp extends a small ridge, on 
 either side of which is sunken a little pit, a favorite seat of 
 decay. The second lower bicuspid is larger than the first, and 
 its lingual cusp is more developed than that of the first lower 
 bicuspid. 
 
 If we compare the incisors with the cuspids and bicuspids,
 
 THE TEETH. 21 
 
 we find that there exists a typical analogy between their shapes, 
 which, however, is not the case if we compare the incisors with 
 the molars. 
 
 The violar teeth (Xos. 1, 2, 3, 14, 15, 16, 17, 18, 19, 30, 31, and 
 32) are the largest in the mouth, and occupy the posterior por- 
 tion of the dental arch. Xormally there are six molars in each 
 jaw, three on either side. The third molar, also called wisdom- 
 tooth, is, however, frequently missing, and in a crowded dental 
 arch may remain nnerupted. This deficiency is, in some fami- 
 lies, characteristic and hereditary. The crowns of the first 
 molars are larger than those of the second, and, in turn, the 
 crowns of the second are larger than those of the third. The 
 grinding-surface of a molar is of a more or less square shape, 
 with rounded angles, and is made up of four or five cusps. 
 Tlie mesio-huccal cusp of a molar usually is a little larger than 
 the others, which fact enables us to determine to which side of 
 the mouth the tooth belongs. 
 
 The crowns of the up2)er molars (Nos. 1, 2, 3, 14, 15, and 16), 
 especially the first and second, usually exhibit a cusp upon each 
 of their angles, of which the mesio-lingual is the largest. The 
 mesio-buccal cusp is connected with the mesio-lingual one by a 
 ridge which runs along the mesial border of the grinding-sur- 
 face. Sometimes we observe upon the mesio-lingual border of 
 the crown of the first and second upper molars a small extra 
 cusp, separated from the large mesio-lingual by a deep furrow. 
 
 The furrows separating the cusps run over the buccal and 
 lingual borders of the grinding-surface. The furrow upon the 
 lingual surfiice usually terminates in a more or less deep pit, 
 which, together with the above-described fissures of the grind- 
 ing-surface, furnishes a favorable locality for the development 
 of caries. The roots of each upper molar are usually three in 
 number, — two Iniccal, much compressed antero-posteriorly, and 
 one lingual or palatal. The lingual root is the stoutest of the 
 three, conical in form, diverging from the axis of the crown 
 toward the palate, and often slightly curved in the direction of 
 the buccal roots. The crown, as well as the roots of the upper 
 third molar, or wisdom-tooth, is liable to great variations. In 
 the majority of instances we find the crown of a third upper 
 molar much smaller and shorter than that of the first or second 
 molar. This molar sometimes has only one straight, short root, 
 but in some instances it is supplied with three, — the typical
 
 22 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 number, — four, or even five. Occasionally the roots of the 
 wisdom-teeth are normally developed, like those of the first and 
 second molars ; mostly, however, they are but rudimentary and 
 more or less compressed, or even conglomerated into one root. 
 
 The grinding-surfaces of the hirer molar teefh (Nos. 17, 18, 19, 
 30, 31, and 32) usually exhibit five cusps, separated from one 
 another by deep farrows, representing a regular cross. The 
 posterior arm of this furrow, as a rule, bifurcates and winds 
 around the fifth cusp. The lingual and buccal portions of the 
 furrow extend into the lingual and buccal surfaces of the tooth. 
 Especially upon the buccal surface of the lower molars the fur- 
 row is quite deep, terminating in a pit, which, like that of the 
 upper molars, frequently decays. The cusps are placed, one at 
 each of the four angles of the grinding-surface, while the fifth 
 cusp, the smallest, is situated upon the posterior border of this 
 surface. The lower molars, with the exception of the third, 
 usually are implanted with two roots, which in the jaw occupy 
 an antero-posterior position and are much compressed in the 
 antero-posterior direction. Occasionally we observe that the 
 mesial root of the first lower molar is bifurcated. 
 
 The Temporary, Deciduous, or Milk Teeth. — In the mouth of 
 an infant, about the sixth month after its birth, we observe the 
 appearance of the first teeth, which belong to the so-called 
 " temporari/" or " deciduous" set. The complete denture of a 
 child is comprised of twenty teeth, which are noted as follows : 
 T I 2; T Ci; TM| = 20. 
 
 (See Fig. 16.) 
 
 The temporar}^ incisor and cuspid teeth are similar to those 
 of the permanent set, though much smaller. The bicuspids are 
 absent. Their arrangement in the dental arch is the same as 
 that of their respective successors ; but the tem[)orary molars 
 occupy on either side of the cuspids the places which in the 
 permanent set are filled by the bicuspids. 
 
 The crowns of the temporary teeth are large in proportion to 
 their necks and roots, the enamel terminating in a rather thick 
 ridge, which is a characteristic feature of all the temporary 
 teeth. 
 
 In the illustration I have adopted the numbering of the tem- 
 porary teeth from one to twenty, adding a T, to distinguish 
 them from the permanent teeth. 
 
 Xo. J 7\ (he rif/kf dipper second niohir^ is the largest of the upper
 
 THE TEETH. 
 
 23 
 
 molars. In shape its crown resembles that of the first perma- 
 nent upper molar; but its roots, besides being smaller, diverge 
 much more from the center than do those of the permanent 
 teeth. The grinding-surface is surmounted usually by four, 
 sometimes by five, cusps, arranged in the same manner as those 
 of the first permanent ujiper molar. 
 
 Xo. 2 T, the ri<j]d xpper Jirst iitol'ir, is considerably smaller than 
 Xo. 1 T. Upon the grinding-surtace we usually find but two 
 cusps, one upon the buccal, the other upon the lingual aspect. 
 They are divided by a deep furrow. There are three roots, 
 which in shape and arrangement are similar to those of molar 
 1^0. 1 T, but somewhat smaller. 
 
 20.T. I9.T. I8,T. f7T. I6.T. 
 
 The Right Temporary or Deciduous Teeth. 
 
 Xo. 3 T, the right upper cuspid, while in its principal character- 
 istics similar to its successor, in proportion is much smaller and 
 shorter than the permanent cuspid. It is implanted by a single, 
 almost cylindrical root. 
 
 Xos. If. T ando 1\ the rijjht upper hdcral xud ctidra/ irn-isors, except 
 in being smaller than their successors, are in their general out- 
 lines much like the latter, only their crowns are shorter in pro- 
 portion to those of the corresponding permanent teeth. They 
 invariably have but one root, of a conical shape. 
 
 Temporary teeth Nos. 6, 7, S, 0, and 10 of the upper jaw, as well 
 as Xos. 11, 12, IS, III., and IS of the lower jaw, are identical in 
 character with their fellows of the opposite side, with the excep- 
 tion that the forms of their crowns are reversed. 
 
 Xos. 16 T and 17 T, the right hirer ocidral and lateral incisors. 
 The principal difference between these teeth and their permanent
 
 24 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 successors is that the former are much smaller, have a more or 
 less conical root, and their enamel terminates at the ,neck in a 
 thick ridge, which is common to all temporary teeth. 
 
 JVo. IS T, the right lower cuspid. Its crown usually is some- 
 what longer than that of the upper temporary cuspid, hut not 
 so stout; while its root, like that of No. 3 T, is nearly conical. 
 
 No. 19 J\ t}ie rigid hirer first molar. Its crown is smaller than 
 that of No. 20 T. Upon its grinding-surface we commonly lind 
 four small cusps. It is implanted by two roots, flattened antero- 
 posteriorly, and diverging considerably from the center. 
 
 ]So. 20 1\ the rigid hirer second molar, is the largest of all the 
 temporary molars. Its grinding-surface is surmounted by four, 
 sometimes five, cusps, arranged in the same manner as those of 
 the first permanent lower molar. It has two roots, which in 
 shape and position are similar to those of the first temporary 
 molar, though much larger, and in some instances almost as 
 stout as those of the permanent lower molars. 
 
 CHAPTER IV. 
 
 INDIVIDUAL CHARACTERISTICS OF THE TEETH. 
 
 Distinguishing- Features between the Temporary and the 
 Permanent Teeth. — The main peculiarity of temporary teeth 
 is that they are much smaller than the permanent ones. The 
 enamel of the temporary teeth terminates at the neck in a rather 
 thick ridge, whereby the necks of these teeth appear much 
 smaller in proportion than those of the permanent teeth. The 
 temporary incisors ofier another marked characteristic in their 
 smooth cutting-edges, while those of permanent teeth, in the 
 juvenile condition, are each of them surmounted by three small 
 protuberances. 
 
 The temporary cuspids are much shorter, narrower, and have 
 a less pointed cusp than their permanent successors. 
 
 The crown of a first temporary molar is so typical that it 
 scarcely will be mistaken for a permanent tooth. Its roots are 
 much smaller than those of a permanent molar, and diverge 
 considerably from the center. 
 
 The second temporary molars, on the contrary, while in the 
 jaws, may sometimes be confounded with a permanent sixth-year
 
 INDIVIDUAL CHARACTERISTICS OF THE TEETH. 25 
 
 molar; but as this always is the fifth tooth from the center, its 
 position will aid us in making the distinction. 
 
 Disting-uishing" Peculiarities between the Upper and Lower 
 Permanent Teeth. — The principal difference existing between 
 the incisors of the upper and those of the lower jaw is that the 
 crowns of the former are much broader than those of the lower 
 incisors. While the crowns of the latter are the smallest in the 
 mouth, they are, at the same time, noticeably compressed laterally 
 toward their necks. 
 
 The upper cuspids, or eye-teeth, are the stoutest teeth possess- 
 ino^ sinsfle roots, much laro^er than the lower ones. The 
 
 CO? O 
 
 cingulum and the ridge upon the lingual surface of the lower 
 cuspids, which are so marked in the upper, are but little devel- 
 oped. 
 
 The main difference between the bicuspids of the upper and 
 those of the lower jaw is that the crowns and roots of the former 
 are somewhat compressed antero-posteriorly, while the roots and 
 the crowns of the latter are nearly cylindrical. There is also a 
 difference in their lingual cusps, which in the upper bicuspids are 
 long, in the lower short, sometimes merely rudimentary. This 
 last is especially often the case with the first lower bicuspid. 
 
 To discriminate between the first and second molars of the 
 upper and lower jaws, it is only necessary to notice the number 
 of their roots, since the former usually exhibit three, the latter 
 mostly but two. Another peculiarity of the upper molars is 
 the arrangement of the furrow upon the grinding-surface, which 
 somewhat resembles the letter H, while the fissure of the lower 
 molars represents a cross. The upper and lower wisdom-teeth, 
 or third molars, might sometimes be confounded with each 
 other, because both are often implanted with a single conglom- 
 erated root. The crown of a lower third molar, however, even 
 though altered, usually represents the general type of the lower 
 molars. Upon the grinding-surface of a lower third molar, 
 therefore, we mostly see the fissure between the cusps more or 
 less in the form of a cross. 
 
 In numbering the teeth, the writer has adopted the system 
 •employed in dental registers and examination tables. (See Figs. 
 14 and 15.) 
 
 No. 1. Right upper third molar, or irisdom-tooth. This is the 
 smallest of the three molars. The crown usually exhibits but 
 three cusps, one upon the lingual and two upon the buccal aspect.
 
 26 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 The mesial cusp is the largest of the three. Usually the third 
 molar has one root, sometimes it has two ; in well-developed 
 teeth three roots may he present. In the last case the grinding- 
 surtace is surmounted by four cusps, similar in arrangement to 
 those of the other molars. 
 
 No. 2. Bight upjyer second molar. This is a trifle larger than 
 No. 1, but smaller than Xo. 3. Its cusps and roots are similar 
 to those of Ko. 3, though its crown is more rounded. Its raesio- 
 buccal cusp is larger than the distal one, and the tooth, as a rule, 
 is possessed of three distinct roots. 
 
 No. 3. Riijht Upper frst molar. This is the largest of the upper 
 molars. Its grinding-surface is of a rhomboidal form, the 
 mesio-buccal and linguo-distal angles being acute, while the 
 disto-buccal and mesio-lingual angles are obtuse. Its mesio- 
 buccal cusp is larger, somewhat lower, and more rounded than 
 the disto-buccal one. It has three distinct roots. 
 
 No. 4- Right upper second bicuspid. The crown of this tooth is 
 larger than that of any other bicuspid. Its lingual cusp is slightly 
 higher and better developed than that of the first upper bicuspid. 
 The mesial portion of the buccal cusp of the cutting-edge is 
 more obliquely inclined than the distal. The root is usually 
 single, somewhat compressed laterally, and holds but one pulp- 
 canal. 
 
 No. 5. Right Upper p'r.^t bicuspid. This tooth is a trifle smaller 
 than Xo. 4, especially in the lingual portion of its crown. The 
 mesial cutting-edge of the buccal cusp is directed more obliquely 
 downward than that of the distal. The root is usually bifurcated, 
 or a groove runs longitudinally on both sides of the root in the 
 median line, indicative of two pulp-canals, wdiich, in most 
 instances, are present. 
 
 No. 6. The ri(/ht upper cuspid has a single, pointed cusp, of 
 which the mesial cutting-edge is directed more obliquely down- 
 ward than the distal. It has one long, stout root. 
 
 No. 7. RigJit i'pp(r lateral incisor. Its crown is much smaller 
 than that of a central, Xo. 8 or 9. The mesial angle of the cut- 
 ting-edge is more overhanging than the distal one, the latter 
 being more rounded. It has a single compressed root. 
 
 No. 8. Rigid upper central incisor. The crown, like that of 
 Xo. 9, is broad and square in its labial aspect. The mesial angle 
 of the cutting-edge is more acute than the distal, which is some- 
 what rounded. It has a single, more or less conical root.
 
 INDIVIDUAL CHARACTERISTICS OF THE TEETH. 27 
 
 The teeth Nos. 9, 10, 11, IJ, 13, 14-, 15, and 16 are identical in 
 shape with the corresponding teeth of the opposite side of the 
 dental arch, with the exception that the general shape of their 
 crowns is reversed. 
 
 No. 17. Left hirer third molar, or irisdom-tooth. Its crown is 
 somewhat larger than that of the upper wdsdora-tooth, but it is 
 always the smallest of the lower molars. The grindiiig-surface 
 is surmounted by four or iive cusps. AVhen there are four, the 
 raesio-buccal cusp is the largest; if, however, five cusps be 
 present, three of them usually are upon the buccal portion of 
 the crown. In most instances it has one or two more or less 
 conical roots, curved toward the posterior portion of the jaw. 
 
 No. IS. Left loicer second molar. The crown is nearly square, 
 somewhat larger than that of No. 17, but not quite as large as 
 that of No. 19. The grinding-surface is surmounted by four or 
 five cusps, of which tAYO are situated upon the lingual and two 
 or three upon the buccal portion of the crown. The lingual 
 cusps are always a little higher, but more pointed, whereas 
 the buccal cusps are broad and round. By the shape and posi- 
 tion of these cusps we are enabled to determine correctly to 
 which side of the dental arch the molar belongs. This molar 
 usually has two compressed roots, of which the anterior some- 
 times holds two pulp-canals. 
 
 No. 19. Left lower first molar. Its crown is almost square. 
 It is the largest of the lower molars. It usually has five cusps, 
 of which two are situated upon the lingual and three upon the 
 buccal portion of the crown. The lingual cusps are pointed, 
 and a little higher than the three buccal ones, the latter being 
 rounder, broader, and a little lower. (3f the buccal cusps, the 
 mesial is usually the largest. This molar generally has two, but 
 occasionally three roots, two anterior and one posterior, and it 
 almost always contains one posterior and two anterior pulp- 
 canals. 
 
 No. 20. Left lou:er second bicuspid. The crown is larger than 
 that of No. 21, its lingual cusp a little lower than the buccal. 
 The lingual cusp of this tooth is much more developed than 
 that of the first lower bicuspid. The mesial cutting-edge of the 
 buccal cusp usually is more obliquely inclined than the distal. 
 The root is mostly single and conical. 
 
 No. 21. Left Imcer first bicusjyid. The crown is the smallest 
 of any of the bicuspid teeth, nearly round in circumference,
 
 28 THE ANATOMY AND PATHOLOGY OF THE TEETH, 
 
 and somewhat bent upon the root toward the hngual portion of 
 the dental arch. The lingual cusp is very small, though pointed, 
 and connected with the buccal cusp by a ridge of enamel which 
 divides the grinding-surface and thereby produces two deep 
 pits. The mesial cutting-edge of the buccal cusp is more ob- 
 liquely inclined than the distal. It usually has a single conical 
 root. 
 
 No. '2:2. Left hicer cuspid. The crown is narrower, but some- 
 times longer than that of an upper cuspid. Its lingual surface 
 is almost Hat, or slightly concave, and the mesial cutting-edge is 
 more obliquely inclined than the distal. Its root is mostly 
 single, but flattened. 
 
 No. 23. Left lower lateral incisor. Its crown is somewhat 
 narrower than that of an upper lateral, but not quite so narrow 
 as that of a lower central incisor. The mesial angle of the 
 cutting-edge usually is similar to that of the distal. The root is 
 much more compressed laterally than that of an upper lateral 
 incisor. 
 
 No. 24. Left hirer central incisor. The crown is narrower 
 than that of any other incisor tooth, being much compressed 
 laterally at the neck. Its root is similar in shape to that of a 
 lower lateral incisor. 
 
 The teeth Nos. 25, 26, 27, 28, 29, 30, 31, and 32 are identical 
 in shape with the corresponding teeth of the opposite side of the 
 dental arch, with the excej)tion that the general configuration 
 of the crowns is reversed. It should be noted, however, that 
 in the lower laterals and central incisors both angles of the 
 cutting-edges are about equal. It is in most cases impossible 
 to determine to which side of the dental arch a lower incisor 
 beloncfs. 
 
 CHAPTER V. 
 
 THE PULP-CHAMBERS OF THE TEETH. 
 
 Every tooth incloses a central cavity, of which the shape 
 corresponds to that of the exterior of the tooth. The coronal 
 portion of this cavity is called the jmlp-chajiiber, while the portion 
 in the root of the tooth is known as the root-canat. It is of 
 the utmost importance to the dental practitioner to be thoroughly
 
 THE PULP-CHAMBERS OF THE TEETH. 
 
 29 
 
 iainiliar with the forms and positions of the pulp-chambers of 
 the teeth, since a proper diagnosis of the difterent diseases of 
 the dental pulp cannot be made without this knowledge. 
 Furthermore, a dentist not well acquainted with the anatomy of 
 the pulp-chamber is liable to expose a pulp unintentionally dur- 
 ing the preparation of a cavity for filling. "Within every cusp 
 of the molars, bicuspids, and cuspids we find a corresponding 
 elevation in the pulp-chamber, while in the crowni of an incisor 
 the cavity is somewhat bifurcated. 
 
 The pulp-chambers, as well as the root-canals, are rilled by 
 myxomatous connective tissue, interwoven with blood-vessels 
 arid nerve-fibers, termed the dental pulp. This tissue also fills the 
 
 Fig. 17. 
 
 Left Teeth in Linguo-Labial and Lixguo-Buccal (Sagittal turning to Frontal) 
 Sections. Reversed to the Right Side. 
 
 protuberances under the cusps of the teeth, these portions being 
 called the horns of the pulp. The latter are the points which, 
 through caries, easily become exposed and diseased. Although 
 we often find carious cavities, and, consequently, exposures of 
 the pulp, about the necks of the teeth, nevertheless in the 
 majority of instances the dental pulp becomes exposed at one 
 or more of its horns. 
 
 G. Carabelli* was tlie first to give illustrations of the pulp- 
 chambers of the teeth, in their various places, but without cor- 
 rect measurements. He published elaborate drawings of the 
 pulp-chambers of both the temporary and the permanent teeth. 
 Upon comparing the charts of Carabelli, however, we find that 
 
 * Svstematisches Hanclbuoh der Zahnheilkuiulo, 18'J4.
 
 30 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 the piilp-chambers of the teeth there depicted do not correspond 
 to those usually met with in this country, which difterence may 
 perhaps be explained l)y the fact that the teeth used hy Cara- 
 belli were of a ditferent type from those of our generation. 
 
 To arrive at satisfactorj^ conclusions in the study of the pulp- 
 chambers of the human teeth, it would be necessary to examine 
 many complete sets of difterent ages, constitutions, and shapes. 
 But the author has only been able to obtain a single set of thirty- 
 two perfect teeth, which were imported from Tramond, of Paris. 
 These teeth are alleged to have come from the mouth of a girl about 
 twenty-two years of age. Correct drawings were made of them, 
 as represented in Figs. 14 and 15. Afterward the sixteen teeth of 
 
 Fig. 18. 
 
 Right Teeth in Lingual and Bcccal (Frontal turning to Sagittal) Sections. 
 
 the left side were ground upon a corundum-wheel, exposing the 
 mesial or frontal aspects of the pulp-chambers, as represented in 
 Fig. 17. The other sixteen teeth, belonging to the right side of 
 the dental arch, were prepared as represented in Fig. 18, exposing 
 the labial aspect (respectively buccal or sagittal) of the pulp-cham- 
 bers. It is a well-known fact that, at ditferent ages of the individ- 
 ual, the pulp-chambers vary greatly in size and shape ; yet, with 
 the knowledge derived from observations made on other teeth, 
 as well as from the chart published by Arkovy,* we ma}^ regard 
 the above teeth as normal for the age of twenty-two years. It 
 is likewise established that the pulp-chambers of the teeth 
 decrease in size with advancing age, and especially when the 
 
 *Diftgno.stik der Zaliukraiiklu'iten, 1885.
 
 THE PULP-CHAMBERS OF THE TEETH. 
 
 31 
 
 enamel of the teeth becomes worn away. In these instances, 
 not only all the horns of the pulp gradually disappear, but 
 sometimes almost the whole pulp-chamber becomes obliterated 
 by the formation of secondary dentine. This condition of the 
 pulp-chambers does not so much depend upon the age as upon 
 the habit of the individual to whom the teeth belong, and upon 
 the articulation of the teeth. Some individuals, especially those 
 
 Fig. 19. 
 
 DN 
 
 Key to the Measurements oi' the Pulp-Chambers of the Teeth. 
 
 A. sagittal section of the right lower first molar. — DN, diameter of neck ; OP, diameter of 
 pulp-charaber ; «, diameter between pulp-charaber and mesial surface: />, diameter between 
 anterior horn of pulp-chamber and external surface of cusp ; c, diameter between posterior 
 horn of pulp-chamber and external surface of cusp: d, diameter between the pulp-chamber 
 and distal surface. B, frontal section of the left lower first molar. — /VjY. diameter of neck ; 
 DP, diameter of pulp-chamber: a, diameter between pulp-chamber and buccal surface; h, 
 diameter between buccal horn of pulp-chamber and external surface of cusp; r, diameter 
 between lingual horn of pulp-chamberand external surface of cusp ; d, diameter between pulp- 
 chamber and lingual surface. 
 
 of a nervous temperament, have the habit of grinding their teeth 
 during sleep, whereby the enamel of the antagonizing surfaces 
 soon becomes worn oft". In other instances a person loses some 
 of the molars and bicuspids, with the result that he is able to 
 masticate with the front teeth only, in which case the enamel of 
 these teeth is soon worn away. In such cases, we observe in the 
 vicinity of the pulp-chamber corresponding to the place of injury
 
 32 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 on the grinding- or cutting-surfaces of the teeth, a formation of 
 secondary dentine, although the individual may not be more 
 than thirty or thirty-five years of age. On the other hand, it 
 sometimes occurs that with people from forty-five to fifty-five 
 years of age there remains a complete set of teeth, with their 
 cusps, as well as the horns of the pulp, still present. Further- 
 more, where we find defects upon the neck of the tooth, called 
 erosion, we observe a great diminution in the size of the pulp- 
 chamber, and especially that portion corresponding to the place 
 of injury in the neck of the tooth. In some chronic constitu- 
 tional diseases, particularly in aneemia, we often meet with teeth 
 the pulp-chambers of which are unusually large. 
 
 Notwithstanding the great differences existing in the size and 
 form of the pulp-chambers of the teeth, it is of great value to 
 know, approximately, the thickness of the dental tissue between 
 the pulp-chamber and the periphery of the tooth, and conse- 
 quently the author has made correct measurements of the thirty- 
 two teeth in twelve different places, as explained b}^ Fig. 19, A 
 and B. 
 
 2 able of Measarements of Fidp- Chambers in Millimeters. 
 
 CO 
 » 
 
 Labial Sections, respectively Buccal 
 or Sagittal. 
 
 ■ aj 
 H 
 ca 
 S 
 
 u 
 9 
 
 
 Mesial 
 
 or Fro 
 
 ntal Sections. 
 
 
 
 a 
 2.1 
 
 h 
 
 c 
 
 d 
 2.1 
 
 DP DN 
 
 a 
 23 
 
 h 
 
 c 
 
 d 
 
 DP 
 
 D N 
 
 1 
 
 4.7 
 
 4.6 
 
 2.9 
 
 7.1 
 
 4.1 
 
 
 2.6 
 
 1.6 
 
 6.5 
 
 2 
 
 2.0 
 
 5.4 
 
 5.6 
 
 2.3 
 
 3.5 
 
 7.8 
 
 10 
 
 1.9 
 
 6.6 
 
 
 2.0 
 
 1.9 
 
 5.8 
 
 3 
 
 2.8 
 
 4.8 
 
 5.0 
 
 2.4 
 
 2.3 
 
 7.5 
 
 N 
 
 2.5 
 
 5.8 
 
 
 2.8 
 
 2.2 
 
 7.5 
 
 4 
 
 2.0 
 
 4.7 
 
 
 2.1 
 
 1.0 
 
 5.1 
 
 12 
 
 1.6 
 
 3.9 
 
 4.5 
 
 2.1 
 
 4.6 
 
 8.3 
 
 5 
 
 1.9 
 
 4.9 
 
 
 1.7 
 
 1.0 
 
 4.6 
 
 13 
 
 2.0 
 
 5.2 
 
 5.8 
 
 2.3 
 
 4.2 
 
 8.5 
 
 6 
 
 2.1 
 
 6.9 
 
 
 2.4 
 
 1.5 
 
 6.0 
 
 14 
 
 34 
 
 5.5 
 
 6.4 
 
 3.2 
 
 4.6 
 
 11.2 
 
 7 
 
 1.6 
 
 3.6 
 
 
 1.7 
 
 1.5 
 
 4.8 
 
 15 
 
 3.4 
 
 5.4 
 
 6.4 
 
 2.4 
 
 5.6 
 
 11.5 
 
 8 
 
 2.4 
 
 6.5 
 
 
 2.2 
 
 1.9 
 
 6.5 
 
 16 
 
 2.5 
 
 5.5 
 
 6.8 
 
 2.4 
 
 59 
 
 108 
 
 25 
 
 1.4 
 
 4.1 
 
 
 1.6 
 
 1.0 
 
 4.0 
 
 17 
 
 2.2 
 
 5.1 
 
 4.9 
 
 2.5 
 
 3.2 
 
 7.9 
 
 26 
 
 1.6 
 
 4.0 
 
 
 1.7 
 
 0.8 
 
 4.0 
 
 18 
 
 2.4 
 
 6.3 
 
 7.0 
 
 2.1 
 
 43 
 
 8.8 
 
 27 
 
 1.9 
 
 6.1 
 
 
 2.4 
 
 1.0 
 
 5.1 
 
 19 
 
 2.3 
 
 50 
 
 6.2 
 
 2.0 
 
 44 
 
 8.7 
 
 28 
 
 2.0 
 
 3.5 
 
 
 1.8 
 
 0.9 
 
 4.7 
 
 20 
 
 1.3 
 
 40 
 
 6.1 
 
 2.5 
 
 2.5 
 
 6.8 
 
 29 
 
 1.8 
 
 4.0 
 
 
 2.0 
 
 1.2 
 
 50 
 
 21 
 
 1.7 
 
 4.7 
 
 4.4 
 
 1.9 
 
 2.5 
 
 6.1 
 
 30 
 
 2.4 
 
 5.1 
 
 4.9 
 
 2.5 
 
 3.6 
 
 8.5 
 
 22 
 
 2.6 
 
 4.4 
 
 
 2.7 
 
 2.5 
 
 7.8 
 
 31 
 
 2.3 
 
 5.4 
 
 6.5 
 
 2.5 
 
 3.8 
 
 8.6 
 
 23 
 
 2.0 
 
 3.5 
 
 
 2.4 
 
 2.1 
 
 6.5 
 
 32 
 
 2.2 
 
 5.2 
 
 6.0 
 
 26 
 
 33 
 
 8.1 
 
 24 
 
 1.8 
 
 3.8 
 
 
 2.1 
 
 1.3 
 
 5.3
 
 THE PULP-CHAMliERS OF THE TEETH. 
 
 33 
 
 Tabt.k of "Me vsr?ii:>rKXTS kkcarpixg tiik Sitiation ok tiik U>ik.ns ok 
 
 THK TULV. 
 
 LOWER TEETH. 
 
 UPPER TEETH. 
 
 5«S 
 
 O P 
 
 
 c 6 
 
 2.^ 
 
 ft ® 
 CO p 
 
 0^5 
 
 5 ^ 
 
 P§ 
 
 = 5-2, 
 
 c^ 
 
 2 S"^ 
 
 » 5 ^ 
 
 
 -! » C 
 
 -2^ 
 
 < a B 
 tc < so 
 
 tt 2 g 
 ffi c S 
 
 -. (B 2 
 
 ® 2 2 
 
 ® C3 ^ 
 
 a-E." 
 
 I I 
 
 
 3"-» 
 * 
 
 ^4 
 
 1 
 
 1 
 
 in 
 
 » 
 
 ^ 1 
 
 o 
 
 en 
 
 
 *. 
 
 en 
 1 
 
 1 
 'l 
 
 •^ 
 
 ZT. 
 
 1 
 
 :^-, 
 
 en 
 
 to 
 
 j_ 
 
 
 i,-. 
 
 o 
 E 
 
 o 
 p 
 
 v» 
 
 f- 
 
 en 
 
 in 
 
 i~ 
 
 f-' 
 
 9" 
 
 f- 
 
 t^ 
 
 .■^ 
 
 E 
 
 i. 
 
 ^ 
 
 in 
 
 rfi~ 
 
 en 
 
 4^ 
 
 eo 
 in 
 
 5* 
 
 bi 
 
 en 
 
 in 
 
 in 
 
 in 
 
 in 
 
 en 
 in 
 
 5" 
 
 1 
 
 
 in 
 
 in 
 
 f' 
 
 Oi 
 
 en 
 
 >»■ 
 
 en 
 
 >f>- 
 
 1^ 
 
 . -. 
 
 s 
 
 >b. 
 
 in 
 
 00 
 
 ^ 
 
 *>- 
 
 CO 
 
 cn 
 
 p" 
 
 .*■ 
 
 P" 
 
 CI 
 
 in 
 
 cn 
 
 cn 
 
 1 
 2d Bicusp. 
 
 
 .■*- 
 
 CO 
 
 >^ 
 
 in 
 
 cn 
 
 S" 
 
 .*- 
 
 in 
 
 in 
 
 to 
 in 
 
 .*" 
 
 cn 
 
 en 
 
 CO 
 
 in 
 
 - 
 
 IstB 
 
 icusp. 
 
 *- 
 
 eo 
 in 
 
 CO 
 
 Cusp 
 
 id. 
 
 
 .*- 
 
 Lateral Incisor. 
 
 .*- 
 
 Ci 
 
 lO 
 
 ?' 
 
 -1 
 
 00 
 
 1 Cent 
 
 ral Incisor. 
 
 w 
 
 en 
 
 IC 
 
 .-' 
 
 -J 
 
 in 
 
 Central Incisor. 
 
 bi 
 
 en 
 
 _eo 
 
 cn 
 
 a> 
 
 CO 
 
 1 Late 
 
 ral Incisor. 
 
 *- 
 
 ^ 
 
 CO 
 
 ■^ 
 
 cn 
 
 ^3 
 
 cn 
 
 1 Cusi 
 
 ji.l. 
 
 
 r^ 
 
 f- 
 
 CO 
 
 en 
 
 - 
 
 en 
 
 CO 
 
 in 
 
 1 ^ 
 1 =■• 
 
 ' IstB 
 
 1 
 
 icusp. 
 
 .-^ 
 
 in 
 
 t^ 
 
 in 
 
 en 
 
 CO 
 
 in 
 
 cn 
 
 en 
 
 CO 
 in 
 
 P 
 
 2d B 
 
 CU«p. 
 
 i 
 
 p 
 
 2 
 2 
 
 o 
 
 1 ^ 
 
 cn 
 
 ri>> 
 
 !^ 
 
 CO 
 
 4^ 
 
 in 
 
 ^ 
 
 — 
 
 ^^ 
 
 ea 
 in 
 
 CO 
 
 in 
 
 .■'" 
 
 cn 
 
 -^ 
 
 » 
 
 in 
 
 en 
 
 in 
 
 in 
 en 
 
 
 ■t^ 
 
 1 " 
 
 1^ 
 
 in 
 en 
 
 y 
 
 1 ..?L 
 
 1 5* 
 
 g 
 
 1 
 
 s 
 s 
 p. 
 
 ' 2 
 
 1 E. 
 
 4.5 4 
 
 C." 
 
 in 
 en 
 
 4.5 4. 5 
 
 
 in 
 
 in 
 i 
 
 en 
 
 ' ♦ 
 
 1 
 1 
 
 1 
 1 
 1 
 
 P' 
 1 
 
 ir.* 
 
 1 I 
 
 
 1 ^- 
 
 2 
 g 
 
 en 
 
 en 
 
 en 
 
 1 
 1 
 
 f" ~ 
 
 1 
 1 
 
 1 
 
 1 
 
 in 
 
 1 
 
 1 
 
 It 
 
 M 
 
 
 
 
 
 72 
 
 o 
 
 
 d 
 
 > 4
 
 34 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 CHAPTER VI. 
 
 THE ARTICULATION OF THE TEETH. 
 
 When we examine the occluding surfaces of a perfect set of 
 human teeth and the manner in which they articulate, we come 
 to the conclusion that the articulation of the teeth is a most 
 wonderful device of nature, forming quite a complicated piece 
 of mechanism. The principles of articulation, both from a 
 practical and a scientific standpoint, are of the greatest impor- 
 tance, and therefore ought to be studied closely by every dental 
 student. The articulation of the teeth is based upon certain 
 g-eometrical and mechanical laws first described by W. G. A. 
 Bonwill.* 
 
 Fig. 20. 
 
 Articulation of a Perfect Set of Teeth of the Right Side— External Surface- 
 
 In observing this articulation, we find that, in the human jaw, 
 a straight line drawn from the buccal surface of the first bi- 
 cuspid to the internal angle of the condyloid process of the lower 
 maxilla will almost touch all the buccal surfaces of the bicuspids 
 and molar teeth. This shows that the teeth named are arranged 
 in an almost straight row from the cuspid to the inner angle of 
 the condyloid process of the lower jaw. We also observe that, 
 with the exception of the upper third molars, every tooth articu- 
 lates with two in the opposing jaw. (See Figs. 20 and 21.) 
 Thus, if a tooth is lost, the antagonist, being retained in its 
 position, is useful to a certain extent, and the regularity of the 
 
 * ''Tlic Cieometrical and Mochanical Law* of the Articulation of the Human 
 Tft'tli." Harri.«s ■•Principles and Praotici-," twelfth edition
 
 THE ARTKJIILATION OF THE TEETH. 
 
 35 
 
 dental arch is not materially disturbed. Again, articulation 
 has been wisely arranged in this manner to offset the work of 
 another law^ of nature, by the operation of which every tooth 
 not articulating with at least one opposing tooth gradually elon- 
 gates, and eventually is cast out of the jaw. We observe that, 
 in a normal articulation, all the teeth of the upper jaw more or 
 less overlap those of the lower, although it must be admitted 
 that a perfectly articulating set of teeth is a rarity in the human 
 mouth. In studying the articulation of the bicuspids and 
 molars, we find that every cusp correctly fits between cusps in 
 the opposing jaw ; and by this arrangement of cusps and depres- 
 sions the grinding-surface is materially increased. The external 
 or buccal cusps of the upper bicuspids and molars are arranged 
 a little outside of the lower arch, — a disposition which enables 
 
 Articulation of a Perfect Set of Teeth of the Right Side— Internal Surface. 
 
 the teeth of the upper jaw, when the pterygoid muscles are 
 brought into action, to articulate with all the teeth of the lower 
 jaw. The lingual cusps of the upper bicuspids and molars are 
 somewhat higher and less pointed than the corresponding outer 
 cusps. In the lower teeth we find this arrangement reversed, 
 and observe that the outer cusps of the bicuspids and first 
 molars are the longer and rounder, while the inner or lingual 
 cusps are the shorter and more pointed. The result of this 
 reciprocation evidently is that, when the lower jaw is moved 
 laterally by the pterygoid muscles, the buccal and lingual 
 cusps of the upper teeth on one side of the mouth play 
 upon the buccal and lingual cusps of the lower teeth, while 
 the lingual cusps of the u[)per jaw on the opposite side of 
 the mouth articulate with the buccal cusps of the lower teeth.
 
 36 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 Hence the teeth not only possess a larger extent of grinding- 
 surface with small proportional bulk, but considerable energy is 
 saved in mastication. At the same time, the pressure upon the 
 teeth exerted by the muscles of mastication is more or less 
 equalized through the entire dental arch. If we examine dif- 
 ferent sets of teeth, we shall notice that great variations exist 
 in the lengths of the so-called over/ntcs. If the upper front teeth 
 overlap the lower ones but little, we invariably find short cusps 
 upon the bicuspids and first molars, while, on the contrary, when 
 the overbite is long these cusps are long and pointed, provided 
 all the teeth occupy their proper positions. On examining the 
 plane of the grinding-surface of the lower bicuspids and molars, 
 we find that the second and third molars stand considerably 
 higher than the first, yet the three crowns form a gradual 
 slope. Regarding the position of the roots of the lower second 
 and third molars, we observe that while their crowns are tilted 
 forward, their roots, on the contrary, are directed toward the 
 condyloid process of the jaw, by which arrangement this grad- 
 ual slope is accomplished. In consequence of this slope in the 
 lower dental arch, the second and third molars of the upper jaw 
 also assume a slanting position upward, rendering the first upper 
 molar the longest of the molar teeth. The object of this arrange- 
 ment evidently is that, when by the sliding movements of the 
 lower jaw the condyloid process is brought forward, the second 
 lower molar articulates against the first upper one, which, being 
 longer than the second and third, opens the jaw sufficiently to 
 allow the articulation of the cutting-edges of the upper and lower 
 front teeth as well as the points of the cusps of the bicuspids. 
 Hence the [)ressure, which otherwise would bear upon the molars 
 only, is equally distributed upon the side as well as the front por- 
 tion of the dental arch. 
 
 "When, because of the loss of the back teeth, a patient for a 
 number of years masticates entirely with the front teeth, the 
 muscles of mastication gradually become contracted, the condy- 
 loid, process leaves its normal place in the glenoid fossa, and 
 occupies a more anterior position. In such cases we observe a 
 slight protrusion of the lower jaw", and the remaining teeth to 
 be considerably reduced in length through mechanical abrasion, 
 brought about by the lateral movements of the lower jaw. 
 Their cutting-edges, formerly more or less sharp, are now 
 broad and flat, similar in form to the i!:rinding-surface of a
 
 THE ARTICULATION' OK THE TKKTJI. 
 
 37 
 
 much-worn l)icuspid. In this instance an acquired abnormal 
 articulation of the lower Jaw is present, which, upon the restora- 
 tion of the teeth to their original length, will cause the condy- 
 loid processes of the lower jaw to resume their former position 
 
 in the glenoid foss*. 
 
 From the article published by W. G. A. Bon will I quote the 
 
 following : 
 
 " The Equilateral Triaur/le ivUhiti fhe 3Iain Triangle. — The out- 
 line drawing (Fig, 22) may be thought ideal. But any one at 
 all acquainted with geometry must be struck with wonder 
 at the marvelous ingenuity of the contrivance based alone on 
 the equilateral triangle. It will be seen that perfection must 
 
 Fig. 22. 
 
 Diagram showing Equilateral Triangle of the Lowkk Jaw. (Aitkr 
 
 W. G. A. BONWILL.) 
 
 be the result, since each part is complete within itself and the 
 whole supporting each individual part. 
 
 " How have I arrived at this divination ? The law is based 
 upon the measurement of over two thousand human skulls. 
 First make an equilateral triangle, four inches; A, A, F. 
 Draw a line from T to F. What is the guide to form the arch ? 
 Know the actual width of the superior central, lateral, and cuspid 
 at their greatest diameter from the mesial to distal surfaces, say 
 If, as in Fig. 22. Measure this off with the dividers, and 
 place one arm at F and describe an arc from D to D through I. 
 Then place dividers at I, and intersect the line Just made from
 
 38 THE ANATOMY AND TATHOLOGY OF THE TEETH. 
 
 F, and it will be found that at D will be found the extremest 
 point of the arch D, F, D, and will be the distal surface of the 
 superior cuspid. Place the dividers at I, and describe the arc 
 from D to D through F, which will constitute the normal and 
 positive arch of the superior jaw. There will he an equilateral 
 triangle from D, F, I on either side of the mesial line at F. 
 The same will be found the base of each superior incisor. 
 
 " Next draw a line from A to D on either side, which will be 
 the guide for the bicuspids and molars as to width and depth. 
 Then, by placing the dividers at A and B, describe another arc 
 to C, which will give the width of tirst superior bicuspid. The 
 line from A to D passes through its palatal base, and will pass 
 through center of base of triangle of this tooth. Form another 
 triangle by drawing a line from H to H, through B, which will 
 pass through the center of the first molar, and will give the 
 width betw^een the palatal surfaces or their depth or thickness. 
 Placing the dividers at I and F, we intersect the line from F to 
 T at Y. Draw a line through Y to E, E, forming another equi- 
 lateral triangle. From B to F is now the radius of another 
 arc, which intersects the line from D to A at V, and the line A 
 to D at 0. A line now drawn E to E through Y intersects the 
 center of the second molar at E, E. 
 
 " Get half the distance between the points at E on the line 
 from D to A, and the width of the first molar is made, and also 
 the second, which is the angle of the equilateral of each. This 
 leaves room between the first bicuspid and first molar, and is 
 the width of second bicuspid ; or it is shown by placing the di- 
 viders at A and Y, and intersecting line from D to A at W, same 
 as from B to C, for the first bicuspid's width. The distance 
 from D to D is the same as from D to the distal surface of the 
 second molar. P to P through Z forms another equilateral tri- 
 angle, giving the wisdom-tooth's })lace in the arch. 
 
 " The arrangement of L and J on the left shows the teeth in 
 the act of mastication, while on the right the inner cusp of 
 molars of the upper and outer of the lower molars come in con- 
 tact when not in use. There is double the surface touching at 
 everv lateral movement."
 
 GENERAL ANATOMY OF THE HUMAN TEETH. 30 
 
 CIIAPTEK VII. 
 
 GENERAL ANATOMY OF THE HUMAN TEETH. 
 
 I. The sockets of the teeth are made up of a thin hiyer of 
 cortical bone, distinctl}' lamellated, and blending with trabeculre 
 of the cancellous bone in the central part of the alveolar pro- 
 cess. The latter we find filled with freely vascularized medul- 
 lary tissue in the juvenile condition; whereas, in advanced age, 
 this tissue is transformed into fat, which, as a rule, is likewise 
 supplied with numerous blood-vessel^^. The socket-walls are of 
 the greatest possible strength, with tlie least mass, since a hollow 
 cylinder is stronger than a solid one. The blood-vessels of the 
 medullary spaces are continuous with those of the periosteum, 
 pericementum, and gums. This explains why sockets easily 
 become necrotic after suppurative periostitis and pericementitis, 
 in event of which maladies a certain amount of the socket is 
 deprived of the nourishing material carried to it by the blood- 
 ve.ssels. (See Fig. 23.) 
 
 II. The compact hone of the socket is covered with a layer of 
 dense connective tissue of broad bundles. This is continuous 
 with another layer of fibrous connective tissue composed of 
 bundles that run obliquely toward the apex of the root of the 
 tooth. The latter tissue bears the name of periccmcntuyn, root- 
 membrane, or alrcolar dental periostettm. Its bundles are firmly 
 attached to the walls of the socket and the root of the tooth. 
 Thus it becomes comprehensible that the teeth can stand enor- 
 mous pressure without injury, as in the process of mastication, 
 in the lifting of heavy weights, or in the suspension of the 
 whole body on a rope, by means of the dentures. "We further- 
 more understand why sometimes a portion of the bony structure 
 is carried away upon the extraction of a tooth. At the same 
 time the pericementum gives a considerable degree of elasticity 
 and a limited amount of mobility to the teeth. This explains 
 the presence of facets upon the approximal surfaces of the crowns 
 of teeth in crowded dental arches. 
 
 III. Similarly the upper and the lateral portions of the alveolar 
 process are covered by fibrous connective tissue, the periosteuin, 
 which blends with the dense fibrous connective tissue of the 
 gum, composed of broad and straight interlacing bundles.
 
 40 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 This firm cushion, the fiain, in a normal condition is but scantily 
 supplied with blood-vessels. The superficies of the gum 
 exhibit numerous finojer-like elevations, the so-called papillae, 
 
 Diagram of the Structure and Implantation of a Normal Incisor Tooth. 
 
 L, cuticle of enamel, Nasmyth's membrane; E, enamel; D, dentine with uniformly dis- 
 tributed canaliculi; /, interzonal layer between enamel and dentine; B, border-line between 
 enamel and ccmentum of neck ; .S'. comentum of neck ; C'e, cementum of root ; Z, interzonal 
 layer between dentine and cementum ; P, pericementum ; A, arteriole of pulp, branching into 
 capillaries; F, vein of pulp, taking up capillaries; iV, medullated nerve-fibers of pulp: Eg. 
 stratified epithelium of gum ; /'r/, papillary layer of gum; /"e, periosteum ; t7(>, cortical bone 
 of alveolus or socket; Ot, cancellous bone-tissue of alveolus; J/, medullary spaces of can- 
 cellous bone.
 
 GENERAL ANATOMY OF THE HIMAN TKKTH. 41 
 
 which contahi loops of capillary blood-vessels. The sum-total 
 of the papillae is termed the papillari/ layer. At its outer surface 
 it is covered with a layer of stratified epithelia. In the strata 
 we observe three forms of epithelia, as in the skin and in the 
 mucous membranes generally. The innermost layer is made up 
 of a single row of columnar epithelia, much elongated in a ver- 
 tical direction and resting upon the connective tissue. This row 
 of columnar epithelia is covered by several rows of cuboidal 
 epithelia, so termed on account of their shape. The layers of 
 cuboidal epithelia are coated by several strata of Hat or pave- 
 ment-epithelia, so called because their length and width are 
 much greater than is their thickness. The pavement layer is 
 composed of a horny substance, and it exhibits properties of 
 life only in the nuclei of the epithelia, the same being the case 
 throughout the flat epithelial covering of the oral cavity. The 
 surface of the gum appears to the naked eye either smooth or 
 slightly granular, since the papillary elevations of the connective 
 tissue and the valleys between them are but slightly pronounced 
 upon the epithelial surface. Continued irritation, as in the too 
 frequent application of the tooth-brush, is, in many instances, 
 sufficient to give the surface of the gums a more or less pro- 
 nounced papillary aspect. 
 
 IV. Dentine is the tissue which composes the main mass of the 
 tooth. It consists of a glue-yielding basis-substance (not carti- 
 laginous, as is often stated), richly infiltrated with lime-salts. 
 The chemical constituents, according to Bibra,* of perfectly 
 dried dentine are, — 
 
 Organic matter (t.xith-cartilai;-!') 27.61 
 
 Fat 0.40 
 
 Pliosph. fluoride oaloiuin ........ 66.72 
 
 Carbonate of calciiuu ........ 3.36 
 
 Pho.spliate of magnesium ........ 1.08 
 
 Other salts 0.83 
 
 The basis-substance is traversed by the denfinal canalicuU, 
 which take their general course from the pulp-chamber toward 
 the summit of the crown, running horizontally in the neck, 
 and in a portion of the root. It is only near the apex that the 
 canaliculi are inclined toward the end of the root. Each canali- 
 culus curves in the general shape of the letter S, slightly toward 
 the pulp-chamber and abruptly toward the periphery of the 
 
 * From Tomes's ••Dental Anatomv."
 
 42 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 dentine. In the region of the crown, upon approaching the peri- 
 phery of the dentine, almost without exception, the canaliculi 
 divide into two or three branches, this branching being termed 
 b/farcnt'Oit. In the region of the neck such a bifurcation of 
 the dentinal canaliculi is exceptional. It is a peculiarity there 
 that the canaliculi do not reach the periphery of the dentine, but 
 stop short of the latter at a distance varying in different teeth, 
 whereas in the root bifurcation is of frequent occurrence. 
 
 Each dentinal canaliculus contains a slightly beaded fiber, the 
 dentinal tibrilla, or, in honor of the discoverer, J. Tomes' s fiber. 
 
 In the crown the dentine is surrounded by the enamel, and 
 in the regions of the neck and root by the cementum. The 
 border-line between these tissues has been termed by W. H. 
 Atkinson the interzonal layer. This layer has been also termed 
 the granular laifer by J. Tomes. It is usually marked by shallow 
 excavations along the periphery of the dentine. Occasionally 
 the ultimate branches of some dentinal canaliculi transgress the 
 interzonal layer, producing either loops or club-shaped enlarge- 
 ments in the adjacent portion of the enamel. The interzonal 
 layer between the dentine of the root and the adjacent cementum 
 may be marked by shallow excavations similar to those in the 
 dentine of the crown, or there may exist no distinct boundary 
 line between the two tissues, 
 
 V. Eneimel. Whereas dentine is undoubtedly a form of con- 
 nective tissue closely allied to bone, enamel bears no resemblance 
 to any other tissue in the animal organism. It starts from epi- 
 thelium, becomes transformed into connective tissue, yet exhibits 
 features characteristic of epithelial structures. The enamel 
 covers only the crown of a tooth. It is thickest upon the sum- 
 mit of the crown, gradually becoming thinner toward the region 
 of the neck, where it terminates in a sloping line, slightly over- 
 lapped by the cementum. The enamel is composed of so-called 
 enamel-prisms, exhibiting transverse striations, the striee of Reizins. 
 Between these enamel-prisms there are narrow interstices which 
 hold delicate beaded fibers, the enamel-fibrillce. The enamel- 
 prisms run a wavy coarse, and we meet with transverse sections 
 intermixed with longitudinal ones so frequently that the idea of 
 interlacing bundles of enamel-prisms forced itself upon previous 
 investigators. Frank Abbott was the first to assert that no 
 such interlacing occurs, and that the appearance of transverse 
 sections intermixed with longitudinal ones is due to the pro-
 
 OENEKAL ANATOMY OF THE HUMAX TEETH. 43 
 
 nouncedly wavy course of ^olne of the bundles, being cut both 
 longitudinally and transversely. 
 
 The outer surface of the enarnel is covered by a thin, horny 
 layer of epithelial tissue, the so-called Xasnu/th's membrane^ or 
 evamel-cuticle. This layer can be rendered visible by the appli- 
 cation of strong chemical agents, and is present only in teeth 
 not as yet worn off by mastication. It is in direct union with 
 the outermost epithelial layer of the gum, which is likewise 
 composed of flat, hornitied epithelia, to a varying degree. The 
 enamel-cuticle is, therefore, the only layer which closes up the 
 fissure between the neck of the tooth and the adjacent gum. 
 
 VI. Cementum. This is a stratum of bone-tissue covering the 
 dentine of the root of the tooth. It starts in an oblique line at 
 the neck, gradually increasing in thickness toward the apex, 
 where it borders upon the beginning of the root-canal. The 
 cementum is, as a rule, covered at its outer periphery by a single 
 layer of calcified protoplasmic bodies, similar to the so-called 
 osteoblasts (Gegenbaur), which are in connection with the fibrous 
 connective tissue of the pericementum. At the neck it is com- 
 posed of a calcified basis-substance, pierced by spindle-shaped 
 protoplasmic bodies. In the root portion of the cementum we 
 observe a distinct lamellation, and here we meet with numerous 
 branching protoplasmic bodies, the cement-corpuscles, bearing a 
 close resemblance to bone-corpuscles. Even in low amplifica- 
 tions by the microscope we frequently notice a union of the 
 ends of the dentinal canaliculi, with offshoots of cement-corpus- 
 cles. From these facts we may infer that each root of a tooth 
 represents a large Haversian system, in which the Haversian 
 canal corresponds to the central pulp-canal and its soft tenants, 
 whereas the outermost layer of the cementum represents the 
 concentrically lamellated cortex. Between these two layers is 
 inserted a broad layer of dentine, traversed by dentinal canaliculi, 
 Avhich we may consider as elongated offshoots of bone-corpus- 
 cles. If viewed in this light, dentine .may justly be considered 
 a modified bone-tissue, peculiar to the structure of the teeth, 
 
 VII. TJ'C Pulp. The central cavity is called pulp-chamber in 
 the crown, and root-canal in the root of a tooth. It is filled Avith 
 a myxomatous connective tissue, in which are distributed blood- 
 vessels and nerves. These enter the pulp-canal at the apex of 
 the root of the tooth. At about the middle of the root-canal 
 a small afferent artery, the arteriole, splits up into capillaries,
 
 44 THE ANATOMY AND PATHOLOGY OF THE TEETH, 
 
 producing tlirougliout the pulp-tissue a rich net-work, termin- 
 ating at the summit of the coronal portion in loops. The capil- 
 laries coalesce with the vein. This vein is a branch of the 
 alveolar vein, into which it carries the blood through the root- 
 canals. There is a large number of bundles of nerves in the 
 pulp, entering the apical foramen in the shape of raeduUated 
 nerve-fibers. Upon approaching the periphery of the pulp they 
 lose their medullary sheaths and become non-medullated, as is 
 the rule with all meduUated nerve-fibers in peripheral organs. 
 During the development of the tooth, the outer surface of the 
 pulp exhibits a row of large protoplasmic bodies, the so-called 
 odontoblasts (J. Tomes), which are in direct connection ^^■ith the 
 tenants of the dentinal canaliculi. In the fully-developed tooth 
 the odontoblasts are not always present, being mostly replaced 
 by irregular rows of medullary corpuscles. The ultimate ter- 
 mination of the nerve-fibrillse can be traced between these me- 
 dullary corpuscles or odontoblasts, but never to a direct union 
 with the dentinal fibers. This fact sufficiently proves that the 
 dentinal fibers are not true nerves. Lymph-vessels are un- 
 questionably present in the pulp, but nothing positive has as 
 yet been ascertained as to their course and origin. 
 
 Anomalous though not Pathological Formations in the Teeth 
 (see Fig. 24). — Among the most frequent occurrences of such 
 formations, w^e notice in the crown of the tooth fields filled with 
 a non-calcified basis-substance. They are known as the i))ter- 
 globular spaces of Czerrnak. Tliey appear as irregular spots, 
 varying in size and shape, but always bordered by concave con- 
 tours. These so-called spaces occur near, though never directly 
 at, the periphery of the dentine toward the enamel, and occa- 
 sionall}- blend with much smaller spaces at the interzonal layer 
 of the neck, or even the root of the tooth. They are traversed 
 by the dentinal canaliculi without the slightest deviation of the 
 latter. 
 
 Of common occurrence in the dentine are fields of calcified 
 basis-substance, lacking dentinal canaliculi. Much rarer are 
 parallel striations of the dentine, indicative of the successive 
 formation of the layers of this tissue. 
 
 In the enamel at the interzonal layer we not infrequently 
 meet wdth globular or club-shaped spaces filled with protoplasm. 
 In the highest expression of this abnormality we find every 
 branch of the dentinal canaliculi to have a club-shaped termina-
 
 GENERAL ANATOMY OF THE HUMAN TEETH. 
 
 45 
 
 tion. Pigmentation and stratification of the enamel are not 
 rare. J. Retzius first drew attention to their presence. The 
 brown pigmentation of the enamel always is most pronounced 
 
 Diagram of an Anomalods though not Pathological Incisor Tooth. 
 
 6', cuticle of enamel, Nasmyth's membr.ine : E, stratified and pigmented enamel ; /.inter- 
 zonal layer between enamel and dentine, with club-like terminations of dentinal canaliculi ; 
 G, dentine with interglobular spaces along the outer periphery : N, cementura of neck, over- 
 lapping the enamel; B. basis-substance of dentine, destitute of canaliculi; X (upper), stratifi- 
 cation of dentine; S (lower), secondary dentine; Z, interzonal layer between dentine and 
 cementum, with club-like enlargements of the canaliculi; Cc, ceinentum of root; /', peri- 
 cementum ; 0, row of odontoblasts at the outer periphery of the pulp; M, medullated nerves 
 of the pulp; Ey. stratified epithelium of gum; Fa, papillary layer of gum; So, socket or 
 alveolus.
 
 46 THE ANATOMY AND PATHOLOGY OF THE TEETH, 
 
 along the peripberv and along tlie strife of the enamel. What 
 the cause of such pigmentations and stratifications may be, we 
 do not know. 
 
 In rare instances the cement of the neck considerably over- 
 laps the enamel. This feature explains certain occurrences in 
 the process of absorption of temporary teeth. Along the inter- 
 zonal layer between the dentine and the cementum we occasion- 
 ally meet with club-shaped spaces filled with protoplasm, and in 
 union Avith the terminations of the dentinal" canaliculi. All 
 these features, including the interglobular spaces, may be con- 
 sidered as the result of an imperfect calcification during the 
 process of development. 
 
 CHAPTER VIII. 
 
 GENERAL HISTOLOGY. 
 
 The animal bod}' is built up of. four main varieties of tissue, 
 viz : 
 
 T. Coimective Tissue. 
 II. Musde-Tissiie. 
 
 III. Nerre- Tissue. 
 
 IV. Epithdial Tissue. 
 
 According to the views of most histologists, both the connec- 
 tive and muscle tissues are products of the mesoblast, the 
 middle layer of the gorm, and the nerve-tissue originates from 
 the epiblast, whereas the epithelium arises from both the epi- 
 and the hypoblast. This view, however, cannot be strictly 
 adhered to, since we know that the central nerve-organs, though 
 originally products of the epiblast, in further development are 
 composed of a tissue of their own, closely allied to connective 
 tissue. The enamel of the teeth is of an epiblastic or epithelial 
 origin, but during further development it changes to a type of 
 connective tissue. 
 
 I. Connective Tissue. — This tissue composes the main mass 
 of the organism. It forms the bony frame or skeleton, the 
 articular surfaces of the joints, or cartilages. As the derma of 
 the skin, it covers the body ; as perimj'sium and perineurium, it 
 accompanies the muscles and nerves ; and as periosteum, it en-
 
 GEXKRAL niSTOLO(JV. 47 
 
 velops all bones. Fat is likewise a sub-variety of connective 
 tissue. The latter is the only tissue serving as a carrier of both 
 blood- and lymph-vessels. 
 
 Up to the year 1873, connective tissue was believed to be made 
 up of cells, — the so-called connective-tissue corpuscles, — and an 
 apparently inert intercellular or basis-substance, varying con- 
 siderably in consistency and chemical constitution. This basis- 
 substance generally is termed glue, a nitrogenous matter for 
 which there exists as yet no chemical formula. Until that time, 
 also, the cells were believed to be isolated individuals, imbedded 
 in cavities of the basis-substance. In the year mentioned, Carl 
 Heitzmann showed that protoplasm in general possesses a reti- 
 cular structure, a fact which has since been proved by photo- 
 micrography. In the basis-substance Heitzmann likewise has 
 shown the existence of a reticulum identical with that of the 
 protoplasm, a fact not as yet generally accepted by histologists. 
 The reticulum, its points of intersection, the granules, and the 
 nucleus are the living or contractile matter proper, and it is this 
 which pervades the basis-substance, as well as the protoplasm. 
 In this view both the animal a.nd the vegetable organisms are a 
 continuous net-work of living matter, — a delicate reticulum^ the 
 meshes of which are filled with a lifeless nitrogenous liquid in 
 the protoplasm, while in all varieties of basis-substance these 
 meshes contain a solid or semi-solid nitrogenous matter. 
 
 We distinguish four varieties of connective tissue, viz: 
 
 A. Mi/xo)naious, or mucoid. 
 
 B. Fibrous, or striated. 
 
 C. Cartilaginous, or chondrogenous. 
 
 D. Osseous, or hong. 
 
 Under the last head belong the dentine and the ceuieidum of the 
 teeth. While the character of ang variety of connective tissue is ex- 
 clusirelg defined by the peculiarities of its basis-substance, it is to be 
 understood that its corpuscles, thoug/i carging in size, shape, and 
 arrangement, are made up everywhere simplg of protoplasm, or, as 
 in dentine, of fibers of living in after alone. 
 
 A. 31gx<miatous, or Mucoid llssue, is the earliest formation in 
 the embryo, and all varieties of connective tissue are of myxo- 
 matous origin. This tissue shows fields of basis-substance cor- 
 responding in size and shape to medullary corpuscles, or proto- 
 plasmic bodies, which have been transformed into a jelly-like 
 mass, though their minute structure has remained unchanged.
 
 48 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 The reticular myxomatous tissue is composed of branching 
 protoplasmic bodies, the meshes of which hold a gelatinous 
 (myxomatous) basis-substance with central nuclei, the rem- 
 nants of previous protoplasmic bodies. (See Fig. 25.) To this 
 type belong the tissue of the placenta, the umbilical cord, the 
 lymph-ganglia, the so-called adenoid layers and follicles of the 
 mucous membranes, and the pulps of the teeth. Fat is a variety 
 of myxomatous tissue held as a basis-substance in a protoplasmic 
 net-work. 
 
 Fig. 25. 
 
 Reticular Mvxomatuis Tissue of a Villus of the Placf.sta of a Human E.MBRvOf 
 Four Months Old. (From C. Heitzmann.) 
 
 E, E, epithelial cover of the yillu? ; B, solid bud of a growing villus ; C, C, capillary blood- 
 vessels, overlapped by the myxomatous reticulum. Magnified 500 diameters. 
 
 B. F'ibrou.<^ or Striated Tissue, derives its name from the striated 
 appearance of the basis-substance, wdiich upon being torn asunder 
 has the aspect of fibrilla?. The bundles of such fibers may be 
 thin and arranged loosely, as in the so-called areolar variety 
 of connective tissue (pia mater, arachnoid, and peritoneum), or 
 they may be densely put together and traversed by large branch- 
 ing protoplasmic bodies. The bundles are either arranged per-
 
 GENERAL iriSTOLOGY. 
 
 49 
 
 fectly parallel, as we observe in the tendon (see Fig, 26), or 
 interlacing and interwoven in all directions, as we find tliem in 
 
 Fig. 26. 
 
 Tknuox of Achilles of a Yooxg Person. Longitudinal Section. Chromic Acid 
 Specimen. (From C. Heitzmann.) 
 
 li, bundles of striated connective tissue, here and there finely Jotted: T(J, tendon cor- 
 puscles within the bundles or between the smallest bundles ; IT, interstitial medullary tissue 
 carrying capillary blood-vessels, C. Magnified 500 diameters. 
 
 the derma of the skin, the periosteum, the perichondrium, the 
 articular and the interarticular ligaments, etc. 
 
 C, Cariilaginou-'i, or Chondrogenous Tissue, is composed of proto- 
 plasmic bodies imbedded in a dense and tough basis-substance. 
 (See Fig. 27.) In the juvenile condition it is traversed by 
 medullary spaces containing blood-vessels. The existence of 
 connections between the protoplasmic bodies, as well as of the 
 reticulum in the basis-substance, was proven by the method ot 
 staining with a solution of chloride of gold and treatment with 
 absolute alcohol. 
 
 There are three varieties of this tissue, viz : 
 The HyaUne Cartilage. 
 The Fibrous Cartilage. 
 The Reticular Cartilage. 
 
 D. Bony or Osseous Tissue. — Of this there are two main varie- 
 ties, viz: The cancellous, epiphyseal, or spongy, and the compnet, 
 or cortical, bone-tissue. 
 
 Cancellous bo»e is the first bone formed in the em])ryo, long
 
 60 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 before the cortical bone makes its appearance. (See Fig. 28.) 
 In human beings it is the only variety of bone present up to the 
 fifth, sixth, or even the seventh month of intrauterine develop- 
 ment. In dogs, cats, and rabbits, at birth, none but cancellous 
 bone is found in the skeleton. This tissue consists of small, 
 interconnected trabecule of bone, surrounding and inclosing 
 spaces of medullary or myxomatous tissue, supplied with capil- 
 lary blood-vessels. The trabeculse are faintly lamellated, and 
 
 Fig. 27. 
 
 *\"' %t'- t'l" <*/® '^U^ - »<'*'^ 'fj? 
 
 
 Hyalink Cartilage from the Condyle of Femur of a Xewly-borx Pup. Chromic 
 Acid Specimen. (From C. Hkitzmann.) 
 
 C, the tissue of the hyaline cartilage, with scattered groups of cartilage-corpuscles; M, 
 medullary spaces, containing blood-vessels and medullary tissue. Magnified 100 diameters. 
 
 hold a number of branching protoplasmic bodies, the bone-cor- 
 puscles. The latter have been known only since 1870, and were 
 discovered by S. Strieker. Previous to that date dry bones, 
 ground thin and mounted in Canada balsam, were resorted to 
 for microscopical examination. In such specimens only the 
 spaces holding the protoplasmic bodies and their offshoots, the 
 so-called canaliculi,w"ere visible. To-day we know that not only 
 each lacuna holds a bone-corpuscle, but that every canaliculus
 
 CfENERAL HISTOLOCiV. 
 
 51 
 
 contains a small fiber of living matter, and the entire basis-sub- 
 stance is traversed by an extremely delicate net-work of such 
 matter, the meshes of which are filled with a glue-yielding basis- 
 substance, saturated with lime-salts. 
 
 Cortical boiie-tis>'iie is composed of parallel lamellae, bunched 
 together in the shape of so-called Haversian systems, extending 
 longitudinally with the longitudinal axis of the bones. (See 
 Fig. 29.) The center of each Haversian system is occupied by 
 
 
 
 to..*.: 
 
 
 TiniA OF A NKWi.Y-jiOKx Prp. Longitudinal Sectio.v. Chromic Ann Specimen. 
 (From C. IIkitzmann.) 
 
 T, trabeculi\} of bone-ti.^suo containing bone-corpuseles ; .1/, inodullary spaces filled with 
 medullary tissue, holding blood-vessels in the most central jiortions. Magnified 200 diameters. 
 
 a medullary canal that holds, besides a straight capillary blood- 
 vessel, a varying amount of medullary tissue. The older the 
 individual, the scantier is this medullary tissue. The lamellated 
 region contains the branching bone-corpuscles, the same as the 
 trabeculte of cancellous bone. The offshoots of those corpuscles 
 are arranged radiately, interconnecting not only all protoplasmic 
 bodies within the bone, but also the medullary corpuscles, 
 and, indirectly, the walls of the blood-vessels. This is an im-
 
 52 
 
 THE AXATO.MY AND PATHOLOGY OF THE TEETH. 
 
 portant fact, since it explains the nutrition of the compact bone, 
 which is sparingly supplied with blood-vessels, though endowed 
 with properties of life. Each large bone, the shaft-bones as 
 well as the lower maxilla, contains in its center a large medul- 
 lary space traversed by cancellous bone-structure. In youth 
 the medullary spaces hold the so-called red medulla, while in 
 more advanced age they contain fat-tissue. Epiphyseal ex- 
 tremities of bones are mainly cancellous and covered by a thin 
 layer of cortical structure, while articular ends are directly 
 coated with hyaline cartilage. 
 
 TiisiA OF A Grown Dog— Cortical Portion. Transverse Section. Chromic-Acid Spk- 
 CI.MEX. (From C. Heitzmann.) 
 
 .S^, Haversian system of lamellae, containing the bone- corpuscles, C, with their radiating off- 
 shoots; M, central medullary, so-called Haversian canal, containing a capillary blood-vessel ; 
 /, interstitial bone-tissue indistinctly lamellated. Magnified 500 diameters. 
 
 II. Muscle-tissue is the motor apparatus proper, and occurs 
 in two varieties, — viz, the sntnoth or involuntary, and the striated 
 or oolantar;! ma.ick-f issue. The former is composed of spindle- 
 shaped protoplasmic bodies, often holding rod-like nuclei in 
 their interior. The contraction of these spindles results in a 
 slow movement of the muscular walls of the cavities of the 
 body, and the larger blood-vessels, arteries, and veins. 
 
 The s(r>'riftd or rohnifarij muscles consist of large spindle-shaped 
 fibers, in which there are disks made up of small prismatic
 
 (tEXKRAL HISTdLOdV. 
 
 53 
 
 pieces, the so-called " sarcous elements." In longitudinal section 
 the disks of the sarcous elements appear in great regularity of 
 arrangement, separated from one another by a slight interstice 
 tilled with a liquid. (See Fig. 30.) The shape and arrangement 
 
 Muscle or Tonguk <jk Max— Chuomic-Ac-id Si'kcimkx. t Fkom C. Heitzmann.) 
 
 Z., longitudinal muscle-fiber, broken oft" and exhibiting its structureless sheath, the sarco- 
 lemina, ^^■ N. medullatod nerve-fiber, terminating in the motor hill. //.• T, transverse section 
 of a muscle-fiber: A", the perimysium, holding capillary blood-vessels, r', and nerves, iV. 
 Magnified 500 diameters. 
 
 of the sarcous elements greatly vary, depending upon the posi- 
 tion of the muscle-fiber at death. Whatever the configuration 
 of the sarcous elements be, they are invariably interconnected 
 by extremely delicate conical threads, both in the longitudinal
 
 54 
 
 THE ANATOMY AND PATHOLOUY OF THE TEETH. 
 
 and transverse directions. The sarcous elements, like the 
 spindles of the involuntary muscles, are formations of con- 
 tractile or living matter. The structure of the muscle-fiber is, 
 according to Heitzmann, identical with that of protoplasm. 
 
 Fici. 31. 
 
 Branch of the Motor Oclli Nkrve oi' Man. (From C. Heitzmann.) 
 
 L. longitudinal, T. transverse section of tlio bundle; PE, e.\ternal perineurium; PI, inter- 
 nal perineurium; ML, myelin investment; A, axis-cylinder; M, transverse sections of 
 muscle-fibers. Magnified 601) diameters. 
 
 The only difference is that in protoplasm the granules and the 
 points of intersection of the minute reticulum are small and 
 arranged without regularity ; Avhereas in the striated muscle 
 the points of intersection are large and of a prismatic or disk-
 
 (iENKK AI, IlISTOLOUY, 
 
 55 
 
 like shape. The coutraction of the protoplasm and that of the 
 iiiuscle-tibers are based upon the same principle. 
 
 III. Nerve-tissue. — As the writer intends to confine himself 
 to but a brief description of the nerves, he will not dwell upon 
 the central nervous organs, the brain and the spinal cord. 
 
 We distinguish two varieties of nerve-fibers, — viz, the mcdid- 
 laicd and the hoii-meduRotaJ. 
 
 The medallated nerve-fibers exhibit to the naked eye a white 
 color, owing to the presence of /iij/cUn, or vcrvc-fat, which sur- 
 rounds the central conducting fiber, the so-called axis-cylinder. 
 In transverse sections of bundles of medullated nerve-fibers we 
 observe around the periphery of the handle a sheath of delicate 
 fibrous connective tissue, the external iKrineurmrn . From this 
 
 Fig. 32. 
 
 Medullated and Nos-jMkdvllated Nerve-Fibkrs from the Retina of a Bull. (From 
 
 C. Heitzmann.) 
 .?', mj'elin sheath, with oblong nuclei and (S-) transverse septa. The myelin oozed out. 
 N, non-medullated nerve-fibers, with varicose enlargements. Magnified 600 diameters. 
 
 layer arise minute offshoots which encircle each nerve-fiber, as 
 t\\^ internal J nrineurium. (See Fig. 31.) Next follows a thin layer 
 of nucleated connective tissue, Schivann's sheath. After this a 
 layer of myelin or nerve-fat, which surrounds the central axis- 
 cylinder. The latter is enveloped by an extremely thin, flat 
 layer of connective tissue, the sheath of the axis-cijlinder. The 
 medullated nerve-fibers, upon approaching the surface of the 
 organ, usually lose their myelin-sheaths, and the hitherto undi- 
 vided axis-cylinder splits up into minute beaded fibrilhe, which 
 directly join the reticulum of the protoplasmic l)odies at the 
 periphery. 
 
 The non-medaUated nerre-fibers are mere axis-cylinders, lacking 
 the myelin investment, but, as a rule, inclosed by an axis-
 
 56 
 
 THE ANATOMY AND PATHOLCx^Y nF THE TEETH. 
 
 cylinder sheath. (See Fig. 32.) At the periphery they split up 
 into axis-fibril] a\ The axis-cylinder has a delicate reticular 
 structure, and the axis-fibrillte are linear projections of the 
 reticulum. The nerve action, probably, is based upon the con- 
 traction of this reticulum of livins^ matter. If the contraction 
 runs centripetally, it is termed sensation ; if centrifugally, it 
 leads, when connected ^vith muscle-fibers, to motion. 
 
 IV. Epithelial Tissue. — The surface of the body, — like all 
 cavities wliich are in direct or indirect communication with the 
 
 Fig. 33. 
 
 Stratified Eimthei.ium of the Skix, covkrixg a Mvxofibro.ma on the Right 
 Shoi'i.der. Vertical Section. (From C. Heitzmanx.) 
 
 /", flat opithelia : Ot. cuboidal epithelia: <'o, columnar epithelia, all the three composing the 
 epithelial layer. A',- I), derma of skin, composed of vascularized connective tissue, C. Magni- 
 fied 600 diameters. 
 
 outer world, — is covered with either a single or a stratified layer 
 of nucleated protoplasmic bodies, the epithelia. These forma- 
 tions are separated from one another by a thin stratum of horny 
 cement-substance, chemically different from the glue of the 
 basis-substance of connective tissue. The cement-substance 
 invariably is pierced by delicate conical offslioots of living 
 matter. Max Schultzc's (horns, interconnecting the epithelial 
 elements. The closed cavities of the body, including those of
 
 (tHXKUAI, lIISTOLOciY. 
 
 57 
 
 the heart, hlood-vessels, and lymph-vessels, are lined by cndo- 
 thelia, — flat, protoplasmic bodies, morphologically identical with 
 epithelia. 
 
 We distinguish three main varieties of epithelia, — viz, thv ti"f, 
 the cuboidal, and the columnar. The last variety often carries fine 
 moving hairs, the so-called rilin. A single layer of epithelium 
 may be constituted of either of the aljove-named varieties. 
 Stratified epithelia, such as we find on the surface of the skin 
 and on the mucous membrane of the oral cavity, including the 
 gums, are made up of three varieties. The lowest layer — that 
 
 Fig. 34. 
 
 Eloou-VeSSELS from the LoOSK AdVENTITIAI, CoXNECTIVE TiSSVE of the SpER.\fATIi' 
 
 Cord OF Man. (From C. Heitzmann.) 
 
 A, artery, with E. endothelial and covering hyaline layer: .1/, smooth musclo layer: 0, 
 adventitial layer : I', vein, exhibitinK the same layers as the artery : ''. capillary blood-vessels, 
 composed of a single endothelial layer, with a surrounding delicate adventitial fibrous connec- 
 tive tissue. Magnified 200 diameters. 
 
 nearest the connective tissue — is composed of a single row of 
 columnar epithelia ; the next, of a number of cnboidal epithelia ; 
 and the outermost, of a number of flat epithelia. The latter, on 
 the surface of the skin, are entirely hornitieJ, whereas on the 
 surface of the oral mucous membrane only the protoplasm is 
 hornified, the nucleus being still endowed with properties of life. 
 (See Fig. 33.) The finest terminations of the sensory nerves, the 
 axis-fibrilhr, run in the cement-substance between the t'pithelia, 
 and there inosculate directly with the thorns, and indirectly 
 with the protoplasmic reticulum, thus rendering all epithelia 
 sensitive.
 
 58 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 Besides protecting the surface of the body, the epithelia have 
 to perform the important duty of secretion. A colony of 
 epitheUa is termed a f/bnid. We distinguish two varieties of 
 glands, — viz, the acinous or berri/shaped, and the tubular. All the 
 mucous and salivary glands emptying their secretion into the 
 oral cavity are of the acinous variety. Quite frequently, but 
 erroneously, these glands are ternied/o?//c?e5, a name that applies 
 to an aggregation of lymph-tissue, and this latter, being a forma- 
 tion of myxomatous connective tissue, never secretes. 
 
 All blood-vessels are lined by flat endothelia. The wall of a 
 capillary is made up of endothelia only. The arteries have, 
 besides the endothelia, a more or less heavy middle coat of 
 smooth muscles, and an outer coat, the so-called adrenfitia, com- 
 posed of flbrous connective tissue. The veins, in structure, 
 resemble the arteries, but have a much less pronounced muscular 
 coat. (See Fig. 34.) 
 
 The lymph-vessels are made up of a single layer of endothelia, 
 whereas the larger lymphatics have a middle muscular coat and 
 an outer adventitial one. 
 
 CHAPTER IX. 
 
 DEVELOPMENT OF CONNECTIVE TISSUE. 
 
 To the minds of Schleiden (1837) and Theodore Schwann 
 (1839) the vegetable and animal organisms were composed of 
 cells and their derivations, — viz, intercellular substance. The cell 
 was considered to be an individual, and composed of a vesicle 
 with liquid or semi-liquid contents, and a central nucleus. An 
 organism, it was thought, was built up of millions of such cells. 
 Each cell might originate spontaneously from an albuminous 
 liquid by the formation of, first, the nucleus, and afterward the 
 cell-wall, similar in shape to two watch-glasses held together, and 
 lastly an accumulation of liquid within the vesicle, the cell-wall. 
 
 Schwann's views, adopted by the Vienna school, guided by 
 Rokitansky, were overthrown in 1852 by Rudolph Virchow,* 
 who stated that a cell was provided with a wall of its own, held 
 a viscid albuminous liquid, and was itself the seat of life, which 
 it was not considered to be by Schwann nor the Vienna school. 
 
 * " Die Cellularpathologie. ' ■ Berlin, 1871.
 
 DEVELOPMENT OF CONNECTIVE TISSUE. 
 
 59 
 
 Virchow held and still holds the view that the organism is com- 
 posed of a large number of individual cells, separated from one 
 another by an intercellular substance, which he considers to be 
 a product of secretion on the part of the cell. He, however, 
 acknowledged one variety of interconnected cells, termed star- 
 
 FiG. 35. 
 
 B 
 
 DlAr}RA.M OF THE STRUCTURE OF CONNECTIVE TISSUE, ACCORDING TO K. ViRCHOW (1852). 
 
 A, structure and development of reticular car^Yar/e.— y. territory of the cell, called inter- 
 cellular substance, considered inert and a product of secretion of the cell. ^^ structure and 
 deveJoptnent of fibrous connective tissue. — G, nucleated cell, lying in a cavity; F, fibers 
 around the cell, considered inert glue and a product of secretion of the cells. 
 
 shaped or stellate, such as we know to exist in the myxomatous 
 tissue. (See Fig. 35.) 
 
 In 1861, Max Schultze,"^' of Bonn, Germany, announced novel 
 views in regard to the construction of cells. He denied the 
 existence of a cell-wall, and said that a cell is a lump of proto- 
 plasm holding granules and a nucleus, endowed with the prop- 
 erties of life. The word " protoplasm" was accepted by him 
 
 *MKller's Archiv, 1861.
 
 60 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 from the botanist, Hugo von Mohl, who, several years before, 
 had applied this term to the contents of vegetable cells. In 
 England, L. S. Beale* almost simultaneously announced similar 
 views, applying the term " bioplasma" to the substance wdiich 
 builds up the cells. This bioplasma was the true living or ger- 
 
 FiG. 36. 
 
 Diagram ok the Structure of Connective Tissue, according to Max Schultze (1861). 
 
 A, struvlure and develojtment of reticular cartilage.— a, territory originally composed of a 
 number of embryonal corimscles, — protoplasm : h, peripheral protoplasmic bodies transformed 
 into inert glue-yielding basis-substance, the central protoplasmic body left unchanged,— carti- 
 lage-cell : c, fully-developed territory. B, structure and development of fibronn connective 
 tissue.— a, elongated protoplasmic bodies around the central cell ; b, fibrous basis-substance, the 
 product of a chemical transformation of protoplasm ; c, unchanged granular and nucleated 
 protoplasm, the connective-tissue cell. 
 
 minal matter, whereas all intercellular substances he considered 
 as ijiert or formed material. Unfortunately, he was led to term 
 the muscles and nerves " formed material" also, and yet these 
 tissues are known to be the most active of the organism. It is 
 
 * " On tin- Structure and Growth of tlie Tissues."' London, 1865.
 
 DEVELOPMENT OF COXNECTIVE TISSUE. (il 
 
 for this reason that Beale's views liavc attracted but little atten- 
 tion. 
 
 Max Schultze's assertions did not directly att'ect the cell-doc- 
 trine, although he admitted that the term " cell" had lost its 
 significance, and that it should be applied only in honor of its 
 discoverers, Schleiden and Schwann. M. Schultze at the same 
 time propounded, concerning the origin of the intercellular 
 substance, new views which must be understood in order to 
 trace the development of the modern researches in the })rocess 
 of inflammation. In the opinion of Virchow, intercelhilar sub- 
 stances were merely a secretory product (^f the cells, whereas 
 Max Schultze proved that these substances are derivations of 
 protoplasm. According to Schultze, a number of protoplasmic 
 bodies become chemically transformed into basis-substance, and 
 thus they are rendered inert and dead. (See Fig. 36.) Beale's 
 doctrine was different, since he said that an originall_y large mass 
 of bioplasma is converted at the periphery into formed material, 
 and only the central portion remains, as forming or germinal 
 matter. 
 
 Soon afterward, E. Briicke, of Vienna, asserted that neither 
 were the granules nor was the nucleus an essential feature of a 
 cell, and consequently he defined the cell as a structureless lump 
 of protoplasm, intrinsically destitute of granules and a nucleus. 
 The expression " structureless" indicated not necessarily that a 
 structure was absent, but that it could not be made out with the 
 microscope. He likewise admitted ^that a lump of protoplasm 
 is the real seat of life, and is able to produce new lumps — i.e., 
 new cells — by proliferation and division, in normal development 
 of the tissues as well as in morbid processes. 
 
 In 1873, Carl Heitzmann, at that time in Vienna, published a 
 series of articles in the Vienna Academy of Sciences,* exploit- 
 ing yet further entirely novel discoveries concerning the struc- 
 ture of protoplasm, and the structure and origin of the basis- 
 substance. 
 
 Heitzmann maintains that a cell, or a lump of protoplasm, 
 hitherto considered structureless, is indeed possessed of a pro- 
 nounced reticular structure. Since he had seen this reticulum 
 in continuous change of place and shape during the locomotions 
 of living protoplasmic lumps, such as ama'bic, colorless blood- 
 corpuscles, etc., he called the substance which builds up the 
 
 * Sitziinffsberichte der Wiener Akadeinie der Wissenscknftcii, 1873
 
 62 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 reticulum the living or the " contractile matter" proper. He 
 designates as formations of living matter the nucleus, the gran- 
 ules, with their interconnecting threads, and an extremely thin 
 layer, inclosing the lump of protoplasm all around. At first the 
 existence of the reticulum was denied by most observers, and 
 
 Fig. 37. 
 
 Diagram or the Stricture of Connective Tissue, accordi.vi; to C. Heitzmaxn (1873). 
 
 A, utruclnri- and ileveloimieiit of retiiiihtr cartila(>e. — a, territory originally composed of a 
 number of embryonal corpuscles,— protoplasm containing a reticulum of living matter; b, peri- 
 pheral protoplasmic bodies in the beginning infill ration with glue-yielding basis-substance, the 
 chemical change taking place in the tluid. filling the meshesof the reticulum ; the central pro 
 toplasmic body left unchanged,— cartilage-corpuscle : o, infiltration with basis-substance further 
 advanced : '/, infiltration with basis-substance accomplished, the reticulum present, but ren- 
 dered invisible. B, xtrurturc and devc/opment of fibrous conmctire tis-'iue. — a, branching and 
 interconnecting protoplasmic tracts; /(, fibers composed of protoplasmic spindles, holding the 
 reticulum of living matter, all interconnected by living matter; c, advanced infiltration with 
 basis-Substance, the reticulum present, but rendered invisible. 
 
 afterward, when they could not any longer deny it, they said that 
 it was not originally ob^^erved by Heitzmann, but was discovered 
 by C. Frommann in 1867. Frommann, it is true, speaks of a 
 reticulum in connective tissue, and in ganglionic cells, but with-
 
 DEVELOPMENT OF CONNECTIVE TISSUE. 63 
 
 out giving ail illustration thereof. He afterward declared that 
 he had never used lenses of a higher power than 450 diameters. 
 To observe the reticulum in the protoplasm with such a poAver 
 of the microscope is simply impossible, even to an experienced 
 eye. Indeed, from 800 to 1000 diameters are required for the 
 study of the reticulum under consideration. That the reticulum 
 exists is to-day a settled fact, the more so as Strieker, in 1890, 
 succeeded in reproducing it by photography, magnifying a living 
 colorless blood-corpuscle of the proteus by means of the electric 
 microscope, with a power of 2500 diameters.* In this photo- 
 micrograph the reticulum in the protoplasm is exactly the same 
 as discovered and described by Carl Heitzmann in 1873. 
 
 That the nucleus is made up of living matter became appar- 
 ently doubtful when, in 1875, the so-called karyokinesis of the 
 nucleus was discovered by Strassburger,Biitschli, Flemming, and 
 others. It was shown that the nucleus is composed of loop-like 
 threads representing stars and double-stars preceding its divi- 
 sion. Since these loops could be stained deeper by certain anilin 
 dyes, especially safranin, than the granules of the protoplasm, 
 it was asserted that the nucleus is composed of a substance 
 of its own, called " nuclein" and "chromatin." It is plain 
 that a substance capable of changing its shape and place must 
 be living matter. The karyokinetic threads assumed a deeper 
 color only on account of their being more bulky than the rest 
 of the reticulum in the surrounding protoplasm. Besides, it 
 was shown that even at the height of karyokinesis, the loops 
 remain interconnected with the surrounding reticulum of the 
 protoplasm, which again proves their identity, Not only do all 
 movements occur in consequence of contraction and extension 
 of the reticulum, but all new^ formations and outgrowths start 
 from this substance, respectively from the granules, the points of 
 intersection of the reticulum. This again proves that the reti- 
 culum is the living matter proper, in the meshes of which there 
 exists a liquid holding nitrogen, but, being a liquid, not endowed 
 with the properties of life. 
 
 Originally every so-called cell is a solid granule of living 
 matter, which in turn becomes vacuoled by an accumulation of 
 liquid, and, at last, is reticulated, in consequence of perforations 
 of the walls of the vacuoles. 
 
 Another discovery of Carl Heitzmann, in 1873, was that the 
 
 * ArbrJfp.a uns: dma Institute fiir e.cperiinentelle PatJiolofflf. 1890.
 
 64 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 intercellular or basis-substance of the connective tissue is not 
 dead or inert, as hitherto supposed, but is alive in the same sense 
 as the cells themselves. The reticulum of living matter visible 
 in the latter is present also in the basis-substance, though ren- 
 dered invisible by chemical changes and a solidification of the 
 originally liquid contents of the meshes in the protoplasm. It 
 has been proven that in all varieties of connective tissue, in the 
 muscles, the nerves, and the epithelia, the so-called cells are 
 interconnected by means of delicate threads of living matter, or 
 indirectly by the reticulum pervading the basis-substance. (See 
 Fig. 37.) 
 
 In the development of all varieties of basis-substance, the 
 protoplasm shares, by a process of chemical transformation which 
 renders it more or less firm and solid. It has also been proven 
 that in the formation of basis-substance the protoplasm does 
 not perish altogether, but only the lifeless liquid portion which 
 is held in the meshes of the reticulum becomes solidified, whereas 
 the reticulum itself remains unchanged. 
 
 Development of Bone-Tissue. — While all varieties of connec- 
 tive tissue develop directly from inditferent or medullary tissue, 
 bone is a, secondary formation, originating either from previous 
 hyaline cartilage or from fibrous connective tissue. The latter 
 is the case with the flat bones of the skull ; the former, with all 
 the rest of the skeleton, including the lower jaw and the greater 
 portion of the upper jaw. In both instances the process is 
 identical ; indeed, AV. X. Sudduth* has shown that even the lower 
 jaw may, in part, develop from fibrous connective tissue, inde- 
 pendently of hyaline cartilage. Whenever hyaline cartilage is 
 about to be transformed into bone-tissue, as in the case of the 
 lower jaw in the sixth week of embryonal life, the cartilage 
 becomes reduced to medullary tissue, a process frequently, 
 though not always, preceded by a deposition of lime-salts at the 
 border of the territories of the cartilage-corpuscles. Sometimes, 
 before the cartilage begins to change into embryonal tissue, a 
 calcified frame of basis-substance is produced. In former years, 
 histologists encountered great difliculties in explaining the 
 origin of the medullary tissue. Some of them — A. RoUet, for 
 example — have gone so far as to assert that the cartilage-cells 
 perish altogether, and that into their places colorless blood-cor- 
 puscles migrate, giving rise to bone-tissue. To-day all such 
 
 *"Tlie Aiat'i-ican System of IX-ntistrv." 1886.
 
 DEVELOPMENT OF CONNECTIVE TISSUE. 
 
 65 
 
 difficulties have vanished, since we know that not only are the 
 cartilage-corpuscles traversed by a net-work of living matter, 
 but that so also is the dense basis-substance. IS^othing is required 
 but a liquefaction of this basis-substance to liberate the reticu- 
 
 Fio. 38. 
 
 Humerus oi' a IIumax Embryo, Five Months Old. Sagittal Section. Chromic Acid 
 Specimen. (From C. Heitzmanx.) 
 
 C, rows of cartilage-corpuscles in elongated groups, due to their territories ; F, frame of calci- 
 fied basis-substance, around which, in the lower portions, the first traces of bone-tissue are 
 noticeable; il/, moduUary space, containing medullary corpuscles. Magnified ;300 diameters. 
 
 luni, whereupon the protoplasmic condition of the tissue is re- 
 estal)lished. The newly-appearing medullary corpuscles, in this 
 view, are nothing but the result of the return to the embryonic 
 condition of the cartilage-tissue. (See Fig. 38.) This process is 
 
 6
 
 66 
 
 THE ANATUilY AM) PATHOLOUY OF THE TEETH. 
 
 followed by an outgrowth of living matter into threads, which 
 afterward, bv vacuolation, become hollowed, and thus blood- 
 vessels are formed holding red blood-corpuscles, even before 
 union with the already permeable capillary system. The spaces 
 filled with embryonal or medullary tissue are bordered by the 
 calcified basis-substance of the previous cartilage, this evidently 
 serving as a support of the cartilage, which, to a considerable 
 degree, has been reduced into protoplasm. Around this calcified 
 
 Fig. 39. 
 
 Vertkbra of a Hvman Embyro, Five Months Old. Horizontal Section. Chrom;' 
 Acid Specimen. (From C. Heitzmann.) 
 
 M, medullary ?iiaec, with central blood-vessels and medullary tissue : B. first-formed globular 
 territories, containing one or two central bone-eorpuseles, with radiating offshoots. The terri- 
 tories lie against the trabeculic of the original calcified basis-substance of the cartilage, /'. 
 Magnified 500 diameters. 
 
 frame the first-formed territories of boue-tissue are seen, with 
 their. convexities lying against the calcified basis-substance. (iSee 
 Fig. 39.) Later a number of such medullary corpuscles unite, 
 coalescing into globular masses of so-called ni/zelojilaxes (Robin), 
 or giant ccl/s (Virchow), in which we frequently notice a large 
 number of nuclei placed at nearly regular intervals, (See Fig. 
 40.) 
 
 Such a globular body is the beginning formation of a territory
 
 DEVELOPMENT OF CONNECTIVE TISSUE. 
 
 67 
 
 of future bone-tissue. In the center of the territory a certain 
 amount of protoplasm remains unchanged, representing the 
 future bone-cor[)Usele, whereas the peripheral portion of the 
 territory becomes infiltrated, first with a glue-3'ielding basis- 
 substance, and afterward with lime-salts. The latter portion is 
 traversed by radiate protoplasmic otfshoots, all of which com- 
 municate wnth the central bone-corpuscle. The formations 
 formerly termed lacmuv, therefore, are nothing but the central 
 
 Fig. 40. 
 
 Ai" -- 
 
 Sltrkace 111- THE S<Ai»ULA (IF A KiTTKv. Chromic Acid Specime-v. ( Frmm C. Ueitzmanx.) 
 
 (', lainellated bone, with bone-uorpuscles ; O, a single territory of bone-tissue liquefied, result- 
 ing in the formation of a multinuclear plastid or coll ; M, coalesced masses of multinuclear 
 plastids or colls. Magnified 600 diameters. 
 
 cavities in the basis-substance, holding the bone-corpuscle. 
 What have been termed caiiaUriOi are the offshoots of the central 
 cavities, holding threads of living matter. In fully-developed 
 bone, the bone-corpuscles and their offshoots are quite conspicu- 
 ous. By decalcification and staining there is rendered visible 
 throughout the whole tcrritorv a delicate reticulum of livino; 
 matter, identical witli that seen in the [irotoplasm itself 
 
 Lcuiidlatrd boiic arises by an arrangement in rows of medullary
 
 68 
 
 THE- ANATOMY AND PATHOLOCY OF THE TEETH. 
 
 corpuscles adjacent to the already formed bone. The large 
 medullary bodies termed osfeobfasts are a preceding stage of bone, 
 just as the odontoblasts are of dentine, and the ameloblasts are of 
 enamel. Either of these bodies, which resemble epithelia, must 
 
 Fig. 41. 
 
 ; > 
 
 .Skull oi- Hima.n Embryo, Foir Months Old. HoiiizoxTAL Sectiox. Ciihomic Acid 
 Specimrn. (From C. Heitzmanx.) 
 
 F, fibrous connective tissue of the pericranium ; M, medullary space, with central )jh)od- 
 ve.'sel: /?, first-formod trabecula of bone ; 0. row of ofteoblasts : C, medullary corpuscles of 
 the inner pericranium, infiltrated with limo-salts. Magnified 500 diameters. 
 
 break up into indifferent corpuscles in order to give rise to 
 permanent bone, dentine, or enamel. 
 
 Whenever bone develops from fibrous connective tissue, the 
 latter is first reduced to cmbrvonal tissue in the same manner as
 
 THH .MIM-TH STRUCTURE OF I>EXTINE. 69 
 
 hyaline cartilage previous to the formation of bone. The fur- 
 ther stages of the production of bone from fibrous tissue are 
 identical with those in the development from hyaline cartilage. 
 (See Fig. 41.) 
 
 The law here laid down is but a brief sketch of the history 
 of development as first established in 1873 by Carl Heitzmann. 
 Ever}^ tissue originates from protoplasm in the state of indiffer- 
 ence, — the so-called emhr//ona/, or medtdlari/ t(ssi(e. No (issue can 
 be transformed into another unless it heis first been reduced to the em- 
 bryonal condition. This law holds good not only in the pro- 
 gressive evolution of the tissues, but also in their retrogressive 
 changes, and in all morbid processes, — i.e., in inflammation or 
 in the formation of new tissue, as the result of an inflammatory 
 process termed " hyperplasia,'" or in the formation of tumors. 
 
 CHAPTER X. 
 
 THE MINUTE STRUCTURE OF DENTINE.* 
 
 Methods. — The best method in the preparation of bone-tissue 
 for microscopical purposes is doubtless the treatment with 
 chromic-acid solution of the strength of from one-half to one 
 per cent. The same treatment has repeatedly been resorted to by 
 different investigators of tooth-substance. The writer has used 
 this solution extensively for this purpose, adopting precautions 
 suggested by his ex[)erience in dealing with bone. These are, 
 to immerse only a few teeth in a large vessel containing a consid- 
 erable amount of chromic-acid solution ; to renew the supply of 
 this every third or fourth day, and to add, to enforce the action 
 of the fluid, very small quantities of dilute hydrochloric acid. 
 Under this treatment the teeth, after a few months, become 
 dark green from the reduction of the chromic acid to the sesqui- 
 oxide of chromium. This method is most effective for softening 
 teeth, both human and animal, when they are still in the jaw. 
 Wonderful results can be obtained by cutting at the same time 
 bone and tooth prepared in this process ; also in preparing 
 
 *"The Distribution of Living ^ratter in Hunum Dentino, Cement, and 
 Enamel." Dental Cosmos, 1878-1879.
 
 70 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 specimens from embryos, in order to study the history of 
 development of teeth. This method is highly recommended, 
 althonsfh the chromic acid only softens the cement and dentine 
 to a certain depth, so that a tooth kept howsoever long in the 
 chromic-acid solution never is fit to be cut through its whole 
 substance at one time. 
 
 The sections so obtained are ready for staining with carmin 
 or hgematoxylin after they have been immersed in and washed 
 with distilled water, also for staining with chloride of gold, 
 which latter may be done in the following way : Thin sections, 
 after having been washed in distilled Avater for twenty-four hours 
 and thus freed from the remnants of chromic acid, are to be 
 placed in a solution of chloride of gold of the strength of half 
 of one per cent., b}' means of glass rods, as metals must be 
 avoided in the treatment with chloride of gold. These sections 
 are to remain in the solution for from half an hour to an hour, 
 and must then be thorouo-hlv washed with distilled water and 
 exposed to daylight for several days, when they are ready for 
 mounting in the ordinary- way in chemically-pure glycerin. 
 
 The greatest objection to the chromic-acid treatment is that 
 enamel never can be obtained in connection with the dentine. 
 If hydrochloric acid has been used in addition to the chromic- 
 acid solution, the enamel is almost completely dissolved. If 
 chromic acid alone has been used, the enamel becomes so brittle 
 that it crumbles into small particles under the knife. Under 
 such circumstances the outer surface of the dentine looks bay- 
 like, owing to the curved lines on the boundary between the 
 dentine and enamel. 
 
 Lactic acid, if diluted suthciently, so acts upon teeth as to 
 dissolve the lime-salts much faster than chromic acid does. 
 Specimens prepared in this way, however, in the writer's expe- 
 rience, are not distinct enough for study with high powers ; hence 
 a tooth, after being softened with lactic acid, has to be immersed 
 in chromic-acid solution for several weeks. But the greatest 
 objection to the use of the lactic-acid solution is the formation 
 of mildew in a relatively short time, and tlie dissolving of the 
 enamel from the teeth. 
 
 The only method which has enabled the writer to obtain speci- 
 mens of teeth provided with all hard tissues is the following: A 
 fresh tooth, or one kept a short time in chromic-acid solution, is 
 sliced under water by a watch-spring saw, and ground as thin as
 
 THE MINUTE STIU'CTURE OF DEXTIXE. 71 
 
 possible upou a corundmn-wheel of a latlie, always being kept 
 under water. The lamella thus obtained should be placed in a 
 large quantity of chromic-acid solution of the strength of half 
 of one per cent, for one or two days, with the view of harden- 
 ing the soft parts of the tooth and dissolving the lime-salts. 
 After this the specimen may be stained with carmin, hreraa- 
 toxylin, chloride of gold, etc., as above described, and mounted 
 in glycerin. 
 
 The saturated solution of picric acid in water may also be 
 used for the decalcitication of a ground slice of a tooth, though 
 the precipitated acid must be afterward removed, either by a 
 brush or tlie blade of a knife. Very handsome specimens can 
 be obtained by staining them with carmin after the treatment 
 with picric acid. 
 
 Examination. — We know that the basis-substance or matrix 
 of the dentine is analogous to that of bone, — i.e., that it is glue- 
 yielding, and at the same time infiltrated with lime-salts. We 
 learned from the researches of E. Neumann that the basis-sub- 
 stance is denser at the walls of the canaliculi, and more resistant 
 to the action of strong acids, which cause the appearance of a 
 sheath around each canaliculus after the solution of the inter- 
 mediate substance of the matrix between the tubuli. Analogous 
 relations also exist in bone-tissue, in which the basis-substance 
 is decidedly denser on the walls of the lacun{« and Haversian 
 canals. 
 
 With low powers we cannot see in the dentine anything more 
 minute than the dentinal canaliculi. These run in curved sig- 
 moidal lines from the boundary of the pulp-cavity to the per- 
 ij)hery of the dentine; they are directed obliquely upward in the 
 crown, and assume a more horizontal direction in the region 
 of the neck, while in the root they remain horizontal or some- 
 times turn downward to a varying extent. Besides the main sig- 
 moidal curvature, each individual canaliculus exhibits a more or 
 less waw course in its way through the dentine, and the individ- 
 ual curvatures are, as a rule, very marked on the outer periph- 
 ery of the dentine. 
 
 The dentinal canaliculi reach the outer surface of the dentine 
 only on the circumference covered by enamel. On the periph- 
 ery coated by cementum, including also the neck, the canaliculi 
 terminate before reaching the cementum, and are replaced by a 
 finely-granular basis-substance greatly varying in width.
 
 72 THE ANATOMY AND PATHOLOGY OF THE TEETil. 
 
 The distribution of the dentinal canalicnli is in the great 
 majority of teeth uniform throughout the dentine, although ex- 
 ceptionally the writer has met with specimens of dentine in which 
 there were smaller or larger territories deyoid of dentinal canali- 
 culi ; which latter looked as if arranged in bundles or groups 
 within the basis-substance. This relation is especially visible on 
 transverse sections of the dentine. An irregular arrana-ement 
 of the dentinal canaliculi is more common in the roots than in 
 the crowns. 
 
 Each canaliculus contains a dentinal fiber. These fibers, 
 when viewed with a power of 500 on good chromic-acid speci- 
 mens, exhibit a pale-gray color, and run without ramification 
 through the middle of the canaliculi up to the outer surface of 
 the dentine. The outlines of these fibers always look beaded 
 and fringed. On specimens treated with chloride of gold, the 
 fibers and their delicate offshoots show a distinct yiolet color, 
 characteristic of living matter within protoplasmic formations, 
 while the space between the fiber and the wall of the canaliculus 
 remains unstained, and the basis-substance between the tubuli 
 only assumes a slight violet tinge. 
 
 Longitudinal sections of dentine, stained with carmin or 
 chloride of gold, if examined with high powers, — from 1000 to 
 1500 diameters (immersion lenses), — exhibit the following : 
 
 The canaliculi of the dentine run in a more or less wavy 
 course through the basis-substance, and are, as a rule, bifur- 
 cated only at the periphery of the dentine, both toward enamel 
 and cementum. Each canaliculus contains a central, slightly 
 beaded fiber, wjiich on its whole periphery sends delicate thorn- 
 like elongations through the light space between the central 
 fiber and the wall of the canaliculus. The thorns are distinctly 
 conical, their bases being attached to the dentinal fibers, and 
 their points directed toward the basis-substance. The smallest 
 thorns spring in an almost vertical direction from the dentinal 
 fiber, while somewhat larger oftshoots may run obliquely through 
 the basis-substance, and directly unite neighboring fibers with 
 one another in the vicinity of the enamel and cementum. 
 
 The basis-substance shows a distinct net-like structure. The 
 light spaces surrounding the dentinal fibers send delicate elonga- 
 tions into the basis-substance, in which, through repeated branch- 
 ing, a light net-work is established, the meshes of which contain 
 the decalcified tjlue-vieldins: basis-substance. The finest off-
 
 THE MINTTE STUrcTrKH oF HKXTINE. 73 
 
 shoots of the dentinal libers can be traced only into the mouths 
 of the elongations of the canaliculi ; on the periphery of the 
 latter, o\ving to their great delicacy, the offshoots are lost to 
 sight. Coarser offshoots of the dentinal fibers, at the localities 
 mentioned before, traverse the basis-substance within its light 
 net-work, at the same time uniting dentinal fibers directly, and 
 sending slender conical oftshoots into the liglit net-work of the 
 basis-substance. (See Fig. 42.) 
 
 The dentinal fibers are either in direct connection with coarser 
 
 Root of Molar St.visei) wiih Chi.okidk of Gold. 
 
 D, dentine; C, cement with branching bone-corpuscles; f^, dentinal fibers with their trans- 
 verse offshoots ; F-, ramifications of dentinal fibers and their union with the offshoots of cement- 
 corpuscles. Magnified 1200 diameters. 
 
 offshoots of the protoplasmic bodies of the cementum, or the light 
 net-Avork of the basis-substance of the dentine is in communi- 
 cation with that of the basis-substance of the cementum. 
 
 The latter condition prevails at the periphery of the neck of 
 the tooth, where the basis-substance of the dentine is pierced 
 not by larger offshoots of the dentinal fibers, but only by a deli- 
 cate net-work, through which the connection between dentine 
 and cementum is indirectly established. 
 
 AVhere the dentine is in contact with the pulp, the dentinal
 
 74 THE ANATOMY AND PATHOLOGY OF THE TEETH, 
 
 fibers communicate directly with the odontoblasts (John Tomes) 
 in a growing tooth, and with the protoplasmic bodies of the pulp 
 in a fully-developed condition, where no regular odontoblasts 
 can be seen. 
 
 In cross-sections of dentine the dentinal canaliculi are visible 
 in the shape of circular or oblong holes; the center of each is 
 occupied by the dentinal fiber, which has the shape of a small 
 roundish dot. Again we see that the periphery of the dentinal 
 canaliculus is sharply marked, and repeatedly interrupted by 
 light oftshoots leading into the light net-w^ork that pierces the 
 basis-substance between the canaliculi. The central fibers look 
 very distinct and dark violet in specimens stained with chloride 
 of gold, and send slender, conical, radiated oftshoots through the 
 surrounding dentinal canaliculi, respectively tow^ard the mouth 
 of the light interruptions in their walls. 
 
 Fig. 43. 
 
 
 Af^- 
 
 6. 
 
 Ckoss-Sbctio.v of Dentine of Incisor. Cross-Section of Dentine of Incisor. 
 
 Stained with Chloride of Gold. Stained with Chloride op Gold. 
 
 Main Mass of Dentine. View from Outer Periphery of 
 
 Dentine, near Enamel. 
 
 /', dentinal canaliculi witli the central dentinal fibers, the latter with star-like offshoots; B, 
 the basis-substance between the canaliculi, pierced by a delicate light net-work. Magnified 
 2000 diameters. 
 
 In directly transverse sections, one, two, or sometimes even 
 three such oftshoots can be seen in a star-like arrangement. 
 Each oftshoot springs with a broad base from the central den- 
 tinal fiber, wdiile its pointed end always is directed toward the 
 perforation in the wall of the canaliculus, where, as a rule, it is 
 lost to sight. Slightly oblique sections of the canaliculi exhibit 
 both transverse and longitudinal projections of the dentinal 
 fibers. In such an oblique section we ma}' succeed, by cautiously 
 changing the focus, in seeing star-like radiated oftshoots up to 
 five in number, all arising from a single dentinal fiber. 
 
 Toward the boundary between dentine and enamel, and 
 dentine and cementum, as is well known, the dentinal canaliculi
 
 THE MIXLTE STRUUTLRE OF DENTINE, <0 
 
 ramify, and according to tbeir ramifications also the dentinal 
 fibers bifurcate, becoming the thinner the nearer they are to the 
 surface of the dentine. Both longitudinal and transverse sec- 
 tions of this part of the dentine show details identical with the 
 main mass of the dentine, the only diflt'erence being that near 
 the periphery of the dentine the fibers are more delicate and 
 more closely arranged. (See Fig. 43.) 
 
 In some teeth I have met on the periphery of the dentine of 
 the crown with the so-called " interglobular spaces" (Czermak), 
 which may be considered as remnants of the embryonic con- 
 dition of the dentine. They represent lacunae of greatly vary- 
 ing sizes, bounded by curved lines, the convexities of which are 
 directed toward the central cavity. These spaces sometimes 
 contain protoplasm, — that is to say, embryonal elements which 
 have not been transformed into basis-substance and not calcified. 
 The dentinal fibers enter the protoplasmic bodies, and each fi.ber 
 is united with the net-work of the protoplasm by means of deli- 
 cate thorn-like projections. At other times the basis-substance 
 of the dentine is developed within the interglobular spaces, but 
 devoid of lime-salts. In this instance the dentinal fibers, with- 
 out investment and without changing their course, pierce the 
 basis-substance and send offshoots to this through the surround- 
 ing light spaces. 
 
 The dentine shows, in general, though not constantly, peculiar 
 formations where it approaches the enamel and cementum. 
 These formations, however, being in close relation to the cover- 
 ing tissues of the tooth, I prefer to describe in the chapter on 
 cementum and enamel. 
 
 Results. — The dentinal canaliculi are excavations in the basis- 
 substance of the dentine, each containing in its center a fiber of 
 living matter. Besides the dentinal canaliculi, there exists an ex- 
 tremely delicate net-work within the basis-substance of the den- 
 tine, into which innumerable otfshoots of the dentinal fibers pass. 
 Although evidently, by reason of its delicacy, we cannot trace 
 the living matter throughout the whole net-work in the basis- 
 substance, we are justified in assuming that not only are the den- 
 tinal canaliculi, but so also is the whole basis-substance of the 
 dentine, pierced by a delicate net-work of living matter. The 
 living matter of the dentine is in direct union with that of the 
 protoplasmic bodies of the pulp, of the cementum, and of the 
 enamel.
 
 /6 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 Further researches into the minute structure of dentine have 
 been made by John I. Hart,* of which the following is an abstract : 
 
 "Method. — A freshly extracted tooth, preferably a deciduous 
 one, is sawed into sections, either vertical or transverse, with 
 the precaution that the tooth, and the instrument employed, are 
 kept constantly moist with a one or two per cent, solution of 
 sodium chloride. The object of this procedure is to prevent the 
 drying up and consequent shrinkage of all soft constituents of 
 the dentine, — viz, the dentinal fibers and their offshoots. The 
 slab thus obtained is ground first with a coarse corundum-wheel 
 on the lathe, and afterward on a corundum-slab of medium 
 grit, always under a weak solution of table-salt. I wish to lay 
 stress upon the fact that the ground slabs should not be kept 
 longer than two hours in the salt solution, lest the dentinal 
 fibers should become hydropic, and, swelling up, completely 
 fill the canaliculi. Before staining, with a camel's-hair brush 
 cleanse the specimen of the adhering debris resulting from the 
 grinding. The next process is staining with a one-half of one 
 per cent, solution of chloride of gold, or a one per cent, solution 
 of hyperosmic acid. Since the latter has proved inferior to 
 the former, it has been abandoned, and chloride of gold is ex- 
 clusively employed. Tv/o ways have been adopted. Pour the 
 chloride-of-gold solution over the slab and leave it immersed two 
 hours, carefully shutting off the light; then transfer the slab 
 with a wooden spatula, carefully avoiding all metallic instru- 
 ments, into a six per cent, solution of glacial acetic acid for two 
 hours. Repeat this procedure, — viz, staining with the gold 
 salt and decalcifying with acetic acid from ten to twelve hours, 
 after which the now pliable slab is left exposed to strong day- 
 light in distilled water until it has assumed a dark-violet color; 
 or expose the slab to the action of the gold salts for ten hours, 
 and then to the solution of acetic acid for the same length of 
 time, and expose to light in distilled water. The latter method 
 is preferable, although the specimens are sometimes partially 
 overstained and become too dark for examination. After the 
 required color is reached, brush the specimen gently in order to 
 remove the precipitations of the gold salt, and mount in chemi- 
 cally-pure glycerin. 
 
 "There is a marked difterence in the behavior of enamel and 
 that of dentine in the process of decalcification by acetic acid. 
 
 * "Minute Structure of Dentine." Dental Cosmos, 1891.
 
 THE MINLTE STRLCTURE OF DENTINE. 77 
 
 Enamel at first breaks up into prisms witli transverse blocklets, 
 similar to those obtained bv treatment with dilute hydrochloric 
 acid. Upon the approach of complete decalcification, the 
 enamel becomes extremely brittle, and breaks up into small 
 pieces if the least pressure is exerted upon it. After complete 
 removal of the lime-salts, there is left, as first seen and described 
 by Dr. Frank Abbott as early as 1878, only a delicate reticulum, 
 — the last residue of organic material. 
 
 " Dentine resembles enamel only in this particular, that in 
 incomplete decalcification, blocklets of lime-salts are seen 
 throughout the basis-substance. After complete decalcification 
 a tough, pliable slab is left, which, even though exposed to some 
 pressure, will not break asunder. Obviously the glue-yielding 
 basis-substance and its tenants are not corroded or affected in 
 the least by the six per cent, solution of acetic acid. All this 
 acid accomplishes is the removal of the lime-salts deposited in 
 the basis-substance, thereby rendering clear its minutest struc- 
 ture. Exposure of a ground slab of dentine to the action of 
 the gold solution for three hours renders the dentinal fibers 
 plainly visible and tinted a pale violet. Exposure of six hours 
 will stain the dentinal fibers dark violet, and will bring out 
 clearly the broader offshoots. An exposure of from nine to ten 
 hours is necessary to bring forth the more minute conical off- 
 shoots emanating from the dentinal fibers and the minutest 
 structure in the basis-substance. 
 
 " Main Mass of Dentine.— If successfully stained portions are 
 placed under an amplifying power of from 1000 to 1200 
 diameters, striking features become recognizable in the dentinal 
 fibers themselves. Should the method described above be faith- 
 fully carried out, we will invariably see portions of a varying 
 extent suitable for the amplification just stated. It makes no 
 difierence whether water or cedar-oil immersion is resorted to. 
 
 " The dentinal fibers in the main mass of the dentine do not 
 look homogeneous, as in the unstained condition, but appear 
 hollowed out in their interior by light spaces, so-called 
 vacuoles, of greatly varying sizes. These vacuoles are plainly 
 visible if the ground slab is left exposed for the shortest }>ossible 
 time to the salt water. If this exposure is protracted for days, 
 the vacuoles will ap[)oar enlarged and almost continuous within 
 the dentinal fibers. Doth longitudinal and transverse sections 
 exhibit the vacuoles: I have obtained the most distinct imaoe.
 
 78 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 however, in thiu longitudina] sections, where but one layer of 
 dentinal fibers was visible. (See Fig. 44.) 
 
 " From the rather uneven periphery of the dentinal fibers 
 arise a smaller number of broad and a large number of delicate 
 conical ofl:shoots, all of a dark-violet tint. These ofl'shoots 
 pierce in an almost rectangular direction the light space of the 
 dentinal canaliculus, and inosculate with a minute dark-blue net- 
 work pervading the whole basis-substance of the dentine. This 
 net-work being present throughout the basis-substance, serves 
 
 Fi.i. 4 4. 
 
 Main Mass of Dentine of a Tempurahy Tooth, Stained with Chloride of Gold, 
 Decalcified with Acetic Acid. 
 
 F, F, dentinal fibers, partly vacuoled ; B, B, basis-substance, traversed by a reticulum. 
 Magnified 1200 diameters. 
 
 for a direct interconnection of all dentinal fibers. The net-work 
 appears uninterrupted wherever sufficiently stained, although we 
 may fail to trace the connections in some limited portions of 
 the basis-substance. In transverse sections of the dentinal 
 canaliculi, such as we invariably obtain in longitudinal sections 
 of the crown, and, as a matter of course, in transverse sections 
 of any part of the tooth, we notice features identical with those 
 of longitudinal sections. (See Fig. 45.)
 
 TIIK MINTTK ?^TRrcTURE <iF ItENTINE. 79 
 
 " The dentinal fibers of somewhat varying diameters exhil)it 
 hollow centers in many instances. From their periphery, broad 
 and narrow oifshoots spring forth in a considerably larger 
 nnmber than ever visible in sections of teeth not treated with 
 chloride of gold. The basis-substance appears to be traversed 
 by a dark-violet reticulum of the same character as that of longi- 
 tudinal sections. Oblique sections will of necessity show an 
 apparently larger number of dentinal canaliculi and their tenants 
 than longitudinal or transverse sections in a given area of den- 
 tine. Here we often obtain the impression that rectangular oif- 
 shoots of one dentinal fiber inosculate directly with neighboring 
 fibers, thus furnishing a pretty figure of a ladder with minute 
 rungs. 
 
 Fig. 45. 
 
 Dentine of Temi>oi;ai!Y Tooth. Tkaxsvekse Section of Canaliculi, Stained with 
 Chloride of Gold, Decalcified with Acetic Acid. 
 
 /•', F, dentinal fibers, with radiating offshoots piercing the space of the canaliculi ; B, D, basis- 
 substance traversed by a delicate reticulum, in conuecUon with the dentinal fiber. Magnified 
 1200 diameters. 
 
 " All that I have described thus far as being present in tlie 
 main mass of the dentine is plainly visible only in the dentine of 
 teeth that were alive at the time of extraction. If life has l)een 
 destroyed to a varying extent by an alveolar abscess or pyorrhea 
 alveolaris, the image furnished by the dentine is so characteristic 
 that we recognize at the first glance the extinction of life. 
 Several times have I ground teeth without knowing that they 
 were dead. The microscope revealed the fact. (See Fig. 46.) 
 
 " In longitudinal sections, only the canaliculi are conspicuously 
 prominent, exhibiting delicate and numerous interruptions 
 along their walls. The dentinal fibers appear shriveled up to
 
 80 
 
 THE ANATOMY AND PATHOLO(iY OF THE TEETH. 
 
 rows of minute granules, not always in tlie center of the canali- 
 culus, but frequently quite near to one of the walls. The gran- 
 ules often appear interrupted to a considerable extent, and some- 
 times the remnants of the dentinal fibers are missing altogether. 
 No conical oftshoots emanate from the remnants of the dentinal 
 fibers. The basis-substance shows a rather faint and indistinct 
 reticulum, lacking connections hi numerous places. In trans- 
 verse sections of dead portions of the dentine we obtain a strik- 
 ing image. (See Fig. 47.) 
 
 Fig. 46. 
 
 Dentixk of a DE.kii Tempor.\ry Tooth. St.\ined with Chloride of Gold, Decalci- 
 fied WITH Acetic Acid. 
 
 (J, C, canalieuli, holding shriveled dentinal fibers ; S, B, basis-substance, holding a shriveled 
 reticulum. Magnified 1200 diameters. 
 
 " AVe see the dentine pierced by light spaces at almost uniform 
 distances, many of which contain dark-violet granules or ves- 
 tiges of a previous dentinal fiber. There are but scanty and 
 incomplete indications of conical ofishoots emanating from the 
 shrunken dentinal fillers. The basis-substance is of the same 
 character as found in longitudinal sections. The basis-substance 
 shows a rather indistinct dark-violet reticulum with numerous 
 interruptions. The facts here described suffice, in my judg-
 
 THE MINUTE STRUCTURE OF DENTINE. 
 
 81 
 
 raent, to determine the nature of the reticulum pervading the 
 whole of the dentine ; it is of necessity the living matter which 
 is plainly marked in living, and shriveled and reduced to a row 
 of granules in dead teeth. Since we know of no tissue consti- 
 tuted of nerves, we cannot support the suggestion of John 
 Tomes, that dentinal fibers are but nerve-fibers carrying sensa- 
 tion from the periphery to the center. Since we know that non- 
 medullated nerve-fibers have the same structure as the dentinal 
 fibers, we must conclude that both the nerves and dentinal fibers 
 are made up of living or contractile matter, the contraction of 
 which is facilitated by the presence of vacuoles. For, according 
 to modern researches, the conduction of sensation centripetally 
 
 Fig. 47. 
 
 Dentixk of a Dead Tkmpohary Tooth. Traxsvkrse Section of Caxamculi, Stained 
 vrith chlokide of goi.d, decalcified with acetic acid. 
 
 C, C, dentinal canaliculi. holding shriveled dentinal fibers ; B, B, basis-substance, containing 
 a shrivolod, indistinct roti.'uluui. Magnified 1200 diameters. 
 
 and of motion centrifugall}' is very probably instituted by the 
 contraction of living matter. 
 
 " Interzonal Layer between Dentine and Enamel. — In all the 
 provisional teeth that I have examined, a zone of varying breadth 
 was visible along the outer periphery of the dentine, conspicuous 
 by a darker violet stain than the rest of the dentine. In fact, 
 this region is rather prone to be overstained and become too 
 dark for examination with high powers ; hence, we should ex- 
 amine this region before it has assumed a deep stain, owing to a 
 protracted exposure to light. The first feature which strikes us 
 upon approaching the outer periphery of the dentine is the 
 
 7
 
 82 
 
 THE ANATOMY AND PAT110L0(iY OF THE TEETH. 
 
 beaded appearance of the dentinal iibers, lacking vacuoles in this 
 situation. The fibers are bifurcating, as is well known, and, 
 becoming more and more delicate, correspondingly exhibit more 
 and more beads. The reticulum into which the lateral conicnl 
 oftshoots of the dentinal fibers inosculate is extremely dense, — 
 much more so than in the rest of the dentine. The densely 
 reticulated zone usually corresponds to the depth of the bifur- 
 cations of the dentinal fibers; in other words, it commences in 
 a rather abrupt line in the height in which bifurcations begin 
 to appear. (See Fig. 48.) 
 
 Fig. 48. 
 
 Dkxtine ok Tkmpokaky Tooth, near Enamel, Stained with Chloride of Gold, De- 
 calcieied with acetic acid. 
 
 B.B, boundary of dentine toward enamel: 7, /, interzonal layer (Atkinson), with a dense 
 roticuhim, dentinal fibers bifurcating; />,/>, main mass of dentine, holding beaded dentinal 
 fibers. Magnified 1200 diameters. 
 
 " The presence of this dense reticulum of living matter evidently 
 explains the fact that the interzonal la3'er between enamel and 
 dentine is so extremely sensitive. I am sure that every dentist 
 is made aware of this striking fiict when cutting into dentine. 
 The dentinal fibers rarely enter the enamel in human teeth, but 
 the reticulum of the dentine is continuous with that of the 
 enamel. This connection, however, I was unable to trace
 
 THE MINUTE STRUCTURE OF DENTINE. 83 
 
 myself, as in all m}- specimens the enamel was dissolved and 
 
 removed by the camel's-hair brnsli prior to mounting. 
 
 "Interzonal Layer between Dentine and Cementum at the 
 
 Neck of the Tooth. — Ever since John Tomes drew attention to 
 
 the peculiar fact that the dentinal fibers stopped short of the 
 
 cementum, special attention has been paid to this region of the 
 
 dentine, since it is also known to be more sensitive than the rest 
 
 of the dentine. According to Tomes, ' the greater de£i:ree of 
 
 . ... j» 
 
 sensitiveness observable m the dentine immediately below the 
 
 enamel, — that is, at the point of ultimate distribution of the den- 
 tinal " tubes," and consequently of their contents, — may be fully 
 accounted for on the supposition that the latter are organs of 
 sensation, the highest sensibility of which is confined to their- 
 branches.' 
 
 " This hypothesis does not find foundation in the region of the" 
 neck, where l)ifurcations of dentinal fibers are often missinsr or 
 are scanty. There is only a uniformly granular layer visible in 
 unstained and ground specimens between the surface of the 
 dentine and the terminal points of the dentinal fibers. Still, the 
 sensitiveness at the neck is undoubtedly even greater than that 
 of the interzonal layer of the crown. Bodecker drew attention 
 to the fact that in the great majority of teeth the finest ter- 
 minations of the dentinal fibers are Iqst to sight in a net-work 
 somewhat coarser than that of the basis-substance of ordinary 
 dentine. Sometimes, he says, the dentinal canaliculi upon ap- 
 proaching the periphery become slightly dilated, so as to pro- 
 duce slender pear-shaped cavities, in accordance with which the 
 terminating dentinal fibers exhibit slight enlargements. 
 
 " I can corroborate this statement from what I have seen in 
 my own specimens of temporary teeth. Several times I have 
 met with peculiar formations in this region, which, as far as I 
 am aware, have not as yet been described. (See Fig. 49.) In 
 unstained slabs of temporary teeth I have seen coarsely granular 
 layers in the dentine at the region of tlie neck, with which the 
 dentinal fibers directly inosculated. After deep staining with 
 chloride of gold, the granular layers became dark violet and 
 easily recognizable with low powers of the microscope. I found, 
 as a rule, one or two granular layers like narrow ribbons run- 
 ning along the outer periphery of the dentine, close to the 
 cementum. A much more irregular and broader granular 
 layer was seen at a certain distance below the surface, produc-
 
 84 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 ing wavv lines, and being in connection externally witli a more 
 uniformly granulated layer, and internally with the dentinal 
 fibers. This peculiar configuration was plainest at the portion 
 of the cementum made up of spindles at the neck of the tooth, 
 and gradually faded downward, where the lamellated layer of the 
 cementum began to make its appearance. High powers of the 
 microscope revealed the intimate structure of this portion. 
 (§ee Fig. 50.) 
 
 Fig. 49. 
 
 Nkck (IF Tempodary Tooth. Longitudinal Section, Stained with Chloride of Gold, 
 Decalcified with Acetic Acid. 
 
 />, D, dentine, main mass; N, N, dentine of neck, bordered upward and downward by coarsely 
 granular layers; C, V, cementum of neck; P. P, shreds of pericementum. Magnified 400 
 diameters. 
 
 " The fibers in this situation appear reduced in caliber, and 
 show a beaded structure much the same as at the periphery of 
 the crown. These fibers either terminate in pear-shaped en- 
 largements, or in irregularly-shaped dark-violet lumps, which 
 send delicate oftshoots in all directions, serving as an intercom- 
 munication between them. The large number of these luiiips 
 causes the granular a})pearance of the dentine. The following 
 broader zone, which with lower powers has appeared uniformly 
 granular, is now dissolved into a rather coarse reticulum — much 
 coarser than that of the interzonal layer of the crown. This 
 reticulum shows stray irregular fibers. Both the latter and the 
 lumps are in close connection with the reticulum.
 
 THE .MINUTE STRUCTURE OF DENTINE. 
 
 85 
 
 "At the outermost periphery we again notice one or two rows 
 of enlargements, which, judging from the regularity of their 
 arrangement, correspond to the bases of the spindles, building 
 up the cementum of the neck. This large amount of living 
 matter satisfactorily explains the extreme sensitiveness of the 
 region of the neck. 
 
 " Results. — To sum up my observations, I must maintain the 
 presence of a reticulum of living matter throughout the dentine. 
 
 Fig. 50. 
 
 Dkntink or Neck of Temporary Tooth, Stained with Chi.oridk of Gold, Decalci- 
 fied WITH Acetic Acid. 
 
 D, D, dentine; (?, G, coarse globules, into which the dentinal fibers inosculate; N, JV, den- 
 tine of nouk, with a coarse reticulum, lacking fibers; C, C, cementum of neck, bordered by a 
 granular layer toward the dentine. Magnified 1200 diameters. 
 
 It is decidedly coarser than that seen and described by Frank 
 Abbott in the enamel. It is most delicate in the interzonal 
 layer of the crown between dentine and enamel, and coarsest in 
 the region of the neck bordering on the cementum. 
 
 " My assertion finds proof by comparison of living with dead 
 teeth, for in the latter the dentinal fibers were reduced to a 
 series of granules, and the basis-substance appears irregularly 
 dotted or spotted, instead of being reticular. The microscope
 
 S6 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 therefore easily reveals the difference between living and dead 
 teeth. Another point of coniirmation is that the portions of the 
 dentine being most sensitive are richest in the supply of living 
 matter, not in that of the fibers which are missing in the inter- 
 zonal layer of the dentine of the neck, but in that of the basis- 
 substance." 
 
 Further researches into the presence of the reticulum in 
 dentine have been published by Carl Ileitzmann,* as follows : 
 
 " Dr. Bodecker had collected a large number of teeth that were 
 filled for months and years. The first tooth he ground thin was 
 a bicuspid with two cavities in its crown ; one filled with cement, 
 the other with silver amalgam, — both plugs having been in the 
 cavities for years. How great was his surprise when, examin- 
 ing the border of the cavity previously filled with amalgam, he 
 saw a dark-brown discoloration of the dentine, not directly along 
 the border of the cavity, but some distance away from it, and 
 in this brown zone the dentinal canaliculi, respectively* their 
 tenants, the dentinal fibers, crowded with black dots, and their 
 offshoots rendered wonderfully plain by a black deposit. In the 
 darkest portion the reticulum was easily seen with compara- 
 tively low powers of the microscope, — viz, 500 diameters. (See 
 Eig. 51.) 
 
 " The border of the cavity is, in the upper portion, seen in 
 the breadth of the specimen, and here it holds a number of 
 black metallic particles, evidently not of the amalgam itself, 
 but of a sulphur-combination of the silver or quicksilver. The 
 zone of the dentine directly bordering the cavity is, apparently, 
 destitute of structure, showing but faint traces of canaliculi ; 
 of a high refraction, obviouslv in a state of consolidation, a 
 reactive process subsequent to the filling. Close beneath this 
 consolidated layer follows a dark-brown zone, diffusively pig- 
 mented, and here we see the dentinal canaliculi crowded with 
 black metallic particles, considerably widened and sending black 
 offshoots into the basis-substance between the canaliculi. The 
 offshoots are comparatively scarce and large toward the enamel, 
 where the unstained canaliculi show only the usual bifurcation. 
 The offshoots are more numerous upon entering the dark-brown 
 region of the dentine, and in the darkest portion are so numer- 
 
 * " Demonstration of the Reticulum in Dentine with Low Powers of the Micro- 
 scope." Transactions of the Xcw York Odontolo<;ical Society, 1892.
 
 THE MINUTE STRUCTURE OF DENTINE. 
 
 87 
 
 ous and so delicate that the power of five hundred diameters is 
 insufficient to dissolve the minutest l>ranclies, all of which in- 
 osculate into an extremely delicate hlack reticulum. All the 
 features, the coarse and fine ottshoots and their union into a re- 
 
 Fui. 51. 
 
 
 Ground Bicuspid. Cavity of the Cro'wn prkviously filled with Axial(;am. 
 
 E. enamel ; i), D, dentine ; B, boi-dor of cavity ; .S'. solidified dentine along the border of the 
 cavity : 7?, reticulum, brought forth by the amalgam. Magnified 500 diameters. 
 
 ticulum, are identical with the image obtained hy John I. Hart 
 in living- dentine, treated with chloride of gold. 
 
 " How did the metallic particles reach the dentinal canaliculi,
 
 88 THE ANATOMY AMD PATHOLOGY OF THE TEETH. 
 
 and produce such an image at a certain distance away from the 
 border of the cavity ? There is but one answer possible to this 
 query. The metallic particles were taken into the living matter, 
 probably before the consolidation was accomplished at the bor- 
 der of the cavity, and carried farther, at the same time render- 
 ing visible the reticulum, interconnecting the dentinal libers. 
 It would be impossible to understand the loading of the den- 
 tinal fibers, which run a parallel course and are separated from 
 one another by the intervening basis-substance, unless by the 
 presence of transverse connections of the fibers, as actually 
 shown by the reticulum. This reticulum is, in fact, so plain 
 that any tyro must see it, and the specimen alone is suflicient to 
 remove the doubts of even the most skeptical minds. 
 
 " Fig. 52 represents the neck of a molar whose pulp years 
 ago was treated by Wilhelm Herbst, of Bremen, Germany, with 
 his method, made know^n in this country by Dr. Bodecker. Dr. 
 Herbst applies cobalt upon the exposed or inflamed pulp of the 
 crowai ; a few days afterward he excises the pulp down to the 
 root-canals; introduces tin foil, which he grinds down at the 
 bottom of the cavity, thus shutting off the pulp of the root- 
 canals from contact with air, or other filling-materials placed 
 into the cavity of the crown. The remarkable outcome of 
 Bodecker's examination of the teeth sent by Herbst is that the 
 pulp remains alive in the root-canal, and is sufiticient to endow 
 with life the whole tooth, though its crown is entirely deprived 
 of its pulp. This fact becomes intelligible only upon the pres- 
 ence of interconnections between the parallel dentinal fibrill?e ; 
 for the dentinal fibers could not possibly be kept alive in the 
 crown, unless by unions with the fibrillte of the roots, the only 
 ones kept directly alive by the pulp-tissue of the roots. This is 
 an indirect, though stringent proof of the presence of the reticu- 
 lum. The direct proof is furnished by the visible interconnec- 
 tions of the fibrillte along the neck of the tooth, of a brownish 
 color, in a slightly brownish basis-substance. After having 
 examined many hundreds of teeth under the microscope in all 
 sorts of pathological changes, I have never met with such a dis- 
 coloration in the dentine so frecjuently observed in the enamel. 
 It is quite possible and reasonable to assume that the metallic 
 salt, originated at the border of the cavity, was transferred into 
 the dentinal fibers and their offshoots, and was, at last, depos- 
 ited in the fibrill?e and their otfshoots in the region of the neck,
 
 THE MINUTE STRUCTURE OF DENTINE. 
 
 89 
 
 which, as John I. Hart's researches prove, abounds'in living 
 matter for in excess of any other portion of the dentine. This, 
 I admit, is a hypothesis, to which I resort for lack of a better 
 
 Ground Molar. Thf Illp h.emolsli treated b^ the Herbst Method. The Cav- 
 ity FILLED WITH AMALGAM. 
 
 C pericementum; 0, osteoid layer of cementum ; P, protoplasmic bodies at the interzonal 
 layer between cementum and dentine ; G, granular layer of dentine of the neck : D, dentine of 
 neck. A few club-shaped enlargements of dentinal canaliculi. The reticulum brought forth 
 by the amalgam. Magnified 500 diameters. 
 
 explanation ; it is nearest to my mind, after thirty-two years of 
 studv of the teeth, having become so thoroughly convinced of
 
 90 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 the life of all constituent tissues of the teeth. The specimen 
 under consideration exhibits an ill-calcified dentine, for it shows 
 numerous protoplasmic bodies at the border of the dentine 
 toward the osteoid layer of the cementum, and club-shaped 
 enlargements of some dentinal fibrillfe. The granular layer of 
 Tomes in the dentine of the neck destitute of dentinal canali- 
 culi is narrower than in thoroughly calcified teeth; but present, 
 nevertheless." 
 
 CHAPTER XL 
 
 THE MINUTE STRUCTURE OF ENAMEL.* 
 
 The best specimens for examination of enamel I obtained by 
 grinding fresh teeth, and staining them for one hour with a half 
 per cent, solution of chloride of gold. 
 
 Up to this time the impression of most examiners has been 
 that the enamel is built up of bundles of rods, or prisms, cross- 
 ing one another, and traversed by faint vertical lines, which give 
 each of them the appearance of a column, subdivided into small 
 squares. The enamel-rods doubtless exist, and are "wavy near 
 the dentine, and straight on the periphery and the main mass of 
 the enamel. They may be considered as columns of a calcified 
 substance, between which minute spaces are left, analogous to 
 the cement-substance of epithelial formations. 
 
 In longitudinal sections we see delicate beaded fibers, which 
 occupy the central portion of the interstices l)etween the enamel- 
 rods. These fibers I propose hereafter to term the " enamel- 
 fibers." (See Fig. 53.) 
 
 From such a fiber arise very minute conical fibrillar, which 
 traverse the tiny intervals between the fiber and the neighboring 
 outlines of the rods, and fade aw^ay where they enter the latter. 
 The columns of the basis-substance themselves are pierced by 
 delicate canaliculi, running in an almost vertical direction to the 
 enamel-rods, regularly enough to give the appearance of squares, 
 although these are much smaller than usually represented in the 
 books. In the midst of a minute square, light canals are seen, 
 not infrequently running parallel with the outlines of tlje 
 
 *"The Distribution of Living Matter in Human Dentine, Cement, and 
 Enamel.'' Dcninl Cosmos, 1878-1879.
 
 THE MIXl'TK STRrCTlRE OF EXAMEL. 91 
 
 €iiamel-rod. The square fields thus produced by the rectangular 
 crossing of liglit channels look, under the power of 1200 diame- 
 ters, iinely granular. In specimens not fully decalcified it is 
 impossible to decide whether there is a light net-work within 
 the enamel-prisms analogous to that in the basis-substance of 
 the dentine and cementum, or whether the granular appearance 
 is merely due to the deposition of lime-salts. In thoroughly de- 
 calcified specimens of enamel, however, such as were first made 
 by Dr. Frank Abbott, there is no difiiculty in seeing, with high 
 powers, the reticular structure of protoplasm. 
 
 Cross-sections of the enamel, which we obtain also in longi- 
 tudinal sections of the tooth, on account of the different direc- 
 tions of the bundles of the enamel-rods, plainly exhibit the 
 irregular polyhedral fields of the intersected enamel-rods. The 
 
 Fir;. 53. 
 
 
 
 ■a 
 2a 
 
 .-..^ 
 
 Longitudinal Section op Enamel. 
 ER, enamel -rods, traversed by prevailing vertical spaces; EF, enamel-fibers, branching and 
 partly uniting by delicate oifshoots. Magnified 1200 diameters. 
 
 light interstices between tlie polyhedral fields contain in many 
 instances delicate beaded fibers, surrounding the polyhedral 
 fields of the enamel-rods. The fibers, if cut transversely, have 
 the appearance of dots. They connect with one another directly 
 or by means of intervening delicate threads. 
 
 Extremely fine thorns traverse in a vertical direction the light 
 space between two neighboring enamel-rods, even where a fiber 
 is not visible (see Fig. 54). 
 
 The rods of the enamel are, on an average, half the diameter 
 of the columns of the basis-substance in dentine; therefore four 
 columns of the former will correspond to two of the latter, and 
 consequently two dentinal fibers will answer to four enamel- 
 filjers. Sometimes in the cross-section of an enamel-rod I have 
 met with roundish formations occupying the center of the rod, 
 one or two in number, which, owing to a denser granulation 
 and a surrounding shell, had the appearance of nuclei. The
 
 92 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 enamel-fibers run a very straiglit course toward the surface, 
 and are, on the average, a trifle thicker here than near the 
 boundar}^ of the' dentine. 
 
 The outermost surface of the enamel is covered by flat epi- 
 thelia (Nasmyth's membrane), which in the transverse section 
 have the appearance of shallow spindles ; not infrequently there 
 occurs also a stratified epithelium on the surface of the tooth. 
 The enamel-fibers are in connection with these epithelial bodies, 
 which, if detached, show delicate offshoots adhering in regular 
 intervals — the broken enamel-fibers. Sometimes the surface of 
 the enamel is coated by a thin uniform layer of protoplasm, 
 with regularly scattered nuclei. In such an instance single epi- 
 thelia are not traceable, though scarcely any doubt can arise 
 about the epithelial nature of this layer. 
 
 Fig. 54. 
 
 -eB 
 
 XF 
 
 Cross-Sectiox of Enamel. 
 
 ER, rods of enamel, partly exhibiting formations like nuclei ; the light interstices between 
 the rods traversed by delicate beaded fibers, EF, or by vertical thorns. Magnified 2000 diameters^ 
 
 At the place of junction of the enamel with the dentine a 
 direct connection is not infrequently seen between the enamel- 
 and dentine-fibers. The latter, through repeated bifurcations, 
 being closely brought together, continue their course into the 
 enamel-fibers without any interruption. The direction of the 
 fibers of the two tissues, however, is almost never identical, in- 
 asmuch as the enamel-rods, and consequently the enamel-fibers, 
 as a rule, owing to their wavy course in this situation, are ob- 
 liquely intercepted upon the dentine. 
 
 We can often trace dentinal fibers up into the enamel for a 
 varying distance, without finding a distinct union between the 
 enamel- and dentine-fibers, as the former do not reach the sur- 
 face of the dentine, but terminate above its level in different 
 heights, while the zone close above this is occupied by a delicate.
 
 THE .MIXITE STRUCTURE OF ENAMEL, 93 
 
 irregular net-work, analogous to that of the dentine. Here no 
 rods of enamel are visible either in longitudinal or transverse 
 sections, but with low powers of the microscope only a finely- 
 granular layer is presented. 
 
 In many places the dentinal canaliculi, upon entering the 
 enamel, suddenly become enlarged, and form more or less dis- 
 tinctly spindle-shaped cavities of greatly varying diameters, an- 
 alogous to the spindle-shaped enlargements on the boundary of 
 the cementum. (See Fig. 55.) These enlargements either run 
 
 Fio. 5-5. 
 
 ;?fflv - TS 
 
 t / 
 
 Uniox of Dentine with Enamel. 
 
 Z*, dentine; E, enamel ; DF, dentinal fibers, in union with large protoplasmic bodies, P, or 
 directly running into enamel-fibers, EF ; the latter often are lost in the delicate, irregular net- 
 work on the bottom of the enamel. Magnified 1200 diameters. 
 
 in the main direction of the dentinal canaliculi or deviate ob- 
 liquely. They invariably contain protoplasmic bodies which 
 plainly show the reticular structure, and sometimes contain one 
 or more compact clusters to be considered as nuclei. The 
 spindle-shaped protoplasmic bodies are in direct connection at 
 their proximate ends with the terminations of the dentinal fibers 
 that have arisen from their repeated bifurcations, while on the 
 distal end they may show delicate fibers, viz, enamel-fibers, or 
 delicate conical thorns, traversing the light space between the 
 surface of the protoplasmic body and the wall of the cavity. 
 These thorns are lost to sight on passing into the net-work at
 
 94 THE ANATOMY AND PATHOLOUY OF THE TEETH. 
 
 the bottom of the enamel. In some places, especially on the 
 cusps, the spindle-shaped enlargements of the dentine-fibers 
 are quite numerous, and of an almost uniform size and direc- 
 tion, forming regular rows of spindles within the enamel. In 
 the teeth of younger individuals, the spindle-shaped enlarge- 
 ments are comparatively larger and more regular than in the 
 teeth of old people. 
 
 The boundary-line between the dentine and enamel is either 
 straight or slightly w^avy, and with more or less deep bay-like 
 excavations, analogous to those on the boundary between dentine 
 and cementum. The concavities of the bays are directed toward 
 
 Fig. 56. 
 
 VI 
 
 ■D 
 
 - / J_J_ . / -^ ^ L.,:^ 
 
 Z>, dentine; E. enamel; /'.protoplasmic foiuiations at the boundary between both tissues ; 
 EF, union with enamel-fibers ; DF, with dentine-fibers. Magnified 1200 diameters. 
 
 the dentine. (See Fig. 56.) In this interzonal layer at the bottom 
 of the bays we meet with fibers occupying the curved spaces 
 between dentine and enamel, or we see in a correspondingly 
 bent course protoplasmic bodies directly connected with the 
 dentinal fibers downward, and with the enamel-fibers upward. 
 In specimens stained with chloride of gold, the dentine is always 
 much deeper in color than the enamel, hence the relations de- 
 scribed are plainly marked on such specimens. 
 
 Results. — 'The enamel is traversed by fibers of living matter 
 located in the interstices between the enamel-rods. The fibers 
 are connected with one another by delicate fibrillpe, piercing the 
 enamel-rods in a vertical direction. Besides these rectangular
 
 THE MINUTE STRUCTURE OF EXAMEL. 95 
 
 unions, the basis-snbstance is traversed by a minute net-work of 
 living matter. The enamel-fibers send conical thorns toward 
 the enamel-rods, and such thorns are visible in all interstices 
 between the enamel-rods. The enamel-fibers are continuous on 
 the outer surface with the covering layer of flat epithelia, and 
 on the inner surface with the dentinal fibers. The latter con- 
 nection is either direct or indirect through a net-work of living 
 matter, or through intervening protoplasmic bodies in the inter- 
 zonal layer. 
 
 Further researches in this field have been made by Frank 
 Abbott.* Of their results the following is an abstract : 
 
 "As to enamel, I have never seen the minute relations marked 
 so plainly in permanent as I find them in temporary teeth. 
 Here the enamel-rods are narrower, and the interstices between 
 them wider, than in permanent or adult teeth. A power of 500 
 diameters of the microscope is sufiicient to show plainly in the 
 temporary teeth relations rendered visible in permanent teeth, 
 only by very much higher powers. 
 
 " The cut, Fig. 57, is made from a drawing taken with a 
 power of 1200 diameters (immersion). In the enamel the 
 enamel-rods, the fillers in the interstices between the rods, the 
 lateral otfshoots of the fibers, and the light reticulum within 
 the rods are represented. As a striking feature, I wish to em- 
 phasize the direct connection of the fibers of the dentine with 
 those of the enamel. Thus the width of an enamel-rod is in 
 full correspondence with the width of the fields of basis- 
 substance of the dentine, after the bifurcation of the dentinal 
 fibers, near the boundary between dentine and enamel. In 
 preparing this specimen, it happened that on several portions of 
 the crown a larger portion of the enamel was ground away than 
 was intended ; so much so that only shreds of enamel in con- 
 nection with the dentine were left. On one of these places 
 delicate beaded fibers (F) were seen, isolated at their upper 
 ends, while their lower ends could be traced into interstices 
 between the enamel-rods, and into connection with the ends of 
 the dentinal fibers. N'o doubt here the mechanical injury done 
 to the enamel has luckily led to a tearing out of a few enamel- 
 fibers, which accident plainly illustrates their presence." 
 
 * "The Minute Anatomy of Di.'ntine and Enamel." Denial Ojsmos, 1880.
 
 96 THE ANATOMY AND PATHOLO<iY OF THE TEETH. 
 
 The same author, in an article, " A Contribution to the Study 
 of the Minute Anatomy of Enamel,"* says, — 
 
 " Dr. George AV. Weld, in a paper entitled ' The Destructive 
 Energy of the Tincture of the Chloride of Iron on the Teeth : 
 an Experimental Study,' read before the New York Odontologi- 
 cal Society, June 8, 1886, and published in the Dental Cosmos 
 for October, 1886, page 627, draws attention to a novel method 
 of treating enamel for the purpose of decalcification. 
 
 Fig. 57. 
 
 ^. 
 
 \\K 
 
 
 ^ \ m. 
 
 
 
 f 
 
 ■' j: ' h. 
 
 
 
 (^'' 
 
 
 \) :i 
 
 
 v,\ 
 
 t 
 
 r 
 
 
 ^^ 1 
 
 
 4 
 
 \ ] ) vA^^/x : \ \ Vlll 
 
 D, £>, dentine, with bifurcating fibrilhu toward the enamel ; E, E, enamel with beaded fibrillse 
 between the rods; /".free fibrillffiof enamel, the rods being torn away. Magnified 120 3 diameters. 
 
 " Dr. Weld minuteh' describes how a specimen (thin slab) of 
 enamel previously treated with a six per cent, solution of acetic 
 acid, while watched under the microscope, in consequence of 
 a jarring of the instrument, became broken in pieces, and the 
 enamel-rods isolated, so as to resemble a ' bunch of sticks.' He 
 asserts that ' this method will perhaps ultimately be the means 
 
 * Dental Cosmos, 1887.
 
 TJIE MINUTE STRUCTURE OF ENAMEL. 97 
 
 of throwing some light on the matter of the distribution of 
 lime-sahs and living matter in the enamel,' but he does not, so 
 far as is known, follow up the study. 
 
 " The method, as I have used it, is as follows : A freshly- 
 extracted tooth, or one placed, immediately after its extraction, 
 in dilute alcohol for a time, is ground, under water, as thin as 
 practicable; then placed in a six per cent, solution of acetic 
 acid, and left there for at least twelve hours even if the speci- 
 men be very thin, and for eighteen hours if slightly thicker ; 
 the acid is then poured off and the specimen repeatedly washed 
 with distilled water, and then placed in a concentrated ammo- 
 niacal solution of carmin for twelve hours. After its removal 
 from the carmin solution it is again washed with distilled water,, 
 and the enamel detached from the dentine with two needles.- 
 This process is easily accomplished, but a slight frill of the 
 organic substance of the enamel is usually left attached to the 
 dentine, and we obtain the enamel itself in small pieces. I have 
 used two other reagents, — viz, a one-half per cent, solution of 
 chloride of gold, and a one per cent, solution of hyperosmic 
 acid. The specimens are subjected to the action of the former 
 from twelve to twenty hours, and to the latter from one to three 
 hours; after which they are carefully washed with distilled 
 water; then treated with the acetic-acid solution as before 
 stated. They are again washed; then mounted in glycerin, 
 care being taken that they are not broken during this part of 
 the process, their weakened condition from the action of the 
 acetic acid having rendered them very brittle. Such a speci- 
 men, when viewed with a power of from 400 to 500 diameters, 
 presents the following features: The enamel-rods are plainly 
 recognizable (running their usual way, slightly wavy near the 
 dentine, and straight toward the periphery), owing to the fact 
 that the interstices between them are widened. Another feature 
 presents itself which is quite striking, — viz, that the cross-bars 
 within the enamel-rods also are widened, and plainly marked. 
 
 "We often meet with specimens of enamel where, toward the 
 dentine, the rods are entirely lacking, or very indistinct, and 
 much narrower than those a little distance from the dentine. 
 Should the bundles of rods assume a fan-shaped appearance, as 
 is sometimes seen in the neighborhood of the dentine, the inter- 
 stices between such bundles may be found filled with a granular 
 material, or with oblique or transverse sections of rods, occup}'-
 
 98 THE ANATOMY AND PATHOLOGY OF THE TEETH, 
 
 ing comparatively a small field. This latter appearance has 
 undoubtedly led previous observers to conclude, and to make 
 the statement, that the enamel is composed of interlacing 
 bundles of rods. In a longitudinal section of enamel we find 
 comparatively few transversely-cut bundles of rods, whereas 
 obli<|uely-cut bundles are met with quite frequently. This fact 
 leads to the conclusion that the appearance of interlacing is 
 simply due to the presence of bundles of rods running in a 
 more than usually wavy course, but never transversely to the 
 general direction of the rods, 
 
 " The manner in which the acetic acid acts to produce the 
 widening of the interstices, in my judgment, is as follows : In the 
 process of grinding, the edges or borders of the rods are more 
 or less exposed in every specimen, and probably the organic 
 basis-substance is more or less disturbed. The edges being thus 
 exposed to the action of the acid, the same as the ground sur- 
 faces of the rods, are dissolved away, and the interstices become 
 widened, while the fiat surfaces of the rods themselves are not 
 perceptibly affected. This serves to explain also the widening 
 and bringing so distinctly to view the ' cross-bars' in the rods, 
 which also contain a minute amount of organic matter. Thin 
 specimens of enamel treated with the same solution of acetic 
 acid, if viewed with a power of from 500 to 600 dia- 
 meters, clearly establish the above facts, since we can invari- 
 ably trace all degrees of dissolution of lime-salts, from a slight 
 Avidening of the interstices to the coarse granulation of the rods, 
 then to the fine granulation, with the preservation of their 
 general appearance, and finally down to their complete disap- 
 pearance, nothing being left but the organic portion. The 
 appearance in the field of the microscope is now very striking, 
 it being finely granular, pale, and traversed by innumerable 
 parallel filaments. Even moderately thick specimens may be- 
 utilized for bringing to view completely decalcified fields, by 
 exerting a gentle pressure upon the covering-glass, I would 
 not, however, recommend broken enamel-rods for microscopical 
 research, as in my judgment such specimens are entirely worth- 
 less, I prefer to confine my studies to shreds in which either 
 the traces of the previous rods are recognizable, or the fibers 
 run a parallel and unbroken course. The foregoing description 
 holds good for the majority of specimens of enamel. There are 
 exceptions, however, Occasionall}' we find specimens with
 
 THE MINUTE STRUCTURE OF EXAMEL. 
 
 99 
 
 Fig. 58. 
 
 Fig. 59. 
 
 
 y 
 
 \ 
 
 1 
 
 \ V 
 
 Begixxixg Decalcification of Enamel, 
 BY A Six Per Cf.xt. Solutiox of Acetic 
 Acid. 
 
 The interstices between the enamel-rotls and 
 the cross-bars of the rods widened. The rods 
 exhibit slight organic structure, in consequence 
 of the abundant presence of lime. Magnified 
 500 diameters. 
 
 Fig. 60. 
 
 
 Examel Completei.y Decalcified, through 
 THE Agency of a Six Per Cent. Solution 
 OF Acetic Acid, Slightly Stained with 
 Chloride of Gold. 
 
 The upper portion of the figure shows slightly 
 oblique, and the lower very oblique, sections of 
 the enamel-rods. The boundary lines of the 
 prisms are made up of highly glistening elastic 
 ledges, at the sides of which there are visible 
 oblique sections of enamol-fibers in connection 
 with a delicate grayish reticulum pervading 
 the rods. This reticulum is especially dense in 
 the central portion of the rods, as shown in 
 the lower half of the figure. Magnified 1200 
 diameters. 
 
 Advanced but not Complete Decalcifica- 
 tion of Enamel, through the agency 
 of a Six Per Cent. Solution of Acetic 
 Acid. 
 
 The interstices very marked, but not mate- 
 rially widened ; their tenants, the enamel- 
 fibers, plainly visible. The cross-bars do not 
 appear in the shape of interstices, but in deli- 
 cate transverse lines. The organic structure 
 begins to appear, owing to partial removal 
 of the lime-salts by solution. Magnified 500 
 diameters. 
 
 Fig. 61. 
 
 Completely- Decalcified Enamel Deeply 
 Stained with Chloride of Gold. 
 The enamel -fibers appear in the shape of 
 dark-violet, beaded threads, in connection with 
 a grayish-blue reticulum within the enamel- 
 rods. The transverse threads corresponding 
 to the cross-bars are but slightly marked. 
 In the lower portion of the figure the reticulum 
 is partly torn away, leaving the enamel-fibers 
 protruding and rendered plainly visible. Mag- 
 nified 1200 diameters.
 
 100 THE AXATOMY AND PATHOLOGY OF THE TEETH. 
 
 unusually narrow prisms, or perhaps lacking them altogether, 
 in comparatively large districts. "Whetherthis feature is due to 
 advanced age, malformation, or some pathological condition, I 
 am unable to say. The higher powers of the microscope (1200 
 to 1500 diameters) give a highly gratifying image of the structure 
 of enamel. Partially decalcified rods appear to be composed of 
 irregular lumps, of high refraction, invariably arranged in the 
 shape of irregular squares, which serve to complete the "rods ; 
 the irregular interstices separating the glossy lumps are traversed 
 by delicate grayish threads. The interstices causing the appear- 
 ance of cross-bars through the rods are traversed by minute 
 grayish, beaded filaments, sending ofi'shoots into the fields of 
 the rods between them. The longitudinal interstices between 
 the enamel-rods, in many places, show long, beaded filaments, 
 on either side of which we observe a light space. This space 
 again is traversed by conical threads arising from the enamel- 
 fibers, and penetrating the interior of the rods themselves. 
 
 " In thoroughly decalcified enamel, I have often met with a pe- 
 culiar appearance. "Whether carmin, chloride of gold, or osmie 
 acid had been used for staining the specimen is immaterial, 
 — the rods appear to l)e surrounded l:»y a glossy, smooth, or 
 beaded border, between which can be seen the light interstices. 
 Sometimes there is one such ledge for two neighboring rods, 
 without any intervening interstice. In oblique sections the 
 ledges are best marked on the distal portions of the rods, over- 
 lapping their neighbors in a shingle-like manner; while in 
 transverse sections the glossy border may be seen all around the 
 rods. It is evident that these ledges cannot be mistaken for the 
 enamel-fil)ers proper; nor can we conclude that the ledge is an 
 optical phenomenon, caused, as it were, by the thickness of the 
 rods, since the ledge is often found slightly protruding beyond 
 the border of the specimen. The only explanation I can sug- 
 gest for this is that the borders of the rods are made of a denser 
 kind of Inisis-substance, kindred to the elastic substance, and 
 similar to that which we observe in the basis-substance of the 
 dentine surrounding the canaliculi. In the center of the rod 
 we not infrequently see a somewhat more compact accumulation 
 of a pale gray substance than in the rest of the rod. 
 
 " Completely decalcified portions of the enamel exhibit a most 
 beautiful reticulum, especially in specimens treated with chloride 
 of gold, and not the least doul)t can arise as to the fact that the
 
 TIIK MINUTE STIUCTURE OF CEMEXTUM. 101 
 
 enamel-fibers, l)eiug the most conspicuous formations, are in an 
 uninterrupted continuity with the reticulum of liv'ing matter 
 pervading the whole enamel." 
 
 CHAPTER XIT. 
 
 THE MINUTE STRUCTURE OF CEMENTUM.* 
 
 The zone of dentine is not continuous everywhere about the 
 pulp-cavity. Around the apices of the roots the cementum, 
 although tlie outermost la3'er of the tooth, immediately lines the 
 cavit}'. 
 
 In the cementum delicate parallel striations are to be seen, 
 identical witli the lamellfe of a Haversian system, and, as a rule, 
 more plainly marked near the periphery than near tlie dentine. 
 The lamellae exhibit a more or less concentrical arrangement 
 around the pulp-cavity, easily demonstrable on cross-sections. 
 
 Within the basis-substance of the cementum there are numer- 
 ous branching spaces, in correspondence with the lacunae of 
 bone. The offshoots of these spaces in the cementum, like the 
 spaces themselves, are very marked in dry specimens, because 
 of their being filled with air. In chromic-acid specimens, on 
 the contrary', the offshoots are much less prominent, and the less 
 so the more thoroughly the decalcification has been eftected by 
 the acid. Xo essential difi^erence is noticeable in the lacun?e 
 and canaliculi of ordinary bone from those of the cementum; in 
 both tissues there exists great variety in the general arrangement, 
 in the size of the lacunse, and in the number and ramifications 
 of their oft'shoots. 
 
 The walls of the lacuna; and the coarser ott'shoots, if viewed 
 witli a highly magnif\-ing lens (immersion 1000 to 1500 diam.), 
 appear interrupted at their peripheries by light openings, which 
 lead into a light, delicate net-work, piercing the whole basis- 
 substance to such an extent that the meshes have to be con- 
 sidered only as fields of calcified glue-yielding basis-substance. 
 
 Each lacuna contains a protoplasmic body, with a central 
 nucleus, — the cement-corpuscle. The nucleus sometimes is 
 
 * " The Disti-ibutii)ii of Living Matter in Human Dentine, Cement, and Enamel." 
 Dental Cosmos, 1878-1879.
 
 102 THE AXATOMY AXD PATHOLOGY OF THE TEETH. 
 
 relatively large, and surrounded only by a narrow seam of jiroto- 
 plasm ; while in some small lacunie a body of the appearance 
 of a nucleus is present without a noticeable amount of surround- 
 ing protoplasm. The net-like structure of both the nuclei and 
 the protoplasm is plainly visible in all cement-corpuscles. From 
 the periphery of each corpuscle arise conical offshoots, of which 
 the coarser ones penetrate into the larger offshoots of the 
 lacuna, while the finest offshoots of the protoplasm traverse the 
 light rim between the wall of the lacuna and the periphery of 
 the protoplasm, being directed toward a light interruption on 
 the boundary of the lacuna. 
 
 Cement-corpuscles, on the average, are round or spindle- 
 shaped bodies, the long diameter of which corresponds to the 
 direction of the lamellae. In the teeth of juvenile and middle- 
 aged persons we meet with cement-corpuscles three or four times 
 surpassing the size of ordinary- ones, in which two or three 
 nuclei are visible. Instead of multinuclear bodies, a number of 
 medullarv nucleated elements mav fill a laro-e lacuna, all these 
 elements being connected with one another by very delicate 
 threads. The longitudinal diameter of such large lacunte is 
 sometimes, therefore, an axis from which those elements radiate 
 vertically to the direction of the lamelhe. 
 
 Xumerous cement-corpuscles send broad and branching off- 
 shoots through the basis-substance in a direction perpendicular 
 or oblique to the lamellae, and not infrequently a direct union is 
 established between two or three cement-corpuscles by means 
 of such large oftshoots. (Fig. 42, page 73.) 
 
 In some teeth broad, spindle-shaped spaces pierce the ce- 
 mentum radiately, all of them containing protoplasm with deli- 
 cate offshoots directed toward the net-work in the basis-substance. 
 Xay, sometimes medullary spaces traverse the lamellae in differ- 
 ent directions, which spaces contain, besides a varying number 
 of medullary elements, capillary blood-vessels evidently in con- 
 nection with the capillaries of the pericementum. These forma- 
 tions may be considered as remnants of the embryonic condition 
 of the cementum, and are never present in large numbers. All 
 protoplasmic formations within the cementum, though greatly 
 varying in shape, are alike in being connected with one another 
 by the delicate net-work that pierces the basis-substance. 
 
 At the periphery of the cementum, on the line of its connec- 
 tion with the pericementum, the net-work of the protoplasm is
 
 THE MINUTE STRUCTURE OF CE.MENTUM, 
 
 103 
 
 usually very broad, and the fields of the basis-substance show 
 a preyailing globular ap})earance. Also numerous spindle- 
 shaped protoplasmic bodies are seen in connection with the 
 cementum in an oblique arrangement, forming the transition 
 into the structure of the pericementum. Between the calcified 
 cementum and the striated connective tissue of the pericementum 
 there often exists a narrow zone, occupied by closely -packed 
 spindle-shaped protoplasmic bodies only. In the pericementum 
 itself there are less numerous, partly nucleated protoplasmic 
 
 Fru. 62. 
 
 ..-'1 
 1, 
 
 ^ 
 
 
 
 ^' / 
 
 ,1J 
 
 
 Traxsitiox oi' Dkntine into Cemkntcm, ■n'lTHitur a Marked Bduxdary. 
 
 C, branching ceniont-corpusclo ; P, spindlo-shaped cement-corpuscle ; both in direct connof- 
 tion with dentinal fibers, !•', which bifurcate within the eanalieuli of the dentine, 1). Magni- 
 fied 1200 diameters. 
 
 bodies, between which the fields of an apparently homogeneous 
 glue-yielding sul)stance are seen. (See Fig. 62.) 
 
 The connection between dentine and.cementum is established 
 either by a gradual change of one tissue into the other, without 
 a distinct line of demarcation, or there exists a boundary 
 formed by a more or less marked wavy line, presenting irregu- 
 lar bay-like excavations. Lastly, it occurs that between the 
 bay-like excavations and the dentine there is interposed a
 
 104 THE AXATOMY AND PATHOLOGY OF THE TEETH. 
 
 stratum of the structure of cementum, with a gradual change 
 of the tissue of the former into that of the latter. (See Fig. 63.) 
 Where a gradual change takes place, the dentinal canaliculi 
 show irregular, mainly spindle-shaped enlargements, which stand 
 in the direction of the dentinal canaliculi themselves, or run 
 obliquely through the basis-substance of the cementum. The 
 distal end of such a spindle is, as a rule, in connection with a 
 
 Fig. G3. 
 
 J, ^/i / ;■ id \ '^ '^"^ 
 
 ^ ■ ' \ t Vf.' + A 
 
 
 ^ 
 
 ■c? 
 
 Transition of Dkxtink into Cement, ayith an Intehmediatk Laykk of Cement-stri:c- 
 
 TUEE. 
 
 D, dentine: F, bifurcating dentine-fibers, in union with elongated cement-corpuscles, C^ ; 
 these are imbedded in a basis-substance blending with that of dentine. The regular cementum 
 is characterized by branching corpuscles, U-. Magnified 1200 diameters. 
 
 regular lacuna of the cementum, or Avith an analogous forma- 
 tion of a neighboring dentinal canaliculus. Manv of the latter 
 simply pass into the light, delicate net-work characteristic of the 
 basis-substance of cementum. The dentinal fiber is in direct 
 union with the protoplasm, which fills the spindle-shaped spaces, 
 or it is lost to sight upon entering the net-work of the basis- 
 substance of the cementum.
 
 THE MINUTE STRUCTURE OF CEMEXTUM. 105 
 
 "Where a bouuclaiT with l)ay-like excavations is present be- 
 tween dentine and cementum, spindle-shaped enUirgements of 
 the dentinal canaliculi may be seen, much smaller than in the 
 former instance. The majority of the dentinal canaliculi, 
 however, reach the boundary of the cementum after repeated 
 bifurcations, by which the caliber both of the canaliculi and 
 of their central fibers is gradually diminished. 
 
 A connection of the dentinal fibers with the coarser oti:shoots 
 of the cement-corpuscles is often observed. The light net-work 
 of the basis-substance of the dentine always passes into that of 
 the cementum. Xot rarely, also, on the bottom of a bay-like 
 excavation, partly nucleated protoplasmic bodies are present, 
 into which the dentinal fibers inosculate. The connection 
 between these and the coarser ofl:shoots of the cement-cor- 
 puscles under these circumstances is established by such inter- 
 vening protoplasmic bodies. 
 
 The Neck of the Tooth. — There are certain peculiarities about 
 the minute anatomy of the neck of the human tooth which, so 
 far as I can judge from the literature within my reach, have not 
 heretofore been mentioned. 
 
 John Tomes''' in describing the distribution of the dentinal 
 tul>es, says, "Near the neck they stop short of the cementum." 
 
 This assertion is in accord with the writer's observations. 
 In the great majority of teeth neither the canaliculi nor their 
 tenants, the dentinal fibers, reach that part of the cementum 
 w^hich surrounds the neck. Xear the periphery of the dentine 
 bifurcations of the canaliculi — and consequently also of their 
 tenants, the dentinal fibers — take place, some of the finest ter- 
 minations of which run to the boundary between the dentine 
 and cementum. As a rule the finest terminations of these 
 fibers are lost to sight in a net-work somewhat coarser than that 
 of the basis-substance of ordinary dentine. The minute elonga- 
 tions of the dentinal fibers can also l)e traced into the light net- 
 work with more distinctness than elsewhere in the dentine. 
 Sometimes the dentinal canaliculi, upon approaching the periph- 
 ery, become slightly dilated so as to produce slender pear-shaped 
 cavities, in accordance w'ith which the terminating dentinal 
 fibers exhibit slight enlargements. 
 
 The boundary between dentine and cementum presents a 
 w^avy line, traversed by delicate threads, or occupied by spindle- 
 
 * '• System of Dental Surgery,"' 1873.
 
 106 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 shaped protoplasmic formations, all of -which are in union with 
 direct or indirect elongations of the dentinal fibers. 
 
 The cementum around the neck forms a narrow layer, "which 
 is cut off obliquely at the place of junction with the enamel. 
 Both the cementum and enamel in this situation — being of the 
 same width — are separated by a boundary which runs from the 
 outer periphery obliquely downward to the dentine. This rela- 
 tion I found in the majority of teeth, and it is only exception- 
 ally that I have met with cementum regularly overlapping the 
 enamel. The cementum on the neck is built up of delicate 
 prisms, or spindles, arranged vertically to the surface of the 
 dentine. The prisms represent the fields of the basis-substance, 
 and are separated from one another by light rims, holding beaded 
 fibers, or traversed by delicate vertical threads. In transverse 
 sections, when the prisms are cut obliquely, they exhibit irregu- 
 lar opaque fields separated from one another by light rims. 
 
 These formations closely resemble the protoplasmic bodies 
 of the pericementum next to the cementum, alluded to in the 
 former chapter; hence I do not hesitate to consider the bon}^ 
 formation on the neck as being produced by calcification of the 
 osteoblasts of the pericementum. The cementum on the neck 
 of the tooth is devoid of lamellae and lacunae, which appear 
 deeper below, together with all the characteristic features of the 
 fully-developed structure of the cementum. The lamellae 
 become the more distinct, and the lacun{\?, with their contents 
 (the cement-corpuscles), the more numerous, the broader the 
 diameter of tlie layer of the cementum. 
 
 The outer surface of the cementum is covered on its upper 
 part with epithelial elements closely resembling those of Xas- 
 myth's layer of the enamel. This layer turns over into the 
 epithelial coat of the gum. Farther down, the cementum, 
 though still endowed with properties characteristic of the neck 
 of the tooth, is surrounded by the fibrous connective tissue of 
 the pericementum. 
 
 I have met in one instance with striking formations on the 
 neck of a tooth, Avhich I consider anomalous, but not quite 
 pathological. Here the ordinary cement of the neck is inter- 
 rupted by grooves or pits containing the elements of perice- 
 mental tissue. The inner periphery of the pit is covered with 
 a well-developed, evidently isolated formation of cementum. 
 The island of the cementum is broadest above the bottom of the
 
 Till-; .MINUTE STltLCTUKE OK CE.Mi; NUM. 107 
 
 pit, and slopes down along the walls of the pit, until it is lost 
 within the layer of the cementum of the neck. (See Fig. 64.) 
 
 Results. — The cementum, as well as ordinary bone, is provided 
 with lacunae and canaliculi. The lacunos contain nucleated proto- 
 plasmic bodies, and the canaliculi hold oft'shoots of the living 
 matter of the protoplasm. The whole basis-substance of the 
 cementum is traversed by a delicate net-work, which in all pro- 
 bability contains living matter, though this is traceable only in 
 
 £^-. 
 
 I- 
 
 [■■■•.. 
 1^ 
 
 B: 
 
 Fig. 64. 
 
 -v-V- 
 
 ^^T"^ 
 
 
 
 z> 
 
 
 I 
 
 r 
 
 ft 
 
 ■DP 
 
 AxoMALous Formation of Cementum on the Neck of a Human Tooth. 
 
 D, dentine ; DF, dentinal fibrilliB ; iV, cementum on neck of tooth, with spindle-shaped 
 or prismatic fields of basis-substance : DP, depression in the cementum of the neck, filled with 
 elements of pericementum surrounded superiorly by a zone of regularly developed cementum, C; 
 P, pericementum. Magnified 1200 diameters. 
 
 its thorn-like projections from the periphery of the protoplasm 
 and its larger offshoots. The living matter of the cementum 
 is uninterruptedly connected Avith that of the periosteum, and 
 continuous Avith the living matter of the dentine, either through 
 intervening protoplasmic bodies in the interzonal layer, or 
 directly Avith the dentinal fibers. 
 
 The cementum covering the neck of the tooth is dcA^oid of 
 lamcUcV and protoplasmic bodies. It is built up of directly calci- 
 fied osteoblasts of the pericementum, presenting their prismatic 
 shapes, and everyAA'here traversed by a net-Avork of living matter.
 
 108 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 This is in conuectioa either with the epithelium of ISTasmyth's 
 layer or the pericementum, and with the dentine mainly through 
 the intervening net-work in the hasis-substance of the latter. 
 
 Investigations concerning the structure of the cementum have 
 been pul)lished by Carl Heitzmann and F. A. Roy,* of which I 
 offer the following : 
 
 " Method. — A recommendable method for the study of the 
 microscopical structure of the cementum is to grind a tooth as 
 thin as possible, always keeping it moist with a one per cent, 
 solution of table-salt. First, with a fine saw or with a corundum - 
 stone in the lathe, a coarse slab is made of the freshly-extracted 
 tooth, which afterward is ground thin on a corundum-slab, and 
 finished on an Arkansas stone. The specimen is not allowed to 
 become dry for a moment. After brushing away the debris from 
 grinding, the specimen is directly mounted in chemically -pure 
 glycerin, or staining with ammoniacal carmin may be resorted 
 to, though such a stain is of comparatively little value in the study 
 of cementum. Some of our illustrations are made from specimens 
 prepared in the manner just described. They are especially 
 plain when examined immediately after mounting, but rarely fit 
 for higher powers of the microscope, — powers .exceeding from 
 500 to 600 diameters. After several weeks, when the glycerin 
 has thoroughly saturated the specimen, the minute features are, 
 as a rule, less conspicuous than in the freshly-mounted specimen. 
 
 " The method first employed ])y William Carr, in 1889, for 
 bringing to view the minutest structure of the dentine, is a pro- 
 tracted stain with a one-half of one per cent, solution of chloride 
 of gold, of plates ground thin with the finger on grinding-stones 
 and corundum-slabs, and a subsequent complete decalcification 
 by means of a six per cent, solution of glacial acetic acid. This 
 method has also enabled John I. Hart to obtain perfect speci- 
 mens of dentine. The same procedure we have adopted for 
 clearing up the minutest features in the structure of the ce- 
 mentum. Freshly-extracted teeth are placed in a one per cent, 
 solution of talde-salt and ground thin, as before stated. It is 
 important to leave the extracted teeth a short time only in the 
 salt solution, — a few hours at the utmost, — since the protoplas- 
 mic formations of the cementum become hydropic and unstain- 
 able with chloride of gold if left in the solution for days. This 
 
 * Transactions of the New York Odontolo^ical Society. 1892.
 
 THE MINUTE STRUCTURE OF CEMENTUM. 109 
 
 tissue, being directly exposed to the salt solution, is att'ected by 
 it sooner than the dentine. Special care must betaken in keep- 
 ing the slabs moist with a weak solution of table-salt, lest the 
 specimen become dry, and the lacuna; and the coarser canalicnli 
 filled Avith air, by which the details are rendered indistinct, or 
 obliterated completely. After the slab — immaterial whether a 
 longitudinal or a transverse section — has attained a sufficient 
 degree of thinness, as proven by mounting on a slide and cover- 
 ing with the thinnest possible covering-glass, it must be washed 
 carefully and repeatedly with a cameFs-hair brush, under con- 
 tinuous renewal of the salt solution. Next the slab is placed in 
 a one-half of one per cent, solution of chloride of gold, in which 
 process all metallic instruments must be avoided, the simplest 
 spatula being a match shaped with a penknife. If several sec- 
 tions should be ready for treatment with chloride of gold, it is 
 necessarv to see that each one be in free contact with the gold 
 solution. Specimens overlapping one another prevent a perfect 
 stain, because they will not allow the desired contact and pene- 
 tration with the gold solution." 
 
 " The time required for exposure to the gold-salt is somewhat 
 different with different teeth, probably because of the variable 
 amount of lime-salts infiltrating the cementum. The best re- 
 sults we have obtained were on temporary teeth left in the gold 
 solution from six to seven hours, — certainly a shorter time than 
 is required for staining the dentine. The following exposure 
 for ten hours to a six per cent, solution of glacial acetic acid is, 
 as a rule, sufficient for complete decalcification of the cementum, 
 and now the specimen may be exposed to broad daylight for a 
 number of days, until it has assumed a dark-violet or dark- 
 purple color. The only precaution required at this stage of the 
 procedure is to renew every day the distilled water in which 
 the specimen lies, in order to prevent the growth of mildew. 
 A drop of chemically-pure glycerin added to the distilled water 
 is a sure means of keeping away the mildew. The mounting of 
 such specimens is invariably done in glycerin, — the only medium 
 which allows the examination with the highest powers of the 
 microscope. 
 
 " AVe admit that the results obtained in the described manner 
 of treating cementum were not unifornily satisfactory, in contra- 
 distinction to those in the preparation of dentine, in which failures 
 are exceptional. We cannot account for the fact that s]iei'imens
 
 110 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 of different teeth which we knew to be alive and perfectly fresh, 
 yielded good images only occasionally. Cohnheim, the dis- 
 coverer of the gold-stain, met with the same accidents. Some- 
 times the basis-substance assumes a deeper color than the con- 
 tents of the lacuna? ; the latter may remain so pale even as to 
 imitate features of devitalized teeth. Specimens well stained, 
 however, exhibited all features so handsomely that we thought 
 best to describe this method, leaving the invention of new pro- 
 cedures to other observers. It is especially the acetic acid which 
 we suspect of yielding unsatisfactory results, and other acids — 
 perhaps diluted sulphuric acid — may have to be resorted to in 
 future trials. Owing to the unequal efficiency of the method 
 employed, we will abstain from statements which are of the 
 utmost importance to the practitioner, — viz, the definition of the 
 living from the non-living part of the cementum in pulpless 
 teeth. The results of our examination seem to be sufficiently 
 interesting, however, so far as they go, to deserve presentation. 
 
 " Cement of the Roots. — We have examined quite a number 
 of roots of teeth, both deciduous and permanent, in specimens 
 ground thin under the protection of an indifferent liquid, — a one 
 per cent, solution of table-salt. Our intention has been to study 
 the features of the cement-tissue in freshly-ground specimens, 
 before they were exposed to the influence of a solution of 
 chloride of gold. What we saw in many instances has not up 
 to this time been described. (See Fig. 65.) 
 
 " 'With low powers of the microscope, we find on the surface 
 of the cementum shallow pits that render the border-line, in a 
 longitudinal section, hilly or wavy. This corresponds to th6 
 rough, slightly-pitted aspect of the surface of the roots, viewed 
 with the naked eye. The lamellated portion of the cement 
 tapers toward the neck of the tooth, and becomes the broader 
 as it approaches the apices of the roots. In this portion of the 
 cement-tissue the parallel lamellae are conspicuous, and we notice 
 scattered in the basis-substance a number of cement-corpuscles 
 which differ from ordinary bone-corpuscles only in being more 
 irregular, often elongated, apparently arranged without regu- 
 larity, certainly without parallelism to the lamella?. Besides the 
 cement-corpuscles, we notice a number of lines running from 
 the surface to the dentine, and piercing the lamelhe at right or 
 acute angles, often in union with the cement-corpuscles. The 
 course taken by these lines, which in their parallelism bear
 
 THE .MIXUTE STRUCTURE OF (EMEXTU.M. 
 
 Ill 
 
 somewhat the aspect of dentinal fibers, is always devious from 
 the latter, with which they produce obtuse angles. "We have 
 failed to find an immediate union of dentinal fibers with the 
 fibers piercing the cementum. The lamellated portion is fol- 
 lowed by a layer, indistinctly lamellated or striated, likewise con- 
 taining cement-corpuscles, and likewise traversed by radiating 
 lines. This layer, either indistinctly lamellated or entirely 
 destitute of lamellie, we propose to term ' the osteoid layer of 
 the cementum.' At the boundary of the osteoid layer, toward 
 
 Fig. 65. 
 
 Rout ov a Gijiicnd Bicuspid, showing a Combination' of Lamki.t.ated and Osteoid 
 
 Cemkntum, 
 P, pericementum; T. thickness of the specimen; L, lamellated cementum; 0. osteoid ce- 
 mentum; Z, interzonal layer between cementum and dentine: f>, dentine. Magnified 20() 
 diameters. 
 
 the dentine, a layer of numerous small protoplasmic bodies is 
 seen in our specimen, similar to those of an ill-calcified enamel, 
 and probably due to a deficient calcification of the cementum. 
 This layer is rather exceptional. The dentinal canaliculi either 
 stop short of the interzonal osteoid layer, or a limited number 
 of canaliculi is seen to directly run into the interzonal layer, 
 where they inosculate with the coarse proto}tlasmic reticulum. 
 " The aspect of the cement-corpuscles in the distinctly lamel-
 
 112 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 lated portion is rather peculiar in ground specimens, mounted 
 in glycerin, when viewed with medium powers of the micro- 
 scope, 500 to 600 diameters. The lacunse appear filled with 
 protoplasmic bodies, in the center of which we notice oblong 
 nuclei. From the periphery of the bodies numerous offshoots 
 break forth, which either directly connect neighboring cement- 
 corpuscles, or are lost in the basis-substance. Innumerable fine 
 offshoots are seen to emanate from the coarse ones, and by 
 
 Fig. 66. 
 
 Lamellated Cementum of the Root of a Ground Bicuspid. 
 
 C, C, cement-corpuscles branching and interconnecting : E, incomplete reticulum, produced 
 by the finest offshoots of the cement-corpuscles ;r-i,'i', boundary-lines of the lamellae. Mag- 
 nified 600 diameters. 
 
 these finest off'shoots an indistinct net-work is established, par- 
 ticularly plain in the vicinity of the cement-corpuscles. The 
 basis-substance appears coarsely granular, but no reticulum 
 proper can be made out with this amplification. The basis- 
 substance is pierced by peculiar fibers Avhich intersect the 
 lamellae at right or acute angles, often are bifurcate, and in 
 many instances are independent of the cement-corpuscles or 
 their offshoots, while in other instances they distinctly inoscu- 
 late with the two last-named formations. (See Fig. 66.)
 
 THE MINUTE STRUCTURE OF CEMENTUM. 113 
 
 " The question arises, AVliat are these fibers in the cementum ? 
 The first idea suggesting itself is that we have to deal with per- 
 forating fibers, first described by Sharpe}' in specimens of dry 
 bone-tissue. Charles S. Tomes* says, 'Like bone, cementum 
 is also sometimes found to contain Sharpey's fibers; tliat is to 
 say, rods running through it at right angles to its own lamina- 
 tion, and, as it were, perforating it. These are probably calcified 
 bundles of connective tissue.' 
 
 " Sharpey's fibers are never seen in specimens decalcified by 
 solutions of chromic acid. Histologists assert that they are 
 elastic fibers, not perishable after treatment of the specimen 
 with caustic potash. The fibers in the cementum, on the con- 
 trary, are canaliculi in the basis-substance, holding protoplasm, 
 or rather living matter, which feature renders them akin to 
 dentinal fibers. We propose the name of ' piercing cement- 
 fibrilla^' for their designation. 
 
 " The ultimate analysis of the tissue of cementum is possible 
 only after exposure to a solution of chloride of gold and subse- 
 quent decalcification with acetic acid. (See Fig. 67.) 
 
 " We see the cement-corpuscles, the nuclei of which often 
 appear a trifle lighter than the rest of the protoplasm. The 
 reticular structure of the latter is })lain in many corpuscles. 
 Numerous coarse and innumerable fine oft'shoots break forth 
 from the periphery of the cement-corpuscles. Close around 
 the latter and their coarse oft'shoots a light rim is present, tra- 
 versed by the minutest conical ofishoots, which rim obviously 
 corresponds to the wall of the lacunae and canaliculi. The walls 
 are rendered indistinct by the decalcification of the specimen. 
 The whole basis-substance is traversed by an extremely minute 
 reticulum of a dark-violet color, interconnecting all cement- 
 corpuscles. The behavior of this reticulum toward chloride of 
 gold clears up the nature of it : living matter produces the net- 
 work in the protoplasm, as well as in the basis-substance. Of 
 this reticulum, however, the meshes must be considered as the 
 basis-substance proper, composed of what we term glue or gela- 
 tin, and saturated with lime-salts. The boundary zone or 
 interzonal layer between dentine and cementum is conspicuous 
 by its bay-like excavations. In this region wo easily recognize 
 the union of most of the dentinal fibers with coarser ofishoots 
 
 "A Manual of Dental Anatomy.'" Philadelphia, 1876. 
 9
 
 114 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 of the eementTeorpuscles, — a fact already established by Bo- 
 decker. An immediate union of the living matter of the den- 
 tine with that of the cementum is fairly plain, since from six to 
 eight hours' exposure to the solution of chloride of gold was 
 sufficient to bring to view the reticulum in the cementum, 
 whereas ten hours' exposure is needed, according to John T. 
 Hart, to stain the reticulum of the dentine to a satisfactory 
 degree. Xo doubt, in a living tooth, the whole cementum is a 
 
 Fiu. 67. 
 
 Root (if a Mdi.ak ix Longitidinal Skctkix. SiAiNEn with Chloridk ok Gold. 
 
 P, nuc-leated protoplasmic body with coarse, dark-violet oflFshoot.s; C, basis-substance of ce- 
 mentum, pierced by a violet delicate reticulum; D, D, dentine. Most of the dentinal fibers 
 unite with offshoots of cement-corpuscles. Magnified 1200 diameters. 
 
 tissue, endowed with properties of life, the same as is dentine. 
 Life is not conlined to the cement-corpuscles and their coarser 
 oilshoots, but extends all through the basis-substance, being 
 active within the reticulum that pervades the protoplasm ; and 
 active also within that of the basis-substance. The study of the 
 pathology of cementum has furnished ample proof for the cor- 
 roboration of this statement. 
 " Osteoid Cementum. — The tissue of the cementum covering
 
 THE MINUTE STRUCTURE OF CEMENTUM. 
 
 115 
 
 the neck of the tooth is difierent in its microscopical structure 
 from the main mass of the cementum. It is known that the 
 thin layer of this tissue gradually blends with the cementum 
 proper. First the prisms of the neck-layer disappear, and a 
 granular layer makes its appearance, destitute, as yet, of lamellse 
 and cement-corpuscles, exhibiting a few faint striations, and tra- 
 versed, as in our specimen, occasionally, though not always, by 
 piercing cement-tibrilla'. (See Fig. 68.) 
 
 " This formation is probal)ly what Charles S. Tomes* 
 
 Root of a Ground BicrsiMD in Longitudinai, Skction. Transition of riiio Ckmknti'M 
 
 OF THE NkCK into THAT OF TIIK RooT. 
 
 /', pericementum ; 7', thickness of the specimen ; 0, osteoid layer of the cementum; />, den- 
 tine ; L, protophismic bodies at the interzonal layer between dentine and cementum. Magnified 
 200 diameters. 
 
 describes in the following words : ' The matrix of the cementum 
 is sometimes apparently structureless, at others tinely granular 
 or interspersed with small globules.' We wish to term it the 
 ' osteoid layer' of the cementum. By the name ' osteoid' the 
 histologists designate a tissue kindred to bone, saturated with 
 lime-salts, lacking bone-corpuscles or showing but few of them, 
 and without lamelhe. All this characterization holds good for 
 the portion of the cementum under consideration. Its history 
 
 *"A Manual of Dental Anatomy. ' riiila(lcli)hia. 1876.
 
 116 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 of development will be cleared up some day, when the develop- 
 ment of cementum will be studied in human teeth, — a study not 
 as yet accomplished. 
 
 " The osteoid layer shows, as it nears the lamellated cementum, 
 a few irregular bone-corpuscles. The lamellated portion starts 
 from the periphery of the root, and soon becomes broader and 
 suppUed with regular, freely-branching cement-corpuscles, with 
 the result that the osteoid structure, in the majority of the teeth 
 examined, is lost to sight. In the specimen from which the 
 
 Fig. 09. 
 
 
 
 Root of a Ground Molar in Longitudinal Section. Transition of Osteoid into 
 
 Lamellated Cementum. 
 
 P, pericementum ; T, thickness of the specimen ; //, lamellated cementum ; 0, osteoid ce- 
 mentum : Z, interzonal layer between dentine and cementum ; J), dentine. Magnified 200 
 diameters. 
 
 illustration is taken, the dentinal fibrilke stop short of the 
 osteoid layer, a feature so characteristic of the anatomy of the 
 neck. I^ear the interzonal, layer, between the dentine and the 
 osteoid tissue, a few small protoplasmic bodies are seen, into 
 which dentinal fibers inosculate. 
 
 " Not infrequently the osteoid layer does not perish, even 
 though lamellated cementum has made its appearance ; nay, the 
 osteoid layer may be seen all around the root, as an intervening 
 formation between dentine and cementum. Fig. 69 is taken
 
 THE MINUTE STRUCTURE OF CEMENTUM. 117 
 
 from such a specimen. Here we see the beginniDg of a lamel- 
 lated formation, between which and the dentine are protophxsmic 
 bodies, with a number of long and parallel offshoots, of the 
 aspect of piercing fibers. The interzonal layer, in this instance, 
 is conspicuous by a large number of interconnecting protoplas- 
 mic bodies, in union on their upward course with cement- 
 corpuscles, and on their downward course with dentinal fibers. 
 This peculiar formation is traceable all along the roots, and 
 signifies an incomplete deposition of lime-salts at the time of 
 
 Fig. 70. 
 
 OsTEDiD Layer of thk Root of an Ixcisok. Loxgitcdixal Skctiox. Staixkd avith 
 
 Chlohide of Gold. 
 
 P, protoplasmic body, with scanty, coarse offshoots; 0, coarse offshoot, apparently in no con- 
 nection with a protoplasmic body; B, basis-substance of tho osteoid layer, traversed by a deli- 
 cate reticulum. Magnified 1200 diameters. 
 
 the formation of the cementum. The dentine of this tooth is 
 fully developed, lacking even the so-called interglobular spaces 
 in the crown. 
 
 " In order more thoroughly to understand the structure of the 
 osteoid layer, we have applied to such specimens the protracted 
 gold stain, with subsequent decalcification by means of diluted 
 acetic acid ; the image thus obtained was a striking one indeed. 
 (See Fig. 70.)
 
 118 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 " "We observe small, odd-shaped protoplasmic bodies of a dark- 
 violet color, exhibiting bnt a limited number of coarse oiFshoots. 
 Besides, coarse dark-violet fibers traverse the basis-substance, 
 making a coarse net-work, arranged without apparent regular- 
 ity, and also, as it seems, lacking connections with larger proto- 
 plasmic masses. This latter feature may be due to a curved 
 course of the fibers, the union with cement-corpuscles being 
 severed l»y the process of grinding. The whole basis-substance 
 is seen to l)e traversed by a, comparatively speaking, coarse, 
 dark-violet reticulum, in union with the protoplasmic bodies, as 
 
 Fig. 71. 
 
 Osteoid Cementum of the Root of a Ground Bicuspid. 
 
 (J, osteoid layer of the cementum, with scanty protorlasmic bodies and piercing cement- 
 fibrillaj ; Z, interzonal layer between dentine and cementum, with numerous branching proto- 
 plasmic formations ; D, dentine with scanty protoplasmic bodies. Magnified 600 diameters. 
 
 well as with the coarse fibers. Unquestionably the reticulum is 
 the living matter proper, which endows the osteoid layer with a 
 considerable degree of vitality and sensibility. 
 
 " The peculiar interzonal formations, represented in Fig. 69, 
 we have also examined with higher powers of the microscope. 
 (See Fig. 71.) 
 
 "."We notice small protoplasmic bodies branching and inter- 
 connecting. Upward their uffslioots run into cement-corpuscles, 
 or into piercing fibers of the cementum, whereas, downward the 
 offshoots blend with the dentinal fibers. Even the dentine is
 
 TJiE MrxuTE ^tkucu're of cemextum. 119 
 
 possessed of protoplasmic formations, a certain distance away 
 from the interzonal layer; all of which proves a deficient calci- 
 fication just at the time of the beginning of the development of 
 the ceraentum. The specimen from which the drawing is made 
 was not stained with chloride of gold, and not decalcified ; hence 
 the reticulum of the basis-substance is only indicated, not con- 
 spicuous. Xo doubt, however, can arise about its presence. 
 
 " Cementum of the Neck. — BiWlecker was the first to accurately 
 describe the minute anatomical features of the cementum of 
 the neck. IIow defective the knowledge of this region was, 
 even sixteen years ago, is best shown by a quotation from 
 Charles S. Tomes, who says,* ' Where the cementum is very 
 thin, as, for instance, where it commences at the neck of a 
 human tooth, it is to all appearance structureless, and does not 
 contain any lacun?e.' The cementum of the neck, as is well 
 known, forms an extremely thin layer, sharply bordered toward 
 the enamel, and sometimes even overlapping the latter. Bodecker 
 speaks of directly calcified prisms in the neck-cementum, which, 
 in his opinion, ma\' be considered as osteoblasts, infiltrated with 
 lime-salts. Sometimes the prismatic structure is not pronounced, 
 but a row of spindles is seen arranged in a direction almost 
 perpendicular to the surface of the tooth. Larger and smaller 
 spindles alternate, the latter sometimes being so small as to con- 
 vey the impression of fibers. 
 
 " There is a slight discrepancy between the statements of 
 Bodecker and our own observations. We fully concur with him 
 as to the calcified prisms ; but the spindles, sometimes very con- 
 spicuous even to medium powers of the microscope, we cannot 
 consider as formations of the basis-substance. Rather, we 
 should regard the spindles and alternating fibers as protoplasmic 
 formations, which fill the interstices between the prismatic pieces 
 of the cementum of the neck. This tissue, in our opinion, is 
 either composed of prisms alone, with intervening light and 
 parallel spaces, or of prisms, between which are protoplasmic 
 bodies of spindle shape, alternately broad and narrow, in the 
 latter instance having the aspect of coarse fibers of living mat- 
 ter. Thus the uniformity in the structure of the cementum of 
 the neck is established. We hope Dr. Bodecker, with wliom 
 we thoroughly concur in all other points, will pardon our heresy 
 
 * " A Manual of Dental Anat..iny." Philadelphia. 1876.
 
 120 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 and eventually satisfy himself that our conception renders this 
 structure more comprehensible than does his. (See Fig. 72.) 
 
 " Considerable interest attaches to the layer of dentine 
 directly subjacent to the prismatic layer of the cementum of the 
 neck. We are indebted to John Tomes for the knowledge of 
 the fact that the dentinal fibers, in this situation, stop short of 
 the cementum. AVe may say that nowhere does the structure 
 of the teeth vary in aspect so greatly as in the dentine in the 
 region of the neck. There are scarcely two teeth perfectly 
 alike in this region. The simplest form is when the prismatic 
 layer is directly followed by a granular layer of dentine, lacking 
 
 Neck of a Bicuspim in Luxgitudixal Section. Stained ^riTH Chloride of Gold. 
 
 P, pericementum: T, thickness of the specimen; N, cementum of the neck, composed of 
 prisms and intervening spindles and fibers : Z, stratified interzonal layer; B, coarsely reticu- 
 lated layer of dentine, destitute of dentinal fibers. Magnified 1200 diameters. 
 
 canaliculi. That the granulation means a rich reticulum of 
 living matter, coarser than in an}^ other part of the dentine, 
 and rendering the neck excessively sensitive, John I. Hart has 
 proven, fully in accordance with Bodecker's statements. This 
 simple arrangement, however, is rare. In many instances there 
 are layers of stratifications between the cementum and the 
 granular dentine, greatly varying in breadth and in numbers. 
 The appearance of strata, in accord with the conception of John 
 I. Hart, means that alternate layers, rich in living matter, and 
 others scantily supplied with it, build up the neck-region of the
 
 THE MINUTE STRUCTURE OF CEMEXTUM. 
 
 121 
 
 dentine. Club-like or pear-shaped spaces, filled with proto- 
 plasm, are often seen to pervade the granular layer of the den- 
 tine with a peculiar regularity, and often in connection with 
 dentinal fibers, which otherwise do not reach the boundary of 
 the cementum. In E'ig. 72 we find represented in the granular 
 layer of the dentine coarse, dark-violet dots, forming points of 
 intersection, and far too small to be termed protoplasmic bodies 
 or cells in the sense of older his'tologists. All these features 
 
 Fig. 73. 
 
 Neck of a Ground Bicuspid. Anomalous Arraxgemext of Layers of the Cementum 
 
 AND the Dentine. 
 
 P, pericementum ; T, thickness of the specimen : S, stratifieil layer of cementum, composed 
 of halved prisms; Z', outer lamellated layer; G, outer granular layer; L-, inner lamellated 
 layer; G-, inner granular layer; Z)', thoroughly calcified glossy layer; //-, inner prismatic 
 layer: /^ normal dentine. Magnified 200 diameters. 
 
 seem to mean a markedly augmented amount of living matter, 
 which renders all surgical interference in the region of the neck 
 so painful. 
 
 " The most complicated structure that we have ever seen in 
 the region of the neck is illustrated in Fig. 73. 
 
 " The figure is taken from a ground bicuspid, which shows at 
 its crown a distinct mechanical abrasion. The stratifications
 
 122 THE ANATOMY AND PATHOLOGY .OF THE TEETH. 
 
 extend all over the root. It is impossible to bring them into a 
 relation with the mechanical abrasion, and we should consider 
 this formation a rather anomalous one. The layers are as fol- 
 lows : The outermost portion, directly bordering the cementum, 
 is composed of large, regular prisms, which show faint longi- 
 tudinal lines and are halved by distinct fissures in a direction 
 parallel to the surface; this layer extends to the close vicinity of 
 the enamel, and far down along the root, directly changing into 
 stratified cementum, devoid of cement-corpuscles, so far as the 
 specimen shows. This is the only layer that belongs to the 
 cementum, since in the neighl)orhood of the enamel the dentinal 
 fibers are traceal)le up to the prisms, pervading a granular basis- 
 substance as yet l)ut slightly stratified. Soon afterward the 
 dentine begins to exhibit a nuralier of layers, which may be 
 defined as composing a narrow outer, and a broad inner, lamel- 
 lated stratum, between which strata lies the ' outer granular' 
 zone, somewhat varying in breadth along the root. These three 
 strata are pierced by extremel}- delicate radiating lines, which 
 closely resemble dentinal fibers. The next layer to form is the 
 ' iimer granular,' greatly changing in breadth in diflterent por- 
 tions of the root. This layer holds small, angular protoplasmic 
 formations, and, obviously, corresponds to the granular layer 
 subjacent to the cementum of the neck in normal teeth. In- 
 wardly there follows a zone (D^) marked by a high gloss due 
 to an intense calcification of the basis-substance, pierced l)y 
 scanty angular protoplasmic bodies. The innermost stratum 
 appears to be composed of prisms or spindles, far less regular 
 than those of the cementum. A sharp line of demarcation, in 
 which not the slightest anomaly can be made out, closes this 
 layer at its approach to the normal dentine. All these layers 
 are seen down to nearly half the length of the root, where the 
 specimen is cut off". 
 
 "Exceptionally there is observable in the dentine of the roots 
 stratification, consisting of narrow, light lines, arranged nearly 
 parallel to the Surface, causing an interruption in the course of 
 the dentinal fibers, l)ut never a change in their direction. Strati- 
 fication of the dentine at the neck is far more common, but has 
 never been seen as yet in such perfection as in the specimen 
 illustrated in Fig. 73. What the cause of such stratification is, 
 future studies in the history of dev'elopment of the dentine of 
 the roots and the cementum will elucidate.
 
 THE .>[rNUTE STRUCTURE OF CEMEXTUM. 
 
 123 
 
 " Devitalized Cementum. — We have grouiul a number of teeth 
 which, to judge I'roui their naked-eye appearance, were pulpless 
 and devitalized. After the exposure of thin slabs obtained 
 from such teeth to the solution of chloride of gold, with subse- 
 quent decalcification with acetic acid, the image under the 
 microscope was striking. (See Fig. 74.) 
 
 "• The most conspicuous features were the empty lacunee, desti- 
 tute of nucleated protoplasm, but t^ontaining granular clusters 
 
 Fig. 74. 
 
 Cemkxtum op the Root ok a Dkvitalizkd Molar. Staixkd with Chloride of Gold. 
 
 Z, lacuna, holding shriveled protoplasm; 6', empty canaliculi ; /?, basis-substance, pierced 
 by a light reticulum. Magnified 1200 diameters. 
 
 of a dark-violet color, obviously the shriveled remains of pro- 
 toplasm. Numerous canaliculi arose from the lacunte, all of 
 Avhich were empty. The finest offshoots of both the lacunie 
 and canaliculi produced alight net-work in the dark-violet basis- 
 substance, — an image which corresponds to dry and also to ne- 
 crotic bone. Unfortunately, some specimens of living, freshly- 
 extracted teeth furnished, after the same chemical treatment, 
 identicallv similar fisfures. Such an untoward result has also
 
 124 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 occurred to other investigators who resorted to the gold method. 
 The cause of such failure may have been, that the extracted 
 teeth were left too long under the influence of the table-salt 
 solution ; or, possibly, the acetic acid worked in a wrong way. 
 All we can say is, that whenever such a negative result was 
 obtained, the whole cementum had been affected, so much so that 
 we are at a loss to state whether or not the devitalized cementum 
 is dead all through, up to the pericementum. Future examina- 
 tions, carried out with improved methods, will probably settle 
 the question where the boundary between dead and living tissue 
 is, this being a matter of the greatest importance to the prac- 
 titioner.'' 
 
 CHAPTER XIII. 
 
 SYNOPSIS OF THE DEVELOPMENT OF THE TEETH. 
 
 From a morphological point of view, we might, as several 
 writers have done, consider the teeth to be dermal structures. 
 Their analogy to the skin is, indeed, striking, if we compare the 
 crown of a tooth with a papilla of the skin, especially when the 
 former is in a state of formation, — viz, about the tifth month 
 of intra-uterine development. Here we observe a knob-like for- 
 mation of connective tissue, the dental papilla, similar to a skin- 
 papilla, supplied with blood-vessels and covered by an epithelial 
 tissue, the enamel-organ. 
 
 The teeth, during their early stage of development, are com- 
 posed of only two tissues, — i.e., the enamel and the dentine, the 
 cementum of the root being developed after birth. 
 
 The tirst process in the formation of teeth in the human sub- 
 ject is the evolution of a furrow extending the whole length of 
 the future alveolar process. This furrow appears at about the 
 sixth week of intra-uterine life. (See Fig. 75.) Shortly afterward 
 we observe along the furrow a row of hillocks in the oral epi- 
 thelium, growing down into the substance of the future jaw. 
 This hillocked epithelial formation is called an enamel-cord, and 
 as development proceeds, the enamel-cord is formed which 
 becomes the enamel-organ of each tooth. About the third 
 month this epithelial cord widens at its distal extremity, which 
 assumes the shape of a l^ell-jar at the end of the cord. The for-
 
 SYNOPSIS OF THE ])EVELOPMENT OF THE TEETH. 125 
 
 Fro. 75. 
 
 Transverse Sfciihn hi 1 m i > w (i\ Ldu m J \\\ m a Ult.m\n ].\i i.i.\ o m\ \\ eeks Old. 
 E, epithelium of oral mucosa; T. tongue: V, blood-vessels; B, base of oral cavity; F, fur- 
 row in transverse section. Magnified 75 diameters. 
 
 Fig. 76. 
 
 Epithkli.vi, Cord tfi miwting in thp Fuiike Lnamki Or( an of a Human Embryo 
 
 Thrff MoNiHi Old 
 0, stratified epithelium of the oral cavity ; Co, epithelial cord of the enamel-organ ; .S', short 
 secondary offshoot of the epithelial cord : SP, broad secondary offshoot of the epithelial cord ; 
 EE. e.vternal or outer epithelium ; E (lower), internal or inner epithelium ; M, medullary tissue 
 sprung from previous epithelia. the future stellate reticulum ; /*, dentine-papilla; Ca, capsule 
 or tooth-sac; A' (upper), embryonal tissue, the future fibrous connective tissue of the mucous 
 membrane. Magnified 75 diameters.
 
 126 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 mation throughout is composed of two distinct layers of colum- 
 nar epithelia, continuous with the oral mucous membrane. (See 
 Fig. 76.) At the period iu which tlie bell-shape begins, we see 
 the first trace of the dentinal papilla. About the end of the 
 third month of intra-uterine development we observe that the 
 enamel-organ has changed considerably in shape and size, and 
 we now distinguish the following formations : 1, the epithelial 
 cord; 2, the external epithelium; 3, the internal epifheV.am ; 4, the 
 stratum intertnediuni ; and 5, the stellate reticulum. (See Fig. 77.) 
 We also notice the beginning formation of the tooth-sac, which 
 grows upward from the dentine papilla, gradually encircling the 
 enamel-organ. About the fifth month the external epithelium 
 of the enamel-organ, together with the epithelial cord, l)egin 
 to break into epithelial nests and buds, amid which a pro- 
 fuse formation of red blood-corpuscles and blood-vessels takes 
 place. At this period the internal epithelium covering the 
 crown of the future tooth undergoes a change consisting in a 
 prolongation of the single epithelia, and their sum-total is now 
 called the omelohhist lancr, while those elongated formations 
 covering the dentine papilla are termed ddontohlasts. The amelo- 
 blasts and odontoldasts have been originally in close contact, 
 but with progressing development the dentine begins to form 
 from the periphery toward the center of the tooth ; the enamel, 
 on the contrary, grows from the surface of the dentine outward. 
 These changes appear in about the fifth month, wherein also the 
 first trace of dentine is seen, while the enamel begins to form at 
 about the sixth month. Before calcification takes place, there 
 becomes visible on the outermost portion of the ameloblnsts a 
 delicate light zone, consisting of embryonal or medullary cor- 
 puscles, from which the enamel originates. The odontoblasts 
 at the periphery of the dentine papilla likewise undergo a 
 transformation into medullary corpuscles, and by their calcifica- 
 tion give rise to the basis-substance of the dentine. The odonto- 
 blasts, as well as the medullary corpuscles sprung from them, 
 are interconnected by delicate threads of living matter. These 
 threads, in coalescence with the offshoots of the odontoblasts, 
 produce the dentinal fibers. The odontoblasts and ameloblasts, 
 therefore, are not directly transformed into the tissues, dentine 
 and enamel, which they respectively re})resent,but must be con- 
 sidered as provisional formations. During development, the den- 
 tine is formed of globular territories, proven by the occurrence
 
 SYNOPSIS OF THE DEVELOPMENT OF THE TEETH. 
 
 127 
 
 of interglobular spaces, and bj the retrogressive processes of 
 absorption in temporary teeth, in caries and eburnitis. In this 
 process, the similarity of dentine-tissue with bone-tissue is ren- 
 dered evident. 
 
 The cementum is formed after birth ; the remains of the 
 
 Fig. 77. 
 
 Epithelial Cokd TK!i.\ii.\.\riN(i in the Enamel-Oimjan of a Human Embryo Five Months 
 
 Old. 
 
 0, stratified epithelium of the oral cavity: S'P, secondary offshoot of the epithelial cord; 
 Co. epithelial cord of the enaini^l-organ ; .1/, my.xomatous tissue of the enamel-organ ; EJi\ 
 external or outer epithelium ; IK, internal or inner epithelium ; /, stratum intermedium, 
 between inner epithelium and myxomatous tissue; /-", papilla; Ca, capsule or tooth-sac; /'. 
 fibrous connective tisi^ue of oral mucosa. Magnified 75 diameters.
 
 128 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 tooth-sac changing into medullary corpuscles, from which the 
 cementuni is developed in the same manner as bone-tissue. 
 
 The twenty anterior, permanent teeth are developed from 
 enamel-organs, being offshoots from those of the temporary 
 teeth. All the permanent molar teeth are an offspring of the 
 enamel-organ of the second temporary molar teeth. 
 
 The writer's views concerning the development of the teeth, as 
 here propounded, differ considerably from those entertained by 
 previous authors. To enal:)le future investigators to satisfy 
 themselves of the correctness of his assertions, the result of 
 eight years of labor, the following is presented as the method 
 resorted to in tlie pursuit of this study, one of the most 
 fascinating subjects of microscopical research : 
 
 To prepare microscopical specimens of embryonal jaws for 
 researches in the history of the development of the teeth, the 
 jaw-bones (preferably the lower) are excised from the foetus, — 
 care being exercised not to squeeze the specimen, — and are 
 Y)laced in a one-fifth of one per cent, solution of chromic acid. 
 The liquid must be changed every third or fourth day, and the 
 strength of the chromic-acid solution gradually increased to one- 
 half of one per cent., until the hard tissues, by the removal of 
 the lime-salts, are sufficiently soft to be cut with a razor. All 
 trials to determine the degree of softness of such a specimen 
 must be made by means of a needle, and not with the fingers. 
 The epithelial structures are especially liable to be crushed, 
 unless handled with the utmost care. The greatest obstacle to 
 obtaining perfect specimens is caused by the fact that the enamel- 
 organ is withdrawn from the dentinal cap, and the epithelia 
 are detached from the connective-tissue structures, a cavity 
 being thus formed whose walls offer no resistance to the cutting- 
 instruments, and are thus easily detached from their normal 
 position. 
 
 . After having tried different methods of imbedding, the author 
 has come to the conclusion that the best material for this purpose 
 is celloidin, softened in absolute alcohol and dissolved in sulphuric 
 ether. The specimen, previous to imbedding, must be dehy- 
 drated by immersion in absolute alcohol for twenty-four hours. 
 It is next kept in a mixture of equal parts of sulphuric ether 
 and absolute alcohol about twenty-four hours longer. Then it 
 is held in a rather thin solution of celloidin for about two 
 days, after which it is ready for mounting upon a cork. When
 
 DEVELOPMENT OF DENTINE. 129 
 
 such a specimen is cut, it will usually be found that the spaces 
 between the dentine and enamel, which are due to the shrinkage 
 of the myxomatous tissue of the enamel-organ, are filled with 
 celloidin. If, however, it is found, upon cutting, that such a 
 space has not been completely filled, a very thin solution of cel- 
 loidin may be poured into it. A section-cutter is of great 
 advantage, since by its use a large number of thin and uniform 
 specimens can be obtained in a comparatively short space of time. 
 Chemically-pure glycerin is considered far superior to Canada 
 balsam as a mounting medium, the tissues of the object pre- 
 senting in this medium a more distinct appearance. If high 
 powers of the microscope are to be employed, only glycerin- 
 mounted specimens will give satisfactory results. 
 
 CHAPTER XIV. 
 
 DEVELOPMENT OF DENTINE.* 
 
 Dentine, as is universally admitted, is strictly an offsiH'ing 
 of connective tissue produced by the papilla, a formation of 
 embryonal tissue, crowded with medullary corpuscles. (See 
 Fig. 78.) 
 
 It appears about the end of the second and the beginning of 
 the third month of intra-uterine life, at a time when the extrem- 
 ity of the epithelial cord has flattened and assumed a cup-shape. 
 The cavity of this cup is filled with the papilla, which sends 
 prolongations along the outer wall of the cup, the future sac of 
 the tooth. The more this is deepened and widened, the larger 
 will be the papilla. If the cup of the enamel-organ shows de- 
 pressions corresponding to a bicuspid or molar tooth, we shall 
 find corresponding elevations upon the papilla extending into 
 them. 
 
 The papilla is originally supplied with but few capillary 
 blood-vessels. With advancing growth, however, the vascular 
 supply becomes greater, especially in its periplieral portions, 
 where a delicate fibrous connective tissue is developed, — the so- 
 called tooth-sac. In the seventh month of fcetal life, we observe 
 
 * ' ' Contributions to the History of Development of the Teeth. ' ' By C. Heitzmanu 
 and C. F. "\V. Bodeckor. Ttir Independent Practitioner, vols, viii and ix. 
 
 10
 
 130 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 a perfect vascular apparatus traversing the papilla, consisting of 
 arteries, veins, and capillaries. If examined with low powers of 
 the microscope, the papilla appears to be composed of small, 
 globular, highlj-refracting corpuscles, amid which is seen a 
 scanty basis-substance. AVith high powers of the microscope, 
 we observe globular or oblong corpuscles of small size, which 
 are either compact and homogeneous, or possessed of a distinct 
 reticular structure in their interior. Between small groups of 
 such medullary corpuscles, spindle-shaped tracts appear, corre- 
 sponding to the boundaries of the future territories of the myxo- 
 matous tissue, the reticulum of which in the human subject is 
 alwaj's incomplete, never attaining the degree of development 
 
 Fig. 78. 
 
 Medullary Tis.sue of the P.\filla df a Humax Embryo of Four Months. 
 
 The small shining medullary corpuscles form clusters, around which we observe an irregularly 
 developed myxomatous net-work. Magnified 1200 diameters. 
 
 seen in the enamel-organ. The largest medullary corpuscles are 
 observed in the middle of territories surrounded by a certain 
 amount of basis-substance. Both these corpuscles and the basis- 
 substance have a distinct reticular structure. (See Fig. 78.) 
 
 The more the papilla increases in size and advances in devel- 
 opment, the less frequent are the homogeneous and small 
 medullary corpu.scles, while the granular corpuscles are larger, 
 each being surrounded by a small amount of basis-substance. 
 Along the periphery of the papilla, however, there is invariably 
 present a narrow zone, in which the medullary corpuscles are 
 more numerous and more shining than in the rest of the papilla.
 
 DEVKLdl'MENT OF UENTKNE. 131 
 
 In the fifth month the outermost periphery of the papilla is fre- 
 (|uently found to be composed of a hyahne rim, beneath which 
 is a narrow zone of medulhiry corpuscles. The hyaline rim 
 corresponds to the so-called structureless layer, or basement 
 membrane so often seen between epithelial and connective-tissue 
 formations. When the enamel-organ is detached from the 
 papilla, — and this detachment is, as al)ove said, very frequent, — 
 the outer surfiice of the basement membrane appears beset with 
 an extremely delicate fringe, evidently the torn connection be- 
 tween the papilla and the adjacent enamel-organ, or the amelo- 
 blasts. High powers of the microscope reveal in the apparently 
 structureless layer a faint reticular formation, and marks of a 
 division into medullary corpuscles. 
 
 At the beginning of the fifth month, we usually find along the 
 periphery of the papilla the first traces of peculiar, elongated 
 corpuscles, known as odontoblasts. These formations are ob- 
 long, pear-, club-, or spindle-shaped, arising from the coalescence 
 of a number of medullary corpuscles, including that portion 
 which has been previously transformed into basis-substance. 
 The odontoblasts are sometimes seen directly beneath an already- 
 formed layer of not yet calcified dentine. The latter, in this 
 case, is sufficiently characterized by the presence of delicate 
 branching dentinal canaliculi, holding the slender dentinal 
 (Tomes) fibers. We often observe these fibers to be in direct 
 connection with adjacent odontoblasts. If an odontoblast ter- 
 minates in a sharp point, one offshoot directly connected with 
 a dentinal fiber is seen to arise from the point. If an odonto- 
 blast has a broad basis, two or more offshoots may arise from 
 it and run, in the shape of dentinal fibers, into the adjacent 
 dentinal canaliculi. It may also happen that an offshoot of an 
 odontoblast takes another direction, and instead of passing into 
 a dentinal canalicuhis, runs parallel with the Ijorder of the 
 already-formed dentine. Fully-developed odontoblasts are not 
 often seen in direct union with dentine, and this is especially 
 true along the lateral portions of the dentinal cap. It is far 
 more common that medullary corpuscles are present between 
 the odontoblasts and the dentine, and that the offshoots of the 
 odontoblasts run between these medullary corpuscles in order 
 to reach their respective dentinal canaliculi. Fully-developed 
 odontoblasts are rarely seen at the apex of the papilla. Usually 
 medtdlary corpuscles only are present in this locality, or they
 
 132 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 are interposed between the odontoblasts and dentine. * l!Tot in- 
 frequently we observe in the forming dentine layers as are 
 represented in Fig. 79. 
 
 The odontoblasts have arisen from the fusion of a number of 
 
 DM I)T 
 
 First-Formed Dentine of a Human Fo-itus of Six Months. 
 
 Z>, calcified layer of dentine with marked globular territories; 1)T, dentine composed of a 
 non-calcified basis-substance, likewise globular : />3/, row of medullary corpuscles before the 
 formation of basis-substance ; O, odontoblasts, the offshoots of which run between the medul- 
 lary corpuscles into the dentinal canaliculi ; £", enamel. Magnified 1200 diameters. 
 
 medullary corpuscles, and are present where, at the time, the for- 
 mation of dentine is not actively in progress. TVhenever this 
 is the case, the odontoblasts break up into medullary corpuscles,
 
 DEVELOPMENT OF DENTINE. 133 
 
 which are directly transformed into the basis-substance of the 
 dentine. The otfshoots of the odontobhists, that are seen to 
 run directly into the dentinal cunaliculi, appear between the 
 medullary corpuscles as soon as the odontoblasts split up into 
 such corpuscles. The otfshoots are formations of living matter 
 seen to emanate from a compact layer at the base and the 
 borders of the odontoblasts. The dentinal fibers remain in 
 situation after the formation of medullary corpuscles, or they are 
 newly formed between the medullary corpuscles, as soon as the 
 dentinal eanaliculi arc formed. The odontoblasts are not direct 
 dentine-formers, but provisional formations, from which arise 
 the medullary corpuscles, and these are changed into the basis- 
 substance of the dentine. Odontoblasts, therefore, the same as 
 ameloblasts, are provisional formations, and dentine, as well as 
 enamel, originates from medullary corpuscles in the same manner 
 in which all forms of coimective tissue are known to arise. 
 
 It is the rule that the medullary corpuscles are at first trans- 
 formed into a basis-substance, which is as yet destitute of lime- 
 salts. In specimens stained with carmin, this zone of non- 
 calcified dentine assumes a bright red color, in contradistinction 
 to the calcified portion, which either remains unstained or 
 assumes a greenish tint by the reduction of the chromic acid. 
 Another distinction between the non-calcified and the calcified 
 basis-substance is that the latter has a markedly higher degree 
 of refraction than the former. When we examine such a speci- 
 men with high powers of the microscope, we at once become 
 convinced of the identity of the structure of both the non-calci- 
 fied and the calcified dentine. We observe a markedly reticular 
 structure in both, and in many instances fine filaments, emanat- 
 ing from the dentinal fibers, are seen to penetrate the reticulum. 
 
 At the periphery of the dentine, the bifurcations of the 
 dentinal eanaliculi and their tenants are always plainly marked. 
 This feature obviously arises from an aggregration of smaller 
 medullary corpuscles than those appearing at a later period of 
 development. At the same time, the reticulum in the basis- 
 substance is more delicate in the region of the l)ifurcations, and 
 consequently the meshes of the basis-substance appear narrower 
 in the first-formed dentine than in that which is formed at a 
 later period. We sonietinics observe, in connection with longi- 
 tudinal sections of dentine, transverse sections which are of 
 great interest. (See Fig. 80, BC.) Here it is seen that tlie
 
 134 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 calcification first starts at the periplierv of the fieUls farthest 
 from the tlentiiial caiialiculi. Thus a coiii[iaratively coarse net- 
 work of calcified l)asis-sul)stance is established, in the meshes 
 of which we observe either an uncalcified basis-substance or 
 unclianged protoplasm, whereas the central jiortions of the 
 
 M 
 
 ^, 
 
 BB 
 
 i 
 
 i?\9 
 
 f I 
 
 4J 
 
 First-Formed Dentine ok the Molar Tooth of a Human Fo:tis of Six Months. 
 
 T>B, basis-substance of non-calcified dentine ; DL. basis-substance of calcified dentine, both 
 in longitudinal section ; DC, calcified dentine in cross-section. Magnified 1200 diameters. 
 
 meshes are occupied l>v the dentinal fibers in transverse or 
 oblique section. The latter appear larg-er in inverse ratio 
 to the amount of calcareous matter that has been deposited. 
 From their periplierv arise the s|>okes. also seen in fully-devel-
 
 DEVELOPMENT OF DENTINE. 185 
 
 Oped dentiiK'. \\hicli traverse a liu'lit i-'nii — tlic futui'c canali- 
 culus. The border of the canaliculus is often marked hy a 
 circular or crescentic formation, possildy the future rim of 
 elastic suhstancc of the dentinal canaliculi. 
 
 The line of the non-calcitied basis-suhstauce -forming- the 
 houndary toward the niedullarv corpuscles is fouiul to he either 
 straight, stair-like, or slightly wavy. This feature is never 
 observed close to the periphery of the dentine, but always 
 some distance away from it. These wavy contours unquestion- 
 ably correspond to the glol)ular territories of which the basis- 
 substance is compose(L Previous researches regarding dissolu- 
 tion of the dentine of temporary teeth, in caries and in the 
 ]»rocess of eburnitis, esjiecially in the latter, have strongly 
 jtointed toward the i>resence of globular territories in the 
 dentine, the same as in bone-tissue. The history of develop- 
 ment corroborates the presence of such territories, since they 
 are of very common occurrence in developing dentine of man, 
 as well as of different animals. Their origin is explained in a 
 grouping together of a certain number of medullary eor})UScles 
 previous to their transformation into l)asis-suT)stance. Each 
 globular territory is pierced by a number of dentinal canaliculi, 
 without the least interrujition in tlieir course. We desire to 
 lay special stress upon the fact that such territories become 
 conspicuous oidy after calcification of the basis-substance 
 has taken place. Under the theory that the odontol)lasts are 
 directly transfoi'med into dentine, the formation of globular 
 territories was inexplicable. In morl)id processes, Ave observe 
 the glol)ular territories of the dentine breaking up into a num- 
 ber of medullary corpuscles. The history of development 
 teaches us that each tei'ritoi'y arises from a number of smaller 
 <'orpuscles. Thus the foi'mation, dissolution, inflammation, 
 and refornuition of dentine lu'come ]>lain. 
 
 Since Ozermak has drawn attention to nncalcitied fields in 
 the dentine of many ti'etli. and calle(l them " interglobular 
 spaces," a great deal of speculation has been indulged in to 
 explain this occuri-ence. Such spaces are never present, as far 
 as tln' writers ]ia\e ol>ser\-ed, close to tlu' peripliery of the den- 
 tine, but are always found some distance from the bifurt-ations 
 of the dentinal canaliculi, and sometimes are scattered tlirough- 
 out the dentine. These spaces are filled \vh\\ a non-calcified 
 basis-substance, or with medullary- cori>uscles that ha\'e not
 
 136 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 been trans^formed into ba^is-substanee. We have often ob!?erved 
 within these spaces irregular globuhir territories, invariably 
 marked bv the contours of such territories, but never causing a 
 deviation of the course of the dentinal canaliculi. 
 
 Fig. 81. 
 
 Anomalous Fok.mation of Dentine i'uom a Human FtKirs of .-^ix ^Months. 
 
 r, papilla of the tooth, with a few blood-vessels, and no odontoblasts. The medullary cor- 
 puscle?, close below the dentine, are arranged in groups, corresponding to the future territories 
 of the dentine; CD, non-calcified basis-substance of the dentine: I>, calcified dentine ; S, 1, 2, 
 and 3, stratifications of the dentine; ^'/V, ill-calcified basis-substance of the dentine, in con- 
 nection with Si, composed of globular territories. Magnified 500 diameters. 
 
 Tile origin of such interglol)nlar sjtaces is traceable to the 
 earliest stages of the fornnition of the dentine. (See Fig. 81.) 
 In exceptional cases even fully-developed dentine will a}>pear 
 composed of hiyers, or witli faint C(jncentrically-arrai)gcd nnirks,
 
 DEVELOPMENT OF DENTINE. 
 
 137 
 
 truvt'i'sod without interruption l»_v tlie dentinal canaliculi. Both 
 the stratitie-ation and the intergh)l)uhir .s}»aces are caused by a 
 faultv de}»osition of lime-salts in tlie emhrvonal development of 
 the dentine. Their cause is prol)al)lya temporai'v interruption 
 of deposition of lime-salts, owing to transient ailments of the 
 mother. These rather anomalous formations of dentine again 
 prove that the basis-substance is made up of gl<)l)ular territories, 
 and these, again, of medullary corpuscles. 
 
 In tlie foetus of the cat, the sheep, and the d(.)g, the process 
 
 Fig. 82. 
 
 Papilla and Adjacent Dentine op Fcetus op a Pig. 
 
 P. myxomatous tissue of the papilla, with irregularly branching corpuscles, and an abun- 
 dance of myxomatous basis-substance; (\ (\ capillaries, partly fully formed, and partly in the 
 process of formation ; 0, layer of odontoblasts ; J), dentine. Magnified 500 diameters. 
 
 of the formation of dentine is the same as in man, in all essen- 
 tial features. The same rule holds good for the history of the 
 develoi)ment of dentine in swine. This dentine, in <levelop- 
 ment, difters slightly from that of man, mainly in the structure 
 of the papilla. (Fig. 82.) 
 
 The ]»a[»ina of the foetus of a [tig is comi)Osed of irregular, 
 branching, and partly connecting protoplasmic bodies, some- 
 wdiat resemblinii' the stellate reticulum of tlie enamel-origan.
 
 138 
 
 THE ANATOMY AXD PATHOLOGY OF THE TEETH. 
 
 These corpuscles are uniformly distriluited in an al)undant mass 
 of basis-substance, which, with lower powers of the micro- 
 scope, appears finely granular. High powers, however, reveal 
 the delicate net-work essential to all the varieties of a myxo- 
 matous l)asis-substance. This tissue is traversed 1)V a moderate 
 numl)er of blood-vessels, mainly capillaries, Avhich show in some 
 places characteristics of the stages of development from the 
 original solid cords of protoplasm to the vacuolization and ap- 
 pearance of endothelia upon their walls. Toward the periphery 
 of the papilla, spindle-shaped bodies make their appearance, 
 
 Fig. 83. 
 
 Fig. 84. 
 
 Od(int(iblasts. with Adjacent Dentine, from the F(>:tus of .\ Pig. 
 0. odontoblasts ; D, dentine. Magnified 1200 diameters. 
 
 evidently arising (at least to a great extent) from the living- 
 matter previciusly hidden in the myxomatous l>asis-substanee. 
 By an increase in the size of one, or the confluence of several, 
 such si>indle-shaiied corjiuscles, the odontoblasts arise, and they 
 are often seen in contact with the already-formed dentine. 
 Close study of specimens has satisfied us that the odontoblasts 
 do not directly form tbe basis-substance of the dentine, but 
 here, as well as in men and otlier animals, are merely transi- 
 tional fornnitions.
 
 DEVELOPMENT OF DENTINE. 139 
 
 111 the condition of rest the odontohhists c>fter an excellent 
 <)l»})ortnnity to study their relation to the dentine. If they lie 
 Hii'ainst tlie (k'litine with a l)roa<l l)asis, four or five oftshoots 
 (as rejireseiited in Fiu'. 83) may he seen to enter the adjacent 
 eanalieuli, all of which arise from one odontol»last. If, on the 
 contrary, the (uloutohlasts terminate, toward the dentine, in a 
 ](oint, a siiiu'le dentinal fiher will spring" therefrom, as repre- 
 seiitt'd in Fig. 84. It may also happen that a single odontoblast 
 exhihits no otfsiioots, in which instance Ave o])serve, between 
 the hase of the odontoblast and the dentine, delicate filaments 
 which run along the l)order of the dentine, and from which arise 
 the dentinal fibers. The ojiposite ends of the odontoblasts are, 
 rouo-hlv siieakint>", itointed, and likewise elono^ated into delicate 
 fibers. These fibers, as well as the lateral portions of the odonto- 
 l)lasts, are interconnected with all their neighbors by means ot 
 delicate thorny ofl:shoots. 
 
 The results of further researches in this field , as follows, have 
 been published by Frank Abbott : * 
 
 '• The only formations deserving of the term ' cells' are the 
 odontoblasts, those peculiar, elongated bodies (of a shape and 
 size to remind one of columnar epithelia) usually seen at tlie 
 periphery of the papilla in developing, and at the periphery of 
 the pulp-tissue in developed teeth. 
 
 " We know of these peculiar protoplasmic l)odies that they send 
 ofishoots (the dentinal fibers) upward into the dentine, ofishoots 
 laterally connecting one with another, and other ofishoots down- 
 ward, uniting them with the medullary elements of the papilla. 
 
 " The first to see and describe all these ofishoots was Franz 
 !Boll, in 1868, and he was corroborated by Waldeyer, in 1869. 
 Before these oftshoots w^ere known, attempts at explaining the 
 formation of dentine were made, first by A. Kolliker, in 1852, 
 in his hand-book of histology. On page 385 he says, ' In the 
 formation of dentine not the whole pulp is concerned, but only 
 its outermost layer of epithelium-like cells, which, by a contin- 
 ual prolongation of the original cells, dmlvr a njidiniioiis iiviltipli- 
 c/i/i'dii of i/ic ih/i-J( /\ apparently keep up the same thickness. 
 
 " ' I am not willing to maintain that one and the same cell is 
 sufficient for the whole duration of the formation of dentine, 
 for I consider it as quite possible that, from time to time, the 
 
 * " Odontoblasts in their Relation to Developing Dentine." Dental Cosmos, 1888.
 
 140 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 dentine-cells are replaced by others forming at their inner side. 
 What I deny is, that the whole pulp is transformed and ossified 
 from without inward." 
 
 " Kolliker, at that time, knew nothing about the presence of 
 dentinal fibers. To explain the formation of the dentinal canali- 
 culi, he, on page 386, discusses the following three possibilities : 
 
 " 1. The canalicnli are the remnants of the cavities of the den- 
 tinal cells, which, in the process of ossification, become thickened 
 and hardened in their walls, but are not perfectly closed, 
 
 '• 2. The canaliculi originate from the nuclei of the dentinal 
 cells, which elongate and coalesce, but retain their central cavities. 
 
 " 3. The canaliculi are produced by a process of resorption in 
 the previously homogeneous dentinal tissue, in a manner analo- 
 gous to the formation of the Haversian canals, or the canaliculi 
 in the cementum. 
 
 •' Of these three possibilities, Kolliker considered the first as 
 the most probable for the formation of the main canaliculi, and 
 was convinced that the third possibility alone can explain the 
 origin of the fine-branching canaliculi. He distinctly states 
 that no other tissue is concerned in the production of dentine but 
 the cells which later were dubbed odontoblasts, and that these, 
 by a successive taking up of the lime-salts, become dentine. 
 He therefore, as early as 1852, although upholding until then the 
 secretion theory, adopted, and from that time up to date has 
 unswervingly maintained, as regards the formation of dentine, 
 the opposite or transformation theory. About ten years later, he 
 and John Tomes discovered the dentinal fibers, and, with the 
 acknowledged evidence of these fibers within the canaliculi, and 
 their connection with the odontoblasts, the difliculties in ex- 
 plaining the formation of dentine have considerably increased. 
 
 •' Are the dentinal fibers remnants of the central portion of the 
 odontoblasts, whose lateral portions become transformed into 
 basis-substance ? Are the dentinal fibers formed between the 
 odontoblasts after the latter have become basis-substance? So 
 great, indeed, seemed the puzzle, that quite recently R. R. An- 
 drews deemed it advisable to reiterate a previously-expressed 
 opinion of E. Klein and others, that there are two sets of odon- 
 toblasts, some with broad bases which become basis-substance 
 altogether, and others pear- or spindle-shaped, with long pro- 
 jections, which become the dentinal fibers. These latter they 
 termed ' fibril-cells.'
 
 DEVELOPMENT OF DENTINE. 141 
 
 " It would seem to require a very limited amount of histo- 
 logical or microscopical experience to satisfy oneself of the un- 
 tenableness of these views, as, with not a very high power, 
 projections may he seen running from every odontoblast into 
 the canaliciili of the formed dentine, some giving off one, some 
 two, some three such projections ; while even as many as five 
 offshoots have been seen arising from a very broad end of an 
 odontoblast, and penetrating the canalicuh. The ' fibril-cells,' 
 therefore, are nothing but narrow wedges between broad-based 
 odontoblasts, especially numerous where the periphery of the 
 papilla forms a sharp curvature, as on the pointed cusps. 
 
 " Several questions, however, require our close attention in the 
 history of the development of dentine. One of tliese is, Are 
 the odontol)lasts absolutely necessary as a stage }>rt'liminary to 
 the formation of dentine ? And secondly, how is it that the 
 odontoblasts })ro(hice a continuous mass of dentine from the 
 periphery to the pulp, if they are converted into basis-substance 
 in layers ? For Ave know that the dentine is only in exceptional 
 cases stratified, whereas one would expect such lines of stratifi- 
 cation to be of common occurrence, if one row of odontoblasts 
 after another were to be converted into basis-substance. 
 
 " As to the first question, we are unable to give a positive 
 answer, but take it for granted that the response should be 
 affirmative, and that the odontoblasts are a prere(piisite to the 
 formation of dentine. We often see, at the summit of the 
 papilla, medullary tissue bordering the already-formed dentine 
 without a trace of odontoblasts. Through the researches of 
 John Tomes, we know that the odontoblasts originate in the 
 coalescence of medullary corpuscles of the papillary tissue; 
 and Ave knoAv, furthermore, that the odontoblasts again return 
 to the medullary condition before becoming infiltrated with 
 lime-salts. It appears possible that previous odontoblasts have 
 been transformed into medullary tissue, and no new ones pro- 
 duced at that particular period. 
 
 " To the second question, whether or not the odontol )lasts form 
 a single row for the time being, thus inv<^lving an interruption 
 in the a}>iK'arance of the basis-substance of the dentine, a positive 
 answer can l)e given, in accord with the observations of Kolli- 
 kcr in 1852, above quoted. The difierence, however, between 
 his views and ours is. in our judgment, sufficiently marked to 
 demand attention.
 
 142 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 " lie declares that there is hut one row of odontoldasts capable 
 of producing dentine, and that these become continuous by a 
 proliferation of the nuclei of the original single row. He dis- 
 tinctly denies that the pulp as a whole can be converted, layer 
 after layer, into odontoblasts. We, on the contrary, agree with 
 John Tomes in the view that the medullary corpuscles of the 
 papillary tissue are progressively converted into odontoblasts, — 
 a view which explains the fact that, with the advancing growth 
 of the dentine, the Inilk of the papilla diminishes. We add 
 another point, — viz, th<if c<ich odont(ih1<ist, ichile being redared to 
 medtdlari/ corpuscles at ds distal or peripheral end, is beimj added to 
 by an attachmeid of medullary corpuscles of the papillary tissue at 
 its proxiiUid or central end. 
 
 '' Undoubtedly there are periods of comparative rest, in which 
 a fully-developed odontoblast borders the dentine, and dips into 
 the papillary tissue with sharply-defined contours, with its nar- 
 row and pointed end. As soon, however, as the building of 
 dentine is resumed, the peripheral end of the odontoblast is seen 
 to have divided itself into medullary bodies again, and, simul- 
 taneously, rows of medullary corpuscles are superadded to the 
 opposite or central end. 
 
 " A beautiful illustration of this process may be seen in the 
 developing tooth of a l»ig's fcetus, ten centimeters long. (See Fig. 
 85.) Here we see several rows of odontoblasts, bordering the 
 non-calcified portion of the basis-substance of the dentine. At 
 that portion, in which unchanged odontoblasts stand against the 
 dentine, others are attached to the uppermost row, likewise in 
 full development. This we consider as a condition of compar- 
 ative rest. At that [)ortion, on the contrary, in which the 
 odontoblasts are replaced by medullary corpuscles toward the 
 dentine, without a distinct l:)oundary-line between the two, we 
 see rows of medullary corpuscles attached to the inner ends of 
 the odontoldasts, whereby the transverse diameter of the odonto- 
 blastic layer is noticeably broadened. In the former instance, 
 the layer of odontoljlasts is fairly well marked toward the pap- 
 illary tissue; in the latter instance it is indistinct, the odonto- 
 blasts blending with the papillary tissue. 
 
 " High powers of the microscope still better illustrate this view. 
 (See Fig. 86.) At the same time it becomes evident that the den- 
 tinal fibers, originally attached to and connected with the 
 odontoblasts, become situated l)etween the medullary corpuscles
 
 DEVELOPMENT OF DENTINE. 
 
 143 
 
 ±iIG. 80. 
 
 '■^F 
 
 DC 
 
 Tooth of a Pig's Fujtus 10 Centimeters Long. 
 D D ealcifiea dentine; Z>a non-calcified dentine; 0. row of odontoblasts partly fully fomed, 
 panly for ;;': 3/ odontoblasts broken up into -eduUary corpuscles mthe^rooe. of forma- 
 tion of dentine ; P. vascularized myxomatous tissue of papiHa. Magnified 400 diameter..
 
 144 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 Fig. 86. 
 
 DM 
 
 Tooth of a Pig's Fo-;tus 10 Centimeteks Long. 
 
 I>. T), calcified dentine ; I)(\ non-calcified dentine : DM, dentine in the process of formation 
 from medullary corpuscles: O. odontoblasts in multiple rows, spindle-shaped elements wedged 
 in between the broad odontoblasts; M, medullary corpuscles arisen from odontoblasts, such 
 con)U3cles also attached to the distal ends of the odontoblasts. jNIagnifiod 120U diameters.
 
 DEVELOPMEXT OF DENTINE. 
 
 145 
 
 Tooth of a Human FffiTVS Six Months Old. 
 
 7), n, calcified and stratified dentine ; DC, DC, non-calcified dentine, the border of the calci- 
 fied dentine being marked by glolmlar tormations; <K odontoblasts splitting into medullary 
 corpuscles toward the donline. and showing rows of such corpuscles at the distal ends; M, 
 medullary corpuscles ready for the transformation into basis-substance of dentine; /", P, 
 myxomatous tissue of papilla. Magnified 600 diameters. 
 
 11
 
 146 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 Fig. 88. 
 
 Tooth of Human Fffixus, Sf.vkx Months. 
 
 D, I), dentine calcified ; DC, non-calcified basis-substance of dentine, close above the capil- 
 lary blood-vessels broadened and visibly raade up of medullary corpuscles : C, capillary blood- 
 - jssel in transverse and longitudinal section : .1/. M, medullary corpuscles ready for infiltration 
 T. 'th basis-substance : MO. MO. medullary corpuscles arranged in rows for tbe formation of 
 odi -itoblasts. Magnified 1200 diameters.
 
 T)?]VI"]LOPMEXT OF DENTINE. 147 
 
 as soon as the toriuer are converted into the hitter. Wher- 
 ever Ave iiotioe rows of inedullarv corpuscles at the inner ends 
 of the odontoldasts, delicate fil)rill'<i2 are seen coursing l)etween 
 their rows or groujis. 
 
 Since, accordinij: to our views, the myxomatous basis-sub- 
 stance of the papillarv tissue is supplied with living matter, the 
 same as are the so-called cells, there is no difficulty in explain- 
 ing the origin of new protophismic bodies from the previous 
 myxomatous basis-substance, for the benefit of continuous addi- 
 tions to tile odontoblasts. 
 
 The facts jnst descril»ed are well illustrated in tlie developing 
 teeth of a liuinau fu-tus trom six to seven months old. (Sec 
 Fig. 87.) 
 
 The cusp of the dentine shows stratification, although no 
 odontoblasts are seen at the summit of the papilla. At the 
 sides of the cusps, odoutobhists make their appearance, broken 
 up into finely-granular medullary corpuscles, toward the non- 
 calcitied basis-substance of the dentine, and augmented in their 
 l)ulk by rows of glistening, almost homogeneous, medullary 
 corpuscles, toward the papillary tissue. Occasionally we meet 
 with a basis-sul)stance of dentine not yet calcified, and still ex- 
 lnl)iting its composition of medullary corpuscles. (See Fig. 88.) 
 
 Upon stndying this specimen, all doubts as to the origin of 
 the basis-substance of the dentine must vanish. All previous 
 attempts at ex}>laining how the odontoblasts are converted into 
 dentine must [)rove futile in the face of such a specimen. 
 Although we adnnt that such a plain instance is only excep- 
 tionally seen, we thought it to be so instructive and so con- 
 vincing that we had an illustration made with a very high power. 
 With the fiicts advanced, a hitherto mooted question seems to 
 have found solution. 
 
 As to the fpiestion why dentine in all its stages of develop- 
 ment appears to be a continuous mass, and l)ut exceptionally 
 interrupted by marks of stratification, the explanation is that 
 the odontobhists themselves are continuous. Xot that the 
 origiiud odontoblasts are preserved and augmented from the 
 perijihery toward tlie in-nter; but all that is converted of an 
 odontoblast into dentine, at its peripheral })ortion, is nuide good 
 by the addition of medullary corpuscles at their central ends 
 or portions, from the tissue of the [tapilla, — protoplasmic bodies 
 and basis-substance, both.
 
 148 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 CHAPTEE XV. 
 
 DEVELOPMENT OF THE ENAMEL.* 
 
 The history of the development of the tissues of the teeth is 
 not intelligible on the .basis established by the researches of 
 Eemak. According to this observer, the epiblast and the 
 hypol>last are epithelial formations, and give rise to epithelial 
 tissues and their derivations only. The mesoblastis connective 
 tissue, including the muscles, the blood-vessels, and the lymph- 
 vessels. Early investigators in emV)rvology were embarrassed 
 in attempting to explain the origin and formation of the central 
 nervous system (brain and spinal cord), which unquestionably 
 has its origin in the epil>last, although "in full development it 
 contains a large amount of connective tissue, and blood-vessels ,^ 
 which are intermixed with nerve-substance proper, such as the 
 gray substance, the ganglionic corpuscles, and the axis-cylin- 
 ders. For that portion of the e}til)last which gives rise to the 
 nerve-centers, some authors have proposed the name " neuro- 
 epithelium." This would im[»lv that from an original epithe- 
 lial structure, tissues may arise which have no resemblance to 
 epithelia, and do not contain any, excejit in the ventricular 
 lining of the brain and the central canal of the spinal cord. 
 It is admitted, therefore, that a certain [)ortion of the epithelium 
 of the embryo contains protoplasm, Avhich, in turn, becomes 
 gray substance, forms the ganglionic corpuscles and axis- 
 cylinders, as well as the investment of the latter, — the myelin 
 or nerve-fat, — and the |icrineurium or neuroglia, which all 
 authorities admit to be a delicate librous connective tissue. 
 
 The history of the development of the enamel likewise 
 furnishes striking proofs of tlie fact that the theory of exclu- 
 siveness, so far as tlie e^dblast is concerned, is not tenable. We 
 have demonstrated that the original epithelial cord of the 
 enamel-organ serves for cari'viug a certain amount of building 
 material into the depth of the connective tissue. This material, 
 however, loses its epitlu-lial nature as soon as it gives rise to 
 the enamel-organ proper, whicli is myxomatous connective 
 tissue. The fact was establislied that the tissue termed enamel 
 
 * " Contributions to the History of Devc4opment of the Teeth." By C. Heitz- 
 mann and C. F. W. Bodeckcr. Thf liiilriii„ih'}ii Vrdridionrr^ vols, viii and ix.
 
 DEVELOPMENT OF THE EXAMEL. 14:9 
 
 is epithelial in its origin only, and that it is chano-ed from its 
 original character shortly hefore becoming enamel ])roper. 
 We must admit that enamel will not he formed unless upon an 
 epithelial basis, the epithelium in this instance being the 
 conveyer of the protoplasm from which enamel originates. 
 But to assert that enamel is an epithelial structure throughout, 
 w«'uld be as erroneous as to call the brain and the spinal cord 
 epithelial structures. 
 
 From an organo-genetic point of view, we may say that the 
 outer senses of the animal organism, serving for perceptions 
 from the outer world, are formations of the outer investment 
 of the animal, its epiblast. The brain, being the most highly 
 perfected organ of sensual perception, continuously takes its 
 growth from the epiblast. The same may be said of the teeth, 
 
 Fig. 89. 
 
 Human Embryo Six Weeks Old. Frontal Section. 
 
 T, tongue ; L, lip ; B, base of oral cavity; F, furrow, in transverse section, funnel-shaped. 
 Magnified 25 diameters. 
 
 which, in some lower order of amphibious organisms, such as 
 Chelonia, are nothing l)ut horny ledges, or a thickening of the 
 epithelium. Even at the height of development their growth 
 is continuous from the epildast, and they are, at least as far as 
 the enamel is concerned, derivations from it. 
 
 Let us now consider the direction takt'ii l)y the ejiithelial 
 i-ord of the (.'namel-organ into the (U'ptli of the connective 
 tissue, up to the time when the enamel-organ is ready for the 
 formation of the rnamel. Tiie first trace of the future tooth 
 in the human embryo is xisililc al>oiit the sixth Aveek of intra- 
 uterine life, when the epithelium of the oral cavity is as yet 
 little developed. Here we notice a furrow, which is situated 
 close behind the lip, an<l is succeeded by an elevation of medul- 
 lary tissue. (See Fig. 89.)
 
 150 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 After this period follows the formation of an epithelial peg, 
 appearing not at the bottom of the primitive dental furro^Y, 
 hnt at some distance from the latter. This peg appears as a 
 reduplication of the epithelial layer covering the elevation 
 behind the furrow. (See Fig. 90.) 
 
 Shortly afterward, the epithelial hill has gained in height 
 considerably, and from the point which connects the hill with 
 
 Fig. 90. 
 
 Base of Oral Catitt of Humax Embryo Two Months Old. Frostal Section. 
 T, tongue: L, lip; B, base of oral cavity; F, furrow; £'^, epithelial hill; EP, epithelial 
 peg. Magnified 2-5 diameters. 
 
 Fig. 91. 
 o 
 
 Base of Oral Cavity of Human Embryo Two and a Half Months Old. Frontal 
 
 Section. 
 EH, epithelial hill ; 0, epithelial lining of base of oral cavity ; F, furrow ; EC, epithelial 
 cord of enamel-organ ; EO, club-shaped enlargement of the epithelial cord, the future enamel- 
 organ. Magnified 2-5 diameters. 
 
 the rest of the oral epithelium, the original peg has elongated 
 into an epithelial cord. A striking feature of this cord is that 
 from its periphery arise blunt or slightly-pointed offshoots, 
 while at the same time its distal end is noticeably broadened, 
 the epithelia being arranged in radiating tracts throughout, 
 but most markedly in the club-shaped enlargement of the distal 
 end. (See Fig. 91.)
 
 DEVELOPMENT OF THE ENAMEL. 
 
 151 
 
 In the third month of embryonal life, the epithelial hill still 
 remains a prominent formation. From the point of its junc- 
 tion with the other epithelium arises the epithelial cord, which 
 varies, to some extent, both in width and in its course. Some- 
 times the cord runs nearly parallel with the base of the oral 
 cavity, becomino; devious on the way to its club-shaped distal 
 end. Its periphery is slightly fluted, and from its lower contour 
 arise scanty but strongly-marked epithelial oftshoots, the signi- 
 ficance of which is not perfectly plain. We may assume that 
 a large secondary offshoot forms the epithelial cord of a future 
 permanent tooth, but as to the significance of the short second- 
 ary offshoots we can only suggest that the epithelium primarily 
 
 Fig. 92. 
 
 Base op Oral Cavity op a Human Embryo Three Months Old. 
 
 EII. epithelial hill ; F, furrow, sharply marked and lined by a heavy layer of flat epithelium ; 
 0, base of oral cavity ; EC, epithelial cord ; EO, club-shaped end of the epithelial cord, the 
 future enamel-organ ; .S', secondary offshoot ; SP, secondary offshoot, possibly a germ of the 
 permanent tooth ; P, papilla. Magnified 'lb diameters. 
 
 producing the cord at first assumed a direction which afterward 
 was changed. This much is certain, that such short secondary 
 oftshoots perish and disappear in the course of further develop- 
 ment. It would certainly be a bold hypothesis to consider all 
 such short secondary oftshoots germs of supernumerary teeth, or 
 of third dentitions. They are too common as compared with the 
 rare cases in which supernumerary teeth are found. At this 
 stage of development the first trace of the papilla (the future 
 dentine) is noticeable. (See Fig. 92.) 
 
 Sometimes the epithelial cord is broad, exhibiting compara- 
 tively few blunt secondary offshoots. Its course is more or less
 
 162 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 vertical, into the depth of the connective tissue of the jaw. 
 The epithelium within the cord is arranged into groups sepa- 
 rated by trabecul^e somewhat resembling those of true myxoma- 
 tous connective tissue. The club-shaped end of such a cord at 
 this period shows a sliglit separation of the columnar epithelium 
 into an outer and an inner layer, whereas the center of the club- 
 shaped enlargement is occupied by medullary corpuscles, which 
 as yet do not exhibit the characters of a myxomatous reticulum. 
 Unquestionably, this medullary tissue has arisen from epithelia, 
 which originally filled the club-shaped end of the cord, and it is 
 
 Fig. 93. 
 
 Floor of Oral Cavity of a Human Embryo Three Months Old. 
 
 EH, epithelial hill ; f, furrow; 0, oral epithelium ; EC, epithelial cord : .S', short secondary 
 oflFshoot; EO, medullary tissue of enamel -organ; P, papilla, detached. Magnified 25 
 diameters. 
 
 this medullary tissue from which, soon afterward, the myxoma- 
 tous reticulum of the enamel-organ proper originates. (See 
 Fig. 93.) 
 
 We found an epithelial cord of a three-months' embryo pre- 
 senting i)oiiits of interest, since it showed evidences of the 
 germ of a temporary molar. A short oftshoot arose at the 
 place of origin of tlie e]iithelial fc)r<l, while the latter made a 
 few shallow convolutions and then abru}ttly turned dowuAvard 
 in a direction almost at right angles to its former course. 
 
 At the place of the turn a broad e])ithelial layer was per- 
 ceptible, showing the rather thin e[>ithelial tracts before alluded
 
 DEVELOPMENT OF THE ENAMEL. 
 
 153 
 
 to, and ill part, toward tliu adjacent nuMlnllaiy tissne, indis- 
 tinctly Itordcivd. The club-shaped end of the e})ithelial cord 
 was divided into two segments hy an intervening" deep fissnre. 
 The broadest segment, again, showed Idunt protnberances, to 
 which corresponded shallow hills of the snbjacent papilla. 
 The chib admitted of an indistinct differentiation into an ex- 
 ternal and internal epithelium, whereas its center exhibited a 
 few tVunt tracts of e[)itlielia and a hirge amount of medullary 
 tissue, wliich as yet had nowhere begun the formation of a 
 jnyxomatous reticulum. (See Fig. 94.) 
 
 When the embryo lias reached about the fourteentli week, 
 
 Fu). 94. 
 
 Base of Oral Cavity of a Human Embryo Thrkk Months Old. 
 
 A7/, oi)itheIiaI hill; /'.furrow; 0, oral epithelium; EC, epithelial cord of enamel-organ; 
 .S, short secondary offshoot ; SP, broad secondary offshoot, possibly the germ of a permanent 
 molar ; EG, club of the epithelial cord filled with medullary tissue (the future enamel-organ ) ; 
 P, papilla. Magnified 2o diameters. 
 
 the epithelial cord is of special interest, on account of the ap- 
 pearance of two distinct layers at its distal end, the internal 
 and the external epithelium, between which the myxomatous 
 enamel-organ makes its a])p».'arance. Tlie papilla, at this point 
 of develo}iment, has a distinct neck, being of a mushroom 
 shape. At its distal iicriphcry it is lun'deri'(l liy a thin layer of 
 fibi'ous connective tissue extending upward along the external 
 epithelium to a certain height, and }>roducing what has been 
 termed the follicle, or tooth-sac. In one of our specimens the 
 epithelial cord emanates with a broad base from the ei>ithelial
 
 154 
 
 THE AXATOMY AND PATHOLOGY OF THE TEETH. 
 
 liill, having at this point several short and blunt offshoots 
 directed downward. Its general course is almost parallel to the 
 floor of the mouth. The enamel-organ originates from its distal 
 end in an abrupt rectangular manner, with a somewhat narrow 
 neck. The external epithelium extends into a solid peg, with 
 a slight sigmoidal curvature, obviously the germ of the future 
 permanent tooth. (See Fig. 95.) 
 
 In another specimen of the same period, the epithelial cord 
 arises from the base of tlie epithelial liill, with a narrow neck, 
 in immediate connection with a solid epithelial peg, running a 
 downward vertical course, with a slio-ht sigmoidal curvature. 
 The epithelial cord itself shows Idunt offshoots upward as well 
 as downward, the former being characterized by a distinct con- 
 centric arrangement of their epithelia. The general course of 
 
 Fk;. 95. 
 
 Base of Oral Cavity of a Human Embryo Three and a Half Months Old. 
 EH, epithelial hill : 0, oral epithelium ; EC, epithelial cord ; SP, secondary offshoot of a 
 permanent tooth, arising from the external epithelium of the enamel-organ; jFO, enamel - 
 organ of a distinctly myxomatous character; P, papilla ; F, follicle. Magnified 25 diameters. 
 
 the eitithelial cord is slightly downward. Its cup-shaped distal 
 end is marked by three prolongations, the concavities of which 
 correspond to two myrtle-leaf-shaped papillae. Evidently, this 
 is the germ of a future temporary molar. No trace of a corre- 
 sponding permanent tooth was visible at the distal end of the 
 e}»ithelial cord. The external epithelium is very broad, and 
 visible only along the broad cup. The enamel-organ is narrow, 
 but possesses a pronounced m^'xomatous structure. (See Fig. 
 96.) 
 
 The fourth month of embryonal life differs from the previous 
 stage only as the myxomatous enamel-organ gains considerably 
 in volume, with a simultaneously-marked differentiation into 
 its two l)oundarv layers, the external and the internal epithe- 
 lium. The }ia]>illa, at this stage, likewise, has gained in bulk.
 
 DEVELOPMENT OF THE ENAMEL. 
 
 155 
 
 and its onvelopinii' laver of fibrous c-onncctive tissue exteuds 
 farther up aloni^ the eouvexitv of tlie c'U]» of the euamel-orgau. 
 In one of the speeiniens, the epithelial hill is extremely marked, 
 and contains a central vacuole, possibly the first step toward its 
 destruction, since shortlv afterward no trace of it is found. 
 
 Fig. 96. 
 
 Floor nv Okal CAvrrir ok a Human E.mbryo Three and a Half Months Old. 
 EH, epithelial hill ; 0, oral epithelium ; EC, epithelial cord of enamel-organ ; SP, second- 
 ary offshoot, possibly the germ of the permanent tooth ; EO, enamel -organ ; P^ and P", double 
 papilla ; F, follicle. Magnified 25 diameters. 
 
 Fig. 97. 
 
 Floor ok Oral Cavity ok a Human Embryo Four Months Old. 
 A'//, epithelial hill; 0, oral epithelium; £"6", epithelial cord with numerous offshoots; SP, 
 ' '■ ' "—-="- F, follicle. 
 
 A//, epithelial hill; 0, oral epithelium; £"(', epithelial cord with numerous off: 
 secondary peg of permanent tooth ; EO, myxomatous enamel-organ ; P, papilla ; 
 Magnified 25 diameters. 
 
 The epithelial cord begins with a narrow neck, and has numer- 
 ous oblique secondary otishoots, mainly at its upper periphery. 
 The arranii:emeiit of the epithelia. into tracts is marked along 
 the epithelial cord, not only of the temporary but also of the 
 permanent tooth. (See Fig. 97.)
 
 156 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 In another specimen of the same age, the epithelial hill is 
 iibsent. The cord has Init a limited numher of offshoots, some 
 of which are pediculated, and some have the shape of a lancet. 
 The peg of the permanent tooth is conspicuous by its devious 
 course. (See Fig. 98.) 
 
 When the embryo is ajt the age of four and a half months, 
 the development of the enamel-organ has still further pro- 
 ceeded; its myxomatous tissue is plainly marked, and the 
 papilla has correspondingly gained in bulk. The specimen 
 illustrated is noteworthy for its short vertical epitlielial cord, 
 which is directly in connection with the lining epithelium of 
 the oral cavity. The secondary offshoots are but short, and no 
 trace of a peg for the permanent tooth is visible in this section. 
 The cup of the enamel-organ is lobulated, evidently belonging 
 to a future molar. (See Fig. 99.) 
 
 The next question to be considered is, How does epithelium 
 grow from an originally small point into a comparatively long 
 epithelial cord ? JMost oliservers agree that epithelium has an 
 independent growth, and that its elements l»y division and 
 multiplication will produce e[)ithelium, and no other tissue. 
 During tlie last fourteen years many microscopists have studied 
 the so-called indirect division of "individual cells,"' which 
 became tracealile after the application of certain reagents, 
 especially safranine. This dye rendered visible a filamentous 
 structure in the nucleus, apparently independent of the sur- 
 rounding protoplasm, which did not take up the stain of the 
 safranine. The filaments produced beautiful star-shaped figures, 
 with ecpiatorial divisions leading to a fission of the original 
 nucleus, and the process lias been termed karyokinesis or utitosis. 
 
 In fresh specimens, or those preserved in a chromic-acid solu- 
 tion, the filamentous structure of the nucleus does not exist, or, 
 at least, is not plainly visible, although Bizzozero, of Italy, 
 claimed that safranine will bring out the filamentous structure 
 of the nucleus even in chromic-acid specimens. The filaments 
 taking up the dye were termed chromatin, and all those remain- 
 ing pale, achromatin; and it was claimed that these were two 
 different substances. Considering the fact that the filaments 
 are produced only by certain reagents, we should be loth to 
 assume that the structure thus rendered visible really corre- 
 sponds to the unstained and living epithelium. The doubts 
 become still stronger, if we recall the fact that living matter is
 
 DEVELOPMENT OF THE EXAM EL. 
 Fig. 98. 
 
 157 
 
 Floor of Oral Cavity of a Human Embryo Four Months Old. 
 
 0, oral epithelium ; EC. epithelial cord ; S, short pediculated offshoot ; -SW, secondary off- 
 shoot, lancet-shaped : SP. secondary peg of permanent tooth : EO, enamel-organ ; P, papilla ; 
 F, follicle. Magnified 25 diameters. 
 
 Fig. 99. 
 
 Enamel-Oroax and Papilla of Human Embryo Four and a Half Months Old. 
 
 0, oral epithelium : EC, short epithelial cord ; S, secondary offshoot ; EO, enamel-organ ; 
 P, papilla ; /', follicle. Magnified 25 diameters.
 
 158 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 stained deeply by the same reagent, if present in a compact 
 mass, where thin layers of it remain unstained, as is the case in 
 the protoplasm which surrounds the central nucleus. From 
 this point of view the terms chromatin and achroniatin be- 
 come superfluous, especially if we admit that the living matter 
 during life is in constant motion, particularly in the process ot 
 growth, although its continuity may temporarily be interrupted. 
 What we see in a growing epithelial cord, with high powers 
 of the microscope, is depicted in Fig. 100. 
 
 Fig. 100. 
 
 Epithelial Cord of the Examel-Orgax ok a Human E.mbryo Threp: a.vd a Half 
 
 Months Old. 
 
 E, epithelial cord ; C, connective tissue. Magnified 8<Xl diameters. 
 
 We observe epithelia along the borders of the cord which 
 are elongated and bear the name of columnar epithelium : while 
 the central portion is filled with epithelia which exhibit about 
 an equal diameter in all directions, and are termed cuboidal. 
 Both varieties sliow dift'erences in the size and structure of 
 tlieir nuclei. Some nuclei are very large and distinctly reticu- 
 lar, others are small and nearly compact, often appearing as if 
 split up into several lumps, Avith a vacuole or plasmatic space. 
 Sometimes a nucleus is elongated or irregular in shape, another
 
 i>i:\ i:i,()i'.Mi;.\T of the enamel. 159 
 
 being glol^iilar or vesicular. Again, we see e})itlielia much en- 
 larged, holding in their interior several nuclei. An epithelium 
 in this condition has been termed hy previous observers " the 
 mother cell."' Not infrequently we observe solid, spindle-shaped 
 bodies in the cement-substance, between two epithclia. All 
 these forms become intelligible only under the assumption that 
 epithelium is composed of protoplasm, in which the living 
 matter greatly varies in size and shape, according to the state 
 of growth and new formation. The cement-substance is often 
 absent, and thus large protoplasmic masses become conspicuous, 
 with a varying number of nuclei. Where the cement-substance 
 is present, it is usually traversed by radiating lines, which are 
 the connecting bridges of the living matter. Again, these 
 lines may coalesce into solid masses, presenting spindle, pear, 
 or club shapes, from which new epithelia arise, as shown by 
 Louis Elsberg. 
 
 The way, therefore, in whicli epithelium grows is by the 
 augmentation of its living matter, and the appearance of new 
 cement-substance, — that is, new lines of demarcation, in which 
 process the continuity of the living matter, though temporarily 
 interrupted in certain foci, in the whole remains preserved and 
 unbroken. In the epithelial cord of the enamel-organ the 
 connecting spokes in the cement-substance are prominently 
 marked in all its layers and stages of development. 
 
 We now proceed to consider the changes of the enamel-organ 
 aljout the beginning of the fifth month. If we examine the 
 cup-shaped enlargement of the enamel-organ at this period, we 
 observe a distinctly-marked border composed of columnar epi- 
 thelia, whereas the interior of the cup is filled with medullary 
 corpuscles, which, in the center, present the so-called stellate 
 reticulum. At the end of the fourth and the beginning of the 
 fifth month, we invariably find some epithelial cords, which, at 
 tlieir interior ends, are broadened and contain a distinctly marked 
 stellate reticulum. (Fig. 101.) 
 
 The first (piestion to be entered into is. Whence comes the 
 myxomatous tissue known as the stellate reticulum in the inte- 
 rior of the cup ? According to our present knowledge of the 
 tissues of the mammalian organism, we are entitled to call the 
 stellate reticulum a myxomatous tissue, which is a variety of 
 connective tissue. This tissue occurs most extensively in the 
 embrvonal ora'anism, and remains throuii'liout life in the fullv-
 
 160 
 
 THE- ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 developed body only in a limited niimbtr of organs, sue-h as the 
 pulp of a tooth, the lyniph-iranglia, and the so-called adenoid 
 tissue, which properly ought to be called lymph-tissue, and i* 
 
 Fig. 101. 
 
 fi-^4W 
 
 Epithelial Cord terminating in the Enamel-Organ. Human Embryo at the End ok 
 THE Fourth or the Beginning of the Fifth Month of Intra-Uterine Life. 
 
 0. stratified epithelium of the oral cavity; TT, epithelial cord of temporary tooth; PT, 
 epithelial cord of permanent tooth ; N, epithelial nests and buds at the bottom of the furrow 
 and along the cords of both the temporary and permanent teeth ; M, myxomatous tissue of the 
 enamel-organ (stellate reticulum ); iTi", external (outer) epithelium; IE, internal (inner) 
 epithelium ; /, intermediate layer between inner epithelium and myxomatous tissue ; P, papilla 
 with numerous blood-vessels; E, embryonal or medullary tissue crowded with medullary cor- 
 puscles at a certain distance from the epithelial formation. Magnified 50 diameters.
 
 DEVELOPMENT OF THE ENAMEL. 161 
 
 distributed throughout the mucous membranes, especially 
 during the early periods of life. Unless we assume that the 
 enamel-organ is a tissue entirely different from all others enter- 
 ing into the structure of tlie 1)ody, we must call it myxomatous 
 connective tissue. 
 
 Those who adhere strictly to the teachings of Thiersch and 
 Waldeyer will l)e loth to admit that epithelium can ever change 
 into connective tissue. Researches thus far, however, have led 
 us to the conviction that such a transformation is by no means 
 impossible. The thyroid gland, for instance, is originally com- 
 posed of alveoli lined by epithelia. Shortly after birth, how- 
 e^'er, the epithelium is replaced by a medullary or lymph- 
 tissue. The whole central nervous system (the brain and spinal 
 cord) originates from the eml)rvonal epiblast, which is strictly 
 ei)ithelial in nature. J^evertheless, nobody will maintain that 
 the central nervous system, so richly supplied with blood-ves- 
 sels, is an epithelial structure, except in the lining of the ven- 
 tricles of the brain, and the central canal of the spinal cord. 
 There may be advocates of the exclusive nature of epithelial 
 -tissue who miglit think of an immigration of medullary cor- 
 puscles between the epithelia of the enamel-organ for the bene- 
 fit of the formation of the stellate reticulum, but there is not 
 the least indication of such a process in any of our specimens. 
 On the contrary, we can prove a gradual transformation of the 
 epithelia into myxomatous tissue. 
 
 In the third month of iiitra-uterine life, we observe, inside 
 of the epithelial cup of the enamel-organ, a zone entirely occu- 
 pied by medullary corpuscles, and even in the fourth and fifth 
 months such a gradual transition is distinctly traceable (Fig. 102). 
 
 Those who still adhere to the cell doctrine will never be able 
 to understand how medullary tissue arises from epithelia. Ac- 
 cording to our views, however, there exist no individual cells, 
 but layers of protoplasm, in which the living matter is dis- 
 tributed in a reticular arrangement. Every particle of the 
 living matter is able to grow from the size of a minute granule 
 to that of a solid lum}>, in which afterward takes place a dif- 
 ferentiation into a peripheral protoplasm containing compara- 
 tively little living matter, and a central body, termed nucleus, 
 with a larger amount of living matter. 
 
 The inner epithelia, at the period mentioned abc)ve, exhibit 
 augmented nuclei and small glistening"granules near the fold, 
 
 12
 
 162 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 EE 
 
 EM 
 
 Lower Edge of the Cl'p of the Examel-Orgax, showing the Recurvation of the- 
 External into the Internal Epithelium, at the End op the Fourth Month ok 
 Intra-Uterine Life. 
 
 EM, embryonal or medullary tissue ; EE, external epithelium, composed of cuboidal epi- 
 thelia: T, cuboidal epithelia turning into columnar epithelia : IE. inner epithelium breaking 
 down into medullary tissue and giving rise to the spindles comiiosing the intermediate layer, 
 close above the internal epithelium : M, myxomatous tissue, or stellate reticulum, bounded 
 toward the external and internal epithelium by the intermediate layer, and continuous with the- 
 medullary tissue filling the border of the cup ; P, papilla. Magnified 500 diameters. 
 
 Fig. 103. 
 
 Inner Epithklum of the ENAMKL-0R<iAN of a Human Embry<i of Four Months of 
 
 Intra-Uterine Life. 
 
 E, inner epithelia connected with each other by delicate thorns, traversing the cement-sub- 
 stance. In their interior vacuoled lumps are seen of greatly varying sizes, which toward the 
 enamel-organ are split up into smaller reticulated corpuscles, all being interconnected by deli- 
 cate oflfshoots ; /, intermediate layer composed of spindle-shaped medullary corpuscles; M^. 
 beginning formation of the myxomatous reticulum, in the meshes of which we observe nucle- 
 ated protoplasm. Magnified 1200 diameters.
 
 DEVELOPMENT OF THE EXAMEI.. 1(J3 
 
 correspondinu" in position to tlie ncn-k of tlio tiiture tooth. The 
 more we turn to the center of tlie eiip, the more shall we be 
 striU'k by the [iresenee of glistening- homogeneous lumps in the 
 epithelia, until we have reached the center of the cup, where 
 we observe that epitheliuni lias l)een transformed into a number 
 of such lum]»s in a regular arrangement, wliicli reminds us of 
 their origin from previous epithelia. The original epithelia 
 gradually become enlarged, and at last are split up into a 
 number of medullarv corpuscles. As a rule, this process of 
 transformation is most marked in the original epithelia at the 
 portion directed toward the stellate reticulum, whereas, in that 
 portion nearest the papilla, the epithelial character may still be 
 preserved. (Fig. 108.) 
 
 The medullarv corpuscles Hrst assuming a spindle shape, 
 constitute the intermediate layer {strtitam iiiterniediain). The 
 innermost spindles are in connection with a comparatively 
 coarse net-work, representing the first trace of the stellate re- 
 ticulum. The trabecules of this reticulum are composed of 
 solid or vacuoled spindles, inclosing spaces which appear to be 
 filled with a distinctly reticulated protoplasm, holding central 
 nuclei. The latter exhil)it a varying number of coarser gran- 
 ules, the so-called nucleoli. 
 
 Xot infrequently the intermediate layer is missing, which 
 fact affords the l)est opportunity for observing the gradual 
 transition of the homogeneous globules arising from tlie epi- 
 thelia into nucleated protoplasmic bodies, and finally into the 
 myxomatous reticulum. Changes similar to those described 
 take place in the central portions of the external epithelia, and, 
 as it seems, even precede the changes of the inner epithelia. 
 Thus the original columnar bodies of the outer epithelium are 
 reduced to a roAv of cuboidal epithelia, as seen in Fig. 102, EE. 
 The medullary corpuscles are slightly enlarged ; their nuclei, 
 at first [dainly visible, are likewise split up into a delicate re- 
 ticulum, and l)oth become infiltrated Avitli a myxomatous basis- 
 substance. The peripheral portions of the original medallary 
 corpuscles, on the contrary, are solidified into nucleated forma- 
 tions of living matter, re}>resenting the stellate reticulum proper. 
 The meshes of the myxorjiatous tissue in tlie stellate reticulum 
 arc originally small, and correspond in size to the medullary 
 corpuscles, from which they arose. The corpuscles of the 
 stellate reticulum are mostly solid. ater, several medullary
 
 164 
 
 THE ANATOMY AND PATHOLOfiY OF THE TEETH. 
 
 corpuscles are reij^uired for the formation of a large field of 
 basis-substance. The original stellate retknlun), in this view, 
 must fall back to an embryonal or medullary tissue before 
 changing into a more perfect myxomatous tissue, such as we 
 obserye from the end of the tiftli month of foetal life up to the 
 full deyelopment of the enamel. (Fig. 104.) 
 
 Toward the end of the fourth and the Ijf ginning of the fifth 
 month, the stellate reticulum is composed of nucleated proto- 
 plasmic bodies, with a yarying number of branching and inter- 
 connecting ofishoots. With low powers of the microscope, the 
 basis-substance in the meshes, inclosed by tlie corpuscles and 
 
 Fig. 104. 
 
 t5> 
 
 "4' 
 
 Stell.vte Reticolu.m, or Myxom.vtous Tissue, of the Enamel-Organ or a Human 
 FcETUS OF Five Months of Intra-Utekine Life. 
 
 Magnified 1200 diameters. 
 
 their oftshoots, appears to l>e homogeneous and structureless. 
 The highest powers, however, reveal in this basis-substance the 
 presence of a delicate reticular structure, even without the 
 addition of anj' reagent. This structure has arisen by a direct 
 transformation of the original medullary corpuscles into basis- 
 substance. In the highest development of the stellate reticulum, 
 such as seen in the seventh and eighth months of tuetul life, the 
 nucleated corpuscles are more slender, and the reticulum is com- 
 posed mainly of delicate branching and interconnecting fillers. 
 The further clianges of the external epithelium are of con-
 
 DEVKLOPMENT OF THE ENAMEL. 
 
 165 
 
 siderable interest. While about the fourth month of.intra- 
 uterine lite the inner portions of the external epithelium are, 
 as mentioned above, transformed into medullary tissue and 
 participate in the formation of the myxomatous enamel-organ, 
 a single ro^v of cuboidal epithelia is left. From the remains of 
 
 Fn;. 105. 
 
 Bl'llDING OF THK EXTF.RXAT, EpiTllKLIUM 01' THE EXAM KL-OrG AX OF A HUMAN FWTUS 
 
 Sevkv Months Old. 
 
 iV, myxomatous reticulum of the enainel-orgm ; <', delicate fibrous connective tissue: E, 
 epithelial bud arisen from the external epithelium ; /', large protoplasmic body filled with 
 glistening coarse granules : li, newly-formed blood-vessel. Magnified 500 diameters. 
 
 this external epithelium, a new growth takes place, of a markedly 
 centrifugal ehara<ter. By a multiplication of the epithelial 
 elements, solid buds and knol)s are formed, well known to pre- 
 vious observers. (Fig. 105.)
 
 166 THE ANATOMY AND PATHOLOGY OF THE TEETH, 
 
 These buds are at first in continuity with the external epithe- 
 lium, and have a distinct layer of outer columnar and a varying 
 number of inner layers of cul)oidal epithelia. They are 
 characterized by a brownish color, common to all epithelial 
 formations. We ol)serve that, l)0th in the central portions of 
 these buds and along- the original row of the external epithe- 
 lium, a transformation takes place into medullary corpuscles, 
 the same as we observe toward the myxomatous enamel-organ. 
 This medullary tissue develops into connective tissue of a 
 decidedly fil>rous character. Thus we ol^serve numerous inter- 
 ruptions in the external epithelium, partly filled with medul- 
 lary and partly with fibrous connective tissue. The latter is in 
 direct connection with the myxomatous reticulum, or this con- 
 nection is established by spindle-shaped corpuscles, resemfding 
 those of the intermediate layer close al)Ove the internal epithe- 
 lium. 
 
 At the time when the buds sprout from the external epithe- 
 lium, an active new formation of Idood-vessels and blood- 
 corpuscles takes place in the immediate vicinity of the buds. 
 At first we notice large protoplasmic bodies with coarse gran- 
 ides, which were known to Theodore Schwann, in 1839, by the 
 name of blood-cells. With the increase of the size of these 
 l)odies, the granules likewise become coarser, and assume the 
 properties of the so-called ha^matoblasts. These grow up to 
 the size of red blood-corpuscles, and we not infre(|uently en- 
 counter in the bays between the fuids, gToui)s of haMuatoblasts, 
 or fully-developed l)loo(l-coriniscles, a}»[tarently isolated and in 
 no connection witli blood-vessels. At last, ea]>i]]ary blood- 
 vessels arise from the conference of blood-cells, which are filled 
 witli red blood-corpuscles. The splitting of the external ejiithe- 
 lium into isolated Inids and nests of an epitlielial character is 
 especially nuirked near the neck of the future tooth. (Fig. 106.) 
 At this place the anu)Uiit r)f myxomatous enamel-organ in a 
 seven-months foetus is usually small, since a great quantity 
 of it has already been transformed into enamel-tissue. But 
 even here a fcAV small and isolated epithelial nests are seen, sur- 
 rouufled by a large number of cajiillary blood-vessels, filled with 
 blood-corpuseles. It is evident that all these blood-vessels 
 are newly formed, and iikUhmI we can trace the formation of 
 blood-vessels in this situation step by step. Even the myxo- 
 matous trabeeuhe of the enamel-organ participate in the fornui-
 
 DEVELOPMENT OF THE EXAMEL. 
 
 167 
 
 tioii ot" cajiillarv l)loo(l-vessols. "We liave seen closed spaces, or 
 vesicles, sprmia- from tlie l)asis-snl)staiu'e of the myxomatous 
 tissue, tilled with hajmatoldasts and red hlood-corpuscles, partly 
 in connection with already-formed or forming capillaries. I^o 
 
 Fk;. 106. 
 
 
 
 
 l-BV 
 
 :^BE 
 
 EE 
 
 iA^^'*." 
 
 Isolated Epitheiivi Nesis oi the PLvct oi fhf En vmei -Ok( v\ tnRKESiMiNDiNi; to 
 THE Neck, oj the Futlre Tooth or a Him.4n Fcetus Sfc^E^ Months Old. 
 
 M, my.Komatous reticulum of the enamel-organ ; A, row of ameloblasts : /.intermediate layer 
 composed of sijindles and tilierj : 7>, vesicle filled with haematoblasts and red blood-corpuscles ; 
 1', capillary blood-vessel forming from trabecular of the myxomatous reticulum ; B V, irregular 
 spaces filled with hivmatoblasts and red blood-corpuscles, lined by endothelia and in an incom- 
 plete connection with forming capillaries: KL\ epithelial nests, the remnants of the external 
 epithelium. Magnified 500 diameters. 
 
 douht the living matter inelused in the liasis-suhstanee has 
 grown into htvmatohlasts. This proeess is indicated 1)V the 
 api>earance either of coarsely-granular or of compact glistening 
 nuclei in the meshes of mvxomatous retieiilum.
 
 168 
 
 THE AXATOMY AND PATHOLOdY OF THE TEETH. 
 
 Wherever we ol)t,erve epitlit'lial nests, they are invariably 
 enlarged, toward the enamel-organ, by spindles and fibers of 
 an intermediate layer. Their scarcity and diminutiveness at 
 the place corresponding to the neck of the tooth indicate that 
 they are completely transfn'med into mednllary tissne. Con- 
 sidering the fact that at the end of the intra-nterine develop- 
 ment the enamel-organ is nearly exhansted, and the enamel 
 which is formed np to that time is comparatively thin, there 
 is good reason for the assnmption that the medullary tissne 
 
 Fig. 107. 
 
 DissoLUTiux OF Epithelial Cord of the Ena.mki, -Organ into Isolated Clusters of a 
 Human Fcetus Five Moxths Old. Horizontal Section. 
 
 r*, fibrous connective tissue with scanty blood-vessels: A\ epithelial nest composed of large, 
 flat, almost epidermal-like scales, producing onion-like layers around the central group; this 
 nest is surrounded by tracts composed of cuboidal epithelium; E, clusters of cuboidal epi- 
 thelia holding concentrically arranged epithelial nests; R, remnants of epithelia transformed 
 into clusters of medullary corpuscles. Magnitied 100 diameters. 
 
 Sprung from the previous external. epithelium is the source for 
 the completion of such enamel as we observe npon temporary 
 teeth when they emerge from their sockets. 
 
 Of special interest are concentrically stratified globular nests 
 and buds, in which the epithelia apj»ear flattened and arranged 
 in the shape of an onion. Such nests are often lacking alto- 
 gether, and sometimes they are present in small numbers in 
 tlie center or at the peripliery of the c|tithelial cord. Some-
 
 DKVELOPMEXT OF THE ENAMEL. 
 
 169 
 
 times their nunilxT is very lari^e. The centers of the nests are 
 occasionally tilled with globules of liiu'h refraction, possibly 
 colloid material or cleidin (liorn fat). In some specimens the 
 
 Fig. 108. 
 
 DD 
 
 FiRST-FousiEu Dentin K .\m> Enamel of Hi'm.vx Fcetus, Seven Months. 
 
 E. onamel-cap; i>, calcified dentinal cap; DD, non-calcified dentine ; 0, row of odontoblasts; 
 /'.papilla, with blood-vessols ; -1/, stellate reticulum of enamel -organ ; 7/7, inner epithelium; 
 EE, clu.sters of the remains of the outer epithelium ; C, fibrous connective tissue. Magnified 50 
 diameters. 
 
 epithelial structure of the peg is little marked, especially in 
 places where the epithelial peg produces broadened layers, with- 
 out sharp contours toward the surrounding connective tissue.
 
 170 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 In such places tracts are seen composed of rows of solid nuclei, 
 or solid cords, between which tine gTanular protoplasm is visi- 
 hle. Such tracts have been repeatedly alluded to in the descrip- 
 tion of the early forms of deyelopment of the epithelial cord 
 of the enamel-organ. It is quite possible that in such places a 
 transition takes place from the epithelial to the medullary, and 
 from this to connectiye tissue. This is rendered prol)al)le by 
 the fact that the broadened portions of the epithelial cord have 
 sliarp contours only on one side, whereas the opposite periphery 
 almost l)lends with the adjacent connective tissue, without a 
 distinct line of demarcation l)etween the two kinds. While we 
 admit that the original epithelial peg and cord are of a marked 
 epithelial structure, at the same time we claim that in the 
 advancing process of growth the epithelium does not retain its 
 specitic structure, Init blends with or is transformed into connec- 
 tive tissue. (See Fig. 107.) 
 
 The formation of enamel commences al)Out the sixth month 
 of foetal life, at a period when the dentine, which begins to form 
 about the fifth month, has assumed a certain thickness. About 
 the seventh month. Aye observe at the summit of the papilla a 
 comparatively broad cap, the dentine, and above this a some- 
 what narrower layer of enamel. (Fig. 108.) 
 
 Investigations of the deyelopment of enamel are rendered 
 difficult by the fact that the enamel-organ is almost inyariably 
 found to l:)e detached from the enamel and the i)apilla. This 
 l>erplexity may be ol)viated, at least to a certain extent, l)y till- 
 ing the cavity between the enamel-organ and the enamel with 
 crlloidin. The cavity or space is evidently the result of shrink- 
 age of the delicate myxomatous tissue in the enamel-organ. A 
 peculiar asymmetry is often met with, one side being very 
 broad and the other very narrow. Peculiar indentations, also, 
 are often seen in the course of the inner epithelium. Wliether 
 or not all of this is artiticial, and due to shrinkage, we are unable 
 to state, Init it is certain that as soon as the enamel l)egins to 
 appear there are marked ditfereuces in the structure of the 
 inner epitlielium. At the bottom of the enamel-organ, corre- 
 sponding to the future neck of the tooth, the inner e})ithelium 
 is found to be transformed into medidlary tissue, and the e(\<j:e 
 between the inner and outer epithelium is likewise filled with 
 medullary tissue. Higher up, along the borde'r of the papilla, 
 Avhere theri' is as vet no enamel, we find formations that
 
 DEVELOl'MENT OF THE EXA.MEL. 171 
 
 reseml)le the oriu'inal L'}»itlielia, but wliieli in tliis condition are 
 termed ameloblast^*. The intermediate layer, in connection 
 with the amelol)lasts in this stage, is always markedly devel- 
 oped. Still hio-her up, where ready-formed enamel is present, 
 the amelohlasts are much less regular, and we observe that 
 they again split u]) into medullary corpuscles. From this we 
 draw the concbision that the original inner epitlielium is trans- 
 formed into medullary corpuscles, wliii-h give rise to the amelo- 
 hlasts, and that the latter, before being transformed into enamel, 
 once more l)reak up into medullary tissue. 
 
 In a specimen pre}>ared from a human fuetus of five months, 
 there is scarcely a trace of the inner epithelium left: we see 
 nothing of that tissue except a succession of small glistening 
 medullary corpuscles, which, by their arrangement in rows, 
 remind us of their origin from previous epithelia. This tissue 
 remains plainly visible even in the sixth and seventh months of 
 foetal life, especially, as mentioned above, at the fold correspond- 
 ing to the edge of the enamel-organ in the region of the future 
 neck of the tooth. Higher u[>, the medullary corpuscles, which 
 previously were scattered, once more assume a line-like arrange- 
 ment, and o-raduallv take the shape of narrow elongated cor- 
 puscles, not always distinctly nucleated, and these elongated 
 bodies, somewhat resemlding the original columnar epithelia, 
 are termed amelohlasts. (Fig. 109.) 
 
 One of the striking features in this }»rocess of transformation 
 is the presence of a layer forming the outermost portion of the 
 enamel-organ toward the papilla (Fig. 109, P). This layer, 
 with low powers of the microscope, appears to l)e made up of 
 finely-granular ]»rotoplasm Avith intersi)ersed granular iniclei. 
 Above this, marks of diAision appear in the proto})hismic layer, 
 and the marks corresjiond to the Ixtundary lines of the rows of 
 the glistening medulhiry corpuscles, the forerunners of the 
 future amelohlasts. There is a transitional stage, as referred to 
 in Fig. 109, in which the inner pc)rtions of the amelohlasts are 
 made up of several glistening medullary corpuscles, whereas 
 the outermost portion is finely grannhir, or made up of a deli- 
 cate reticulum. The amelohlasts in the seventh month of foetal 
 life are distinctly-marked formations, and are present only on 
 places where enamel has not \Qt been formed. They are in 
 junction, side l)y side, from the region of tlie neck to the sum- 
 mit of the cr()\vii. They are com]>osed of finely-granular pro-
 
 172 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 toplasm, with one or ^^everal nuclei, or sometimes without any 
 distinct nucleus. Their general form is columnar, slightly 
 broadened toward the papilla. Often, however, they exhibit 
 parallel contours, or a wedge-shape, between two neighboring 
 
 Fk;. 109. 
 
 Segment near the Fold ok the E.namel-okgas, cokkksponiuxg to the Neck of the 
 Future Tooth of a Human Foetus of the Seventh Month. 
 
 PI', papilla ; S, stellate reticulum in an early stage of development; M, medullary corpuscles 
 in a nearly uniform distribution, becoming elongated higher up, and arranged in rows; A, 
 ameloblasts at an early stage of formation, composed of medullary corpuscles ; P, protoplasmic 
 bodies producing the outermost portion of the enamel-organ. Magnified 1200 diameters. 
 
 funnel-shaped ameloblasts (see Fig. 106, A). All ameloblasts 
 are interconnected by delicate conical threads traversing the 
 licrht interstices between them. Their laver is easily distin-
 
 DEVELOPMENT OF THE EXAMKL. 
 
 173 
 
 guisluMl from tlie strllatt,' ri'ticuliun liy tlio iiitennediato layer, 
 which is composed of spindles and li])ers. From their l)ases 
 delicate short ofltshoots often emanate (Tomes's processes), which, 
 however, do not exhihit any reii'ular arrangement. Where the 
 layer of ameloldasts is detached from the surface of the papilla, 
 similar short processes emanate from the surface of the latter, 
 and it is obvious that all these fine offshoots serve for an inter- 
 connection Itetween tlie amelohlasts and the medullary cor- 
 puscles of the papilla. 
 
 Fig. no. 
 
 FrRST-FoKMED Enamel ok a Humax Fo;tuS of Six Munth.s. 
 />, dentine bounded toward the enamel by bay-like excavations: ^.enamel composed of 
 prismatic pieces: ^1, rows of medullary corpuscles sprung from previous ameloblaats. Magni- 
 fied 1000 diameters. 
 
 Still nearer the summit of the crown the amelohlasts once 
 more lose theii' character, and once more break up into medul- 
 lary corpuscles, more or less retaining thk'ir row-like arrange- 
 ment. We ol)serve that the medullary corpuscles ■\\hich lie 
 nearest to the ali-eady-formcd (U'litine are finely granular, 
 whereas the rows some distance ahove are coarsely granular or 
 homogeneous. Tliese finely-granular medullary corpuscles are 
 at last infiltrated with lime-salts, and thus is produced the 
 enamel proper. (Fig. 110.)
 
 174 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 The first trace of eniuiiel, as is well known, appears about 
 the sixth month of intra-uterine life, at a period when a certain 
 amount of dentine has already been formed. The outer sur- 
 face of the dentine exhibits bay-like excavations, in which we 
 often observe a fiat layer of a finely-granular protoplasm, analo- 
 gous to that found in the teeth of adults. Above this layer we 
 see prismatic pieces of calcified l)asis-substance irregularly dis- 
 tributed, since the enamel-prisms, as a rule, do not reach the 
 surface of the dentine, l:)ut are replaced by a homogeneous 
 (Tomes's granular) layer. Yet al )0ve tliis the enamel-prisms are 
 easily recognizable, and appear to be composed of more or less 
 regular square pieces. We can see a deposition of lime-salts 
 along the borders of the }trisms, while their central }»arts often 
 exhibit one large nucleus, or several coarse granules. The 
 interstices between the rows of these square pieces frequently 
 exhil)it delicate fibrillpe, the enamel-fibers, which are in connec- 
 tion with broader protoplasmic tracts, lying in the boundary 
 between the enamel and the dentine. These enamel-fibers send 
 lu'anches through the transverse interstices of the square pieces. 
 Everywhere delicate oftshoots are seen, indicating that the living- 
 matter of the previous medullary corpuscles is y»reserved, even 
 after their infiltration witli lime-salts. 
 
 In the eighth and ninth months of tcetal life, both the enamel 
 and the dentine form soli<l caps, corresponding to the summit 
 of the crown of the tooth, and the one is superimposed upon 
 the other. In decalcified specimens of these tissues, when they 
 have been stained Avith carmin or chloride of gold, we observe 
 a striking analogy in the structure of the enamel to that of tlie 
 dentine. With a magnifving power of 500 diameters, it is difii- 
 cult to differentiate l)etween dentine and enamel. The fibers 
 in the canaliculi of the dentine closely resendde those of the 
 interstices between the enamel-rods. Even the highest powers 
 of the microscope exhibit a close resemlilance of both tissues, 
 more especially after the lime-salts have been c()m]>letely re- 
 moved by means of reagents. 
 
 Let us now ask the question, AVliat is the ultimate fate of 
 the epithelial cord of the enamel-organ ? 
 
 In the earliest stage of its development we meet witli num- 
 erous lateral ofl^'shoots and sprouts, which, preceding their 
 ultimate disappearance, are visible in the sha}ie of medullary 
 corpuscles. The destiny of the cord is obviously to }iroduce
 
 DEVELOPMENT OF THE ENAMEL. 175 
 
 the eiiaiiit'l-orii'an tbr tlie formation of the enaiueL This pro- 
 cess is accomplished with the iifth month of intra-nterine life. 
 In the latter part of the fourth, and in the tifth month, the 
 oriij;;inal e}iithelial cord nndcri^'oes peculiar chanii'es, which have 
 attracted the attention of nnni y previous observers. The main 
 change consists in the l>reaking up of the epithelial cord into 
 innumerable clusters of a more or less markedly epithelial 
 structure, between which tibrous connective tissue has appeared, 
 completely isolating the clusters. Changes of this descri[)tion 
 are best seen in horizontal sections of the jaws. (See Fig. 107.) 
 
 With low powers of the microscope, we observe a large 
 number of clusters which are distinctly marked in specimens 
 preserved in chromic-acid solution. They have a brownish 
 color, and may be either sharply outlined or more or less 
 blended with the adjacent connective tissue. Many of these 
 clusters hold concentrically-arranged e}»ithelial nests, and, 
 judged by their size and shajie, they must have originated from 
 a very active new growth of ejiithelium, which is indii-ated 
 also by a number of buds sprouting from the original clusters. 
 The buds have been pushed apart by fibrous connective 
 tissue, since many of them appear entirely isolated, and as if 
 imbedded in the fibrous connective tissue. Higher powers of 
 the microscope reveal the fact that the process of dissolution of 
 the original cpitliclial cord is identical with that of the disso- 
 lution of the external e})ithelium, the only difi'erence being 
 that in the latter process numerous newly-formed Idood-vessels 
 })articipate, whereas in the l)reaking up of the e[)ithelial cord 
 the new formation of blood-corpuscles and blood-vessels is not 
 very conspicuous. (See Fig. 111.) 
 
 The smallest isolated clusters, still recognizable hj their 
 brownish color, only show traces of a division into epithelia 
 through an intervening cement-substance. Most of them rep- 
 resent protoplasmic masses, with nuclei of varying size, inter- 
 spersed at more or less regular intervals. Such clusters are 
 often found surrounded by an almost homogeneous layer of a 
 so-called basement-membrane. In the next stage, the cluster 
 splits up into nie(hdlary corpuscles at its periphery, whereby 
 its size is consideral)ly diminished, and the basement-membrane 
 lost. Ultimately the multinuclear protoplasmic mass, or the 
 medullary corpuscles, split up into delicate spindles, which 
 l)econie infiltrated with l)asis-substance, therebv assuming' the
 
 176 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 cliaraeteristie features of fibrous connective tissue. Some- 
 times we meet with single brownish corpuscles iml>e(l(led in 
 fibrous connective tissue, and in size surpassing the nuclei of 
 the latter. Such formations are possibly the last remnants of 
 previous epithelia, that have escaped transformation into con- 
 nective tissue. 
 
 The ultimate tVite, then, of the epithelial cord of the enamel- 
 
 DlSSOLUTIOX OF THE EPITHELIAL CORU (JF EnaMEL-OrGAX OF A HlMAN F(ETUS FiVE 
 
 Months Old. Horizontal Section. 
 C, capillary blood-vessel holding red blood-corpuscles; B. B, multinuclear protoplasmic 
 masses arisen from the original epithelial buds; B, remnants of previous epithelia partly 
 transformeil into medullary corpuscles; E. single protoplasmic body, probably epithelium ; M, 
 medullary corpuscles in transition to fibrous connective tissue. Magnified Si)0 diameters. 
 
 organ is the same as that of the external ejtithelium, the cord 
 being partly transformed into connective tissue. The further 
 the development of the enamel and the enamel-organ proceeds, 
 the less is visible of the original epithelial cord, although small 
 epithelial clusters may be recognizable even in the sixth and 
 seventh months of fcptal life.
 
 DEVELOPMENT OF THE ENAMEL. 
 
 177 
 
 "We have nlready alluded to the pussil)ility that the epithelium 
 present l)et\veen the outer surface and the enamel serves as 
 stored-up material for the increase of the enamel, a possilnlity 
 assumahle since at the time of l)irth tliis tissue has hy no means 
 attained the full thickiu'ss whicli we ol)serve at the time of the 
 
 \it^^~^(-^i^y^. 
 
 ^>, 
 
 
 
 / ^ 
 
 Tooth ok a Human Fcetls Sevkx and a Half Months Old. VKuriCAi, Section. 
 
 P, papilla: D, dentine; E, enamel; IE, internal epithelium; EO, enamel-organ; EE. 
 external epithelium; H, remnants of epithelial cord: EN, epithelial nest; EP, pit filled 
 loosely with flat epithelia ; RM, rete mucosum ; Ei), horny layer of the oral mucosa. Magnified 
 50 diameters. 
 
 eruption of the tooth, and since, also, on that }tart of the surface 
 corresponding to the summit of the enamel there is no proper 
 enamel-organ left for the further growth of enamel-tissue. 
 The epithelial cvjrd does not, hoAvever, completely disappear
 
 178 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 toward the end of intra-uterine life. Near the surface of the 
 oral mucosa we often meet with comparatively large spaces 
 filled with loosely-arranged flat epithelia of the character of 
 epidermal scales, as illustrated in Fig. 112. 
 
 Thus tar we have l:)een unable to trace the connection of 
 such a large pit with the rete mucosum, or surface of the oral 
 epithelium. But there can l)e no doubt as to the origin of the 
 pits. They must have arisen from the original epithelial cord, 
 since the epithelial cord of the permanent tooth nlay be traced 
 from their periphery. The cord in our specimen is broadened 
 at its distal end and surrounded by a small papilla correspond- 
 ing in every respect to the developing temporary tooth in an 
 embryo of about three and a half months. The epithelia filling 
 the pit are arranged loosely, similar to those of the horny 
 layer of the oral mucosa, and many of them hold glistening 
 granules of what possibly is eleidin. The boundary of the 
 pit is made up of a single row of cuboidal epithelia, which in 
 some places may produce stratified hills and protrusions. The 
 pit corresponds to the summit of the temporary tooth, and its 
 destiny seems to be to prearrange the route for its eruption. 
 Between the lower periphery of the pit and the upper bound- 
 ary of the enamel-organ, or rather its external epithelium, the 
 connective tissue is loose and approaches the myxomatous 
 structure, containing very small groups of epithelium or medul- 
 lary corpuscles sprung therefrom. Such clusters are especially 
 conspicuous in the space between the epithelial cord of tlie 
 permanent tooth and the external epithelium of the enamel- 
 organ, where a large number of capillary Idood-vessels is also 
 visible. 
 
 Among the difterent animals in whose jaws we have examined 
 the process of formation of the enamel, we may mention the 
 following : 
 
 Kittens, at the time of birth, show all stages of the formation 
 of teeth, and especially the breaking up of the inner epi- 
 thelium into medullar}', and afterward into myxomatous, tissue, 
 which is easily tracealde. All the details, however, correspond 
 to those observed in liuman beings. 
 
 In a newly-l)orn pup the formation of enamel was found to 
 be, in all essential points, identical with its formation in ^nan. 
 
 The foetus of a })ig afibrds an excellent example for the study 
 of the formation of ameloblasts from medullary corpuscles.
 
 DEVELOPMENT OF THE ENAMEL. 
 
 179 
 
 (Fisi". 113.) The ameloblasts are arraiiii'ed with great regularity, 
 heing alternately wedge-shaped in op[»osite directions. Their 
 reticulum is very wide, and the horizontal threads traversing 
 the iuterstiees are quite plain. From their 1 >ases arise a varying 
 numl>er of offshoots, directed toward a peculiar tissue which 
 occupies the space hetween the ameloblasts and the already- 
 formed dentine. This tissue appears granular witli low powers 
 of the microscope. High ]>owcrs, however, plainly reveal a 
 
 M, Myxomatous enamel-organ : A, A, rows of ameloblasts of a markedly reticular structure ; 
 0'. granular layer between the dentine and the ameloblasts. Magnified 1200 diameters. 
 
 reticular structure, traversed by delicate til)rill{e in connection 
 with the reticulum. The presence of nuclei in this tissue indi- 
 cates its origin from medullary corpuscles. 
 
 The fretus of a land), about ten centimeters long, shows a 
 large layer of ameloblasts. (Fig. 114.) In places where the 
 ameloblasts lie close to the dentine, no tibrilhe are seen, but 
 where the layer of ameloblasts is detai-hed, a large numV)er of 
 tibrillte ajipear, evidently belonging to the dentine. This is less 
 calcitied and takes up a deep carmiii stain, contrary to the 
 fully-calcitied central }iortion of tlie dentine, that usually re-
 
 180 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 mains unstained. Here is wedged in bet\veen the dentine and 
 the ameloblasts a hiver found only as belonging to the sheep. 
 The ameloblasts break up into medullary corpuscles before 
 forming enamel, in the same manner as in human beings and 
 other animals that we haye examined. 
 
 Section of a Tooth of a Sheep's Fcetus, about Tex Ckntimkters Loxg. 
 
 D, dentine in transverse section ; /', fibers drawn out from the non-calcified portion of the 
 dentine; A, layer of ameloblasts partly in connection with the dentine. Magnified 1200 diameters. 
 
 Valuable researches in the study of the deyelopment of the 
 enamel haye been published by Frank Abbott,* as follows : 
 
 *" Growth of Enamel. ■■ Dented Cosmos, 1889.
 
 DEVELOPMENT OF THE ENAMEL. 181 
 
 "A. Kolliker, in his ' Haudl^ook of Histology of Man' (1852), 
 ijspeaks of development of enamel in the following terms : 
 ^ The development of the dental substances lias always been 
 considere(l a rather difficult topic. The relations are the simplest 
 in the enamel, wliere not the slightest doubt prevails that the 
 enamel-cells, by a complete calcification, become transformed 
 into enamel-fil»ers (enamel-rods). As soon as a small portion 
 of the cells, without any preliminary de})Osition of lime-parti- 
 cles, is being ossified, we recognize a small lamella of enamel 
 over the somewhat larger dentine cap, wliich has also recently 
 originated. The deposition of lime proceeds in the cells from 
 within outward till the}' have at last been transformed into 
 enamel-fibers and simultaneously transgress on new cells, by 
 which means the layer of enamel is broadened. While this is 
 going on, the enamel-membrane has not disappeared at the 
 place Avhere the ossification has started. On the contrary, we 
 find this membrane always of the same breadth so long as the 
 deposition of the enamel lasts, which proves that the ossified 
 portion of the membrane is continuously being replaced by an 
 additional mass. Ap[)arently this is done, not l)y the produc- 
 tion of new cells, but by a continual outgrowth of the original 
 ones. The enamel-organ (stellate reticulum) is certainly of 
 great importance in tlie l>uilding up of enamel, and owing to 
 its richness in albumen and a gelatinous mass in its meshes is, so 
 to speak, a pantiw from which the enamel-membrane derives 
 the material for its growth, being at some distance from the 
 blood-vessels. In fact, we see this spongy tissue losing in its 
 bulk during the development of enamel, and finally disappear- 
 ing when the formation of enamel is completed.' 
 
 '' I Avill here add that to Ivr)lliker the enamel-membrane means 
 a layer of epitlielia. He descril>es the enamel-organ as lieing 
 made up of anastomosing star-shaped cells, or a reticular con- 
 necti^'e tissue, which in its meshes contains a large amount of 
 albumen and a li(|uid ricli in mucus. The same author, in his 
 work on the ' History of Development of Man and Higher 
 Animals,' in 1879, claims that the stellate reticulum of the 
 enamel-organ in appearance is identical with comiective tissue, 
 but is really nothing but a peculiarly transf )rraed epithelium. 
 K()lliker, therefore, in 1852, held an ojiiniou that Ave consider 
 to-<lay the correct one, whic-h he very materially modified, 
 almost to the point of abandonment altogether, years later.
 
 182 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 This autlior was tlie first to announce that tlic tlu'orv <>t" cxchi- 
 siveness is not tenabk', in the process of develojiment from tlie 
 three original embryonal layers, the ' ectoderm,' the ^ meso- 
 derm,' and the ' entoderm,' or, using Balfour's terminology, 
 the 'epiblast,' the ' mesoblast,' and tlie 'hypoblast'; and still 
 he narrows his views to an almost im-redible degree, in the 
 chapter upon development of enamel. 
 
 "John Tomes, in bis 'Dental Physiology and Surgery' (Lon- 
 don, 1848: Philadelphia, 1853), gives wonderfully accurate 
 drawings of what he calls enamel-imlp, or columnar tissue, now 
 known as ameloblasts. On i»age 102 he exjilains the develop- 
 ment of enamel-rods or fibers in the following words: 'The 
 cells being formed in lines, eventually become contiuent; the 
 points of union being sometimes transverse, and at other times 
 oblique. At this stage the earthy elements are received, and 
 the lines of union between the com])onent cells of the libers 
 become less distinct, and are eventually lost, leaving a continu- 
 ous fiber. The nuclei, from the first very small, are altogether 
 lost in the formation of the fibers, or exist as very fine tubes 
 passing through the length of each.' 
 
 " On page 104 we read : ' To the best of my belief the trans- 
 verse strise are due to the alternate dilatation and contraction 
 of the fibers, — each dilatation corresponding to the center of a 
 formative cell, and each contraction to tlie junction of two 
 cells.' 
 
 "From these quotations it l)ecomes evident that John Tomes 
 was a most careful ol)server. Even at that early date, with the 
 limited powers of his microscope, he conceived the full truth 
 when he stated ' that each enamel-rod is the result of a juxta- 
 position of formative cells, between which are left the striae.' 
 He considers the formative cells as the recipients of the cal- 
 careous matter in exactly the same wa}' as we see it to-day. 
 
 " F. Waldeyer, in his ' Handbook of Histology,' edited by 
 Strieker, in Leipzig, 1869, page 347, describes the formation of 
 enamel in the following manner: ' The formation of enamel is 
 done exclusively by the enamel-e}>ithelium, since tlie enamel- 
 prisms are the result of a direct calcification of its long cylin- 
 drical cells. The boundary of petrifaction on 'the cells is by no 
 means linear, but extends downward to an irregular depth, — a 
 fact which likewise is not in favor of the view that a secretion 
 of the enamel-cells is being calcified. After treatment of young
 
 DEVELOPMENT OF THE ENAMEL. 183 
 
 enamel witli dilute acids, the enamel-prisms slightly swell and 
 resume entirely the form of the previous cylindrical cells. 
 The disappearance of the nuclei, in the process of the calcifica- 
 tion of the cells, is of so common occurrence that their absence 
 in the enamel cannot cause any wonder. Enamel, therefore, is 
 to he considered as the petritied dental epithelium.' 
 
 " This author explains the formation of the stellate reticulum 
 by a transformation of the epithelia, and considers its gelatin 
 of a merely mechanical importance, since it keeps an open 
 space for the growing tooth. 
 
 " John and Charles S. Tomes, in their ' System of Dental Sur- 
 gery' (London, 1873, page 253) say, ' The conclusions respect- 
 ing the development of enamel which are most in accordance 
 with appearances observed are these : The columns of the 
 enamel-organ (enamel-cells, internal epithelium of the enamel- 
 organ) are sul)servient to the development of the enamel-prisms, 
 into wliich they by calcification become actually converted. 
 This conversion goes on in the following method : The proxi- 
 mal end of the cell undergoes some chemical change prepara- 
 tory to calcification, and is subsequently calcified ; but this cal- 
 cification does not go on uniformly throughout its whole thick- 
 ness, but proceeds from its periphery toward its interior, the 
 central portion of the cell thus being calcified later than the 
 external portion, which lies at the same level. At the same 
 time that calcification is proceeding inward, in each individual 
 cell, it has united the contiguous cells to each other. The cal- 
 cification of the central portions of the enamel-fibers does not 
 keep pace with that of their exteriors, nor even in fully-com- 
 pleted enamel does it attain to precisely the same characters. 
 In the progress of calcification the nuclei of the enamel-cells 
 disappear, and it is probable, as is believed by Waldeyer, that 
 the internal epithelium of the enamel is reunited by the cells of 
 the stratum intermedium as it becomes itself used up by ad- 
 vancing calcification, converting it into enamel-fibers.' 
 
 '' These authors give credit to Kolliker as the originator of the 
 idea that the enamel-cells do not undergo direct conversion into 
 enamel-fibers, but that the enamel is, as it were, shot out from 
 their ends, — that is, it is a secretion from them, not a deposition- 
 of lime-salts into their own substance. Our cpiotations from 
 Kolliker's original German work, issued in Leipzig in 1852, 
 plainly show that he at that time believed fully in the conver-
 
 184 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 Hion tlieorv. Since the Toiaeses quote from the tifth German 
 edition of Kolliker's liistok.)_iiy, issued in 1867, it is ohvious that 
 he has changed his views, much, in my judgment, to his own 
 disadvantage. 
 
 " The vieAvs announced by C. Heitzmann and C. F. "W. Bo- 
 decker are in harmony witli my own ol)servations, and fur- 
 nish the foundation of wliat I have to add, in tlie way of a 
 more comprehensive idea of the huikling process of enamel, 
 than has heretofore keen advanced. 
 
 "Fig. 115 gives an ilkistration of the views just alkuled to. 
 The figure, it must l)e emphasized, is not diagrammatic, hut 
 copied with the utmost care from a specimen of a human fa^tus 
 six months okl, tke period at wkick enamel begins to appear. 
 Tke dift'erent layers, it will be ol)served, appear separated from 
 one anotker. Tkis is usually tke case even in tke most care- 
 fully prepared specimens, owing to sligkt meckanical injury in 
 cutting, and to skrinkage of tke soft parts ; tke relations, kow- 
 ever, are absolutely correct in tkis drawing. 
 
 "After tke epitkelial }>eg lias grown into tke deptk of connec- 
 tive tissue of tke oral mucosa, in tke twelftk week of eml)ry- 
 onal development, the distal end of this peg kecomes club- 
 skaped, and tken appears tke first trace of medullary tissue, 
 wkick two weeks later plainly skows tke stellate reticulum, 
 Tke clul) at tkis period assumes a cup-skape, wkose concave 
 surface is lined T)y tke internal epitkelium, wkile tke outer sur- 
 face is made up of tke so-called external epitkelium, wkick is 
 in uninterru}»ted continuity witk tke internal epitkelium at tke 
 most }»roniinent border of tke cu]). If Ave examine tke lower 
 edge of tlie cup of tke enamel-organ at al)Out tke sixteentk 
 Aveek of eml)rvonal life, Ave obserA'e a peculiar ckange in tke 
 columnar bodies of tke internal epithelium, Avhich consists in 
 the appearance, in a more or less roAV-like arrangement, of 
 highly-glistening globular bodies, replacing tke previous col- 
 umnar epitkelia. Tkese bodies are eitker solid or sligktly 
 vacuoled, and are formations of liA^ing matter suck as Ave are 
 accustomed to look upon as medullary, embryonal, or indiffer- 
 ent corpuscles in tkeir earliest stage of appearance. Obviously 
 •tkese glistening globules kave originated from tke reticulum of 
 living. matter of tke columnar epitkelia tkemseh'es. We feel 
 justified in tkis conclusion from tke fact tkat Ave can trace, step 
 ky step, tke groAvtk of tkese glistening granules up to tke for-
 
 DEVELOPMENT OF THE EXAMEL. 
 
 185 
 
 matioii of glistening- lunii)S, such as we have termed medullary 
 €'orpuscles. The more the cup of the enamel-organ is enlarged, 
 
 Fig. 115. 
 
 ^ m*!^^^^^'^^^';)^^ 
 
 Tooth of Human F(i:tus, Six Months. 
 
 -P, papilla; D\ non-caleified dentine; /;=, calcified dentine; E, enamel; ^, row of amelo- 
 blasts; M. medullary corpuscles at tlie peripheral portion of ameloblasts; G. globular cor- 
 puscles from which ameloblasts develop; ^i/. buds of external epithelium: /', follicle, made 
 up of fibrous connective tissue. Magnified 100 diameters. 
 
 the more eonspieuous becomes the transmutation of the pre- 
 vious internal e})itlielium into glistening lumps; so much so
 
 186 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 that toward the end of the fifth month of foetal life the original 
 columnar epithelium at the concave portion of the cup has 
 entirely disappeared. In its stead begin to show, first at the 
 deeper portion of the cup, and closely resembling columnar 
 epithelia, other bodies, now known as ameloblasts, or enamel- 
 formers. 
 
 "From this description it seems evident tliat all previous ob- 
 servers — be it said with due respect to their judgment— ^have 
 been in error in the assumption that the columnar epithelia of 
 the internal wall of the cup were identical with the ameloblasts. 
 All these observers have overlooked the intermediate stage of 
 the glistening medullary lumps. In Fig. 115 these lumps are 
 marked G. They are traceable down to tlie neck of the papilla, 
 therefrom to the point of recurvation of the previous internal 
 into the previous external epithelium. The lumps, I Avish to 
 repeat, are extremely glossy, with a high degree of refraction. 
 They are arranged, at first irregularly, in a layer of consider- 
 able breadth, and higher up in rows, and by their coalescence 
 and prolongation give rise to small columns, the ameloblasts. 
 These are seen up to the end of the fifth month of foetal devel- 
 opment at the deepest concavity of the cup and its lateral walls 
 down to varying depths, and closely attached to the now-form- 
 ing dentinal eap. The odontoblasts grow smaller toward the 
 thin extremity of the dentinal ca[), and below its end they 
 appear as blunt and short columns: while, close above, the 
 ameloblasts make their appearance, l)eing traceable all around 
 the outer periphery of the dentinal cap. 
 
 " In the sixth month of foetal life, as is well known, the enamel- 
 cap begins to show; first at the summit of the dentinal cap, 
 where it o-ains its greatest breadth, o-radually becomino* thinner 
 toward the sloping sides, and, as a whole, a trifle thinner and 
 shorter than the dentinal cap. 
 
 " If we now examine the ameloldasts close above the already- 
 formed enamel, we shall observe finely-granular bodies, arranged 
 in a row, between the enamel and ameloblasts. These are best 
 seen in specimens where the hardening and cutting procedures 
 have not caused a detachment of the soft tissues from the hard^ 
 — i.e., the enamel-organ from the calcified enamel. It is seldom 
 that this is accomplished ; but a few of such perfect specimens 
 are in Bodecker's collection, which by his kind permission I 
 have used for my studies and these drawings. Even though a
 
 DEVELOPMENT OF THE ENAMEL. 187 
 
 slight detachment has occurred, tlie enamel-organ still remains 
 intact, and the iinely-grannlar corpuscles at the proximal ends 
 of the ameloblasts remain visilile. 
 
 " What are these finely-granular bodies ? Heitzmann and 
 Bodecker claim that they are medullary corpuscles, holding 
 small and indistinct or no nuclei, and oidy a very small amount 
 of living matter, which accounts for their finely-granular 
 appearance with low powers of the microscope. They further 
 claim that these corpuscles, or the liquids contained in their re- 
 ticulum, become solidified into l)asis-substance, and immediately 
 infiltrated witli lime-salts. They claim also tliat the enamel- 
 rods are built up of rows of such calcified or ' petrified' 
 medullary corpuscles, the successive arrangeriient of which into 
 rows causes the more or less regular appearance of the trans- 
 verse strite of Retzius ; whereas, between the rows, longitudinal 
 interstices will remain, filled, perhaps, with a small amount of 
 cement-substance, differing in its chemical constitution from 
 the basis-substance of the rods proper, and iu its interior hold- 
 ing extremely delicate fibrillae (Bodecker's enamel-fibers) which 
 branch into the transverse stride. Being satisfied that the views 
 of these gentlemen are correct, I will simply add a new feature, 
 to make those views more symmetrical, — and, as it occurs to 
 me, it is a feature of considerable importance, — viz, the changes 
 that take place in the ameloblasts during the process of the 
 formation of enamel. (Fig. 116.) 
 
 " The ameloblasts, as just stated, split up into rows of finely- 
 granular medullary corpuscles, and consequently are reduced 
 considerably in their size. In fiict, it is difficult to find full- 
 sized amelol)lasts at the summit of the enamel-cap, where the 
 l>roduction of enamel is most active, the same as it is impossi- 
 ble to find full-sized odontoblasts at the summit of the papilla, 
 where the formation of dentine is must active. The mutilated 
 ameloblasts in this situation still exhibit nuclei, although their 
 forms are odd, — mostly cut or broken, with offshoots running 
 upward and laterally toward the stratum intermedium. At the 
 same time, peculiar glistening, homogeneous lumps and irregu- 
 lar wedge-shaped nucleated bodies appear between the offshoots 
 of the ameloblasts; not as regular, however, as the original 
 medullary corpuscles were, from which the amelobla.sts origi- 
 nally developed. All these indifferent bodies must have arisen 
 from the living material stored up in the stratum intermedium,
 
 188 
 
 THE AXATOMY AND PATHOLOGY OF THE TEETH. 
 
 close above the ro\v of amelol»lasts. Bv their occasional row- 
 like arrangement I am led to the conclusion that they serve for 
 n restitution or n be ilJing of the amelohlasts (which at their proxi- 
 mal ends have split up into enamel-formers), and thus serve to 
 establish a continuity of the amelohlasts, and, in turn, of the 
 
 Fig. 116. 
 
 
 FlKST-FOH.MF.D EXAMEL OK HuMAN FcETUS, SiX MoNTHS. 
 
 LK dentine; E, enamel toward the dentine, made up of irregular calcified fields, toward the 
 periphery of prisms with transverse interruptions : M, medullary corpuscles, finely granular, 
 from which the enamel-prisms are formed: ^4. amelolilasts. toward the enamel breaking up 
 into medullary corpuscles, toward the periphery rebuilt by such corpuscles: .•!', irregular 
 amelohlasts torn from their connection with enamel: /', fibrous connective tissue, changing to 
 medullary tissue. Magnified SOU diameters. 
 
 enamel-rods, throughout the ^^'hole thickness of the enamel. 
 In a preA'ious article I have endeavored to show that odonto- 
 blasts, being split up at their distal ends into medullary cor- 
 puscles, enter directly into the formation of the basis-substance
 
 DEVELOPMENT OF THE ENAMEL, 18^ 
 
 of dentine, while at the same time, continually superadded to 
 the })roximal ends of the odontohlasts, are medullary corpuscles 
 derived from the living matter of the papilla. Thus the con- 
 tinuity of the odontoblasts and dentine is established, stratifi- 
 cation of the dentine being the exception. I now assert a simi- 
 lar procedure for the ameloblasts, in a reverse direction, owing 
 to the centrifugal direction of enamel-growth. The ameloblasts 
 bcbui broken up at theiv irroximal ends into medullary corpuscles, 
 lohich are directly transformed into blocks of enamel-rods, are super- 
 added to at their distal or periphered ends by medullary corpuscles 
 derived from the stratum irdermcdium. Xormal enamel is non- 
 stratiiied; its rods or prisms run a wavy course, as a rule un- 
 interruptedly from near the dentine to the cuticular (Nasmyth's) 
 membrane. 
 
 "■ j^either the structure nor the development of this tissue is to 
 me explicable on the ground of the cell theory, which suggests 
 that each cell is an individual, and but exceptionally in connec- 
 tion with its neighbor. To us, a cell is a lump of protoplasm, in 
 which the living matter is stored up in different shapes. The 
 glistening globules of small size, having arisen from the proto- 
 plasm of the original columnar epithelia of the enamel-organ, 
 represent a juvenile condition of living matter in its most com- 
 pact aggregation. 
 
 " The medullary corpuscles, sprung from the ameloblasts, show 
 only a delicate reticulum of living matter, being ready for im- 
 mediate transformation into basis-substance and calcification. 
 Between these extreme stages stand the ameloblasts, with their 
 vesicular nuclei, and a markedly heavy reticulum of living 
 matter in their interior. The indifferent corpuscles, serving to 
 supply additions to the ameloblasts, exhibit all intermediate 
 stages between small, globular, glossy and compact globules up 
 to distinctly-nucleated protoplasmic lumps. "Whatever the size 
 and shape of such lumps may be, they are invariably connected 
 with one another by means of delicate offshoots, which vary 
 greatly in thickness and in their course. Each ameloblast sends 
 offshoots toward the dentine in great numbers, known as Tomes's 
 processes. They also run upward toward the intermediate 
 layer, and laterally for the immediate union of neighboring 
 ameloblasts. (See Fig. 117.) 
 
 " Broad and clumsy offshoots, such as depicted by Tomes and 
 Waldeyer, are visible only upon torn and teased ameloblasts. So
 
 190 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 long as these bodies are in site, the offshoots are always delicate, 
 and visible with higher powers of the microscope only, — i.e., 
 from 800 to 1000 diameters. By the splitting up of the amelo- 
 blasts in a longitudinal direction, wedge-shaped pieces arise be- 
 tween funnel-shaped or square bodies. By the coalescence of 
 the lateral offshoots in a longitudinal direction, delicate fibrillae 
 originate between the ameloblasts, known as B(3decker's enamel- 
 fibers. 
 
 "When the formation of a tissue is going on, we conclude, 
 from the great variety of forms of the protoplasmic bodies, that 
 
 Fig. 117. 
 
 Ameloblasts beginxing the formation of Enamel; from Human F(etus, Six Months. 
 
 D, border of newly-formed dentine ; E, first trace of forming enamel ; A, row of ameloblasts ; 
 AP, medullary corpuscles for restitution of ameloblasts ; M", medullary corpuscles just previous 
 to their infiltration with lime-salts; /\ fibrous connective tissue, the so-called intermediate 
 layer. Magnified 1000 diameters. 
 
 there is not for a moment rest either in the growth or in the new 
 formation of living matter. Thus the proximal ends of the 
 ameloblasts, through the intermediate stage of medullary cor- 
 puscles, are metamorphosed into the calcified basis-substance of 
 the enamel-rods. The distal ends exhibit the stages through 
 which the living matter passed before the original ameloblasts 
 were formed. Still the question remains an open one, wdiether 
 or not ameloblasts are an absolute requirement for the produc- 
 tion of enamel after the formation of the rods has once begun. 
 The rows of globular bodies as seen in Fig. 117, M^, strongly
 
 DEVELOPMENT OF THE ENAMEL. 191 
 
 favor a negative answer to this query. Nothing but a transmu- 
 tation of solid globular lumps of living matter into delicately- 
 reticulated medullary corpuscles seems to be required for the 
 building up of the minute blocks of enamel-rods, without the 
 intermediate stage of ameloblasts. AVe must admit, however, 
 that, to symmetry of construction, the part played by these 
 bodies seems essential, although they vary greatly in size, even 
 in the same tooth. We consider ameloblasts as merely provi- 
 sional formations, by no means stable or unchangeable. This 
 conclusion is the same as that we reached in regard to the sig- 
 niticance of odontoblasts. 
 
 " Full development of ameloblasts into oblong or conical 
 bodies — each containing one or two nuclei, sharply bordered 
 by a delicate cuticular formation toward the papilla, and dis- 
 tinctly marked by the intermediate layer toward the enamel- 
 organ — is never seen save under the condition of temporary 
 rest, where the formation of enamel has not as yet started. 
 (See Fig. 118.) As soon as the first trace of enamel is seen, the 
 ameloblasts lose their regularity by being split up toward the 
 dentine, and are superadded to from the intermediate layer. 
 
 " The first-appearing enamel is made up of irregular angular 
 and glistening lumps, greatly varying in size. (See Figs. 116 
 and 117.) The first blocks of enamel-rods show compact edges 
 and comparatively thin and translucent centers, in which even 
 traces of the nuclei of the medullary corpuscles are to be seen. 
 This plainly proves the correctness of the assertion of Tomes, 
 that ' the enanlel-rods are calcified from the periphery toward 
 the center.' The irregularity of the first-formed calcified blocks 
 also accounts for the fact that fissures and breaks are of such 
 common occurrence in specimens of enamel, either ground or 
 cut, at the border toward the dentine, as I have previously 
 demonstrated in an article on the anomalies of enamel, such 
 anomalies being most common in this situation. 
 
 "We now return to the enamel-organ, of which it is known 
 that it begins to show at the end of the third month of intra- 
 uterine life, by the appearance of medullary corpuscles between 
 the internal and external epithelium. From the fourth month 
 to the seventh or eighth the beautiful stellate reticulum known 
 as the enamel-organ comes to view. Although Huxley and 
 Kolliker have stated (in 1850-1852) that this is connective tissue, 
 all modern writers, including Kolliker himself, insist that it is
 
 192 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 a peculiarly-modified epithelium. I contend that this reticulum 
 is true myxomatous tissue, and the stratum intermedium true 
 tibrous connective tissue. The tirst microscopist to descri])e and 
 illustrate tlie intermediate layer was John Tomes, iu 1848, in 
 his work above quoted. This credit is usually given to Hanno- 
 ver, whose work appeared in 1856. 
 
 "As to the significance of the enamel-organ, I must take de- 
 cided exception to the views of most modern writers, — viz, that 
 it serves as a kind of protection cushion, or to preserve an open 
 space for the tooth to grow into. In my opinion, the view first 
 announced by Hertz in 1866 is the correct one, — /.<., that 'the 
 
 Fw. 118. 
 
 A.MEi.OBLASTs AT Rest : KKO.M Dexki.oping Tooth OK Hu.MAN Fu';tis, Six Months. 
 
 A, row of ameloblasts: /. /, intermediate layer: M, myxomatous reticulum ; J', papilla; .S', 
 so-called structureless membrane. Magnified 1000 diameters. 
 
 enamel-organ is stored-iip material for.the benefit of the growing 
 enamel itself,' the same as is the intermediate layer. 
 
 "One tact will strike every observer, — viz, that the enamel is 
 seldom, if ever, perfectly symmetrical in the growing tooth, 
 l)eing on one side broader, to the extent of five or six times, 
 than on the other; sometimes it is found only on one side of the 
 developing tooth, Avhile on the other nothing but delicate fibrous 
 connective tissue is seen. From these facts we must conclude 
 that the myxomatous form of this organ is by no means a 
 characteristic or an absolute requirement.
 
 DEVELOPMENT OF THE EXAMEL. 
 
 193 
 
 " How can we explain the scantiness of this organ at the sum- 
 mit of the crown, where in full development the enamel has 
 the greatest diameter? Can the original enamel-organ, even 
 ever so broad, suffice for the production of the whole enamel ? 
 Is not the enamel-coat of a temporary tooth five, nay, ten times as 
 Ijroad as the original enamel-organ ? All this strongly points to 
 the conviction that the budding external epithelium, and even the 
 primary epitlielial peg, must furnish material for the building 
 
 Fig. 119. 
 
 Developing Tooth of Sheep's Fcetus, 10 Centimeters Long. 
 
 D, dentine in longitudinal and transverse sections ; A, row of ameloblasts at rest ; ^^ amelo- 
 blasts .broken up into medullary tissue, preceding the formation of enamel ; /, /, intermediate 
 layer; M, M, myxomatous enamel-organ ; C, capillary blood-vessels. Magnified 1000 diameters. 
 
 of enamel, no matter what the intermediate or subsequent 
 changes of this tissue may be. 
 
 " In conclusion, I wish to say that I have studied the develop- 
 ment of enamel in pigs and sheep, and have found the relations 
 therein similar to those in the enamel of the human tooth. (See 
 Fig. 119.) In the sheep's foetus, ten centimeters long, the form- 
 changes of the ameloblasts are especially pronounced, since 
 
 14
 
 194 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 shortly before the appearance of the enamel a splitting into 
 medullary corpuscles takes place, for the production of enamel- 
 rods; and at the same time, at their distal ends, new medullary 
 corpuscles show themselves, evidently produced at the expense 
 of the intermediate layer. Both the last-named layer and the 
 blood-vessels in the myxomatous enamel-oriran John Tomes 
 observed and depicted as early as 1848, — an admirable instance 
 of acute observation of lasting: value."' 
 
 CHAPTER XVI. 
 
 FAULTY DEVELOPMENT. 
 
 During the formation of the teeth, constitutional maladies in 
 the possessor have an important influence upon the calcitication 
 of the dentine and the enamel. Any disturljances in the proper 
 supply of lime-salts to the developing dental tissues may result 
 in a malformation of the crown of the atfected tooth, and cause 
 interruptions in the process of calciflcation. The period at 
 which defects in the dentine and enamel are most commonly 
 produced, is after birth. We may also observe such anomalous 
 formations of the crowns of teeth as the consequence of coustitu- 
 tional diseases of the mother during tlie time of pregnancy, or 
 in other instances they may be inherited from the father or 
 even grandfather. Upon the crowns of the affected teeth, which,, 
 at the time of the disease, are a1)0ut to calcify, we notice trans- 
 verse ridges, or grooves and pits, encircling the entire crowns 
 of the teeth, such deformity being the more marked the longer 
 and severer the disturbance has been. The color of these teeth 
 usually is dark yellow, brown, or blue, although in some instances 
 the enamel is found to be abnormally white and opaque. 
 Occasionally, in spots, the crowns are devoid of enamel, and 
 exceptionally we see teeth altogether destitute of enamel. In 
 these cases the exposed dentine is of a dark-yellow or lirownish 
 color. The diseases whieh are l)elieved to produce such deformi- 
 ties are syphilis, rhachitis, small] )ox, scarlet fever, measles, and 
 other inflammatory disturbances of the skin or of the mucous 
 membrane of the alimentary tract, and more particularly of 
 tlie oral cavity. Some writers, especially J. Hutchinson, have
 
 FAULTY DEVELOPMENT. 195 
 
 attriliutcd siu-h dolbrinities of the dental tissues iiiuiiily to 
 la-reditarv sypliilis. At present, however, it is acknowledged 
 that siu'h defective formations may be produced hy other 
 diseases which temporarily arrest the process of calcification of 
 the enamel and dentine. It is l)elieved hy J. Tomes* that 
 defonnities resulting from constitutional disturbances of the 
 mother atleet in the infant the crowns of the temporary teetb^ 
 \vlii(di arc found in such cases to be small, abnormal in shape,, 
 and with but a tliin coating of enamel. This author also states 
 that it has been observed that children, whose permanent teeth 
 were marked by deforme*! enamel, have lost them early through 
 caries, pericementitis, or periostitis. In these instances, it m 
 possible that the defects of the permanent teeth are as much the 
 cause of the pericementitis and the periostitis as the result of 
 constitutional ailments of the mother. 
 
 Furthermore, such disturbances occur at a period when the 
 enamel-organs of the permanent teeth are in their first stage 
 of development. It is therefore inexplicable why these teeth 
 should be marked by deformities, Avhile the crowns of the tem- 
 ]»()rary teeth, at that time in ]»rogress of calcification, are usually 
 normal in ajipearancc. Tlic author has seen a girl about eight 
 years of age, whose remaining temporary teeth were all marked 
 by deformed enamel, while the ]»ermanent incisors and first per- 
 manent molars were possessed of a normal enamel. When the 
 disease has been of a local character, it may occur that it has 
 afi'ected but one or a few teetli in one jaw only, while all 
 the other teeth are normal; although, when the local ailment 
 has extended over the mucous meml)rane of the whole mouth, 
 all the teeth that are in process of calcification will be atfected. 
 By carefully studying the time when the crowns of the teeth 
 calcity, we are enabled to judge at what year of life the child 
 was ill. (See Fig. 120.) Thus, when the illness has occurred 
 during its first year, we notice deformities only upon the cutting- 
 edges of the permaiu'iit central incisors ami the cus[)s of the 
 first pernninent molars; while the disease during the second 
 yvnv of life will mark the permanent central as well as the 
 lateral incisors, and the tirst }>ermanent molars. When the ill- 
 ness of the child hai)[)ens during the third year, the deformity 
 appears about in the middle line of the itermanent centrals, and 
 a little nearer the cutting-edge of the lateral incisors. The 
 
 *" A System of Dental Surgery. " Philadelphia, 1873.
 
 196 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 Fig. 120. (After C. X. Peirce.)
 
 FAULTY DEVELOPMENT. 
 
 197 
 
 buccal cusps of tlie bicuspids and cuspids may either escape 
 iujurv or show a slight defect, but the first permanent molars 
 usuaily are deformed in the same level with the central incisors. 
 If a ciiild has been seriously ill during the fourth year, we find 
 
 Fig. 121. 
 
 Right Upper Pkrm.wknt Centkal Incisor, Mrs. K., Forty-eight Years Old. Ground. 
 
 B, dentine, lacking enamel ; S, secondary dentine, corresponding to bare dentine ; E, narrow 
 layer of pigmented enamel; /, zone of interglobular spaces; P, pulp-tissue; f. C, calcareous 
 deposits in the pulp-tissue ; V, dentine in immediate vicinity of pulp-canal ; 0, narrow layer of 
 osteoid cementuni. Magnified 6 diameters.
 
 198 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 the defective transverse line of the enamel nearer the neck of 
 the permanent central incisors, at ahout the middle of the lat- 
 erals, and, in the case of the cnspids and l)icuspids, on the 
 points of the cnsps, while the first permanent molars are marked 
 similarly as the central incisors, — /.c, near the necks. Some- 
 times it occnrs that children are attacked bv chronic constitu- 
 tional or local diseases immediately after birth, and lasting up 
 to the third or fourth year of life. In such an instance we may 
 notice that the greater portion of the crowns of the permanent 
 central and lateral incisors, as well as the first permanent molars, 
 present a crippled appearance. 
 
 While the above-named maladies usually result in deformities 
 of the crowns of the teeth, we occasionally meet with persons 
 who in their early childhood have l)een seriously ill, but whose 
 permanent teeth are possessed of normal enamel. Although it 
 cannot V)e denied that some of these deformities are the result 
 of constitutional ailments of the child, still the above facts to a 
 great extent corroborate Ab1)ott's statement, to the effect that 
 faulty formations of the enamel are the result of local dit^turb- 
 ances. 
 
 An instance of faulty (levek»pment of the enamel is illustrated 
 in Fig. 121. This represents the right upper permanent central 
 incisor of a lady about forty-eight years of n^'c, who knows of 
 no disease of lier motlier or of her own childhood. The tooth 
 became loose in consequence of cfironic suppurative pericemen- 
 titis, and was extracted. 
 
 The enamel is narrow and intensely pigmented. It is miss- 
 ing altogether in a circumseribed spot of the lingual surface of 
 the tooth near the cutting-edge. The dentine shows a zone of 
 interglobular spaces in the crown, more pronounced on the 
 labial than on the lingual surf ice. Corresponding to the bare 
 surface of the dentine there is a marked formation of secondary 
 dentine, holding irregular and scanty canaliculi. The pulp is 
 normal, and shows a nund)er of calcareous deposits, especially 
 at the beginning of the pulp-eanal. The cementum is altogether 
 of the osteoid t3'[»e, and, although lamellated, is devoid of 
 cement-corpuscles. The process of chronic pericementitis has 
 not affected tlie cenientnni, A\liich nowhere exhibits the bay-like 
 excavations characteristic of cementitis. 
 
 An instance of traumatism of consideral)le interest is the 
 tooth depicted in Fig. 122. It is a right upper permanent cen-
 
 FAULTY DEVELOPMENT. 
 
 199 
 
 tral incisor of a youth twelve years of age, removed on account 
 of the disfigurement as well as the overcrowded condition of the 
 dental arch, the teeth of which were otherwise normal. The 
 mother of the hoy has infornuMl me that the child always has 
 
 Flu. 122. 
 
 RioHT Uppkk Ckntr.vl Incisor of .v Boy Twelvk Years Old. Ground. 
 E, irregular pigmented enamel with vestiges of channels; (\ pigmented channels penetrating 
 the'denthie: B, bare dentine: (?. globule of ill-calcified dentine; Z/Marge bifurcated pulp- 
 chamber; .S7', small central pulp-chamber: .Y. nodule of pigmented enamel: .9, .V, secondary 
 dentine at the borders of both pulp-chambers; li, narrow layer of cementum. Magnified 6 
 diameters.
 
 200 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 had a weak constitution, and during the period of earl}- child- 
 hood was often seriously ill. The boy did not have the upper 
 central incisors till he was four years of age, and their perma- 
 nent successors only made their appearance al)out the tenth 
 year of age. It appears to be improbal)le that general or local 
 disturbances should haye influenced the malformation of this 
 tooth. On the other hand, there is a strong corroboration of 
 the theory of traumatic origin of the anomalous deyelopment of 
 the tooth under consideration. At the cutting-edge we obserye 
 four channels, or rather yestiges of channels, where a series of 
 foreign bodies were forcibly thrust into the enamel-organ 
 shortly after l)irth, or at least during the tirst year of life. 
 Judging from the arrangement of the slightly deyious channels, 
 I sliould infer that the foreign bodies were pliable, though 
 rather lirm and pointed. Such bodies are the bristles of a 
 tooth-brush, which may haye been either Ijitten into b}' the 
 intant, or may by other accidental means haye obtained entrance 
 into the enamel-organ of the tooth. This yiew is the more 
 plausible since we find a detached nodule of pigmented enamel 
 at the floor of the central pulp-chamber, which eyidently took 
 origin from a torn-ofl" piece of the enamel-organ. A portion 
 of the dentine being destitute of enamel, this yiew gains the 
 more ground, because the detached nodule of enamel corre- 
 sponds in its deyious direction to the other tracts of the channels. 
 The tooth has a wide bifurcated pulp-chamber and a small cen- 
 tral one, both exhibiting narrow layers of sec(Midary dentine. 
 The cementum is extremely narrow all over the root, and 
 nowhere developed beyond the formation normally seen at the 
 neck of the tooth. The root was somewhat compressed and 
 grooved laterally. The arrangement of the channels and the 
 injuries produced in the enamel are illustrated in Fig. 123. 
 
 The enamel is colored a light brown, and its prisms, besides 
 being conspicuously wavy, exhibit irregularly-scattered pigmen- 
 tations. In the vicinity of the channels the enamel is of a deep 
 yelloAv-brown color; its jirisms are but scantily developed, and 
 in most places are replaced by a deejj-brown amor}>li()US mass. 
 The dentine along the l)orders of the enamel-globules and 
 pegs shows slight irreguhirities, consisting iu a widening of the 
 canaliculi, or in coarse conical ofl'shoots filled with granules 
 of lime-salts emanating from the enamel-pegs. Around the 
 enamel-pegs the canaliculi converge. At the border between
 
 FAULTY DEVELOPMENT. 
 
 201 
 
 the enamel and dentine there is a globnlar formation, deeply 
 stained with an ammoniaeal solution of carmin. Higher 
 powers of the microscope reveal that this globule is an anoma- 
 lous formation of dentine. (See Fig. 124.) The basis-substance 
 appears finely granular and arranged concentrically. It is 
 
 Fig. 123. 
 
 Portion of Enamel from Cutting-Edge of Crown of Fig. 122. 
 
 E, enamel, deeply pigmented; C. vestige of channel surrounded by a dark yellow-brown 
 irregular enamel; ''-, vestige of channel bifurcating; 6^, globule of ill-calcified dentine; I>, 
 normal dentine. Magnified 25 diameters. 
 
 traversed by extremely faint dentinal til)ers running a radiating 
 course. The peripliery of the globule is surrounded by in- 
 tensely-calcified globular masses, between which are seen inter- 
 globular spaces filled with ])rotoplasm and granular deposits of
 
 202 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 lime-salts. The globules are pierced by scanty and irregularly- 
 formed dentinal canaliculi, wliicli, however, keep the general 
 direction of those of the normal dentine. Both the. intensely- 
 calcified zone around the globule, and the normal dentine, are 
 traversed by broad routes of protoplasm pervaded with coarse 
 grannies of lime-salts. 
 
 Fig. 124. 
 
 Globule of Ill-Calcified Dentine of Fig. 122. 
 
 6-',lbafis-substance uncalcified, with scanty and faint dentinal canaliculi; P, globular calca- 
 reous depoh its around the uncalcified basis-substance ; T, T, tracts tilled with calcareous granules ; 
 1), normal dentine. Magnified 500 diameters. 
 
 That the protrusions and pegs penetrating the dentine really 
 are a tbrniation of enamel-tissue, as is tlie nodule at the floor of 
 the'ccntral pulp-cavity before alluded to, is proven by examina- 
 tion with higher powers of the microscope. (See Fig. 125.)
 
 FAULTY DEVELOPMENT. 
 
 203 
 
 Further] uore, we notice euaiiiel-prisms of an extremely devious 
 course, tlie deviousuess being most pronounced in the center of 
 the peg, where a number of transverse sections of enamel- 
 prisms are met with. Instead of such transverse sections, we 
 frequently notice amorphous and deeply-pigmeuted granular 
 
 Fig. 125. 
 
 Portion of Intekzoxal Layer [jeiweex Dentise Axn Enamel oe CnTTiXG-EDGE of 
 
 Fig. 122. 
 
 G, G, globular protrusions of pigmented enamel; T, tract of anomalous enamel; .-1, amor- 
 phous, deeply pigmented masses, replacing transverse sections of enamel-prisms ; //, highly 
 refractive rims between enamel and dentine ; 1>, normal dentine. Magnified 500 diameters. 
 
 masses, which probably are the result of crushed ameloblasts. 
 The yellow-brown color of the anomalous formation of the 
 enamel is everywhere due to the presence of such amorphous 
 masses, whereas the enamel-prisms appear of a lighter dusky-
 
 204 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 brown color. There is but little doubt that the pigment of the 
 masses is due to a hemorrhage produced at tlie time of the 
 injury. A noteworthy feature is the presence of an intensely- 
 calcified rim between the globules and the pegs of the enamel 
 and the dentine, which is trayersed by the bifurcations of the 
 dentinal canaliculi. 
 
 The writer has obseryed an interesting incident of faulty 
 development in a family of four children and two grandchildren. 
 The four children haye no enamel upon their permanent teeth, 
 while the teeth of both parents were coyered with normal 
 enamel. The teeth of all the children were abnormally small, 
 and the incisors and cuspids eyen smaller than ordinary tem- 
 porary teeth. Their external surface is smooth, of a dark-yellow 
 color, and not abnormally sensitive to thermal changes. The 
 molars mostly have the form of a lower first temporary molar, 
 while the bicuspids are of normal form, but quite small. The 
 cusps of all the molar teeth, when they made their appearance 
 through the gums, were quite sharp, and, becoming a source of 
 irritation to the tongue and cheeks, they had to be rounded off. 
 These teeth soon decayed where the pointed cusps had been 
 removed, and the inner portion of the dentine was extremely 
 sensitive to the touch of the bur. The writer has lately seen 
 the two grandchildren of this tamily, one of which is five and 
 a half, the other six years of age. The latter child has normal 
 temporary, and, as far as erupted, good permanent teeth, while 
 the former has inherited the faulty-developed teeth of his father. 
 This child, although only five and a half years of age, had its 
 upper and lower permanent central incisors and the first per- 
 manent molars fully erupted. The remaining temporary teeth 
 are the, smallest teeth the w^riter has ever seen in any child's 
 mouth. Their enamel, with the exception of the upper second 
 temporary molars, appears to be normal. The latter four teeth 
 each exhibit two pointed cusps, and seem to be devoid of 
 enamel. The four permanent molars, which in general size and 
 shape are nearer normal than those of his fsither's, are sur- 
 mounted by four or five cusps respectively, and appear to be 
 entirely devoid of enamel. The upper and lower permanent 
 central incisors exhibit a bright-yellow color, and are also much 
 larger than those of the father, while their surfaces seemingly 
 lack enamel. They are marked by transverse grooves, princi- 
 pally upon their labial surfaces.
 
 FAULTY DEVELOPiMENJ. 
 
 205 
 
 I shall make use of two valual)le contributions to this topic 
 by Frank Abbott.* 
 
 The lirst deals with anomalous occurrences in the enamel, as 
 follows : 
 
 "I. Anomalous Relation between Dentine and Enamel. — In 
 examining a large number of specimens of ground teeth, I met 
 with formations in two instances which are to be considered as 
 rather anomalous, though not strictly pathological. In one 
 instance, that of a temporary molar, there was on the buccal 
 
 Fio. 126. 
 
 Protrusion of Dentine into Enamel. 
 
 E, enamel; D, dentine; H, hill of dentine with fluted summit; P, protoplasmic bodies in 
 the dentine. Magnified 400 diameters. 
 
 surface a protrusion of dentine into the enamel with a fluted 
 surface, or a surface fluctuating in a series of bay-like excava- 
 tions. This fluting was present also at the junction of the 
 dentine with the enamel in general, but not so marked as iu 
 this protruding spot. The center of this protrusion was occu- 
 pied by an eccentric protoplasmic formation, differing in shape 
 from the ordinary interglobular spaces. The dentinal fibers at 
 the periphery were bifurcated in the usual manner, but very 
 
 * "Studies of the Pathology of Enamel of Human Teeth, with Special Refer- 
 ence to the Etiolosrv of Caries." Dental Cosmos, 1885.
 
 206 
 
 THE ANATOMY AND I'ATHOLOUY OF THE TEETH, 
 
 few of theiii penetrated the enamel. The portion of the 
 enamel neare^^t to the protrnsion was destitute of prisms, while 
 in the immediate vicinity, again, of this portion such prisms 
 were traceable almost in contact with the dentine. The zone 
 immediately above the protrusion was bnt slightly In'ownish, 
 whereas the prisms of the enamel exhibited a very distinct 
 brown pigmentation. 
 
 Fi<;. 127. 
 
 Pkotkuskjn of Dextixk int(j Pathological Enamel. 
 
 E. enamel ; D, dentine ; G, granular enamel ; A, summit of the dentine ; S, sloping borders 
 of the granular enamel. Magnified 200 diameters. 
 
 ''In a second case, that of a permanent cuspid, a ]»r()trusion 
 of dentine was observed, as in the former instance, on the 
 buccal surface near the edge, occupying nearly one-half of. the 
 breadth of the enamel. This protrusion was of a conical shape,, 
 and without a distinct boundary, but blended with an oblong 
 iield of enamel of quite remarkable structure. The dentinal 
 canaliculi exhibited at their peripheral portions numerous bi-
 
 FAULTY DEVELOPMENT. 207 
 
 fui'catious, and teriniiiatiMl in small [>L'ar-sJia[).Ml eulariiX'tnouts, 
 many of wliich could be traced in connectiou with dentinal 
 fibers, whereas tlie most peripheral ones, owing to their devious 
 course, looked isolated. The adjacent enamel showed but very 
 indistinct rods, the main mass of the enamel being occupied by 
 brownish globular tields, separated from one another by irreg- 
 ular interstices closely resembling the interglo1)ular spaces of 
 dentine, though of considerably smaller size. The deepest jiig- 
 nicntation and the largest number of such inter prUinatic spaces 
 occurred along the periphery of this anomalous formation, 
 especially toward the outer surface of the enamel. The vicinity 
 of the enamel proper was marked by the presence of slightly pig- 
 mented rods, more wavy in their course than is normal. Toward 
 the dentine the anomalous formation was sloping, and the line of 
 demarcation between the normal and anomalous enamel exhib- 
 ited either brown and very wavy prisms or small inkr prismatic 
 spaces, decreasing in diameter the nearer they approached to the 
 dentine. I wish to emphasize and call particular attention to 
 the fact that the dentine of this tooth was nowhere traversed by 
 interglobular spaces, the anomalous construction being confined 
 to the enamel. 
 
 "II. Stratification of Enamel. — It is known that dentine, 
 without exhibiting patliological features, yet slightly deviating 
 from its normal structure, is sometimes composed of strata that 
 are more or less distinctly marked, and are altogether independ- 
 ent of the formations known as secondary dentine. We often 
 meet with similar formations in the enamel. We observe, 
 varying in width and more or less sharply marked by a straight 
 line, layers which in longitudinal sections of teeth are concen- 
 tric, the broadest part corresponding to the cusps, the narrowest 
 to the neck of the tooth. 
 
 "■ At the outer periphery of the enamel there may occur 
 strata, which, contrary to the general construction as above 
 described, arc broadest toward the neck and narrowest toward 
 the cusp, though never reaching its summit. In transverse 
 sections the enamel shows simply concentric lines, separating 
 from one another layers of greatly varying diameters. With 
 higher powers of the microscope we ascertain the fact that the 
 lines of stratification, as a rule, do not alter the general course 
 of the enamel-prisms, — in other words, a single enamel-prism 
 will show an oblique line of demarcation, (•(>rresp()nding to the
 
 208 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 Fig. 128. 
 
 Diagram of Stratification of Enamel. 
 
 y^ -pulp-chamber; B, dentine; CL\ CL\ CL\ CL\ cusp-layers of enamel; NL\ NL\ neck- 
 iayers.of enamel.
 
 FAULTY DEVELOPMENT. 209 
 
 general line of stratific-atioii, without Ijeiiii;: altered in its con- 
 struction or its course. An exception to this rule will occur 
 only at the })eripheral portions of enamel, occupied by the 
 tapering ends of the above-described secondary strata, which I 
 would like to term neck-lay crs,\n contradistinction to the central 
 casp-hnjers. The tapering ends of the neck-layers may exhibit 
 enamel-rods, almost jiarallel with the surface of the enamel, a 
 feature which is never seen at the outer peri}iliery of the cusp- 
 layers, where the enamel-roJs are invariably directed more or 
 less perpendicularly to the surface. 
 
 " An understanding of the stratification of the enamel is of 
 the utmost importance in aiding tlie understanding of its pig- 
 mentation and granulation. As I will show later on, both the 
 pigmentation and graiuilation correspond to the general strata 
 of the enamel, thus showing in longitudinal sections of teeth 
 a fan-like appearance, 
 
 " It can scarcely be doubted that the stratification of this 
 tissue is in close relation to the history of its development. We 
 know that the first appearing enamel-cap of temporary teeth, in 
 the seventh month of intra-uterine life, has the configuration of 
 the innermost cusp-layer, — i.e., it is broadest in the direction of 
 the future cusp, and tapers toward the future neck of the tooth. 
 It seems reasonable to assume that the subsequent layers of 
 enamel form on the plan of the first, but there may be a tempor- 
 ary stoppage of its construction, due, perhaps, to slight ailments 
 of the mother before delivery of the child, or slight ailments of 
 the infant after delivery, which causes interruptions in its organi- 
 zation. Slight ailments of a general nature will not interfere 
 with the final result of an otherwise sound enamel ; whereas 
 severe ailments, particularly local ones, may lead not onl}^ to 
 stratification, but to a decidedly pathological condition, which I 
 have before called pigmentation and granulation. These condi- 
 tions invarialdy involve a deficient deposition of lime-salts. 
 
 "III. Anomalous Arrangement of the Enamel-Rods. — In 
 normal enamel, longitudinal sections will, in the majority of 
 cases, exhibit slightly wavy rods, interlaced by comparatively 
 small bundles, cut in a transverse direction. Toward the periph- 
 ery the curvatures of the rods gradually become less, until, 
 when close to the surface, they present a nearly straight course. 
 I have never seen transverse sections of enamel-rods directly in 
 contact with the interzonal layer. 
 
 15
 
 210 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 " Deviations from this rule seem to be rare. Where they exist,. 
 the enamel-rods seem to lack all regularity in their arrangement. 
 It may occur that close to the interzonal layer the enamel-rods 
 show extensive tields occupied by these transverse sections, which 
 gradually blend with oblique and longitudinal ones, producing 
 a wavy appearance, to such an extent that beautiful figures arise,, 
 reminding one of the grain of Ih/nuiii-rifcT. Still more compli- 
 cated figures arise if the transverse bars of the longitudinal 
 rods are unusually conspicuous. In such enamel it may occur 
 that the curvatures of the rods remain very marked up to the 
 surface ; and, consequently, groups of transverse sections may 
 be seen directly at the outer surface. 
 
 " Enamel of this description may be seen only on one portion 
 of the tooth, while the rest is normal. In all my specimens, 
 pigmentation is combined with this curly appearance of the 
 enamel-rods as a marked feature, and tlie interstices between 
 the rods are a trifle wider than normal. Both of the latter 
 features must imply a deficient calcification, and, consequently, 
 extreme brittleness. It is very difficult to obtain perfect speci- 
 mens of such enamel. The dentine subjacent to such anomalous 
 formations is freely supplied with interglobular spaces, which 
 fact is likewise a sign of deficient calcification. 
 
 " IV. Deficient Calcification of the Enamel, without Pigmen- 
 tation. — The friability alluded to under the previous heading 
 is in some instances very marked, — so much so that it is impos- 
 sible to obtain an unbroken slab of a tooth, even with the finest 
 grinding-stones. With low powers of the microscope we 
 observe that the broken ends of the enamel-rods look as if cor- 
 roded, or as if some of them had been displaced or torn ofi" by 
 the process of grinding. Neither pigmentation nor an anoma- 
 lous course of the enamel-rods is necessarily connected with 
 such a condition of the tooth. The most striking feature, how- 
 ever, — a feature visible even with low powers, — is that the 
 enamel-rods are unusually narrow, the interstices between them 
 unusually wide, and their tenants, the enamel-fibers, ver}- promi- 
 nent. The cross-lines of the enamel-rods are likewise consider- 
 ably widened and irregular, so that the fields of l)asis-substance 
 look unusually small and irregular. The reticulum in the 
 immediate vicinity of the interzonal layer is also unusually 
 prominent. 
 
 " Such a condition of the enamel may occur both in tempo-
 
 FAULTY DEVELOI'.MENT, 
 
 211 
 
 rary and permanent teeth, and may be combined "with pigmenta- 
 tion. It is a feature of such deficient enamel that it readily 
 stains with an ammoniacal sohition of carmin, something that 
 normal enamel will not easily do. The subjacent dentine, under 
 such conditions, may either be perfectly developed, as before 
 stated, or be deficient in its formation, as shown by the presence 
 of more or less numerous intergloV)ular spaces. 
 
 "All clinicians have observed, in the enamel of teeth, con- 
 
 Fig. 129. 
 
 ExTREMKLY IrKEUI I.AR COURSE OF RonS IX S i.IGH T I, Y-PuiM ENTEI) EXAMEL. 
 
 The longitudinal rods deviating to a great extent from the field of the specimen, show 
 obli<|ue and transverse sections. The interstices are widened and contain conspicuous enamel - 
 fibers. ^lagnified 1200 diameters. 
 
 genital white or yellow spots, which, if broken into, are found 
 to be of the consistence of chalk. Such spots have been termed 
 ' white decay,' although they do not correspond to the process 
 of caries as we usually understand it. They mean nothing but 
 deficient calcification. Again, all clinicians have seen teeth 
 across which runs a row of pit-holes, in the bottom of which 
 depressions, in many instances, no enamel is to be found. This 
 condition, also, is always congenital, and closely related in its
 
 212 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 origin to pigmentation and the white or yellow spots. In 
 other instances an originally smooth enamel is mntilated 
 mechanically by the process of mastication, with the result of loss 
 of substance, with abruptly broken, jagged edges. Again, we see 
 teeth with a great portion of their crowns coyered by a brown- 
 ish-yellow substance in place of enamel, this substance being so 
 soft as to be easily remoyed, leaying the dentine bare of its 
 coyering and extremely sensitiye to the touch of an instrument, 
 the pressure of food in mastication, etc. These conditions, 
 again, are, in most instances at least, connected with the presence 
 of yjigmentation and the white or yellow spots. We might 
 call them exaggerated cases of the same condition. Obyiously 
 these congenital defects are dependent upon deticient deposition 
 of lime-salts ia the basis-substance, rendering the enamel less 
 resistant and more friable. 
 
 "V. Pigmentation of Enamel. — One of the most common 
 anomalous conditions of the enamel is its pigmentation. Some- 
 times it is so slightly marked that the naked eye discoyers only 
 a slight yellow-brown discoloration ; in other instances it is 
 quite prominent and readily chscernible. Correspondingly, 
 specimens of such teeth under the microscope will exhibit either 
 a dim yellow tint in the enamel or a marked brown discol- 
 oration. The pigmentation may occur either in non-stratitied 
 or in stratified enamel. In the iirst instance there is no demar- 
 cation of the brown spot toward the colorless enamel : only 
 faintly-marked otfshoots of the main spot, tapering toward the 
 dentine, and running in an oblique direction, will indicate the 
 fact that pigmentation has occurred during its formation. In 
 the second instance, on the contrary, if pigmentation inyadcs 
 stratified enamel, there is a close relationship between the two, 
 inasmuch as the deepest stain inyariably corresponds to the 
 boundary line of the strata, tapering toward the neck, and 
 gradually fading toward the proximal end of each stratum. 
 Thus, in longitudinal sections, a beautiful fan-like configuration 
 is produced. 
 
 " The pigmentation may invade all layers of the enamel, often 
 being more marked in the deeper than in the superficial por- 
 tions. Higher powers of the microscope reveal the following 
 facts : Pirst, that the brown discoloration concerns the basis- 
 substance of the enamel-rods only. Secondly, that the inter- 
 stices between the pigmented enamel-rods are widened, — not
 
 FAULTY DEVELOPMENT, 
 
 213 
 
 merely to seeming, and in consequence of the contrast in color, 
 but because of a deilciency in the formation of the basis-sub- 
 stance. Thirdly, that the transverse lines of the enamel-prisms 
 likewise are (at least in many instances) enlarged. Fourthly, 
 that the enamel-tibers and their lateral offshoots are more con- 
 spicuous than iu normal enamel, an<l more so even than in the 
 enamel of temporary teeth, and in many places distinctly 
 beaded. Pigmented portions of the enamel are rather prone to 
 take up a red stain on being treated with an aramoniacal carmin 
 solution. 
 
 Fig 130 
 
 Pigmented axd Granular Examel. 
 
 D, dentine ; ER, layer of slightly itigmented rods broken off; EG, layer of highly pigmented 
 and granular enamel ; EP, stratified pigmented enamel. Magnified 400 diameters. 
 
 " As to the origin of the brown discoloration, I have to say, 
 as a suggestion simply, that at the time of the formation of this 
 tissue there must have been a disturbance in the enamel-organ 
 which interfered with the proper construction of the basis-sub- 
 stance and the deposition of lime-salts. What this disturbance 
 really was, I am unalde to say. ^^any pigments of the body de- 
 pend upon and are closely related to the coloring-matter of the 
 blood. I am loth, however, at this time, to attribute pigmen-
 
 214 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 tation of enamel to the extravasation of blood-corpuscles or 
 diffusion of the coloring-matter of the blood. Careful studies 
 in the history of the development of this tissue must be made, 
 before an attempt at a solution of this question will be admis- 
 sible. One point I am positive about, however, is that this pig- 
 mentation is congenital, invading temporary as w^ell as perma- 
 nent teeth. Acquired pigmentation of enamel seems to be ot 
 comparatively rare occurrence, except as a result of caries. I 
 have seen pigmentations of its surface, of a deep orange color, 
 not penetrating the enamel-tissue in the least. Caries on the 
 surface often causes an orange discoloration, diffused and fading 
 toward the normal portions. Several of my specimens plainly 
 show an invasion of the enamel b}' caries, on spots pigmented 
 congenitally ; secondarily, an orange diffused discoloration has 
 taken place, and here the enamel is likewise prone to take up 
 the carmin stain ; thus beautiful shadings of brown, orange, 
 and red are to be seen, the brown being congenital substances, 
 the orange acquired, and the red artificial. What chemical may 
 lead to an acquired pigmentation or discoloration of the enamel 
 I cannot say. 
 
 " VI, Granulation of Enamel.— Under this heading I propose 
 to describe a peculiar abnormality, which, so far as my speci- 
 mens indicate, is by no means rare. It consists of pear-, 
 spindle-, and club-shaped spaces in the middle of the substance 
 of the enamel. Such spaces were known to exist heretofore at 
 the junction of the dentine and enamel only. They may appear 
 in pigmented, and invariably do in stratified, enamel; the strati- 
 fication in the latter instances being due to their presence. 
 Club-shaped spaces may appear at the distal boundary of one ot 
 the cusp-layers, or there may be several rows of such spaces, 
 varying in extent and degree, but it sometimes occurs that only 
 the outermost cusp- or neck- layers are freely supplied with them, 
 whereas the rest of the enamel is normal or more or less pig- 
 mented. 
 
 " Higher powers of the microscope demonstrate that the 
 spaces are enlargements of the interstices between the prisms 
 and the tenants of the interstices. The enamel-fibers are in 
 direct connection with the contents of the spaces, — i.e., with 
 living matter. The spaces, at their stem-like beginnings, run, 
 accordingly, parallel with the interstices: but in their broader 
 portions may cross the enamel-prisms in different directions.
 
 FAl'l.TY DEVELOPMENT. 
 
 215 
 
 If they are few in number they may protrude from the bound- 
 ary line of a cusp-layer, and penetrate the adjacent cusp-layer 
 obliquely to the main direction of the enamel-rods. In this in- 
 stance I could trace the connections of the enamel-fibers even 
 with the club-shaped ends projecting into the neighborino- cusp- 
 layer. If these spaces are present in large numbers, the enamel, 
 with lower powers of the microscope, will look dark and granu- 
 lar; hence the name, 'granulation of enamel,' which I have 
 ^iven it. 
 
 Fig. 131, 
 
 Granii.ak and Sliohtly Pigmkntei) Examkl. 
 
 Club-, spindle-, pear-shaped, and irregular spaces at the boundary of a cusp-layer in the 
 middle of enamel. Magnified 1200 diameters. 
 
 "Fig. 127 represents this condition of granulated enamel, 
 with a low power. 
 
 "Fig. 131 shows the condition under a high power. 
 
 "In stratified and granular enamel, single strata may be pro- 
 duced by an interruption of the pigmented enamel-rods, by con- 
 vex ends directed townrd the adjacent peripheral cusp-layer. 
 (See Fig. 130.) 
 
 "The interprismnfic spaces of the enamel bear sonae resem- 
 blance to the interglobular spaces of the dentine. I have seen
 
 216 THE ANATOMY AND PATHOLO<iY OF THE TEETH. 
 
 both conditions in a liiglily-marked degree present in one of my 
 specimens. Whenever these intcrprismalic spaces are present 
 along the border of a cusp-layer, they considerably lessen the 
 degree of consistence of the enamel, which, upon being ground, 
 easily breaks off along the dark granular line. 
 
 " The nature of the inferprismafjc spaces is plain enough. 
 They mean an incomplete formation of the enamel, owing to 
 some deticiency of function in the enamel-organ during its for- 
 mation. Obviously, not only the basis-substance is delicient, 
 but also the amount of lime-salts is considerably less than nor- 
 mal ; hence its brittleness and proneness to decay. . 
 
 " Under the foregoing headings I have described a number 
 of anomalous conditions of the enamel, which, at least so far 
 as stratification, pigmentation, and granulation are concerned, 
 mean a deticient formation of the basis-substance, together with 
 decreased deposition of lime-salts. These conditions are, in my 
 judgment, of the utmost importance in the etiology of caries. 
 Ailments either of the mother during gestation or of the infant 
 in the earliest periods of life, obviously cause such anomalies in 
 this tissue. These ailments are known to occur far more fre- 
 quently in retined people, debilitated, as it were, by civilization, 
 than in strong, hard-working, plain-living people, continually 
 engaged in a struggle for life. Thus, I have directly demon- 
 strated and anatomically shown, in a measure, at least, the 
 reasons why refined people are far more subject to caries of 
 the teeth than people lacking such refinement."' 
 
 The other contril)Ution, by Frank Abbott, to the knowledge 
 of faulty development of enamel is Congenital Defects in Enamel.^ 
 
 " Every dental practitioner is more or less familiar with the 
 condition of imperfect or defective enamel upon the crowns of 
 permanent teeth (more especially the incisors and first molars), 
 which I propose to consider under the above heading. These 
 imperfections usually concern the summit of the crown or its 
 vicinity. We see upon an otherwise well-developed crown an 
 almost circular ridge, above wdiich the enamel appears of a 
 grayish-brown color, and in the shape of numerous pointed, 
 thorny projections, the masticating surface of molars appearing 
 as if provided with numerous minute stalactites or stalagmites. 
 (See Fig. 132.) 
 
 * Dental C'o.s//(0.v, 1891.
 
 FAULTY DEVELOPMENT. 
 
 217 
 
 " In some cases tliere are only a few blunt or pointed protru- 
 sions of enamel, between which the dentine is entirely destitute 
 of such covering. In others the dentine is nearly covered with 
 enamel, leaving rows of small round or oblong holes through it 
 to the dentine. These features appear, as before stated, only in 
 permanent teeth, and very seldom are any except the incisors 
 and first molars involved. Whether or not the complete absence 
 of enamel from tlie crowns of incisors, as is sometimes seen, is 
 
 Fig. 132. 
 
 Congenita LLY Imperfect Crown of Lower Molar. 
 
 .S', shortened crown ; C, C, codcs of enamel ; D, dentine without enamel covering. Magnified 
 4 diameters. 
 
 of the same nature, and due to the same causes, I am not pre- 
 pared to say, although it seems probable. 
 
 "In looking with the naked eve at a longitudinal section 
 through a molar, affected as just described, we at once recognize 
 the deficiencies of enamel, the stalactite or stalagmite appear- 
 ance, and the shortening of the crown by about one-eighth of 
 an inch, caused by these deficiencies. 
 
 " These blunt and pointed elevations are made up partly of
 
 218 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 healthy-looking and parti}' of a yellowish-brown enamel. Be- 
 tween the elevations are areas partly covered by an extremel}" 
 thin layer of enamel and partly destitute of it. By grinding 
 the crown of such a tooth in longitudinal section for microscopi- 
 cal examination, the masticating surface presents an extremely 
 striking image. (See Fig. 133.) 
 
 "A well-developed, though slightly-pigmented, enamel is seen 
 to be gradually tapering toward the masticating surface, show- 
 
 FiG. 133. 
 
 Section of Masticating Surface, shotvixg Partial Covering of Enamel. 
 
 E, well-developed enamel : L. i-solated lumps of enamel ; D, D, dentine : /, 1. interglobulai- 
 spaces. Magnified 100 diameters. 
 
 ing marked deficiencies of the outermost layer. These deficien- 
 cies consist of conical depressions at the surface and granula- 
 tions near it. Obviously this condition was caused by an incom- 
 plete calcification of the enamel, from the fact that it has taken 
 up or absorbed a dee]) brown pigmentation. The tapering 
 layer of enamel stops abruptly, leaving the dentine entirely un- 
 covered, as is seen in several places; besides, there are irregular 
 hilly protrusions of an enamel of a deep brown color. These 
 are the protrusions furnishing to the grinding-surface the appear-
 
 FA r I/rY I)E VELOPMKXT. 
 
 219 
 
 aiice of groups of stalactites. Slabs exposed to the action of a 
 half per cent, solution of chloride of gold for one hour, exhibit 
 a dark violet color of the dentine in the crevices between the 
 enamel-lumps, which means that a portion of the lime-salts has 
 been dissolved out, although no destruction of the organic por- 
 
 FiG. 134. 
 
 IsoLATKD Lump of Enamel, Vkry Imperfect. 
 
 P, P, P, protoplasmic projections into the enamel from the dentine ; C, transverse section of 
 ■enamel-prisms; i*, dentine. Magnified 500 diameters. 
 
 tion of the dentine has taken place. At the usual distance from 
 the interzonal layer are seen interglobular spaces. 
 
 " Let us magnify a lump of enamel in this locality live hun- 
 dred diameters. (See Fig. 134.) 
 
 " We notice in this specimen narrow prisms, markedly wavy, 
 and interrupted by faint concentric striations. The prisms, as
 
 220 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 usual, do not reach the surface of the dentine, but at a given 
 distance from it they are replaced by irregular angular pieces. 
 The outermost portion of the lump is of a dark brown color. 
 Penetrating the enamel at varying heights are seen numerous 
 pear-shaped prolongations of the dentinal canaliculi, some ex- 
 tending nearly to the surface. These spaces contain protoplasm, 
 and have become stained a deep violet color by the chloride of 
 gold. Aside from these irregularities the lump seems to be 
 thoroughly calcilied, except in a few spots upon the surface, 
 
 Fig. 135. 
 
 *^ . ' J ^ y ^ ■ _^ ,^ , f/ 
 
 
 Imperfect E.namel. 
 E, well-developed enamel, transverse section ; G, G, granular layer of enamel, with pear- 
 shaped protoplasmic enlargements ; D, dentine, canaliculi in transverse and oblique sections ; 
 /, interglobular spaces. Magnified 800 diameters. 
 
 which have taken a slight violet stain. The exposed dentine is 
 also deeply stained the characteristic violet color in this locality, 
 denoting insufficiency of lime-salts, or an excess, over the ordi- 
 nary, of organic material. 
 
 " In some instances the crown of the tooth maj* be nearly 
 covered with a well-developed or a stratified and slightly-pig- 
 mented enamel, the other portions being coated with a thin 
 layer highly pigmented, again denoting deficiency in lime-salts. 
 (See Fig. 135.)
 
 FAULTY DEVELOPMENT. 221 
 
 *' We present here a transverse section of the crown of a 
 molar. The thin and irregularlv-contoured enamel exhibits 
 only transverse sections of prisms, of a deep brown color. At the 
 interzonal layer numerous pear-shaped protoplasmic spaces are 
 seen penetrating the enamel, and in the region nearest the den- 
 tine the prisms appear as if granular or sieve-like (perforated 
 with numerous small holes), indicative of a lack of proper calci- 
 fication. 
 
 " I will now call attention to some extremely interesting and 
 instructive anomalies in the formation of this tissue, — viz, two 
 distinct varieties of enamel, one upon the other. First we have 
 the anomalous portion grafted or deposited upon a normal 
 enamel, and again anomalous enamel first deposited, with the 
 peripheral portion fairly normal. (See Fig. 136.) 
 
 " This represents a cusp of a molar, with a conspicuously 
 deficient enamel, deposited upon a nearly normal one. The 
 normal portion is slightly pigmented, slightly stratified, and 
 supplied with a moderate number of granulations, near the 
 interzonal layer. The outer or peripheral portion exhibits a 
 layer which ends abruptly on one side, and gradually blends 
 with the normal enamel on the other. This portion is remark- 
 ably deficient in its structure. At the boundary-line between 
 the two portions the enamel-prisms become abruptly devious, 
 their longitudinal course being suddenly changed to a trans- 
 verse one. In the latter portion a few oblique sections are seen 
 alternating with the transverse. The whole portion superadded 
 to the normal is pierced by innumerable granulations, which, 
 owing to their violet color, we must conclude as j)rotoplasmic 
 in structure, and, of course, deficient in lime-salts. The granu- 
 lations are, in some places, arranged in rows, in others scattered 
 irregularly. If a large mass of enamel exhibits prisms almost 
 rectangular to their original normal direction, it is not an evi- 
 dence of interlacing of such prisms, but of their unusually 
 wavy courses. An originally deficient enamel, upon which is 
 deposited a normal one, is represented in Fig. 137. 
 
 " Here we observe numerous layers made up of extremely 
 narrow, interrupted prisms, and at a given line prisms of nornjal 
 width appear, first in transverse, then in longitudinal sections. 
 This specimen aftbrds a good opportunity to trace one and the 
 same prism in longitudinal, oblique, and transverse section. 
 
 " In all the teeth with imperfect enamel that I have examined,
 
 222 
 
 THE ANATOMY AND PATH0L0(4Y OF THE TEETH. 
 
 the so-called interglobular spaces were present in the dentine, 
 indicating a deticient calcification of territories at the period of 
 development which corresponds with that of the formation of 
 enamel. In only one specimen have I seen a devious course of 
 the dentinal fibers and stratification of the dentine. 
 
 Fig. 136. 
 
 Imperfect, C4rafted upon Perfect Enamel. 
 
 />, dentine; /i, boundary zone (interzonal layer) ; A', perfect enamel: £"', imperfect enamel. 
 Magnified 100 diameters. 
 
 " In one instance peculiar formations were seen in the ce- 
 mentum. (See Fig. 138.) 
 
 " The cementum here exhibits distinct lamellations and scat- 
 tered cement-corpuscles, with their longitudinal diameters mostly 
 arranged perpendicular to the direction of the lamellae. The 
 cementum was abruptly interrupted by the dipping downward
 
 FAULTY DEVELOPMENT. -JlJo 
 
 of the pericementum to the close vicinity of the dentine. In this, 
 situation the prolongations of tlie pericementum were hardened 
 by globular depositions of lime-salts, which were conspicuous 
 by a high degree of refraction. 
 
 " This anomaly — altogether ditferent from the process of 
 absorption of the roots of temporary teeth, or that of bone — 
 
 Fig. 137. 
 
 Perfect, Grafted upon Imperfect Esamkl. 
 
 E^, irregular and imperfect layer of enamel; E-, regular layer of enamel ; />, dentine; /. 
 interglobular spaces. Magnified 500 diameters. 
 
 must have occurred at the time of the development of the ce- 
 mentum, which, as is well known, takes place after the forma- 
 tion of the dentine. 
 
 "A remarkable feature in connection with this case was the 
 apparently perfect condition, in the mouth, of the gum and
 
 224 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 alveolus. In the pericementum the microscope revealed noth- 
 ing anomalous except a few scattered calcified patches. It is 
 hardlj possible that there is anj especial connection between 
 this and the morbid process in the enamel, as the enamel is com- 
 pletely formed at a much earlier period than this could have 
 happened. As to the causes which lead to the imperfections in 
 the enamel and other portions of the teetli during the process 
 of development, I will quote as follows from an article on * Den- 
 tition and its Derangements,' by A. Jacobi, M.D., 1862. He 
 says,— 
 
 Fig. 138. 
 
 Irregularities of Cementum. 
 
 P, pericementum ; C, stratified cementum with cement-corpuscles ; E, excavations of 
 cementum filled with pericementum; G, globular stratified depositions of lime-salts; L>, I), 
 dentine. Magnified 100 diameters. 
 
 " ' The enamel of the teeth is subject to several anomalies. It 
 ma}' be either defective or discolored. Its defective formation ap- 
 pears either in excavations dispersed over the surface of the tooth, 
 or there are complete furrows or transverse notches around the 
 crown of the tooth, the body being still covered with or entirely 
 deprived of enamel. This atrophy is the result of those severe 
 diseases which the child may have been suffering from during 
 the development of the enamel. Acute exanthems are said to
 
 FAULTY DEVELOPMENT, 225 
 
 produce the dispersed excavations; acute inflammatory diseases, 
 the furrows ; aud rhachitis has often been observed to be the 
 cause of the entire absence of the enamel. The incisors ot 
 rhachitic children are usually small, appear late, and are very 
 liable to become carious. Acute exanthems are counted among 
 the causes of this anomaly, especially by such writers as classify 
 the teeth with the dermal tissue. Smallpox is related to produce 
 isolated excavations which have a great similarity to the cica- 
 trices remaining after smallpox. To vaccination, also, some have 
 attributed the defective development of the enamel. . . . 
 The mucous membrane of the mouth is very irritable, being 
 accustomed only to amniotic liquor in foetal life, and to milk in 
 the early stage of extra-uterine existence. Every change in 
 the diet, therefore, the bad quality of the material, or artificial 
 nipples, the use of candy, sucking-bags, or alcoholic beverages, 
 coffee, or stimulants of whatever kind, will act as irritants, pro- 
 ducing hyperemia or inflammation in a more or less severe 
 form. ... A more severe form is that known by the name 
 of aphthous stomatitis. The superficial layers of the epithelium 
 are not thrown off during the hypereemic swelling of the mucous 
 membrane, as in erythematous stomatitis, but a real and visible 
 change takes place in the anatomical structure of the follicles. 
 There is a circumscribed, punctated, vascular injection around 
 a follicle which is gradually infiltrated by exudation. The con- 
 secutive swelling increases in proportion, the follicles will burst 
 and exhibit a superficial erosion or ulceration, and the adjacent 
 mucous membrane will be sympathetically affected.' 
 
 " Edmund Lesser says, ' In the majority of haired men, which 
 means congenital growth of hair all over the face (hirsuties), I 
 hitherto have observed that defects or irregularities of the 
 dental system were present, since not only a number of teeth, 
 but the corresponding alveoli, were missing. In some cases of 
 normal dentures a broadening of the alveolar processes was 
 apparent.' 
 
 " Although of epithelial origin, the enamel-organ is of a 
 myxomatous structure, and thus represents a variety of connect- 
 ive tissue. The history of development of enamel (which 
 makes its appearance about the seventh month of fcetal life) is 
 well understood, as far as temporary teeth are concerned, up to 
 the time of birth of the child. Still we know nothing as to 
 the progress of the lateral pegs in laying the foundation of the 
 
 16
 
 226 THE ANATOMY AND PATHOLOiiY OF THE TEETH. 
 
 enamel-organ and the enamel of tlie permanent teeth. We 
 simply conclude that the process is identical with that of the tem- 
 porary teeth, in its development during the earliest years of extra- 
 uterine life. Since the imperfections of enamel, as described, 
 are observable upon permanent teeth only, I, without fear of 
 contradiction, venture the hypothesis that diseases of the oral 
 cavity only affecting the epithelial layers, and the pegs derived 
 therefrom, must cause these defects. Such diseases occur in the 
 oral cavity of young children, under the headings of inflamma- 
 tion (stomatitis), from many causes, leading to the formation of 
 blisters, ulcers, and abscesses. Growth of mildew (so-called 
 thrush) is known to be a fertile source of both such superficial 
 and deep-seated disturbances. 
 
 " Acute exanthems, which sometimes spread to the mucous 
 membrane of the oral cavity, undoubtedly play an important 
 part in causing inflammation of the enamel-organ, which results 
 in producing defective enamel. 
 
 "We can appreciate the probability that inflammation will 
 partially destroy either the original epithelia or the enamel- 
 organ derived therefrom, and thus be the direct cause of defect- 
 ive enamel. A simple obliteration of a number of blood- 
 vessels which freely surround this organ would suflice so to 
 interfere with its proper function as to diminish the amount of 
 lime-salts deposited; the enamel-prisms in such case might 
 develop normally as to size, but show deficiency in calcification. 
 If, with the inflammation and obliteration of blood-vessels, 
 hemorrhage takes place into the enamel-organ, or eft'usion of 
 haemoglobin should occur, pigmentation of the deficiently calci- 
 fied prisms would become intelligible. 
 
 " We can realize that the medullarv tissue ojivins: rise to 
 enamel-prisms will, in consequence of inflammation, be so 
 altered or misplaced that the outcome would be imperfect, in- 
 complete, or devious prisms. As I showed in 1885 that the 
 formation of enamel takes place in the shape of layers for the 
 crown and layers for the neck, we may grasp the possibility that 
 the earliest crown-layers may be fully and regularly developed, 
 while the last crown-layers are interfered with and become 
 defective. Should, therefore, an inflammatory process start at 
 the time of the appearance of the earliest crown-layers, and soon 
 abate, the enamel nearest the dentine will be found imperfect. 
 If the inflammatory disturbance continues for a long period, the
 
 DEVELOPMENT OF CEMENTUM. 227 
 
 result will be a thin and incompletely calcified layer of enamel. 
 Should portions of the enamel-organ be completely destroyed 
 by suppuration, entire absence of enamel at such points will be 
 the result. A number of so-called miliary abscesses in the 
 enamel-organ will lead to a porous or ' pitted' enamel. A 
 limited number of somewhat larger abscesses would cause larger 
 holes or pits, or possibly the entire enamel-organ might be 
 destroyed, leaving the dentine entirely unprotected. 
 
 '' In all the cases of teeth with defective enamel that I have ex- 
 amined, the dentine lias been found fully developed and perfectly 
 calcified, with the exception of quite numerous interglobular 
 spaces. These appear in the dentine at the same period ot 
 development during which the enamel-organ was alfected. This 
 positively indicates the disease or diseases which caused the 
 production of imperfect enamel to have been local rather than 
 general, as has been supposed by some pathologists.'' 
 
 CHAPTER XVII. 
 
 DEVELOPMENT OF CEMENTUM.* 
 
 Our researches into the history of the development of the 
 teeth extend over a period of eight years, and a large collection 
 of specimens has been at our disposal. ^Nevertheless, until re- 
 cently, we hesitated about saying anything upon this topic, as 
 none of the specimens of which we were then possessed revealed 
 anything of interest concerning the development of cementum. 
 This tissue, in human beings, is developed after birth, when the 
 root and its dentine have been fully formed. "We know that 
 at the time of birth only the crowns of the temporary teeth are 
 present, but there is no trace of the roots. At what time the 
 tissue in question begins to appear in the human subject, we are 
 unable to state. The only specimens at our disposal, in which 
 the question of the development of the cementum could be 
 studied, were obtained Irom the lower Jaw of a kitten about six " 
 weeks old. As the course of development of dentine and 
 
 *" Contributions to the History of the Development of the Teeth," by C. 
 Hcitzmann and C. F. W. Bodocker. The Independent Practitioner, vols, viii, i\.
 
 228 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 enamel is almost identical in cats and men, we feel justified in 
 the assLimption that the formation of cementum is likewise the 
 same in both. ^Ve are the more confident because of the knowl- 
 edge that the development of bone exhibits the same features in 
 cats as in men, and because, as is well known, cement is nothing 
 but bone-tissue. 
 
 Fig. 139. 
 
 D 
 
 >' *« ' 
 
 
 
 Apex of thk Root of a Temporary Tooth of a Kitten Six AYeeks Old. Vertical 
 
 Section. 
 
 I), dentine ; t', cementum, in part thoroughly calcified, and partly made up of medullary 
 corpuscles; CB, basis-substance of the cementum, composed of medullary corpuscles; PC, 
 pericementum. Magnified 200 diameters. 
 
 In the above-mentioned specimens, taken from a kitten six 
 weeks old, we observed both the temporary and permanent 
 teeth in place. The temporary teeth were fully developed and 
 their roots perfect, whereas the permanent teeth only exhibited 
 a small cap of dentine and enamel over the papilla, correspond-
 
 DEVELOPMENT OF CEMENTIIM. 229 
 
 ingto a human foetus between the seventh and eighth months of 
 intra-uterine life. Both the dentine of the crown and that of 
 the root, especially of the latter, were partly absorbed, and they 
 exhibited bay-like excavations, which were filled with multi- 
 nuclear protoplasmic masses. 
 
 The cement at the cervix of the teeth in cats is a compara- 
 tively narrow" formation, made up, as in the teeth of men, of 
 delicate spindles arranged perpendicular to the longitudinal axis 
 of the root, between which spindles we observe no cement-cor- 
 puscles. This layer is evidently developed from spindle-shaped 
 medullary corpuscles, of which a whole row is visible in the 
 neighboring pericementum. A direct calcification of these 
 medullary corpuscles leads to the formation of the cementum 
 of the neck. Farther downi, the cementum becomes broader 
 by the addition of a row of medullary corpuscles greatly vary- 
 ing in size, and without distinct lines of demarcation between 
 them. With lower pow-ers of the microscope their protoplasm 
 appears finely granular; with high powers, however, a distinct 
 reticulum is recognizable, the same as in all protoplasmic for- 
 mations. Toward the dentine the medullary corpuscles assume 
 a high grade of refraction, indicative of a deposition of lime- 
 salts, which latter have been removed by the treatment with the 
 €hromic-acid solution. The boundary-line betw^een the dentine 
 and cementum is nowdiere distinctly marked. Still farther 
 down toward the apex of the tooth scanty cement-corpuscles 
 make their appearance, invariably surrounded by a number of 
 iinely-granular medullary corpuscles, without any marked terri- 
 torial formation around each bone-corpuscle. E'earer to the 
 apex the cementum becomes very broad, exhibiting a number 
 of cement-corpuscles. Here this tissue is fully developed around 
 the dentine, but is yet in the process of formation at the periph- 
 ery of the root. The latter portion plainly reveals the manner 
 in which the cementum is developed. 
 
 Like all the tissues of the body, including the dentine and the 
 enamel, the cementum arises from medullary tissue. In this 
 respect cementum and bone-tissue show a striking likeness. 
 The medullary corpuscles from which bone-tissue arises bear 
 the name of osteoblasts, and should any one desire to give a 
 special name to the formers of the cementum, that of cemento- 
 blasts should be admissible. These corpuscles become the seat 
 of a deposition of lime-salts before any cement-corpuscles are
 
 230 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 conspicuous. We observed that the previously-calcified medul- 
 larv corpuscles are decalcified, and after a second calcification 
 some of them remained unchanged, exhibiting an angular shape 
 characteristic of bone- and cement-corpuscles. This stage, how- 
 ever, still represents an incomplete form of cementum. Lastly, 
 another decalcification of the medullary corpuscles takes place, 
 and this time distinct groups of medullary corpuscles become 
 visible, the centers of which are occupied by the cement-corpus- 
 cles, and in this manner the territories of the cementum as well 
 as those of bone-tissue arise. After calcification of the medul- 
 lary corpuscles has been accomplished, neither the medullary 
 corpuscles nor the boundary-lines of the territories are conspicu- 
 ous; but when calcification is incomplete, both the medullary 
 corpuscles and the territories are easily recognizable. 
 
 With high powers of the microscope we more readih' observe 
 the manner in which the cementum is developed. As long as 
 this tissue is imperfect, and not fully calcified, a number of the 
 medullary corpuscles assume a certain degree of refraction which 
 marks partial calcification, whereas some of the medullary cor- 
 puscles retain their protoplasmic nature, and thus represent the 
 cement-corpuscles. Xearer to the dentine the medullary cor- 
 puscles are arranged in clusters, in the center of which we 
 observe the cement-corpuscles. As a rule, each cement-corpus- 
 cle is surrounded by a number of medullary corpuscles repre- 
 senting a territory. I^ot infrequently a territory is indistinctly 
 defined. This is the case wherever the cement-corpuscles are 
 separated from each other by a single row of medullary corpus- 
 cles only, or where the deposition of lime-salts has been com- 
 pleted, whereupon both the medullary corpuscles and the 
 boundary-lines of the territories are lost to sight. (Fig, 140.) 
 
 The question arises. How are tlie offshoots of the cement-cor- 
 puscles formed ? In order to understand this process, we must 
 bear in mind that the medullary corpuscles, even when incom- 
 pletely calcified, exhibit the reticular structure characteristic of 
 all protoplasmic formations. They greatly vary in size, and are 
 separated from one another by light rims, which invariably 
 appear traversed by delicate conical ofi:shoots. It is obvious that 
 the ofi^'shoots are formations of living matter, serving for the 
 interconnection of all medullary corpuscles. Whenever lime- 
 salts are deposited in the meshes of the reticulum of the medul- 
 lary corpuscles, the interstices between them remain free from
 
 DEVELOPMENT OF CEMENTU.M. 
 
 231 
 
 such a deposit. The conical offshoots between the medullary 
 corpuscles coalesce at the centers of the latter into a filament of 
 living matter, — the offshoot of the bone-; or cement-corpuscle. 
 Such a delicate offshoot remains interconnected by the lateral 
 filaments running into the reticulum of the medullary corpus- 
 cles, the same as is the case with dentine- and enamel-fibers. 
 Even where the calcification of the medullary corpuscles has 
 assumed its highest degree, and where all boundary lines 
 
 Fig. 140. 
 
 MB 
 
 CkMKXXUM l.S THE PkOCKSS of FuK^ilATION OF A TKMroliAHY TdOTH (IF A KiTTEN StX 
 
 Weeks Old. 
 
 3f, medullary corpuscles incompletely calcified, but still recognizable: MB, medullary cor- 
 puscles thoroughly calcified in parts and transformed into basis-substance; ('(', cement-corpus- 
 cles partly lying in a completely-calcified basis -substance, and partly occupying the centers of 
 group? of medullary corpuscles, the so-called territories; /?, basis-substance. Magnified 1200 
 diameters. 
 
 between them have disappeared, the reticulum in the basis- 
 substance remains unaltered, and plainly visible witli a good 
 immersion lens, without the addition of any reagent. 
 
 The results of our researches concerning the history of 
 development of the cementum of the temporary teeth of a 
 kitten six weeks old are as follows: 
 
 I. The cementum arises from medullary tissue, the same as 
 bone- and all other tissues of the body.
 
 232 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 II. The medullary corpuscles first become the seat of a deposi- 
 tion of lime-salts before any cement-corpuscles are visible. 
 
 III. The lime-salts are dissolved and redeposited again in the 
 medullary corpuscles, which are arranged irregularly around 
 the cement-corpuscles, the latter, however, remaining free from 
 calcareous infiltration. 
 
 IV. Still later the medullary corpuscles are arranged in 
 groups, the centers of which are the cement-corpuscles, the sum 
 total furnishing the territories around the cement-corpuscles. 
 
 V. The oflTshoots of the cement-corpuscles are filaments of 
 livino- matter, originatino- from the brido^es traversins: the inter- 
 stices between the medullary corpuscles. 
 
 VI. The reticular structure of the original medullary corpus- 
 cles is preserved in the basis-substance even after the completion 
 of the calcification of the latter, and the disappearance of the 
 original medullary corpuscles. 
 
 The development of the roots of the -temporary as well as the 
 permanent teeth has been carefully studied, as far as naked-eye 
 appearance goes, by C. X. Peirce. The illustrations published 
 by him I have copied in the chapter on " Faulty Development," 
 Fig. 120, page 196. My rather limited knowledge of this topic 
 will excuse my reference to an author known to be reliable. 
 
 CHAPTER XVIII. 
 
 THE DEVELOPMENT OF TEETH IX EMBRYOS AFFECTED WITH 
 RHACHITIS.* 
 
 Amoni; the numerous embryos whose teeth the writers have 
 examined, there were three aftected with so-called congenital 
 rhachitis. One of these was a seven-months" fcetus, another 
 seven months and a half, while the third was eight months old. 
 Macroscopically the two former did not exhibit any symptoms 
 of rhachitis, and it was only upon microscopical examination of 
 the jaw-bones that we were enabled to recognize the morbid 
 process, whose characteristic feature is a new formation of hya- 
 
 * ' ' Contributions to the History of Development of the Teeth, ' " bj* Carl Heitz- 
 mann and C. F. "\V. Bodec-ker. Liileju-tKhnt Prm-fitione); vols, viii and ix.
 
 DEVELOPMENT OF KlIACHITIC TEETH IX EMBRYOS. 233 
 
 line cartilage in the place of l>one-tissue. The trabecule of the 
 cancellous bone-tissue were scantier, and the lione-corpuscles 
 within them were much larger, than those in normal bone-tissue. 
 In many places, however, hyaline cartilage was present instead 
 of bony trabecule, and in the medullary spai-es between them. 
 The cartilage-corpuscles often were of a brown color, caused 
 either by previous hemorrhage or by a new formation of blood- 
 corpuscles and htemoglobin. The third fa-tus, which was eight 
 months old, showed the symptoms of congenital rhachitis in 
 such a degree that all bone-tissue throughout the body was 
 lacking, and only in the lower jaw were found a few trabecuhe. 
 This ftt'tus was delivered bv a health v woman, who, during her 
 pregnancy, for a number of months furnished dogs, cats, and 
 rabbits with soup, meat, bread, and vegetables, mixed respect- 
 ively with lactic acid, for the purpose of artificially producing 
 rhachitis and osteomalacia in these animals. These experiments 
 were made by Carl Heitzmanu (see " Microscopical Morphol- 
 ogy," 1883) and proved to be successful. Dogs and cats, treated 
 with lactic acid soon after birth, l>ecame rhachitic, and treated 
 with lactic acid for several months in succession, l)ecame affected 
 with osteomalacia. 
 
 The woman who gave l)irth to this fcptus was healthy during 
 pregnancy, and remained so after delivery. The fcctus, on the 
 contrary, died shortly after birth, from intracranial hemorrhage 
 caused by pressure during labor, on account of the complete 
 absence of cranial bones. 
 
 The abnormal occurrences in the teeth of these three rhachitic 
 embryos were so striking and so numerous that we made an 
 attempt to arrange them under a number of headings, being 
 aware of the fact that different chronic ailments both of a 
 mother and of a fcetus, more especially rhachitis of the footus, 
 reflect on the growth of the teeth, and leave marks in the shape 
 of transverse grooves or furrows upon them. 
 
 I. Premature Eruption of Ill-developed Teeth, found in the 
 lower ja\v of a rhachitic fetus. sc\cn nmnllis old. (See Fig. 
 141.) 
 
 This tooth had reached a stage of development corresponding 
 to about the seventh month of intra-uterine life, but had grown 
 above the level of the gum, and was plainly visible to the naked 
 eye. This specimen helped to settle a mooted question con- 
 cerning the origin of Nasmvth's membrane, — the cuticle of the
 
 234 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 tooth. The writers observed that the flat epithelial layer cov- 
 ering the summit, and the dentine at the deeper portion of the 
 tooth, is a direct reduplication of the flat epithelial layer of the 
 gum. The papilla is moderately supplied with blood-vessels^ 
 
 Fig. hi. 
 
 PuK.MATUKE Eruption of a Lower Incisdk of a Rhachitic Fcetus, SevenIMonths 
 
 Old. 
 (J, gnm ; C, fibrous connective tissue ; EO, myxomatous enamel-organ. Magnified '50 
 diameters. 
 
 and is of a markedly myxomatous structure, especially at its 
 lower part, which appears lobulated. It is bordered by a 
 structureless layer at its lower portion, which we consider a 
 normal feature, and which is always present previous to the
 
 KKVELOP.MENT OF RIIACHITIC TEP:TI[ IN K.Mi;KVO,<. 235 
 
 appearance of odontoV)lasts. The gum is composed of a loose, 
 delicate, librous connective tissue. At the right side of the 
 specimen, near the lower portion of the papilla, there appears 
 an isolated laver of myxomatous tissue, which extends below 
 the papilla, hearing the characteristics of the enamel-organ. Its 
 outer periphery shows a number of l)uds or nests, which are the 
 otfspring of the external epithelium. 
 
 II. Double Papillae. — In the same f(x-tus the writers observed 
 two papilhe of lower bicuspids, which at their bases were united 
 into one continuous broad mass, whereas higher up there was 
 seen a cancellous bonv structure, separating the papillse, which 
 proves that they belonged to two separate teeth. The struc- 
 ture of these papillae was markedly myxomatous, similar in 
 appearance to that of the papillpe of pig's teeth. The enamel- 
 organ appeared to be in full development, being lined l>y the 
 internal epithelium, which was broken up into medullary tissue, 
 and an external epithelium broken up into epithelial nests. 
 Along the internal epithelium peculiar folds and indentations 
 are visible, which the writers propose to describe later on. Xo 
 trace of dentine or enamel was visible upon these germs. 
 
 III. Dwarf Teeth. — In the rhachitic fcetus which was seven 
 and a half months old, the writers met with minute teeth which 
 were in a stage of development corresponding to the age of the 
 fcetus. (See Fig. 142.) 
 
 The papillfie are of very irregular shape, being partly blunt, 
 partly elongated, and sharply marked by a constriction at the 
 place corresponding to the neck of the future tooth. Above 
 the neck the papillte are of the usual lancet or myrtle-leaf shape, 
 exhibiting along their borders either odontoblasts or rows of 
 medullary corpuscles, and showing comparatively^ few blood- 
 vessels. The dentine is curved around the constriction in a 
 marked degree, surrounding the neck of the tooth like a cap. 
 Its canaliculi are wide, but without pathological features. The 
 enamel is likewise to be considered normal, but the enamel- 
 organ is missing in all of these specimens, which indicates that 
 the myxomatous reticulum was exhausted. The external epi- 
 thelium only shows its presence by small epithelial nests and 
 buds along the already-formed enamel. 
 
 A peculiar feature of both the papilla and the surrounding 
 connective tissue is the presence of rusty-brown, needle-shaped 
 crvstals of h;ematoidin. sometimes clustered together in numer-
 
 236 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 OU.3 masses. These are the result of a previous hemorrhage, 
 although it is not explicable how they appear in the papilla, 
 where the blood-vessels are extremely scanty and just in the 
 process of formation. 
 
 IV. Malformations and Malpositions of the Enamel-Organ. 
 — In the teeth of a rhachitic tVetus we not infrequently meet 
 with enamel-organs markedly ditfering from normal ones, the 
 difference mainly consisting in the lack of a myxomatous 
 reticulum. This tissue appears in the shape of small, glistening 
 
 Fig. 142. 
 
 Dwarfed Teeth of a RHACHiTir FfEirs, Sevex and a Half Months Old. 
 
 .4. blunt foot-shaped papilla, with a constriction, from which the dentine starts: i?. elon- 
 gated narrow papilla, from which grows at an acute angle the tooth, again marked by a con- 
 stricted neck. Magnified 50 diameters. 
 
 granules, arranged either in the shape of clusters or of an indis- 
 tinct reticulum. The granules themselves vary somewhat in 
 size, and among them larger granular corpuscles may be seen, 
 which, without any regular arrangement, are yet entitled to the 
 name of nuclei. The meshes of this irregular reticulum hold 
 an apparently structureless mucoid liasis-substance. Besides 
 these irregular formations of the enamel-organ, we sometimes 
 meet with malpositions of it, either in a normal or an anomalous 
 condition, (See Fig. 143.)
 
 DEVELOPMENT OF EIIACHITIC TEETH IN EMBRYOS, 
 
 237 
 
 In this specimen the enamel-organ is located entirely above a 
 tooth, which is likewise anomalous. It is widened in a horizontal 
 direction, nearly parallel to the outer surface of the mucosa. It 
 
 Anomalous Location and Formation of the Examkl-Orcjan oi- a Human Fcetus Seven 
 AND A Half Months Old, affected with Congenital Rhachitis. 
 
 EO, enamol-organ ; EE, external epithelium ; E, enamel ; l>, dentine ; /', papilla. Magni- 
 fied 100 diameters. 
 
 extends downward along the newly-formed dentine and along 
 the upper portion of the papilla. It is lined with medullary 
 tissue and with clusters of epithelia, both being derived from 
 the external epithelium, whereas the internal epithelium is com-
 
 238 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 pletely exhausted for the formation of the enamel. The layer 
 of medullary tissue arising from the external epithelium is 
 broad, but short on one side, and narrow and much elongated 
 on the other side of the enamel-organ. The tooth is anomalous 
 not in its size, nor in respect to the stage of development it is 
 in, but on account of its devious papilla, resembling the teeth 
 illustrated in Fig. 142. The specimen was obtained from the 
 same embryo as those illustrated in Fig. 142. The papilla is 
 constricted at the place where the dentine begins, at the neck 
 of the tooth, below which the papilla suddenly widens and pro- 
 duces a bluntly-elongated body of considerable size, composed 
 of medullary tissue, and holding a number of clusters of hsema- 
 toidin crystals, which are also seen in the neighboring fibrous 
 connective tissue. Another misplacement of the enarael-organ 
 is illustrated in Fig. 141, in which it is depicted as located 
 beneath the base of the papilla. 
 
 V. Folds, Convolutions, and Reduplications of the Epithelium 
 of the Enamel-Organ. — In both rhachitic embryos from which 
 specimens have been taken, we have encountered in the enamel- 
 organ peculiar formations, which we propose to describe under 
 the above heading. N^ear the external epithelium, which at the 
 age designated is invariably split up, we have sometimes found 
 concentrically-arranged epithelial nests, or clusters of medullary 
 tissue, imbedded in an otherwise normal myxomatous reticulum. 
 Far more common than these formations, which depend upon a 
 reduplication of the external epithelium, are foldings and con- 
 volutions of the internal epithelium. (See Fig. 144.) 
 
 The internal epithelium shows, sometimes, simple indenta- 
 tions, which are also observed occasionally in normal teeth of 
 the same stage of development. At other times there is a 
 series of successive convolutions of the internal epithelium. 
 I^eighboring this epithelium the myxomatous tissue of the 
 enamel-organ, as a rule, is in a medullary condition, with and 
 without a pronounced intermediate layer. Obviously, such 
 sinuosities correspond to furrows of the enamel-organ, and very 
 probably may cause the ridges and furrows often observed upon 
 this tissue. The highest degree of reduplication of the internal 
 epithelium is sometimes seen, together with apparently isolated 
 buds of dentine, surrounded by and inclosed in a layer of amelo- 
 blasts and myxomatous tissue. The dentine consists either of a 
 narrow calcareous rim, or a cap in which we may observe dis-
 
 DEVELOPMENT OF KliACHITIC TEETH IX EMlJltVu^. 
 
 239 
 
 tinct dentinal canaliculi. If the dentinal cap appears as a thin 
 calcified ledge, it is composed of calcified medullary corpuscles, 
 beneath which odontoblasts are perceptible. If the ledge of 
 the dentine is broader and supplied with dentinal canaliculi, we 
 notice close beneath it a layer of medullary corpuscles followed 
 by a layer of odontoblasts which are usually in process of break- 
 
 FiG. 144. 
 
 Reduplication of the Internal Epithelium of a Rhachitic Forrus Seven and a 
 Half Months Old, around a Bud of Dentine. 
 
 £"0, myxomatous enamel-organ; ^i5^, external epithelium ; ^, layer of ameloblasts; /£, in- 
 terstitial layer composed of spindle-shaped elements surrounding the ameloblasts; AK A^, layer 
 of ameloblasts toward an already-formed enamel ; M, myxomatous tissue approaching the 
 structure of medullary tissue ; />, dentine with underlying odontoblasts. Magnified 200 diam- 
 eters. 
 
 iiig up into medullary corpuscles. It may be possible that such 
 formations are the starting points of the transverse furrows ob- 
 served upon the labial surfaces of the temporary teeth of rickety 
 children, although these occurrences are far more common on 
 permanent teeth. 
 VI. Anomalies of Enamel. — It is a common feature in teetli
 
 240 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 of rhacliitic children that the interstices between the enamel- 
 prisms are wide, and their tenants, the enamel-fibers, are very 
 distinct, often running a wavy course independent of the con- 
 tours of the enamel-prisms. The prisms themselves are finely 
 granular, without distinct cross-lines. These features are ex- 
 plained by the evidence of a deficient calcification of the enamel, 
 
 Anomalous Enamel of a Rhachitic FtETUs Seven and a Half Months Old. 
 
 EE, enamel-organ of medullary character arisen from the external epithelium ; E, enamel 
 composed of prisms of a markedly wavy course ; M, cluster of medullary corpuscles, — i.e., non- 
 calcified enamel-tissue; IL, interzonal layer filled with medullary corpuscles: /^ dentine. 
 Magnified 500 diameters. 
 
 which allows the cutting of thin sections of the enamel after it 
 has been softened in chromic-acid solution, whereas it is impos- 
 sible to obtain sections of normal enamel in the same manner. 
 In a rhachitic foetus eight months old, we have observed in the 
 enamel dark-brown colorations, which are to be considered as
 
 DEVELOPMENT OF RIlACllITIC TEETH IN EMBRYOS. 241 
 
 pigmentations of the enamel-rods. Another feature in the 
 enamel of rhachitic embryos is a markedly wavy course taken 
 by the enamel-prisms, — so much so that in a strictly longitudinal 
 section alternate layers of enamel-prisms appear, some of which 
 are cut longitudinally, while others are transverse, (See Fig. 
 145.) 
 
 Frank Abbott has already drawn attention to the fact that 
 transverse sections of enamel-prisms, alternating with longitu- 
 dinal sections, are not caused bv an interlacins; of the enamel- 
 prisms, but by a wavy or devious course of the enamel-prisms 
 themselves, and our specimens have furnished satisfactory proof 
 of the correctness of the latter view. 
 
 2^ot infrequently we observe at the summit of the dentine, in 
 the interzonal layer, medullary corpuscles, either arranged in 
 rows or irregularly scattered in the vicinity of the dentine. Such 
 formations scarcely admit of any other interpretation than that 
 the medullary elements, from which the enamel-prisms originate, 
 have not been calcified, but have remained in an embryonal 
 state. (See Fig. 145, M and IL.) 
 
 In specimens from a rhachitic foetus seven and a half months 
 old, the enamel appear&d bordered by a medullary tissue, whose 
 origin could be directly traced from the buds and clusters, the 
 remains of the external epithelium. Here, therefore, our pre- 
 vious assumption, that the external epithelium likewise furnishes 
 material for the increase of the enamel, can be directly proven. 
 
 VII. Anomalies of the Dentine. — The dentine of all rhachitic 
 teeth is conspicuous by wide dentinal canaliculi, in which the den- 
 tinal fibers and their lateral ofiJshoots are easily discernible. The 
 basis-substance shows a more or less marked reticular structure, 
 without the application of any reagent. In a foetus eight months 
 old we found peculiar formations of dentine, which evidently 
 are caused by a deficient calcification of this tissue. (See Fig. 
 146.) 
 
 Such spaces send offshoots upAvard and downward in the den- 
 tine, which represent either conically-widened dentinal canals, 
 or broad routes replacing the same. The spaces and their larger 
 branches are filled with medullary corpuscles in all stages of 
 development. Where the space inosculates with dentinal 
 canaliculi, the tenants of the latter are coarse fibrillse, with 
 spindle-shaped widenings composed of large granule^. Both 
 within these spaces and in their vicinity we observe globular 
 
 17
 
 242 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 formations whicli exhibit the features of badly-developed 
 secondary dentine, or globular dentine, resembling the structure 
 of the dentine of the so-called pulp-stones, or denticles. Spaces 
 
 Fig. 146. 
 
 Medullary Space and Globular Mass in the Dentine of a Tooth of a Rhachitio 
 FffiTUs Eight Months Old. 
 
 M. medullary corpuscles filling a crescentie space in the dentine ; B, branch of the crescentic 
 space replacing a dentinal canaliculus ; G, globular, concentrically-striated mass. Magnified 
 600 diameters. 
 
 of this description resemble the interglobular spaces of Czermak, 
 but they are more irregular and much larger. 
 
 VIII. Anomalies of the Papilla. — The writers have described 
 and illustrated, in Fig. 142, anomalous papillae of peculiar shapes. 
 In such papillie we often observe crystals of hseraatoidin 
 grouped together in clusters, the origin of which must be sought 
 for in an imbibition by the tissue of the coloring-matter of the 
 blood at a very early stage ot" development. The writers 
 furthermore wish to draw attention to peculiar formations met 
 with in the medullary tissue of the papilla. (See Fig. 147.) 
 
 Such globules we have observed only at the summit of the
 
 DEVELOPMENT OF RIIACHITIC TEETH IN EMBRYOS. 
 
 243 
 
 papilla, and in close connection with raedullated nerve-fibers. 
 The globules are pale, finely granular, and with either smooth 
 or lobulated contours. Their interior shows faint marks of 
 division, which indicate that the globules have arisen from 
 medullary corpuscles or clusters thereof. We are unable to de- 
 termine the nature of such corpuscles, which seem to be in 
 relation to newly-forming medullated nerves. All the nerve- 
 
 Fi(i. 147. 
 
 Globules in the Papilla ix a Rhachitic Fa';Tus Seven and a Half Months Old. 
 
 0, G, granular globules, partly smooth, partly lobulated ; iV, ]V, medullated nerves. Magni- 
 fied 600 diameters. 
 
 fibers seem, however, to run between the globules, although it 
 appears in the drawing as if a bundle of nerves inosculated with 
 a globule. This may be explained by the assumption of a de- 
 vious course of the nerve-bundle. 
 
 The most interesting feature of such papillae is that the medul- 
 lated nerves first appear at the summit of the papilla, whereas 
 the lower portions of the papilke are free from nerves, and only
 
 244 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 exhibit scanty capillary blood-vessels. The nerves still appear 
 to be composed of rows of medullated corpuscles, without any 
 trace of the myelin sheath. Whether or not axis-cylinders are 
 present, we could not determine from the longitudinal sections 
 before us. This much is certain, — that the nerves grew inde- 
 pendent of the central nervous system ; that they were in no 
 connection with already-formed nerves of the central nervous 
 system, and, therefore, that they must have arisen from medul- 
 lary corpuscles in essentiall}^ the same manner as other tissues. 
 Those who strictly adhere to the doctrine of exclusiveness in 
 embryology — the doctrine that development proceeds from the 
 three original layers — will try in vain to explain such an inde- 
 pendent formation of nerves in the middle of connective tissue. 
 
 CHAPTER XIX. 
 
 THE DENTAL PULP.* 
 
 Methods. — The best method of preparing pulp-tissue for ex- 
 amination is to place the tooth, immediately after its removal 
 from the mouth, in an aqueous solution of chromic acid of from 
 one-half to one per cent, strength. To this mixture may be 
 added, every third or fourth day, one or two drops of dilute 
 hydrochloric acid, to hasten the process of decalcification. It is 
 important to use a large quantity of the liquid, — not less than a 
 quart for one tooth or a few, — and to renew the same at least 
 every second or third day. After the teeth have been in the 
 chromic-acid solution a few weeks, the peripheral portion of the 
 dentine will become sufiiciently soft to be cut by a razor. When 
 the hard parts of the dentine are reached by the cutting-instru- 
 ment, the extraction of the lime-salts must again be continued 
 in the manner described above, until the pulp-cavity is reached. 
 
 Another method is to split the tooth, as soon as possible after 
 its extraction from the mouth, with a strong pair of excising- 
 forceps. The teeth best adapted for this method are the incisors, 
 cuspids, and bicuspids. By an experienced manipulator the 
 
 •*"Th6 Minute Anatomy, Physiology, Pathology, and Therapeutics of the 
 Dental Pulp." Den fal Cosmos, 1882.
 
 THE DENTAL PULP. 245 
 
 pulps of molars can be extricated from their inclosing walls, but 
 with less success than in the teeth before mentioned. In split- 
 ting, put the cutting-edges of a sharp pair of excising-forceps in 
 the longitudinal direction near the apex of a single-rooted 
 tooth, then exert a sharp and quick pressure, when, as a rule, 
 the tooth will split into halves with the pulp-cavity exposed. 
 Immediately moisten the pulp with a solution of chloride of 
 sodium in water, of the strength of about one-half of one per 
 cent., and then remove the pulp. The greatest care must be 
 taken, in picking the fragments of the tooth from the pulp-tissue, 
 to avoid tearing the organ, as tearing greatly alters the micro- 
 scopical aspect of nerve-tissue. If the pulp is to be stained with 
 carmin,h?ematoxylon, fuchsin, hyperosmic acid, picro-indigo, or 
 chloride of gold, etc., place it in the staining-fluid immediately 
 after its removal from the hard parts of the tooth. 
 
 Among the reagents mentioned, I have found but one of con- 
 siderable value, — viz, the solution of chloride of gold of the 
 strength of one-half of one per cent. This reagent may be 
 applied ro fresh pulps as well as to very thin sections obtained 
 after hardening in chromic acid. These specimens, however, 
 must, as a matter of course, be carefully washed with distilled 
 water before the chloride-of-gold solution is added. The re- 
 agent may be allowed to remain in contact with the specimens 
 for from twenty to thirty minutes, when they should again be 
 washed in distilled water and exposed to daylight. In a few 
 days fresh specimens assume a bright violet color, while sections 
 which have previously been in a chromic-acid solution become 
 brownish-violet. Osmic acid, in solution, one per cent, strong, 
 renders the contours of the constituent tissues, and especially 
 those of the medullated nerve-fibers, more distinct, as it stains 
 the nerve-fat dark green. Both fresh and chromic-acid speci- 
 mens may be treated with osmic acid. Thin sections do not 
 require more than an hour's exposure to this reagent, while 
 whole fresh pulps may be left in it for two or three hours. Ex- 
 cept the aramoniacal solution of carmin, which is known to be 
 excellent for staining certain parts of the tissue, I would not 
 lay stress upon applying any of the other reagents mentioned. 
 
 If we wish to examine the pulp, together with the inclosing 
 dentine, or a pulp-stone, the specimen, previously softened by 
 chromic acid, must be imbedded in a mixture of paratKn and 
 wax, which is best done in the following manner. Place the
 
 246 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 softened tooth in absolute alcohol for about twenty-four hours; 
 then, of rather thick paper, prepare a box somewhat larger than 
 the specimen ; warm the imbedding mixture, which consists of 
 about eight parts of paraffin and one of white wax, until it is 
 bai^ely liquid ; pour enough of it into the paper box about to 
 half-fill it; then take the specimen oat of the alcohol, and as 
 soon as it begins to dry, place it in the paper box and pour over 
 it some more of the paraffin and wax, so as to cover it com- 
 pletely. Care must be taken not to have the imbedding mixture 
 too hot, as it may injure the specimen. The latter, after the 
 mixture has become sufficiently hard, is ready for cutting, when 
 very thin sections can easily be obtained. To-day imbedding in 
 celloidin is used almost exclusively'. 
 
 If a fresh pulp is thin enough, it may, immediately after its 
 removal from the split tooth, be transferred to the slide, with 
 the addition of an indifferent tluid, such as the solution of chlo- 
 ride of sodium, etc. But a slight and careful pressure upon the 
 cover is necessary in order to spread fresh specimens. The 
 fresh pulps of lower incisors, being the thinnest, are the best 
 adapted for examining the system of blood-vessels. In a short 
 time, however, they fade away, and the specimen becomes unfit 
 for preservation. Isolated pulps may be placed between two 
 plates of velvet cork, and thus cut into thin sections with the 
 razor. I would recommend chemically-pure glycerin as the best 
 preserving-fiuid for pulp-specimens. 
 
 The Minute Structure of Pulp-Tissue. — The dental pulp repre- 
 sents the remains of the foniier dentine papilla, and occupies the 
 central cavity of the tooth. It is richly supplied with blood- 
 vessels and nerves, which enter the pulp-chamber at the apex of 
 ever}" root through one or more openings. The tooth for its 
 supply of nourishing material depends upon the pulp and the 
 pericementum. In many instances a tooth, after the death of 
 the pulp, may be retained in its place for years, deriving its 
 blood-supply from the pericementum only. 
 
 If we examine a thin longitudinal or transverse section of the 
 pulp with low powers of the microscope (200 diameters), we 
 recognize a large number of blood-vessels and bundles of medul- 
 lated nerve-fibers. The majority of these blood-vessels are 
 capillaries; the veins are less numerous, and arteries are scarce. 
 Often we find in a pulp only one arteriole ; frequently arterioles 
 lie in the midst of the medullated nerve-bundles. The medul-
 
 THE DENTAL I'L LP. 
 
 247 
 
 lated nerve-bundles mostly run in a longitudinal direction, but 
 not in frequently Ve observe smaller bundles, or single medul- 
 lated nerve-fibers, to diverge from the longitudinal direction, 
 and to run obliquely through the pulp-tissue. 
 
 In transverse sections of the pulp we meet with arteries, veins, 
 
 
 ^^>- 
 
 ..ili^L 
 
 Normal Pilp in Tkansvkkse Section', Stained with Ciii.nKioK or (Joi.d. From a 
 Moi.AR OF A Youth Sixteen Years Oli>. 
 
 0, layer of odontoblasts, arranged in rows of medullary corpuscles; B, granular layer; M, M, 
 myxomatous, erroneously termed "adenoid," tissue; C, C, capillary and venous blood-vessels; 
 jT, T. bundles of meduUatod nerves in cross-section; L, L, bundles! of medullated nerves in 
 longitudinal section. Magnified 75 diameters. 
 
 and capillaries, the first cut across, the others distributed in all 
 directions. The bundles of medullated nerve-fibers are seen 
 most distinctly in transverse sections. Tliey often hold in their 
 interstitial tissue capillary vessels and arterioles, which also 
 appear in transverse sections. In very thin sections it often hap-
 
 248 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 pens that the nerve-fibers fall out, and then we see a roundish 
 empty space bounded by the sharply-defined external perineu- 
 rium. The absence of an endothelial coat renders such spaces 
 easily recognizable m distinction from blood-vessels. (See Fig. 
 148.) 
 
 The main mass of the pulp, as seen with low powers, is com- 
 posed of a delicate fibrous reticulum, containing a large number 
 
 Fig. 149. 
 
 'M^Vv?^ M 
 
 
 1 
 1 
 
 Segment of the Pulp of a First Molar Tooth. Longitudinal Section. 
 
 M, myxomatous connective tissue ; V, vein ; C, capillary blood-vessel ; N, bundle of medul- 
 lated nerve-fibers; F. terminal non-meduUated nerve- fibers; B, protoplasmic layer, contain- 
 ing the terminations of the nerves ; 0, layer of medullary corpuscles in rows, termed odonto- 
 blasts. Magnified 200 diameters. 
 
 of bright corpuscles. Longitudinal sections in many instances 
 exhibit delicate fibrous bundles scattered throughout the reticu- 
 lar structure of the pulp, mostly in the neighborhood of large 
 blood-vessels and nerve-bundles. The fibrous reticulum, in the 
 crown portion, is evenly distributed ; in the root-portions, on 
 the contrary, it is much elongated. Pulps composed of a fibrous 
 connective tissue only, are rather exceptional, and, as it seems,
 
 THE DENTAL PULP. 
 
 249 
 
 their occurrence is without any relation to the age of the per- 
 son. They are always the result of morbid processes. Toward 
 the outer surface of the pulp the reticular structure is, as a rule, 
 denser than in the middle portions. This peripheral part is 
 
 Fig. 150. 
 
 Normal Pllp in Transveuse Section, Stained with Chloride of Gold. From a 
 Molar of a Youth Sixteen Years Old. 
 
 0, layer of odontoblasts, arranged in rows of medullary corpuscles ; li, granular layer; well- 
 developed myxomatous lymph-ti.=suo ; M, myxomatous lymph-tissue, basis-substance still pro- 
 toplasmic ; CL, capillary blood-vessel in longitudinal section; VT, capillary blood-vessel in 
 transverse section; iVZ, bundle of medullatod nerves in longitudinal section; AT, bundle of 
 medullated nerves in transverse section. Magnified 500 diameters. 
 
 surrounded by a wreath of elongated formations arranged in a 
 radiating manner all around the pulp, — the so-called " odonto- 
 blast layer." (See Fig. 149.)
 
 250 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 Higher powers of the microscope (500 to 600 diameters) re- 
 veal a minute reticular structure, consisting of delicate fibers or 
 anastomosing protoplasmic cords, with very small oblong nuclei 
 at their points of intersection. The mesh-spaces inclosed by 
 this reticulum either look pale and finely granular throughout, 
 or there is, besides the pale granular substance, a bright yellow- 
 ish body, either homogeneous or granular, of the size and as- 
 pect of a nucleus. The number of the latter formations varies 
 greatly in diiierent pulps. Where bundles of a fibrous tissue 
 traverse the reticulum, there the latter blend with the former. 
 In the fibrous bundles, besides the delicate fibrillse, we see scanty 
 and small oblong nuclei. (See Fig. 150.) 
 
 As mentioned before, the fibrous connective tissue prevails at 
 the periphery of the larger blood-vessels and nerve-bundles. In 
 transverse sections the latter invariably exhibit a distinct fibrous 
 sheath containing oblong nuclei, — the so-called external perineu- 
 rium. The nuclei imbedded in the sheath do not project above 
 the level of the sheath, as is plainly observable on empty ones 
 where the fibers have fallen out, while the endothelia of blood- 
 vessels of any description invariably protrude toward the in- 
 closed space, thus affording an excellent means of distinction 
 between blood-vessels and empty nerve-sheaths. 
 
 The arteries are characterized by the presence of a layer of 
 smooth muscles, outside of which is seen a slight fibrous coat. 
 The layer of smooth muscles necessarily thickens the walls of 
 the blood-vessels, thus rendering them easily recognizable in 
 transverse sections. The veins, marked by their large caliber, 
 their scanty muscle-fibers, and a fibrous coat, are usually filled 
 with blood-corpuscles. The capillaries are composed of a single 
 -endothelial laver, which is separated from the adjacent reticu- 
 lum by an extremely delicate light rim. They are found cither 
 ■empty or containing a few blood-corpuscles. 
 
 In longitudinal sections the modullated nerve-fibers show the 
 well-known fluted double contour of considerable refraction (the 
 sheath of Schwann). Inside of this is the myelin (nerve-fat) 
 concealing the central axis-cylinder. Schw^ann's sheath exhibits 
 delicate oblong or spindle-shaped nuclei, and external to this we 
 ■observe a very delicate layer of fibrous connective tissue, — " the 
 internal perineurium."' In cross-sections of the nerve-bundles 
 a more or less circular group of medullated nerve-fibers is seen, 
 «ach of which in its center exhibits the axis-cylinder in the shape
 
 THE DENTAL PULP. 251 
 
 of a roundish, glistening dot, the single nerve-fibers being sepa- 
 rated from one another by the delicate internal perineurium. 
 !N'ot infrequently capilhiry and arterial blood-vessels are met 
 with between the nerve-fibers which, at the periphery of the 
 bunilles, blend with the nucleated sheath of the external peri- 
 neurium. 
 
 As to lymphatics of the pulp, I can say that in some speci- 
 mens I have seen branches of vessels of the size of veins with- 
 out an adventitial coat, and composed of large, flat, slightly- 
 protruding endothelia. These vessels I believe to be lymphatics, 
 as they contained a finely-granular coagulated albumen, scanty 
 granular corpuscles, and a very limited number of blood-cor- 
 puscles. As to the distribution of lymphatics, I must abstain 
 from positive statements. 
 
 It seems that pulps containing calcareous globules aftbrd the 
 best opportunity for the study of the lymph-vessels, owing to 
 their dilated condition. Fig. 151 is taken from the coronal por- 
 tion of such a pulp, and beautifully shows the relation of the 
 lymph- and blood-vessels to the bundles of medullated nerves. 
 
 At the periphery of the pulp the delicate reticulum consti- 
 tuting the pulp-tissue is very dense, and its small meshes are 
 supplied with numerous corpuscles looking like nuclei. In this 
 layer we meet with only narrow capillary blood-vessels. The 
 outer surface of this layer is bounded by radiating rows of shining 
 corpuscles of the size and appearance of nuclei. These rows are 
 separated from one another in a longitudinal direction by light 
 rims, in which, frequently, delicate fibrillfe may be observed. 
 
 In chromic-acid specimens stained with carmin, or, still 
 better, in those treated with chloride of gold, high }»owers (1000 
 to 1200 diameters) reveal an extremely minute reticular structure 
 pervading all formations of the pulp-tissue. 
 
 The formations at the periphery of the dental pulp, which 
 were termed " odontoblasts" by J. Tomes, and which by some 
 observers have been considered as epithelium-like formations, 
 under high amplifications exhibit the following: 
 
 Longitudinal bodies, somewhat resembling epithelia, border 
 the pulp in a radiatory direction. Such a field may appear in 
 the shape of a finel^'-granular protoi)lasm or basis-substance, in 
 which there arc imbedded oblong nuclei in varying numbers. 
 The nuclei exhibit coarse granules and a dense reticulum of living 
 matter, while the elongated fields inclosing the nuclei exhibit
 
 252 
 
 THE AXATOMY AND PATHOLOGY OF THE TEETH. 
 
 pale granules and a delicate reticulum. Between these latter 
 formations a narrow light rim is seen, wherein we observe some- 
 times broad, sometimes delicate, fibrillse in connection with the 
 reticulum of neighboring formations, accompanied by delicate 
 conical oiFshoots, which penetrate the surrounding rims at right 
 
 Fig. 151. 
 
 , V?f¥^*H¥ AN^ -i^-te; ■./■■£ 
 
 
 
 Vessels and Nerves of the Crown of a Pulp containing Calcareous Globules. 
 N, N, larpe and small bundles of medullated nerves ; A. arteriole ; F, V, veins ; C. capillary 
 blood-vessel; Z, Z, lymph-vessels; 3/, .V, myxomatous lymph-tissue. Magnified 200diameters. 
 
 angles. In many instances these formations between the odonto- 
 blasts may be traced into the dentinal fibers, lodging in the 
 middle of the dentinal canaliculi. 
 
 It is evident, from what I have seen, that the odontoblasts
 
 THE DENTAL I'ULP. 
 
 253 
 
 furnish the matrix for the basis-substance of the dentine, whereas 
 the dentinal fibers, l)eing formations of living matter, originate 
 between the odontoblasts, (See Fig. 152.) 
 
 In specimens of a nine-months' foetal pulp, sufllciently stained 
 with chloride of gold, I have observed that the medullated nerve- 
 fibers upon approaching the periphery of the pulp are destitute 
 of their myelin sheath, and now, being bare axis-cylinders, split 
 into numerous extremelv delicate beaded fibrilla", — tljc " axis- 
 
 i^l 
 
 
 ^-y ;:.;.. v C^'r-'' ,^ 
 
 Segment of the Pulp of a Temporary Tooth, Stained with Chloride of Gold. 
 
 M, myxomatous connective tissue ; ^V, terminal non -medullated nerve-fibers, in a uniformly 
 granular protoplasmic layer ; 0, rows of medullary corpuscles, termed odontoblasts ; F, dentinal 
 fibers between the odontoblasts; I), dentine. Magnified 1200 diameters. 
 
 fibrillse." They are marked by u dark-violet color, and run in 
 the light rims between the rows of the odontoblasts near the 
 pulp-tissue proper, and are connected with the odontoblasts by 
 means of delicate conical offshoots. In some instances I have 
 observed that these axis-fib rilhie terminated in knob-like extremi- 
 ties. But whether the nerve-fibers directly anastomose with the 
 dentinal fibers I am unable to say. That an indirect connection 
 of the two is established by the intervening reticulum of living 
 matter, I positively assert.
 
 254 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 The results of my researches of the normal pulp are as fol- 
 lows : 
 
 I. The dental pulp is a variety of connective tissue termed 
 myxomatous, representing an embryonal form of it. Some 
 authors have called this form of tissue " adenoid," but this term 
 is admitted to be erroneous. 
 
 II. The myxomatous tissue of the pulp is intermixed with a 
 delicate fibrous connective tissue in varying amounts. 
 
 III. The pulp-tissue is traversed by a closed system of blood- 
 vessels, — viz, arteries, veins, and capillaries. At least one artery 
 is invariably found in the pulp, and it is by no means of excep- 
 tional occurrence that the pulp contains several arteries. Lym- 
 phatics in small numbers are also present. 
 
 IV. The pulp-tissue is richly supplied with nerves, which, in 
 the shape of bundles of medullated nerve-fibers, traverse the 
 myxomatous tissue. Toward the periphery of the pulp they 
 lose their myelin sheaths, become non-medullated, and, in the 
 shape of minute beaded fibrillse, branch between the odonto- 
 blasts. 
 
 V. The odontoblasts at the periphery of the pulp are elon- 
 gated protoplasmic formations with rows of nuclei. They are 
 medullary corpuscles such as we see wherever a new tissue arises 
 from a former one. They Vjuild up the basis-substance of the 
 dentine by solidification (transformation into glue, and infiltra- 
 tion with lime-salts). The reticulum of living matter traversing 
 the odontoblasts remains unchanged in the basis-substance of the 
 dentine. 
 
 VI. The dentinal fibers originate between the odontoblasts. 
 Being formations of living matter, they are in direct connection 
 with the reticulum of living matter, — first of the odontoblasts 
 and afterward of the basis-substance of the dentine. The con- 
 nection between the ultimate nerve-fibrillse and dentinal fibers 
 is very probably an indirect one by means of the intervening 
 reticulum of living matter.
 
 THE PERICEMENTUM. 255 
 
 CHAPTER XX. 
 
 THE PERICEMENTUM.* 
 
 The pericementum (root-membrane, or alveolo-dental peri- 
 osteum, or periodontium, etc., as it has been termed by former 
 writers) is a formation of fibrous connective tissue, identical 
 with the periosteum which covers all bones. It consists of a 
 layer interposed between the roots of the teeth and their corre- 
 sponding bony alveoli, and is common to both. It is continu- 
 ous with the connective tissue — the so-called sub-mucous layer 
 of the gum — and with the periosteum of the maxillae. Its fibers 
 are connected with the cementum of the root as well as with 
 the wall of the alveolus. A few writers have described the 
 pericementum as a double membrane, one portion of which 
 belongs to the root, the other to the alveolus; we ourselves have 
 not been able to see anything that justifies such a discrimination. 
 In many of the specimens examined, the connective-tissue bun- 
 dles of the pericementum may be traced from the socket to the 
 cementum of the root of the tooth, or in connection with the 
 reticular structure in the vicinity of the root. Exceptionally 
 we see, close around the root, a thin layer of very dense and fine 
 fibers, the general direction of which is not quite identical with 
 that of the connective tissue which produces the main mass of 
 the pericementum. The relations between the soft and the 
 hard formations of the jaws are very plain in specimens obtained 
 from grown cats, and in all essential points are in accordance 
 with those perceived in specimens taken from the human jaw. 
 
 The course pursued by the connective-tissue bundles is slightly 
 wavy and oblique, starting from the cementum and running up- 
 ward toward the alveolus. The bundles of this tissue are dense, 
 without many decussations. The parallel direction of the bun- 
 dles begins to change into a diverging one at about the height 
 of the border of the socket, where the bundles become coarser, 
 decussate, and thus produce the elastic connective-tissue cushion^ 
 termed the gum. 
 
 From the anatomical disposition of the pericementum, con- 
 clusions may be drawn as to its physiological action. It is evident 
 that the relatively soft and elastic layer between the two bony 
 
 * " Pericementum and Pericementitis.'' Dental Cosmos^ 1879-1880.
 
 256 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 formations — the cementum and the alveolus — is designed to 
 lessen the concussion upon the jaw-bones during mastication. 
 The oblique direction of the connective-tissue bundles is the 
 most favorable for the suspension of the tooth within its socket, 
 as the bundles correspond to the funnel shape of the socket, in 
 the center of which is situated the conical root of the tooth. 
 The elasticity of the layer of pericementum admits of a slight 
 degree of motion of the roots; hence we understand the forma- 
 tion of facets on the approximal surfaces of the crowns of the 
 teeth in crowded maxillary arches. 
 
 Fig. 153. 
 
 ^^-K- 
 
 Pericementum of Myxomatous Structure. 
 
 D, dentine; C, cementum of neck; P, pericementum; M, multinuclear bods-; V, capillary 
 blood-vessel ; F, fat-globule with a vacuole. Magnified 500 diameters. 
 
 We observe two varieties of pericementum, — one of a reticu- 
 lar structure, termed myxomatous; the other altogether fibrous. 
 The myxomatous variety I have met with, as a rule, in young 
 individuals. It consists of delicate fibers, or bundles of fibers, 
 in a net-like arrangement, and having, in many instances, round 
 or oblong nuclei at the points of intersection. The meshes con- 
 tain either a hyaline, apparently structureless, sometimes finely- 
 granular basis-substance, or they hold protoplasmic bodies, pro- 
 vided with a varying number of nuclei. The nearer to the
 
 THE PERICEMENTU.M. 257 
 
 ceraentum, the narrower is the myxomatous reticulum, and the 
 smaller, therefore, are the inclosed protoplasmic bodies. The 
 latter, in the immediate vicinity of the cementum, stand in more 
 or less regular rows, entirely analogous to the protoplasmic 
 bodies around the developing bone-tissue, known, since Gegen- 
 baur, as " osteoblasts." Some of the meshes of the myxomatous 
 tissue are considerably larger and contain multinuclear proto- 
 plasmic bodies, termed " myeloplaxes" by Robin, of Paris; 
 " giant-cells" by R. Virchow, of Berlin, and " myeloid cells" by 
 English authors. Other meshes hold fat-globules, which, in 
 specimens preserved and hardened in a solution of chromic acid, 
 very often contain closed spaces, — so-called vacuoles. The 
 myxomatous reticulum is traversed by numerous blood-vessels, 
 mainly capillaries and veins, some of which may be seen enter- 
 ing the medullary spaces of the compact bone of the wall of the 
 alveolus, and in connection with' the capillary system of the can- 
 cellous portion of the alveolus. I have met with but few nerve- 
 fibers in m}^ specimens. 
 
 Fig. 153 illustrates a portion of the myxomatous variety of 
 pericementum as shown with a relatively low power. High 
 amplification of the microscope plainly demonstrates the delicate 
 reticular structure of all protoplasmic bodies; the reticulum 
 being visible not only in the contents of the ilieshes, but also 
 within the fibers of the myxomatous reticulum. The latter 
 feature is best recognizable on specimens deeply stained with 
 chloride of gold. The apparently structureless or indistinctly 
 granular myxomatous basis-substance, held in the meshes of the 
 myxomatous reticulum, proves to be of a reticular structure just 
 as well as the protoplasm itself. 
 
 The second variety of pericementum is built up of fibrous 
 connective tissue, which prevails in adults and persons of ad- 
 vanced asre. The bundles of the fibrous connective tissue may 
 be uniform in width throughout the whole pericementum : or 
 there exists a zone of tissue of myxomatous or indistinctly 
 fibrous character close around the cementum. The bundles are 
 built up of a number of fibers which hold a varying amount of 
 protoplasmic bodies ; as a rule, more numerous the nearer to 
 the cementum. On the latter there maybe found rows of osteo- 
 blasts or scattered protoplasmic bodies alternating with Imndles 
 of a delicate connective tissue, which are directly attached to 
 the cementum. In a few instances we see rows of osteoblasts, 
 
 18
 
 258 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 the refracting power of which has been considerably augmented. 
 Such corpuscles look shining and structureless, evidently because 
 of a deposition of lime-salts. The fibrous variety of the perice- 
 mentum also contains fat-globules, sometimes in a surprisingly 
 large quantity. 
 
 High magnifying powers of the microscope reveal a struc- 
 ture of the fibrous connective tissue, as follows : The fibers, a 
 certain number of which combine in the formation of a bundle, 
 are delicate spindles, directly connected with one another at their 
 pointed ends. These spindles are separated from each other by 
 narrow layers of a light substance, to the presence of which 
 Tomsa first drew attention, and for which he proposed the term 
 " cement-substance." This substance is doubtless kindred to 
 the gluey basis-substance which mainly builds up the spindles of 
 the connective tissue. The interstices between the spindles are 
 traversed in a vertical direction by extremely minute threads 
 every way analogous to the thorns in the cement-substance sur- 
 rounding epithelial elements. These threads in many instances 
 ar.e visible in specimens hardened by the chromic-acid solu- 
 tion ; they become very plain when thin sections have been im- 
 mersed in a half per cent, solution of chloride of gold for one 
 or two hours, or until the specimen has assumed a dark-violet 
 color. If the stain be complete, we also recognize that the 
 spindles are not homogeneous, as they look in fresh, unstained 
 specimens, but are rather traversed by a delicate, dark-violet 
 reticulum, the points of intersection of which are slightly thick- 
 ened, and thus represent granules. (See Fig. 154.) 
 
 Between the spindles of the basis-substance protoplasmic 
 bodies are seen the formerly so-called connective-tissue cells. 
 Some of these bodies exhibit shining, compact, oblong nuclei, 
 with a certain amount of surrounding protoplasm, while others 
 are devoid of nuclei, and split into spindle-shaped or polygonal 
 lumps, which in size and shape fully correspond to the element- 
 ary formations of the fibrous basis-substance. Where there is 
 a central nucleus, it is invariably bounded by a light rim, which 
 is pierced by radiating thorns. The latter connect the circum- 
 ference of the nucleus with the granules of the protoplasm next 
 to the nucleus. The protoplasm under all circumstances exhib- 
 its the well-known reticular structure. From the periphery of 
 a protoplasmic body, each being surrounded by a light rim, 
 minute threads spring forth, and run into the reticulum within
 
 THE I'ERICEiMKXTU.M. 259 
 
 the spindles of the basis-substance. The same relations are seen 
 in protoplasmic bodies next to the cementum, — the so-called 
 osteoblasts. The offshoots of these formations run partly to the 
 spindles of the basis-substance and partly into the light reticu- 
 lum within the cementum. In some instances, between the 
 cementum and the osteoblasts there is interposed a small layer 
 of librous basis-substance in the shape of delicate slender spin- 
 dles. The walls also of the capillaries, consisting of a single 
 layer of endothelia, are connected with the neighboring spindles 
 of the basis-substance by means of delicate threads, which tra- 
 verse the light rim around the blood-vessels, — the so-called peri- 
 
 FiG. 154. 
 
 
 
 
 Pericementum op Fibrous Structure. 
 
 C, cemontum of root; /'Z, pericementum, the fibers of which are built up of .^piudles, in 
 longitudinal sevtion ; I'F, pericementum, the elementary spindles of which are finer, and cut 
 obliquely; /•", /'-. protoplasmic bodies, either so-called connective-tissue corpuscles or so-called 
 osteoblasts. Magnified 1200 diameters. 
 
 vascular space. Lastly, such offshoots run also into the light 
 reticulum of the bone-tissue, where the pericementum is attached 
 to the wall of the alveolus. 
 
 In its juvenile condition the pericementum represents a myxo- 
 matous connective tissue, the fibrous portion of which is rela- 
 tively scanty, while the protoplasmic portion prevails. In this 
 instance two varieties of basis-substance occur, — viz, the fibrous, 
 building up the reticulum, and the myxomatous, filling a cer- 
 tain portion of the meshes. This condition arises, first, from the 
 indifferent or embryonal tissue, not only in the pericementum, 
 but in all formations of connective tissue which, when fully de-
 
 260 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 veloped, exhibit a fibrous structure. The onl}- wa}^ to explaiu the 
 formation of the myxomatous tissue is that a part of the proto- 
 plasm constituting the embryonal elements remains unchanged, 
 a part is transformed into spindles of myxomatous reticulum, 
 and a part into myxomatous basis-substance. 
 
 "Whereas the myxomatous variety of pericementum is rich in 
 blood-vessels, the fibrous variety is but scantily provided with 
 them. The broadest portion of the pericementum, that around 
 
 Fig. 155. 
 
 Coils of Arterioles in the Pericemkntum. Horizontal Section. 
 
 C, cementum at the ape.x ; L, longitudinal fibers of pericementum ; T, transverse fibers of 
 pericementum ; C, C, coils of arterioles ; N, N, bundles of medullated nerves in transverse sec- 
 tion. Magnified 100 diameters. 
 
 the apex of the root, shows peculiarly tortuous arteries and 
 arterioles, in some places coiled into tuft-like formations. C. 
 Wedl was the first to describe such arterial tufts in the perice- 
 mentum. Fig. 155 is an illustration of two arterial coils. Tor- 
 tuous arteries we invariably find in tissues and organs exposed 
 to frequent changes in their bulk, and it seems that the slight 
 mobility of the tooth, owing to the varying amount of perice- 
 mentum, accounts for the presence of arterial coils.
 
 ERUPTION' OF THE TEhlTlI. 
 
 261 
 
 CHAPTER XXI. 
 
 ERUPTION OF THE TEETH. 
 
 For the first eight or ten months after birth, infants require 
 only liquid food, and in a normal condition thej have during 
 that period no teeth above the gums. Instead of teeth, upon 
 the anterior portion of the jaws we observe comparatively hard 
 and rougli eminences of the mucous membrane, designed to 
 hold the nipple of the mother's breast in the process of sucking. 
 At the time of birth the cusps — cutting-edges — of the crowns 
 of most of the temporary teeth are situated on a level with the 
 alveolar process, covered only by the mucous membrane. The 
 calcification of the teeth commences at their cusps or cutting- 
 
 30(V>S 
 
 DlAORAM OF ErUI'TIOX OF THE TEMPORARY TeETH. 
 
 edge, and gradually extends to the root. The first teeth usually 
 make their appearance about the sixth or seventh month after 
 birth, although no definite time can be predicated. There are 
 several cases on record of children born witli teeth; while on the 
 other hand, the author has seen children who began to cut their 
 teeth no earlier than at the age of twelve or sixteen months. 
 When the crowns of the temporary teeth make their appearance 
 through the gum, the roots are but partially formed, as is illus- 
 trated in Fig. 120, taken from an article by C. X. Peirce.* 
 
 The time considered normal for the eruption of the tempo- 
 rary teeth is as follows. (Sec Fig. 156.) 
 
 * Dental Cosmos, August, 188-1.
 
 262 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 Diagram of Eruption of Permanknt Teeth of the Upper Jaw. 
 
 Fig. 158 
 
 kL 
 
 V 
 
 'f^c 
 
 
 X 
 
 Y 
 
 > 
 
 '^/-. 
 
 f 
 
 ; 
 
 Diagram of Eruption of Permanent Teeth of the Lower Jaw.
 
 ERUPTION OF THE TEETH. 
 
 263 
 
 The central incisors from the fifth to the seventh month. 
 
 The lateral incisors from the seventh to the ninth moiitli. 
 
 The first molars from the twelfth to tlio fourteenth month. 
 
 The cuspids from the fourteenth to the eighteenth month. 
 
 The second molars from tlie twentieth to the thirtieth month. 
 
 The temporary teetli, under normal conditions, remain in their 
 respective phices in tlie mouth until they are replaced by the 
 permanent teeth, the first of which are usually erupted at about 
 the sixth year. Occasionally we meet with children who shed 
 their teeth earlier, — at the tifth year or even before ; while in 
 other instances the permanent teeth do not appear before the 
 
 Fig. 159. 
 
 Shkdding of the Temporary axd Appkaraxce of the Permanent Teeth, between 
 THE Fifth and Sixth Years. 
 
 eighth or ninth year. We frequently find that a patient has re- 
 tained one or two temporary teeth up to the thirtieth or fortieth 
 year of his age, these being sometimes quite firm in their 
 sockets. 
 
 The time considered normal for the temporary teeth to fall 
 out and to be replaced by their successors is as follow^s. (See 
 Figs. 157 and 158.) 
 
 The central incisors from the sixth to the seventh year. 
 
 The first molars from the sixth to the seventh year. 
 
 The lateral incisors from the seventh to the ninth year. 
 
 The upper first bicuspids from the eighth to the tenth year.
 
 264 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 The lower cuspids from the eighth to the eleventh year. 
 
 The lower lirst bicuspids from the ninth to the eleventh 
 year. 
 
 The upper cuspids from the tenth to the twelfth year. 
 
 The second upper and lower bicuspids from the tenth to the 
 twelfth year. 
 
 The second molars from the twelfth to the thirteenth year. 
 
 The third molars from the tifteenth to the forty-fiith year. 
 
 On the first appearance of the permanent teeth, their roots, 
 like those of the temporary teeth at that period, are not com- 
 pleted. A consideration of the time of calcification of the roots 
 of the teeth is therefore important, especially as the teeth of 
 young patients often are attacked by caries, and sometimes by 
 pulpitis. (See Fig. 159.) It is evident that when the pulp of a 
 tooth with an incomplete root dies, the saving of that tooth 
 becomes very problematical. 
 
 CHAPTER XXII. 
 
 ABSORPTION OF TExMPORARY TEETH. 
 
 At a certain age the temporary teeth become loose, and some- 
 times fall out without causing pain or loss of blood. 
 
 A temporary tooth shed in this manner usually exhibits only 
 a crown somewhat hollowed out underneath, in the place whence 
 the former root united with it, or a small portion of the root 
 may still be present. Upon macroscopical examination we find 
 the concave bottom of the crown worn away into irregular 
 grooves and pits. Some of these bays may contain small 
 pieces of vascularized soft tissue, the " corneous body'" of older 
 writers. Originally, the temporary teeth, like those of the per- 
 manent set, are possessed of roots which gradually become 
 shortened by absorption, as the growth of the permanent teeth 
 proceeds. 
 
 Frank Abbott has thoroughly studied the appearances of the 
 absorption of the deciduous teeth, and has published his results
 
 ABSORPTION OF TEMPORARY TEKTII. 265 
 
 in an essay.* I fully concur with the author in all essential points, 
 and quote from him as follows : 
 
 "The assertion of Tomes, that absorption is due to the pres- 
 ence of a freely-vasculurized papilla, does not explain the decrease 
 of the dental tissues, for the papilla is nothing but medullary 
 tissue, such as we meet with in any |)art of the organism, where 
 one tissue is about to change into another. Such a papilla may 
 be the cause of the absorption, as well as its result. Another 
 assertion, that the medullar}' cells eat out the dental tissues by 
 their active growth, or by their amoeboid motions, is insufficient 
 to explain the loss of the lime-salts in the dental tissues, as well 
 as to explain the presence of circular or semi-circular excava- 
 tions and bays so characteristic of the melting process of the 
 cementum and dentine of deciduous teeth. 
 
 "Since we know that pieces of dead bone or ivory may 
 be absorbed, with figures similar to those found on the surface 
 of temporary teeth, the idea possibly becomes admissible that, 
 owing to the }»resence of an acid, first the lime-salts are dissolved 
 away within certain territories of the dead bone-tissue, in a 
 merely chemical or passive manner, whereupon the soft medul- 
 lary tissue penetrates the spaces thus established. Quite differ- 
 ent, how^ever, will be the conception of this process, if we bear 
 in mind that the temporary teeth, as well as the permanent ones, 
 are made up of living tissues, and an active participation of these 
 tissues must be expected in the process of transformation of the 
 dental into the medullary tissue. As the process of absorption 
 is closely allied to the process of inflammation, and active 
 changes of the dental tissues have, be^'ond any doubt, been 
 proven to follow inflammation, we may a priori expect such 
 changes of the bone-tissue of the temporary teeth in the process 
 of absorption also." 
 
 The process of absorption of deciduous teeth is, indeed, closely 
 allied to the inflammatory process, and may be considered as a 
 physiological type of tissue-changes owing to the presence of 
 some irritating agency. The dissolution of lime-salts in bone, 
 as well as that of the hard tissues of the teeth, probably is due 
 to the presence of lactic acid. The dissolution of the lime-salts 
 may invade dead bone-tissue, or invade pieces of ivory implanted 
 
 '*" Microscopical Studies upon the Aljsorjttion of the Itoots of Tcmponiry 
 Teeth."
 
 266 
 
 THE ANATOMY AN1> PATHOLOGY OF THE TEETH. 
 
 in a living tissue. In such dead bone or ivory we likewise^ob- 
 serve the disappearance of the lime-saUs in the bay-like'excava- 
 tions, which later are tilled with a living tissue growing into the 
 excavations from without. 
 
 When a temporary tooth begins to be absorbed, its constituent 
 
 Fig. IGO. 
 
 Absorption' of Cemf.ntum of a Temporary Tooth. 
 
 J>, eement-corpuscles in division; JV, cement-corpuscles unchanged; B, basis-substance of 
 cementum ; M, M, multinuclear protoplasmic bodies ; F, fibrous connectire tissue. Magnified 
 500 diameters. 
 
 tissues unquestionably are alive, and consequently it is reason- 
 able to assume that the outermost layer of the root, first ex- 
 posed to the irritation, will react as other living tissues do in the 
 inflammatory process.
 
 ABSORPTION OF TEMPORARY TKHTII. 267 
 
 Whether or not dentine and enamel actively participate in the 
 process of absorption is doubtfnl, and up to the present day 
 unproven. 
 
 Absorption of Cementum. — The tirst changes due to absorp- 
 tion are semi-circular excavations or bays on the surface of the 
 root of a temporary tooth, filled with embryonal corpuscles or 
 multinuclear protoplasmic bodies, in connection with the myxo- 
 matous or fibrous connective tissue of the pericementum. 
 According to Abbott, isolated excavations may be seen, the 
 connection of which with the outer surface, though not observa- 
 ble in the specimen, may be present above or below the plane 
 of the section. He says, " By closely watching excavations of a 
 more recent date, at the peri[)hery of earlier ones which are in 
 communication with the pericementum, we notice that the lime- 
 salts and the basis-substance proper arc missing, and are replaced 
 by a uniformlv-granular proto})lasm, or a varying number of 
 faintly-marked medullary elements, each of which may contain 
 a central nucleus." 
 
 Another proof that the tissue of the cementum reacts upon 
 the irritation is that the cement-corpuscles nearest to the eroded 
 surface frequently are found enlarged, glossy, and split up into 
 smaller pieces. (See Fig. 160.) 
 
 The result of such changes is the .appearance of embryonal 
 or medullary corpuscles at the border of the excavation, or of 
 multinuclear bodies, formerly the territories of the cementum, 
 now reduced to protoplasm. 'This indifferent tissue appears 
 connected with librous tissue, abundantly supplied with newly- 
 formed blood-vessels. jSTot infrequently the latter tissue also 
 holds trabecule of newly-formed bone, sometimes to such an 
 extent that the widened sockets of the temporary teeth are tilled 
 with a considerable amount of cancellous bone-tissue. 
 
 Absorption of Dentine. — Dentine, during the process of 
 absorption, if examined with low powers of the microscope at 
 the corroded surface, exhibits a number of bay-like excavations 
 similar to those seen in bone-tissue and the cementum in this 
 process. (See Fig. 161.) 
 
 Since we know that dentine, like bone, is formed from medul- 
 lary tissue clustered together in territories, we are not surprised 
 to find such semi-circular excavations at the exposed surface of 
 dentine during the process of absorption. The bays are tilled 
 either with clusters of embryonal corpuscles, or multinuclear
 
 268 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 protoplasmic bodies, frequently observed in growing as well as 
 in inflamed bone-tissue. These formations are continuous with 
 fibrous connective tissue holding the shortened temporary tooth 
 in position. An important question is, whether or not the den- 
 tine of deciduous teeth participates actively in the production of 
 
 Fig. 161. 
 
 Absorption of Dexti.ve of Temporary Tooth. 
 
 {/.unchanged dentine: 2>, decalcified dentine; i?, zone of bay-like excavations ; P, fibrous 
 connective tissue. Magnified 100 diameters. 
 
 embryonal elements, which afterward develop into fibrous con- 
 nective tissue. This question is as yet unsettled. If, however, 
 we bear in mind that a deciduous tooth with a living pulp, as a 
 rule, remains sensitive up to the time of detachment from the 
 pericementum, the possibility of such participation cannot be
 
 ABSORPTION' (IF TEMPORARY TEETH. 
 
 269 
 
 denied. Abbott is in favor of assuming it, since he observed a 
 widening of the dentinal canaliculi at the borders of the bays, 
 with an increase of the living matter of the dentinal libers. 
 
 Fields of absorption are fre(|uentl.v niet with in the dentine, 
 some distance away from the eroded surface, and apparently 
 
 Fig. 162. 
 
 AiisoRPTioN OF Dentine of a Temporary Tooth. 
 
 I), dentine without signs of reaction ; /, isolated medullary space? : ^'^', medullaiy ."pace filled 
 with indifferent corpuscles and fibrous connective tissue; M, multinucloar body filling a bay ; 
 T, newly-formed territories of bone-tissue; L, laniellated bone-tissue; /', fibrous connective 
 tissue. Magnified 50O diameters. 
 
 isolated. Again, we cannot deny the possibility that such ex- 
 cavations may have been in connection with the surface, and^are 
 filled with ingrowing embryonal or myxomatous tissue. (See 
 Fig. 162.)
 
 '270 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 It is known since J. Tomes, that the bays of the eroded den- 
 tine are often found filled with bone-tissue, either in the shape 
 of territories or of lamellated l)one. The latter may reach such 
 a degree of development that it produces an almost continuous 
 layer all around the absorbed tooth. 
 
 Absorption pf Enamel. — This process is but little studied, on 
 account of its exceptional occurrence, which has been mostly 
 observed in the temporary molars. 
 
 Baj'-like excavations, similar to those observed in the dentine 
 and cementum, occur in absorbed enamel. Chas. Tomes has 
 noticed such bays of the enamel filled with newly-formed bone- 
 tissue, the same as we observe in absorption of dentine. He 
 attributes this rare occurrence to the overlapping of the cement 
 on the edge of the enamel. 
 
 CHAPTER XXIII. 
 
 PHYSIOLOGY OF THE HARD DENTAL TISSUES. 
 
 The latest researches into the minute anatomy of the dental 
 tissues — researches described in previous chapters — necessarily 
 alter the views hitherto held concerning the nutrition of those 
 tissues. Enamel has been considered to be a mere dei:)osit, 
 as it were, of purified lime-salts ; a coat of mail destitute of life. 
 The authors in the foregoing chapters have demonstrated the 
 presence of living matter between and within the enamel- 
 prisms, and consequently affirm that enamel is a tissue with 
 properties of life, although in minimum degree. Dentine has 
 long been known to be a tissue extremely sensitive throughout, 
 especially at the interzonal layer bordering the enamel. 
 
 Nothing, however, was known as to the seat of life in dentine, 
 until myself and others endeavored to prove not only that the 
 dentinal fibers and their coarse offshoots are formations of living 
 matter, but that the basis-substance, so rich in lime-salts, is 
 traversed by an extremely delicate filigree of living matter as 
 well. 
 
 With the facts before us, we ma}- attempt to approach the 
 solution of a hitherto insoluble riddle, — viz, the nutrition of the
 
 PHVSIOLOGV OF THE HARD DENTAL TISSUES. 271 
 
 dentine and of the enamel. No close observer will doubt that 
 the nutrition of the hard tissues of the teeth is — and must be — 
 an active one. This is proven not only by the growth of these 
 tissues, but also by the same tissues' strikingly rapid loss of lime- 
 salts in constitutional diseases, such as neurasthenia, anaemia, 
 etc., and even in pregnancy. How are the lime-salts deposited 
 in the dentine, and how can they be removed to such a degree 
 that dentine, originally hard, becomes in a fcAv months soft and 
 brittle ? 
 
 Looking at the dentinal canaliculi with the highest obtain- 
 able powers of the microscope, we see between the dentinal 
 liber and the w^alls of the canaliculus a narrow, light space, evi- 
 dently filled with liquid, which serves for the carrying of nour- 
 ishing material to the dentine, and for the carrying of efiete 
 material away from it. More than this, even the ultimate 
 fibrillte of living matter within the basis-substance are sur- 
 rounded by a delicate light space holding substances that serve 
 the same purposes. 
 
 If, besides these points, we observe that the dentinal fibrilla? 
 are of a vacuoled structure, and that the ultimate fibrillse have 
 a rosary or beaded appearance, we are prepared to acknowledge 
 the possibility that in living dentine the living matter proper is 
 at no time perfectly at rest ; that, on the contrar3% it is contract- 
 ing, slowly but continuously, and that through its contractions 
 it not only stirs the surrounding column of liquid, but pumps, 
 as it were, nourishing material into the minutest fields of the 
 dentine, or aw^ay from them. The chemical character of the 
 liquid ma}' explain the dissolution of a certain amount of the 
 lime-salts deposited in the blocklets of the basis-substance, 
 which salts, thus being rendered effete, may be carried into the 
 lymphatics of the pulp, and thence into the lymph-system of the 
 body for further elimination. ^Vhy, in one instance, nourish- 
 ing material should be carried from the blood-vessels of the 
 pulp into the dentine, and in another instance carried away from 
 the dentine into the lymphatics, we are as yet unable to under- 
 stand. 
 
 What I have stated concerning the tissue of dentine unques- 
 tionably holds good for the tissue of the enamel also. The 
 latter being at the periphery of the crown of the tooth, farthest 
 away from the source of nutrition, and but scantily supplied 
 with living matter, its nutrition must be extremely slow. Still,
 
 272 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 every dentist must have observed instances of softening of the 
 enamel as the result of constitutional ailments. 
 
 Re-calcification, re-hardening of the enamel, though denied 
 by R. Baume, is certainly a fact. The structure of the enamel- 
 fibers between the prisms, as well as of those traversing the 
 latter, points to the identity of the process of nutrition and de- 
 nutrition with that in the dentine. To preserve the life of the 
 dentine and of the enamel, it is not necessary to have the entire 
 pulp of a tooth intact. The experiments of W. Herbst prove, 
 on the contrary, that only a portion of the pulp-tissue left alive 
 in the pulp-canals is capable of keeping alive the dentine and 
 enamel of the crown of a tooth, as I will show in a subsequent 
 chapter. 
 
 Another important point seems to be explained satisfactorily 
 by our researches into the structure of the dentine, — i.e., the 
 sensitiveness of this tissue. So striking is this fact that a 
 thoughtful observer such as J. Tomes alluded to the possibility of 
 the dentinal fibrillse being nerves. Such a view is not tenable, 
 for two reasons : 
 
 First, it is, according to our advanced conceptions of histology, 
 impossible to admit of the existence of a connective tissue hold- 
 ing nerves alone in its constitntent soft parts. Second, neither 
 have we, nor has G. Retzius in his recent investigations been 
 able to trace a direct inosculation of the dentinal fibrillte with 
 the axis-fibrillpe of the nerves, so abundantly distributed through- 
 out the periphery of the pulp-tissue. As soon, however, as we 
 admit that the dentinal fibrillfe are formations of living matter, 
 the same as are the nerves, all difliculties vanish in explaining 
 the transmission of sensation from the periphery of the dentine to 
 the nerves of the pulp-tissue. Living matter is contractile matter, 
 according to Heitzmann. Xerves are made up of li^dng matter, 
 and, owing to their reticulated or beaded structure, are fittest 
 for that transmission of contractions from the periphery to the 
 nervous centers which we call sensation. Contraction of the 
 dentinal fibers transmitted into the reticulum of the protoplasm 
 at the periphery of the pulp, and thence into the ultimate nerve- 
 fibrillte, — all of which formations are proven to be continuous, — 
 are sufficient to explain the transmission of sensation, or, speak- 
 ing bluntly, of pain. 
 
 As to the sensitiveness of enamel, very little is known. It is 
 denied altogether by R. Baume and others. Nevertheless, the
 
 PHYSIOLOGY OF THE HARD DENTAL TISSUES. 273 
 
 simple experiment of eating a sour apple tends, in my judg- 
 ment, to prove sensitiveness of the enamel. The sensation which 
 attends what is called " setting the teeth on edge," following in 
 this instance, is noticed not only in permanent teeth whoso enamel 
 is ground off, but also in children having perfectly sound enamel 
 upon their temporary teeth. Nobody will explain this sensation 
 on the assumption of a solution of the lime-salts of the enamel, 
 and a penetration of the apple's acid to the surface of the den- 
 tine. It is far more probable that the pain is due to the irrita- 
 tion of the living matter of normal enamel, and the transmission 
 of its contractions to that of the dentine, with which it is con- 
 tinuous. That enamel, under morbid conditions, may become 
 extremely sensitive, is a fact known to every dental practitioner. 
 
 A third point may be cleared up by these researches, — «'.e.,the 
 discoloration of devitalized teeth. The discoloration concerns 
 not only the dentine, but also the enamel; indeed, the latter is 
 the first to show the stain. The absence of a nourishins: fluid, 
 and the shrinkage of the fibrillse of living matter in both tissues, 
 may account for their opacity and change of hue. 
 
 The minute anatomy of the hard tissues of the teeth, lastly, 
 throws light upon the nature of their senile changes. In 
 temporary teeth the dentinal canaliculi are noticeably wider, 
 and their tenants, the fibers, larger than in permanent teeth. In 
 the enamel-tissue the interstices between the prisms are widest, 
 and their tenants, the enamel-fibrillse, largest, in developing teeth, 
 at the seventh month of intra-uterine life. In the enamel of per- 
 manent teeth the interprismatic spaces are very narrow, and their 
 tenants so delicate that both the spaces and the fibrillfe have 
 escaped the notice of previous observers. 
 
 With advancing age, all formations of living matter diminish 
 in bulk, whereas the basis-substance, and the lime-salts held 
 therein, increase in amount. This explains the fact that the 
 teeth of old people have but extremely narrow dentinal cana- 
 liculi, and that the total number of these is noticeably lessened 
 by a transformation of previous dentinal canaliculi into basis- 
 substance. This has been before proven to be likewise true in 
 the case of bone- and cartilage-tissue, by Ileitzmann and Spina. 
 
 The pulp-tissue gradually decreases in amount with advancing 
 age. This is due, as I shall show in a future chapter, to a suc- 
 cessive transformation of the pulp into secondary dentine. 
 Nevertheless, not a single instance is known of the complete 
 
 19
 
 274 TUE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 solidification of a tooth iu old age, even though the pulp-tissue 
 be reduced to a minimum, and the pulp-canals barely accessible 
 to the finest broach. 
 
 Regarding the physiolog}' of the cementum, little can be said, 
 since there are no anatomical facts as yet observed upon which 
 we can base conclusions. The dentine and the enamel derive 
 their nutrient material from the blood-vessels of the pulp. The 
 cementum has an additional source of nutrition in the blood- 
 vessels of the pericementum. Should the pulp-tissue perish, 
 either in consequence of disease or of the application of arseni- 
 ous acid, etc., the dentine and the enamel become devitalized. 
 In the case of the cementum, devitalization from such cause is 
 not an inevitable result, since there remains a possibility of its 
 being kept alive by the pericementum. Kothing positive has as 
 yet been ascertained fixing the boundary at which life ends in 
 the hard dental tissues. 
 
 That with advancing age the teeth become loose and fall out, 
 may be due to a lack of nutrition in the pericementum, as well 
 as to a shrinkage of the sockets in their transformation into 
 fibrous connective tissue. Not a single instance is known in 
 which, with advancing age, the pericementum ossifies, and the 
 teeth become anchylosed; but, on the contrary, in all instances 
 thev loosen and are shed. 
 
 CHAPTER XXIY. 
 
 GENERAL DIAGNOSIS OF THE DISEASES OF THE TEETH. 
 
 The line between normal and morbid processes in the tissues 
 cannot always be distinctly drawn. It is necessary to be thor- 
 oughly familiar with the formation of normal tissues, in order 
 to comprehend their pathological conditions. The formation of 
 secondary dentine and bone upon the wall of the pulp-chamber , 
 of a tooth can hardly be called pathological, whereas the same 
 formation in the body of the pulp often causes marked disturb- 
 ances. 
 
 The art of differentiation of diseases is called " diagnosis," 
 and the ability to discern pathological conditions occurring in 
 the oral cavity is the aim of every thorough dental practitioner.
 
 GENERAL DIAGNOSIS OF THE DISEASES OF THE TEETH. 275 
 
 It is not an easy matter to establish a correct diagnosis in every 
 case of disease of the oral cavity. In some instances the origin 
 of the trouble is quite obscure, and there are many different 
 diseases that exhibit almost similar subjective symptoms. 
 
 The ability to diagnosticate well is only attainable by means 
 of a comprehensive knowledge of the tissnes involved, in their 
 uormal as well as in their diseased states, and such a knowl- 
 edge is only attainable by experience in observation. A dental 
 practitioner who carefully studies the condition of his patient 
 will often be able to advise him of some chronic disorder in his 
 (the patient's) system, even before the latter has any knowledge 
 of it himself. The teeth and gums, therefore, may be regarded 
 as indicators of the general health of their possessor. 
 
 In order to do this, we must carefully notice the color and 
 condition of the gums, the saliva, and the teeth ; the transpar- 
 ency, density, and sensitiveness of the latter, and likewise the 
 consistency of the calculary deposits around them. 
 
 The tartar being important in the diagnosis of constitutional 
 disturbances, I here will add a brief description of its charac- 
 teristic features. 
 
 There are three varieties of deposits found upon the teeth, — 
 viz, the white, tlie yellow, and the green. 
 
 The ichite deposit, or " iiialeria alha,^' as it has j&rst been 
 termed by Leuwenhoek, is of mucoid consistency, principally 
 found upon the labial surfaces of the ten anterior teeth near the 
 gum-margin. It is found upon loose teeth and those not much 
 used. It may accumulate from want of cleanliness, or in con- 
 stitutional disturbances. According to W. D. Miller,* it con- 
 sists of epithelium, salivary corpuscles, masses of bacteria of 
 var3'ing sizes and forms, intermixed with particles of food. 
 Dependent upon the constitution and habits of the person, this 
 deposit may be of an acid or alkaline reaction, and, if abundant, 
 in time may cause a chronic inflammation of the gums and the 
 pericementum. 
 
 Yellow tartar accumulates around the necks of the teeth more 
 or less in every mouth. It is the result of a deposition of lime- 
 salts into the so-called materia alba. When first formed, it is 
 idmost white, but soon becomes yellowish, whereas the portion 
 in contact with the gum mostly is of a darker color, varying 
 from a deep yellow to a dark brown, or even black. The color 
 
 * Dfiiifnl Cos»).<,s, 180-1.
 
 276 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 of this deposit somewhat depends upon the rapidity with which 
 it is formed. Persons atflicted with rheumatism or gout usually 
 have an abundance of yellow tartar, often collected in a com- 
 paratively short space of time, of a light color and soft consist- 
 ency. The healthier the person, the darker is the hue and the 
 harder the consistency of the tartar. Such tartar is found 
 mainly upon the teeth in the neighborhood of the openings of 
 the salivary ducts. Mastication, especially of hard substances, 
 prevents the deposition of salivary calculi upon the teeth; they 
 consequently accumulate more upon that side of the mouth 
 which is least used. 
 
 The green deposit frequently is seen* upon the teeth of juveniles 
 and those who do not clean their teeth properly, besides in per- 
 sons who work in metals or have taken metals or their salts in 
 the form of medicines. It is found mostly on the labial surfaces 
 of the upper front teeth, while the lower ones are seldom 
 affected. The color of the deposit in juveniles varies from a 
 light to a dark grayish- or bluish-green. According to Miller 
 (1. c), who was the first to give this matter careful attention, 
 green deposits may be of organic or inorganic origin. The or- 
 ganic stains upon the teeth are believed to be derived from sul- 
 phomethgemoglobin present in the coloring-matter of the blood, 
 as well as chromogenic color-producing bacteria. The discol- 
 oration of the teeth due to inorganic substances, according to 
 Miller, mainly is produced by copper, iron, mercury, and lead. 
 
 Copper stains are characterized by a greenish discoloration of 
 the labial surfaces of the teeth, principally those of the upper 
 jaw. Together with this stain, a red or greenish-brown line is 
 sometimes present upon the gum-margin. It is found upon the 
 teeth of people employed in the working of copper or its alloys. 
 Occasionally it is also met with in trumpeters, where it arises 
 from the contact of the brass mouth-piece with the teeth. 
 (Miller.) 
 
 Iron deposits are recognized by their brownish color. (Miller.) 
 They are found upon the teeth of persons working in iron 
 factories, and those who take iron compounds as medicines. 
 Iron stains occur more frequently upon the lower than upon the 
 upper teeth. 
 
 The stains of mercury, when arisen from its chlorides, are of 
 a dark-gray or brownish-black color; while the sulphide of mer- 
 cury may cause a greenish deposit. (Miller.)
 
 GENERAL DIAGNOSIS OF THE DISEASES OF THE TEET]I. 277 
 
 Lead, according to Hirt, produces a dark-brown discoloration 
 oil the necks of the teeth of [)ersons sufferinsj^ from lead-poison- 
 ing; besides, we usually find the characteristic bluish line upon 
 the gums. 
 
 It is believed (Robinson, Harris, Leber and Rottenstein, Fox 
 and Harris, Baume, Brandt, Ottolengui, Schlenker, etc.) that 
 the green-stain so frequently observed upon the teeth of juveniles, 
 and those who do not clean their teeth properly, has an injurious 
 effect upon the enamel ; while Miller asserts that the dissolution 
 of the enamel often found under such stains is independent of 
 the latter. True it is that we often see the enamel of the labial 
 surfaces near the gum-margin roughened without being stained. 
 
 Dark-gray or l)lue and cloudy-looking enamel on teeth that 
 are highly sensitive to the touch of an excavator or bur, indicates 
 the tendency to rapid decay. Then the calculary deposits around 
 the necks of such teeth (especially the lower ones) are of a light- 
 yellow or almost white color, and are of very soft, or even 
 slimy, consistency. In many instances the pulps of such teeth 
 are attacked by pulpitis, and die without having been exposed. 
 When the gums are soft, and bleed easily, even at the lightest 
 touch ; when they are coated with viscid mucus, and are more 
 or less detached from the necks of the teeth, these, in general, 
 are signs of a weak constitution, or of an impaired one. 
 
 We often remark the rapid destruction of teeth where there 
 exists a diseased condition of the system, and with our best 
 eiforts we are unable to save them. When the ailment or weak- 
 ness, however, is of temporary duration, as in the state of preg- 
 nancy, the teeth, as a rule, return to the normal character after 
 delivery. If the health of the woman is good, we observe that 
 the saliva soon loses its acidity and visciditj'. The enamel and 
 the dentine gradually regain their former transparency and hard- 
 ness ; the teeth become less sensitive at their necks, and the 
 gums, usually independently of treatment, are restored to a 
 healthy state. 
 
 It is the rule that the above-described conditions of the mouth 
 are symptomatic in weakly-constituted persons, yet exceptionally 
 we remark those conditions in quite healthy people. Where 
 there is a strong general constitution in the possessor, the teeth 
 are commonly coated with yellow or yellowish-white, hard, and 
 transparent enamel. The dentine, as well as the cervical mar-
 
 278 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 gins of the necks of the teeth, are not very sensitive : the calcu- 
 lary deposits are of a dark-brown or black color, and of hard 
 consistency. The saliva is usually neutral, or of slightly alkaline 
 reaction, clear and icatery, not viscid. The gums are of pale red 
 color, hard, do not bleed easily, and are tightly attached to the 
 necks of the teeth. The teeth themselves decay very slowly, and 
 the carious dentine is of a dark-brown or black color. 
 
 Sometimes cavities of decay in teeth of this type are left ex- 
 posed for months, or even years, without any visible extension^ 
 so long as the health of the patient remains good. When, how- 
 ever, through chronic diseases of the kidneys, liver, or the ner- 
 vous system, the health of the patient fails, we soon begin to 
 notice a marked change in the tissues of the teeth and of their 
 surroundings, though the patient, as we. intimated before, is 
 perhaps unaware of his ailment. 
 
 The first visible changes, in such a case, take place. in the 
 gum around the necks of the teeth, especially of the lower 
 incisors. Where three or six months ago we observed hard 
 gums, of a pale rosy color, and tightly encircling the necks 
 of the teeth, we now see on the gum a dark-red or perhaps a 
 bluish band, indicative of the early stages of pyorrhea alveo- 
 laris. The salivary calculus, formerly quite hard, of a brownish 
 color and of slow accumulation, appears now as a yellowish- 
 white, creamy deposit, and more profusely, especially at the necks 
 of the aifected teeth. With the advance of the systemic disease 
 progresses the caries of the teeth, the carious matter being now 
 of a light-yellow color, or white, while the teeth become ex- 
 tremely sensitive, not only to the touch of excavating instru- 
 ments, but even to thermal changes. The saliva is quite viscid, 
 and of a distinct acid reaction. 
 
 The teeth under these conditions soon lose their normal color 
 and transparency, become brownish, bluish, or greenish, and the 
 enamel and dentine are extremely soft. The pulps die readily, 
 sometimes without pain, and frequently are found to produce 
 alveolar abscesses, and extensive necrosis, or cystic formations in 
 tlie jaws. When such signs of a decline in the normal standard 
 of health in the oral cavity are remarked in a patient whom we 
 have known for years, the prognosis is usually alarming. In 
 order to make clear what I have stated, I shall cite two typical 
 cases of my practice. 
 
 Mr. W., about forty-five years of age, of an excellent consti-
 
 GENERAL 1)IA(;X0SIS OF THE DISEASES OK THE TEETH, 279 
 
 tution, consulted me in November, 1880, in regard to the restora- 
 tion of the lingual surfaces and cutting-eclges of his remaining 
 five upper front teeth, and the labial surfaces and cutting-edges 
 of the ten lower front teeth. The teeth wore of a yellowish-white 
 color, with exceedingly hard enamel and dentine. The left 
 upper second molar had been carious over twelve years, but 
 as some one had advised Mr. W. to have the tooth extracted 
 rather than filled, he had allowed it to remain in that condition. 
 The color of the carious dentine of this tooth was brownieh- 
 black, and it was almost as hard as enamel, while the pulp was 
 found to be dead. The fifteen front teeth were restored with gold 
 to their normal length, while the three canals and the cavity of 
 the second upper molar were filled with oxychloride of zinc. 
 Those teeth were quite comfortable till October, 1888, when the 
 lower teeth began to exhibit the symptoms of pyorrhoea alveolaris, 
 and the left upper lateral incisor, during a period of four months, 
 had changed in color to a dark blue. When the pulp-chamber 
 was opened, a great quantity of pus was discharged from the 
 socket, through the tooth, denoting the presence of a chronic 
 alveolar abscess and necrosis. On examination of the other 
 teeth, it was found that most of them were decayed around the 
 necks, while the second upper molar was altogether broken 
 down. 
 
 The carious portion of the dentine was now exceedingly soft, 
 and the necks of the teeth were covered by a yellowish-white 
 mucoid deposit, quite acid in reaction. In response to my query 
 as to the gentleman's health, he replied that he had nevej- felt 
 better in his life. I advised his fiimily to inform his physician 
 that I had grave suspicions regarding Afr. AV.'s general health. 
 An external examination was made, without an analysis of the 
 urine, and no serious danger was reported. 
 
 In time the teeth of the patient were destroyed; some of the 
 lower incisors falling out in consequence of pyorrhoea alveolaris, 
 while others lost their crowns through caries. In October, 1893, 
 he died of chronic parenchymatous nephritis (Bright's disease 
 of the kidneys), though there had been no previous warning of 
 his illness beyond that which I have described. 
 
 Miss P., about eighteen years of age, with a good constitution, 
 was the possessor of an almost perfect set of teeth, except that 
 upon the grinding-surfaces of the four first permanent molars 
 the enamel was not perfectly calcified. The grinding-surfaces of
 
 280 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 these four teeth were restored with gold, in October, 1887. The 
 other teeth were of a bhiish-white color, quite hard, and but 
 little sensitive to excavation. The mouth, as well as the face of 
 the patient, at that time, presented a typically healthy appear- 
 ence. I saw her in June, 1888, May, 1890, June, 1891, when I 
 filled only ordinary cavities in the grinding-surfaces of the teeth, 
 which up to that time were in a normal condition. I saw the 
 patient again in March, 1892, when I noticed a great change in 
 her dentures, gums, and saliva, as well as in her general coun- 
 tenance. The face had changed to a pale grayish hue; the eyes 
 had lost their former brightness; the teeth were quite soft, very 
 sensitive, and of a dark-blue tint. The gums were light pink, 
 except around the lower incisor teeth, where I noticed a slight 
 inflammation. The saliva, although watery, had a distinct acid 
 reaction. Upon examination, I found five large carious ca\dtie8 
 in the teeth, the dentine of which, in the process of excavating, 
 proved to be exceedingly soft and sensitive. Upon the query as 
 to the state of her general health, she replied that she was as 
 well as ever. I advised the patient to see her physician in re- 
 gard to her general condition, but she did not think it necessary, 
 the more so as she intended to leave for Europe in about ten 
 days. Shortly before her departure she did not feel quite well, 
 when her physician was consulted, who announced that she was 
 suffering from a severe disease of the nervous system, Basedow^ s 
 or Grares's disease, to-day termed exophthalmic goitre. 
 
 In the diagnosis of the diseases of the mouth, we must care- 
 fully consider : 
 
 First. The individual characteristics of the patient, the nor- 
 mal standard of his or her health, and ascertain, if possible, 
 whether the system is deranged by temporary or constitutional 
 disturbances, such as menstruation, pregnancy, ausemia, chronic 
 diseases of the nervous system, of the liver, or of the kidneys, 
 the effects of external or hereditary influence, etc. 
 
 Second. Pathological phenomena in distant parts, resulting 
 from reflex action of irritated nerves. 
 
 Third. The minute anatomy of the immediately involved 
 parts, and the laws governing their progressive as well as retro- 
 gressive changes. 
 
 Fourth. The observations of our senses, in physical exam- 
 ination, in the use of instruments, or by other methods.
 
 GENERAL ]»1 .\ti.Nu>lS uF TIIK 1)1S1■;AS^;^ (JF THE TEETH. 281 
 
 Fifth. The subjective syraptoms which are the local or gen- 
 eral phenomena of the disease, as noticed hy the patient himself. 
 
 Sixth. The ditlerentiul diagnosis, whicli is the consideration 
 of tlie features that distinguish one disease from another dis- 
 ease, wlien there are like symptoms in both. 
 
 Tlie prognosis consists of the conclusions arrived at in a sum- 
 miiig up of all the above-intimated phenomena, collectively 
 considered. 
 
 In physical examination of the diseases of the oral cavity, we 
 employ, besides onr sense of sight, the senses of touch, hearing, 
 and smell; sometimes, also, light, percussion, heat, and cold. 
 
 At sight we are, in many cases, enalded to determine the 
 general state of a patient's health. Before making a physical 
 examination of the oral cavity, we ought to observe the shape, 
 color, and expression of the patient's face and eyes, as well as 
 his general countenance. To be able to see the dift'erences of 
 the normal tissues of the oral cavity from those that are dis- 
 eased, we must become familiar with their normal appearance. 
 "We should study the normal color and aspect of the gums and 
 tongue of persons of different constitutions. We shall then be 
 able to discover conditions of inflammation in the oral cavity, 
 -even where these are slightly indicated, recognizing thom by 
 the mere diflerence in color which the inflamed mucous mem- 
 brane exhibits in contrast to the normal one. 
 
 The sense of touch is of great importance, and is one that 
 ought to be cultivated to perfection by every dental student. It 
 is employed either directly at the point of the index finger, or 
 indirectly by means of a probe or any other instrument. In 
 •most cases of pericementitis and periostitis we are enabled to 
 ascertain by means of the index finger to what degree the in- 
 iiammatory process has advanced. In a physical examination 
 we should always compare the diseased part of the oral cavity 
 with the corresponding usually normal portion of the opposite 
 side. In this investigation the finger will easily find whether 
 or not there exists a swelling on the gums, which portion is 
 hard, unyielding, and of normal temperature, or soft, hot, and 
 •fluctuating. More important, however, than the examination 
 by the point of the finger, is that which exercises the sense of 
 touch through the medium of an instrument. This can be de- 
 veloped to accuracy only by ample practice. We may train our 
 sense of touch to such perfection that we become able to ditt'er-
 
 282 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 entiate between all tissues with which the probe comes in con- 
 tact, determining whether the substance touched be soft tissue, 
 or enamel, or dentine, compact or cancellous bone: distinguish- 
 ing also whether the latter tissue be liviug or necrotic, and dis- 
 criminating from one another steel, gold, amalgam, etc., when 
 they are hidden from view. 
 
 The most frequent examination of the dental practitioner is 
 the search of the teeth for carious cavities. In many instances 
 these are easily found. There are patients who experience pain 
 as soon as a small cavity exists, which may hardly have pene- 
 trated the interzonal layer. In other instances we encounter 
 patients who have many cavities, and the teeth in many places 
 broken down, and who, notwitlistanding, have never complained 
 of toothache. In the latter cases, examination should be made 
 carefully on all surfaces of the teeth; whereas, in an instance of 
 the former description, the patient himself may designate the 
 locality of the caries. 
 
 In examining the teeth for caries, we employ a mouth-mirror 
 and a delicate steel exploring instrument. The teeth frequently 
 decay on their approximal surfaces; and where they stand so 
 close together that we cannot penetrate the interstices even with 
 the finest broach, it becomes difiicult to determine whether or 
 not the tooth contains a carious cavity. In the majority of 
 teeth decayed on the approximal surface, the cavity may be 
 detected in the incisors, the cuspids, and the bicuspids by a 
 bluish line on the respective labial or buccal surfaces, when 
 concentrated daylight or electric light is thrown under the 
 lingual surfaces. When a carious cavity is small, however, we 
 may fail to detect it even by transillumination of the teeth. In 
 such a case we are obliged to separate the teeth slighth', either 
 at once by a screw separator, or gradually by cotton or wood 
 wedges or other suitable means. 
 
 Examination of the teeth should always be systematic. We 
 ought to begin, regularly, with the last molar, either of the upper 
 or the lower jaw. In examining a single tooth, much may be 
 overlooked, — perhaps even the seat of the trouble, since it fre- 
 quently liappens, where two or three teeth are decayed on the 
 same side of the mouth, that the patient attributes the pain to a 
 wrong tooth. The grinding-surfaces of the teeth should be first 
 carefully explored, then the approximal, next the buccal, respec- 
 tively labial and lingual surfaces, and at last the necks slightly
 
 GENERAL DIA(;XOSIS OF THE DI.^ EASES OF THE TEETH. 28^3 
 
 beyond the gums. For the latter purpose, it is advisable to re- 
 peatedly moisten the exploring instrument with a solution of 
 corrosive sublimate, 1 to 1000, although the instrument may 
 have been thorough!}' sterilized before. The exploring instru- 
 ment should be handled very delicately between the thumb and 
 the first two fingers, somewhat like a pen in writing. The in- 
 strument should be moved along the surfaces of the teeth mainly 
 by the muscles of the fingers, wdiereas the joint at the wrist 
 ought to be employed but exceptionally. When a cavity is deep, 
 and we expect to find the pulp of the tooth exposed, it is desir- 
 able to exert a sligiit pressure in the region of the pulp, a small 
 piece of cotton making a satisfactor}' interposition. Xo pointed 
 instrument should be introduced into a deep carious cavity in 
 the vicinity of the pulp. 
 
 If the patient feels no pain upon slight pressure with cotton, 
 this means that the pulp is either not exposed or is partially or 
 wholly devitalized. In every instance of deep-seated caries it is 
 advisable to remove the decayed dentine by as large an exca- 
 vator or round bur as the cavity will admit. Small instruments, 
 by perforating the protecting thin layer of dentine, are likely to 
 enter a healthy pulp, and besides causing severe pain to the 
 patient, ma}' produce acute pulpitis, w^hich is likely to cause the 
 death of the pulp. 
 
 Percussion. — When the hammer of a piano is thrown against 
 one of the expanded wnres, it causes the wire to vibrate and 
 produce a sound. Similarly, if we slightly hammer with an in- 
 strument upon a normal tooth, we cause the tooth and its sur- 
 rounding tissue to vibrate and produce a sound, which, however, 
 in duration and resonance cannot be compared with that pro- 
 duced by the string of the piano. 
 
 In the practice of medicine, the diagnosis of some of tlie 
 diseases of internal organs is based upon sounds, produced by 
 hammering upon the external surface of the body under which 
 the diseased organ is situated. The latter, according to its con- 
 sistency and condition, upon percussion, renders back a resonance 
 characteristic of the organ when normal. In its pathological 
 conditions the sounds it returns in percussion are materially 
 altered from those of the normal state. In dental practice, 
 slight percussion upon the teeth by means of the point of a 
 finger, or with an instrument, aids us to arrive at a diagnosis of 
 some of the forms of pulpitis and pericementitis. Especially in
 
 '284 THE AXATOMY AND PATHOLOGY OF THE TEETH. 
 
 cases of pericementitis iu its earliest stages, often when the 
 patient as vet has felt no pain nor discomfort in the aflected 
 tooth, we shall be able to notice, upon percussion of the tooth, 
 a sound somewhat duller than the normal; while its neighbor, 
 or its fellow on the opposite side of the mouth, upon percussion, 
 produces a normal sound. In comparing the resonance of a 
 tooth with that of its neighbor, or that of a tooth on the oppo- 
 site side of the niouth, care must be exercised to strike similar 
 teeth in the same direction. For satisfactory results much 
 depends also upon the position of the tongue, the lips, and the 
 lower jaw. If the mouth is wide open, the resonance of the 
 teeth will be higher in pitch than when the mouth is nearly 
 closed. In percussion of the teeth, we notice five difl:*erent 
 sounds, — viz, the high, the loic, the clear, and the dall, as well as 
 a somewhat f>/mpaiu((r sound. When the mouth is wide open, we 
 obtain the high sound ; when nearly closed, the low one. When 
 we hamnier slightly upon the crown of a normal tooth, we 
 obtain a clear sound. If, on the contrary, percussion is made 
 upon a tooth which in the process of pericementitis has become 
 loosened in its socket, we shall perceive a distinct dull sound. 
 A somewhat tympanitic sound is produced by percussion upon 
 the second upper bicuspid, still more pronounced in the first 
 molar of the upper jaw. 
 
 In physical examination, we also have to consider the general 
 condition of all the teeth in the mouth. The teeth of some 
 patients, upon percussion, always give out a dull sound. These 
 teeth usually are somewhat loose in their sockets, although 
 their pericementum appears normal. Such patients may be 
 young or in the prime of life, whereas we meet with persons 
 quite old whose teeth, firm in their sockets, produce a clear 
 sound on percussion. We have to take into consideration, 
 also, the number of roots which the tooth possesses. As a 
 general rule, we find that a tooth with two roots gives out, 
 on percussion, a sound a trifle clearer than does a tooth of but 
 one root, while the upper molars give the clearest sound of all. 
 Therefore, in making, by means of percussion, a diagnosis as to 
 a bicuspid or molar tooth, it is advisable to compare its sound 
 with that of the corresponding tooth on the opposite side of the 
 mouth. The six anterior teeth of the upper jaw, if normal, 
 yield, on percussion, sounds nearly equal in clearness. There 
 is, however, sometimes a slight difference in the sounds rendered
 
 GENERAL DIAGNOSIS OF THE DISEASES OF THE TEETH. 285 
 
 by the upper incisors from those of the cuspids, a difference 
 probably due to the length of the roots. In a series of percus- 
 sions from the first upper bicuspid to the second upper molar, 
 we notice a gradual increase in the pitch of the sound, due to 
 the existence of the antrum, which, being filled with air and 
 communicating with the nasal cavities, causes a more or less 
 tympanitic resonance. 
 
 Although, as in cases of hyperostosis of the roots, the sounds 
 produced by percussion on the corresponding teeth of opposite 
 sides of the mouth are not always identical, yet, with experi- 
 ence, we will soon be able to differentiate between the sounds 
 of a tooth with a normal, and of a tooth with an inflamed, peri- 
 cementum. In cases of slight circumscribed pericementitis, we 
 are often enabled to localize the inflamed portion in the peri- 
 cementum, unless this be situated on the mesial or the distal 
 surface of the root, and unless the crowns of the teeth stand 
 in close contact with those of their neighbors. Percussion 
 upon the crown of a tooth in the direction of the inflamed spot 
 will produce a somewhat dull sound. Therefore, if pericemen- 
 titis is seated in the lingual portion of the root of the tooth, 
 slight percussion upon the labial, respectively buccal surface of 
 the crown, in the direction of the inflammation, will produce a 
 duller sound than that evoked when, by the same instrument, 
 the tooth is tapped on the lingual surface. If, on the contrary, 
 pericementitis is seated in the apex of the root, percussion in 
 that direction upon the crown of the tooth will evoke the char- 
 acteristic dull sound. In this manner we are often enabled to 
 ascertain which of the roots of a molar or first bicuspid tooth 
 is inflamed. The degree of the dullness of the sound depends 
 upon the degree of the inflammatory condition of the perice- 
 mentum. Therefore, the more diffused the inflammation around 
 the root of the tooth, the duller will be the sound and the greater 
 the sensitiveness on percussion. Thus the character of the 
 sound produced by percussion of the teeth principally depends 
 upon the continuity, the elasticity, and the surroundings- of the 
 vibrating tissue. In more advanced stages of pericementitis, on 
 percussion of the affected tooth, we notice, besides a distinct dull- 
 ness in sound, sensitiveness or pain, increasing in severity with 
 the advance of the inflammatory process of the pericementum. 
 
 By our Simse of smell we detect septic conditions of the oral 
 cavity, especially in diseases of the antrum and the pulp. In
 
 '2S6 THE AXATOMY AXD PATHOLOGY OF THE TEETH. 
 
 order to arrive at a proper diagnosis, it is necessary to be 
 acquainted with the peculiar odors characteristic of an inflamed 
 condition of the antrum, as well as of gangrene of the pulp. 
 There is, also, in the breath of some patients, a peculiar sweetish 
 odor, which somewhat resembles that of chloroform, and is 
 characteristic of a febrile or otherwise diseased state of the 
 system. All these peculiarities should be carefully noticed, as 
 sometimes they may aid us in making a diagnosis. 
 
 In diagnosticating pathological conditions of the pulps of the 
 teeth, we also employ the agencies of hcdf and cold, by means 
 of water, air, or the spray of the chloride of methyl. Extreme 
 cold, directed suddenl}- to the tissues, produces local anesthesia, 
 as is observed in the application of the chloride-of-methyl spray. 
 Extreme heat has the same effect as extreme cold, causing irri- 
 tation and death when its operation is persistent. Thermal 
 changes wrought suddenly on the tissues, especially those of the 
 teeth, induce pain by causing rapid contraction or expansion of 
 the living matter. In thermal change, however, not suddenly 
 produced, but wrought by mild degrees, heat has the oppo- 
 site effect on the tissues to that of cold. In general, heat favors 
 activity in the circulation, while cold depresses it. The con- 
 tinued application of heat, therefore, induces an engorgement of 
 the capillaries, at the same time diminishing the quantity of 
 blood in the larger vessels, as well as in internal organs. The 
 continuous application of moderate cold to the tissues induces a 
 contraction of the smaller arteries, and thereby diminishes the 
 quantity of blood. The blood-vessels are under the control of 
 the vaso-motor nerves. Anything, therefore, which stimulates 
 or depresses the nerves, affects the blood-supply in the region of 
 the affected vaso-motor nerve. In the diagnosis of chronic 
 pul}»itis, the application of heat and cold is sometimes the only 
 trustworthy means of finding the seat of ailment. In many 
 instances, as I shall show in a later chapter, the patient localizes 
 in one part the pain which really belongs elsewhere. A sudden 
 application, through a syringe, of cold air or ice-water, or of hot 
 air or hot water, to the unaffected teeth and to the affected tooth, 
 as a rule, speedily defines the locality of the disease; the response 
 of intensified pain following the injection into the actually dis- 
 eased quarter. Care, however, should be taken that but one or two 
 teeth be brought under the direct action of the heat or cold, a pre- 
 caution which the practitioner carries out by covering the other
 
 GENERAL DIAGNOSIS OF THE DISKASKS uF THE TEETH. 287 
 
 teeth tightly with bibulous paper or a napkin, and removing, 
 \vith a saliva-ejector, the hot or cold water that has been used. In 
 cases of a doubtful diagnosis as to the vitality or deadness of a 
 tooth, the application of the chloride-of-methyl spray is the best 
 means of determining the fact. Applied to a living tooth, it 
 causes pain : to a devitalized tooth the ap]>lication is j)ainless. 
 
 Jj'xjid, either plain or augmented, or by ap])liances of art, is 
 another agent which we frequently em[)loy in diagnosticating 
 diseases of the antrum, also in ascertaining whether the pulp of 
 a tooth is dead or alive, and in the search for carious cavities. 
 
 In 1881, Louis Elsberg, in an address before the Odontologi- 
 cal Society of Xew York, explained the manner in which at 
 that time he was accustomed to illuminate the mouth and larynx 
 by means of Trouve's apparatus. This exposition of his pro- 
 cedure did much to further the improvement of the method, 
 and to bring to perfection the illuminating apparatus now in 
 use. The process commonly followed has been called " trans- 
 illumination" by W. Freudenthal, who gives a good description 
 of it in a paper read before the Xew York Academy of Medi- 
 cine, in 1891. The instrument most eftectively employed is a 
 small electric lamp placed under the hard palate, in the patient's 
 mouth, which should be closed as nearly as possible. The lamp 
 will then illuminate the whole middle region of the patient's 
 face, and even the eyes. When both antra are in a normal con- 
 dition, the illumination is uniform on both sides of the face. If, 
 on the contrary, there is in one of the antra an abnormal growth, 
 or merely a thickening of the lining membrane, the light-rays 
 are obstructed, and according to the extent of the obstructing 
 tissue will the aifected part be less illuminated, or altogether 
 dark. The same process may be effectively imrsued in the ex- 
 amination of devitalized or carious teeth. To this end the lamp 
 is held as in the former inspection, the patient's jaws being nearly 
 closed, but the lips kept open. In such illumination devitalized 
 teeth appear opaque, while the teeth with living pulps are quite 
 transparent. In some instances the teeth stand so close together 
 in the dental arch that we are unable, even with the finest broach, 
 to search their joined surfaces for carious cavities. In this case 
 transillumination is especially employed with advantage upon 
 the ten or twelve anterior teeth. Cavities that exist in the jux- 
 taposed surfaces of these teeth obstruct the light-rays and show 
 corresponding dark spots.
 
 288 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 CHAPTER XXV. 
 
 IRRITATION AND NEW FORMATIONS OF DENTAL TISSUE. 
 
 In the chapter on the physiology of the teeth I have indicated 
 the manner in which sensation is carried from the surface of the 
 enamel and of the dentine to the pulp; viz, that this is very 
 prohably accomplished by the alternate contractions and expan- 
 sions of the living matter, and that intense contractions induced 
 by highly irritating agencies result in the sensation of pain. AVe 
 may admit as a fact the existence of contractions in the living 
 matter in such slight degree as not only to be painless, but even 
 devoid of unpleasant sensations. 
 
 Such slight contractions, if continuous, are what cliniciana 
 term "irritation." Continuous, though slight, contractions of 
 the living matter, conveyed from the periphery to the center of 
 a tooth, may suffice directly to excite contractions of the living 
 matter of the pulp-tissue, and, indirectly, through reflex action, 
 to influence the vaso-motor nerves of a limited region of the 
 blood-vessels of the pulp-tissue. 
 
 In either case, we may infer an increased afilux of nourishing 
 material to the irritated part, in which a morbid process takes 
 place, which, naturally, becomes more evident when it reaches 
 the stage of inflammation. The first change in the affected 
 tissue is its reduction to an embryonal or protoplasmic state. 
 The pulp-tissue is made up of a myxomatous tissue holding but 
 little basis-substance, — a characteristic embryonal condition. 
 The presence of small globular lumps of nearly homogeneous 
 living matter, scattered through the basis-substance, and closely 
 resembling lymph-corpuscles, has induced previous observers to 
 term the pulp-tissue an "adenoid tissue," since the lymph-gan- 
 glia, throughout the animal body in general, are constructed on 
 the type of pulp-tissue. Tlie lymph-ganglia were, some forty 
 years ago, considered as glands ; and they, and the lymph-fol- 
 licles as well, were called, accordingly, "lymph-glands." This 
 error was committed mainly by German histologists, headed by 
 E. Briicke. To-day we know that the lymph-ganglia are strictly 
 connective-tissue formations, lacking epithelia, the essential 
 secreting constituent of a gland. Hence the terms " lymph- 
 gland" and " adenoid tissue," which convey the idea of a gland- 
 like structure, have been justly abandoned; and, to-day, reject-
 
 IRRITATION AND NEW FORMATIONS OF DENTAL TISSUE. 289 
 
 ing the word " adenoid" with its misleading significance, we 
 speak of a " lymph-tissue," which we know to he myxomatous. 
 
 Should the lymph-tissue of the pulp be reduced to its embry- 
 onal condition as above indicated, the protoplasm present before 
 transformation into myxomatous basis-substance reappears, and 
 may break up either into odontoblasts or into osteoblasts. In 
 the former case, the result of irritation of the pulp-tissue will 
 be dentine : in the latter, bo/ie. 
 
 Odontoblasts are known to be a fore-stage in the production of 
 dentine. If these appear in consequence of irritation, they are 
 never so regular as those of primary, well-developed dentine. 
 Before eburnilication the odontol)lasts must break up into rows 
 or clusters of indifferent or medullary corpuscles, all intercon- 
 nected by means of delicate threads of living matter. From 
 these threads arise, as a result of the coalescence of the inter- 
 connecting threads, coarser iibrill?e of living matter, the future 
 dentinal libers. 
 
 The original odontoblasts and their derivations, the embryonal 
 corpuscles, being irregular in shape and unevenly distributed 
 and grouped, will, in turn, produce a dentine irregular in struc- 
 ture, scantily provided with dentinal fibers, and often stratified. 
 Such dentine we term secondary dentine. 
 
 If osteoblasts have been the outcome of the structural change 
 of the pulp-tissue, these osteoblasts, again, will break up into 
 embryonal corpuscles, but, after accomplished calcification of 
 the basis-substance, they will produce bone-tissue. The lime- 
 salts necessary for the production of secondary dentine or 
 osseous tissue are, doubtless, supplied by the capillary blood- 
 vessels, from the serum of the blood circulating therein. It is 
 possible that the capillaries traversing different organs t»f the 
 animal body hold chemically different contents. The eclectic 
 power by means of which the contents of the capillaries are 
 drawn into the permeated tissues, rests, very probably, in the 
 endothelial walls. Thus the endothelia of the capillaries of the 
 pulp are fittetl mainly for the emission of a serum rich in lime 
 solutions, though many capillaries in the irritated part are known 
 to perish, becoming obliterated, solidified, and broken up into 
 embryonal tissue. 
 
 The so-called pulp-stones are nothing but secondary dentine 
 or secondary bone, either sessile, i.e., attached broadly to the 
 wall of the dentine, or pediculated, i.e., attached to the dentinal 
 
 20
 
 290 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 wall by a comparatively narrow foot ; or, lastly, isolated in the 
 pulp-tissue, lacking attachment altogether. C. "Wecll has an- 
 nounced the theory that pulp-stones are the result of an involu- 
 tion or reduplication of the odontoblast layer of the pulp, 
 directed from the periphery into the center. This view is 
 marred by the fact that the pulp-tissue, if irritated, is capable 
 of producing odontoblasts as well as osteoblasts, in any part of 
 it. To me it seems that merely a slight and steady irritation of 
 a certain portion of the pulp is sufficient for the production of 
 pulp-stones, either of a dentinal or of a bony type, or, as may 
 occur, a mixture of both. 
 
 I have stated before that the formation of secondary dentine 
 or secondary bone from the pulp-tissue is the result of a slight, 
 though incessant, irritation of this tissue, frequently unper- 
 ceived by the person affected. It does not, however, invariably 
 escape the attention of the patient. There are individuals who 
 have a dull uncomfortable sensation in the jaw, whenever the 
 formation of secondary dentine is in progress, though not able 
 to locate this sensation in a single tooth. Others complain of 
 pain in the dentine, which becomes agonizing whenever the 
 teeth are exposed to changes of temperature. Still others are 
 not troubled in the region of the dentures at all, but suffer from 
 neuralgia in various branches of the trigeminus, in branches of 
 the vagus, or even of the cervical plexus. 
 
 The irritations here spoken of may be caused by the wearing 
 off of the crowns through advanced age, by caries, by a recession 
 of the gums at the necks of the teeth, by erosion and mechanical ab- 
 rasion irrespective of age, by inflammatory processes in the peri- 
 cementum, etc. In some cases, however, no such cause can be 
 discovered, while, nevertheless, secondary dentine or pulp-stones 
 may be found to have developed in the pulp-tissue, even in the 
 case of adolescents from sixteen to twenty years of age. In 
 such cases we account for this fact on the theory that frequent ex- 
 posure to different extremes of temperature, as in eating hot 
 dishes and ices, drinking hot and ice-cold liquids, may cause the 
 trouble. 
 
 Irritation may affect not only the pulp-tissue, but the dentine 
 directly. This is apparent when we notice the consequences of 
 applying caustic or metallic filling-materials. In such cases the 
 irritation, in the portions of dentine that surround the fillings, 
 leads to an increased afflux of serum, saturated with lime-salts,
 
 IRRITATION AND NEW FORMATIONS OF DENTAL TISSUE. 291 
 
 and, consequently, to the obliteration of a numljcr of dentinal 
 caiialiculi. The canaliculi and their tenants, the libers, are then 
 transformed into basis-sul^stance, as I shall show in a further 
 chapter. 
 
 An increase of bulk, termed "hyperostosis of the cementum," 
 is of not very uncommon occurrence in this tissue. Doubtless 
 slight but incessant irritation is here, again, the cause of the dis- 
 turbance. As to the source of the irritation, we are as yet in 
 the dark. Wm. H. Atkinson has alleged that hyperostosis of 
 the cementum occurs only in such a tooth as lacks an opponent. 
 This assertion, however, has been disproved by observation. It 
 is possible that a congenital surplus of pericementum in the 
 patient is productive of the enlargement of the cementum. In 
 this case the movement of the tooth in mastication would slightly 
 exceed the normal degree. The constant irritation of the peri- 
 cementum under such conditions might cause an increase in the 
 amount of the cementum. The clinical symptoms of hyper- 
 ostosis are just as obscure as those of the growth of secondary 
 dentine. In some cases the patient is wholly unconscious of the 
 ailment ; in others he feels uneasiness, faint discomfort, or even 
 dull pain; again, in others, it may cause reflex irritation in 
 'remote parts, — neuralgia, etc. 
 
 In this chapter I have endeavored to outline a process sum- 
 marized in the title " Irritation Causing a New Formation of 
 Dental Tissue." !N"o strict boundary-line can be drawn between 
 this process and that which results in the formation of tumors. 
 According to A. Llicke, irritation and inflammation sooner or 
 later come to a standstill, and cease to be instrumental in pro- 
 ducing new tissue; whereas tumors grow indefinitely, never 
 coming to rest during life. 
 
 In the absence of a better definition, I shall adopt that of 
 Liicke, and discuss in a separate chapter the congenital or 
 acquired tumors of the teeth.
 
 292 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 CHAPTER XXVI. 
 
 SECONDARY DENTINE. 
 
 In the preceding chapter I have stated that in the event of 
 irritation on the surface of the tooth, the pulp-tissue reacts and 
 produces secondary dentine. 
 
 Secondary dentine occurs in two forms: first, seconaary 
 dentine in contact with primary dentine and lining the pulp- 
 cavity ; and second, dentine in the middle of the pulp-tissue. 
 Whereas the etiology of secondary dentine of the former variety 
 is plain, always being the result of an irritation on the surface 
 of the tooth, the origin of the so-called pulp-stones is not under- 
 stood. The latter formations are often met with, and often induce 
 pulpitis. 
 
 From the upper jaw of a lady forty years of age, I extracted 
 the cuspids, one of w^hich I split to obtain the pulp; the other 
 I ground thin immediately after its extraction, for the purpose 
 of studying enamel. Only one longitudinal section could be 
 prepared. The results were as follows : 
 
 The crown was built up of dentine terminating in the ordinary 
 peak, and surrounded by a well-developed cap of enamel, the 
 outermost point of which was lost, evidently in the grinding. 
 (Fig. 163, PD.) A marked brown discoloration in the usual 
 fan-like arrangement is noticeable in the enamel, mainly in the 
 immediate neighborhood of the dentine, but without any decay. 
 
 The dentine, beginning at the neck and extending down into 
 the root, is divided into tw^o layers, one internal, occupying 
 four-fifths of the root, and one external, of the thickness of the 
 cementum of normal teeth. These two layers of dentine are 
 sharply marked by the difference in the carmin stain, the inner 
 portion being very pale, the outer deeply colored. The boundary 
 between these two layers is everywhere well defined by a scal- 
 loped line, the concavities of which look outward. In some 
 places several such scalloped marks run perfectly parallel, close 
 to one another. The boundary line, how^ever, is traversed by the 
 dentinal canaliculi and their tenants without change of direction. 
 The outermost portion of the dentine of the root is surrounded 
 by cementum, not thicker than is seen on the necks of teeth of 
 normal development. In this layer faint parallel striations are 
 recognizable, therefore an indistinct lamellation. The cementum
 
 SECONDARY DENTINE. 
 
 293 
 
 i ^'Ightly thicker on one side of the apex of the root, exhibiting 
 there u scanty number of cement-corpuscles, which on all other 
 porticus are wanting. 
 
 The minute structure of the ccraentuin is identical with that 
 of liie Meek of a normal tooth, — built up of delicate wavy 
 8pi. die- with narrow interstices. These spindles are missing 
 only -n t)iat side of the root where, as mentioned, cement-cor- 
 pus'^les are present and the basis-substance exhibits a relatively 
 coarse srranulation. 
 
 Fig. 163. 
 
 ^P2> 
 
 Seotion- oi- thk Crown- of ax Anomalous Upper Cuspid Tooth. 
 D, D, dentine : I'D. point of dentine ; E, E, enamel : SD. secondary dentine. Magnified 50 
 •diameters. 
 
 The boundary between dentine and cementum is sharply 
 defined. The former bears the characteristics of dentine in the 
 vicinity of the neck, as the canaliculi stop short of its surface 
 and are replaced by a coarsely-granular basis-substance. Fig. 
 164, taken from the lower portion of the root, illustrates the 
 relations just described. Nearest to the puli)-chamber there is
 
 294 
 
 THE ANATOMY AXD PATHOLOGY OF THE TEETH. 
 
 a zone of scanty and irregular dentinal eanaliculi, the formation 
 which we are accustomed to call " secondary dentine." ISText 
 to this is a broader layer of dentine, in which the dentinal 
 eanaliculi run in bundles and in a slightly irregular wavy course. 
 Then we see a broad portion of fully-developed dentin^ (D), the 
 eanaliculi of which do not reach the cementum, but, beneath 
 
 Fig. 164. 
 
 ^C-^ 
 
 i-^ 
 
 ■>. 
 
 LD 
 
 Root of an Anomalous Cuspid Tooth. 
 
 D, primary dentine : LD, secondary dentine, composed of two zones : /', pulp ; C, cementum ; 
 PC. pericementum. Magnified 300 diameters. 
 
 the latter, are replaced by a coarselj'-granular net-work. The 
 scalloped boundary between LD and D is plainly marked. On 
 the outer surface appears the relatively narrow layer of ce- 
 mentum (C) with its lamellated structure, and, attached to this, 
 remnants of the pericementum {PC) are visible. Higher mag- 
 nifying powers of the microscope give an insight into the minute
 
 SECONDARY DENTINE. 
 
 295 
 
 structure of the dentine and cementiim (see Fig. 165), taken from 
 the place just described. In the layer of dentine the termina- 
 tions of the dentinal fibers are seen bifurcated and leading to- 
 ward the light reticulum, in which we assume the presence of 
 living matter. The lamellated cementum is provided with a 
 number of curved spindles, evidently of protoplasmic nature, 
 which in their general direction correspond to the course of the 
 dentinal fibers, while the basis-substance between the spindles 
 appears finely granular. On that portion of the cementum of 
 the root which is provided with cement-corpuscles a distinct 
 
 Fig. 165. 
 
 Root of an Anomalous Cuspid Tooth. 
 1), dentine ; C, cementum ; P, pericementum. Magnified 1000 diameters. 
 
 boundary between dentine and cementum is wanting. The 
 pericementum everywhere is attached to the cementum by rows 
 of spindle-shaped bodies in the same manner in wliicli we see it 
 on the necks of normal teeth. 
 
 In this tooth, therefore, the cement-layer is replaced by a 
 regularly-developed layer of dentine, the former being very thin, 
 and, with the exception of a limited portion, devoid of cement- 
 corpuscles. Evidently the tooth originally had a very large 
 pulp-chamber, which, with advancing age, was reduced by the 
 formation of dentine, first regularly and afterwards irregularly
 
 296 
 
 THE ANATOMY AXD PATHOLOGY OF THE TEETH. 
 
 provided with dentinal canaliculi. The central portion of the 
 dentine is occupied by " secondary dentine." 
 
 In the crown, a conical portion, the blunt lower edge of which 
 binds the pulp-cavity (see Fig. 163, SD), exhibits a structure 
 which doubtless has all the essential properties of dentine, 
 though in a considerably more irregular arrangement than 
 ordinary dentine. The regular dentine terminates almost 
 abruptly all around the cone of the irregular dentine. On the 
 
 Tig. 166. 
 
 Cusp of ax Anomalous Cuspid Tooth. 
 
 D, dentine: SB, secondary dentine; P^. pear-shaped protoplasmic bodies on the boundary 
 between primary and secondary dentine, sending large oftshoots, 0, downward ; P-, protoplasmic 
 body without offshoots. Magnified 500 diameters. 
 
 apex of the latter are visible large, irregularly-shaped branching 
 spaces, which invariably contain partly-nucleated protoplasmic 
 formations. (See Fig. 166.) The spaces and their respective ten- 
 ants, the protoplasmic bodies, are mainly pear-shaped, with their 
 bases directed toward the regular dentine, and their elongations 
 passing into the irregular dentine. From the broad bases arise 
 numerous conical offshoots, by means of which a direct com- 
 munication is established with the dentinal fibers of the regular
 
 SECONDARY DEXTIXK. 297 
 
 dentine, while other oftshoots inosculate with analogous forma- 
 tions on the apex, thus producing a coarse net-work. From the 
 pointed lower ends of the pear-shaped spaces originate wavy 
 canaliculi, whichfreelyanastomose with one another, and traverse 
 the whole mass of the central portion of the crown in a prevail- 
 ing radiate arrangement. Their numher is more scanty than in 
 the regular dentine, so much so that relatively large territories 
 of the hasis-substance are altosrether devoid of canaliculi. The 
 latter, like the canaliculi of normal dentine, hold delicate beaded 
 fibers of living matter, with the difference that, on the average, 
 the fibers of normal dentine are finer than those of the second- 
 ary formation. Some of tliese fibers are provided with lateral 
 conical oft'shoots directed toward the basis-substance, which itself 
 shows a delicate reticular structure essentiall}- of the same char- 
 acter as I have seen in regular dentine. 
 
 The middle portion of the pulp-cavity is bounded by a narrow 
 zone of dentine, which is possessed of canaliculi in a smaller 
 number than the main mass of dentine. This zone, besides, is 
 characterized by a deep carmin stain, while the regular dentine 
 remained almost unstained. The stained portion is inserted 
 upon the regular dentine by means of numerous shallow excava- 
 tions, and its surface is irregularly jagged toward the pulp-cavity. 
 In the apex of the root, the irregular formation of dentine 
 again is much thicker than in the middle portion, and provided 
 with numerous roundish spaces, all of which contain protoplasm, 
 and communicate with the irregular, wavy canaliculi of the 
 boun lary layer of the pulp-cavity. 
 
 From the facts recorded in dental literature, it is evident 
 that there are several causes universally agreed upon as to forma- 
 tions of secondary dentine. These causes are mainly : first, 
 advanced age ; second, caries of the primary dentine ; and third, 
 injuries on the external surface of the tooth. 
 
 Carl Heitzmann, in 1872,* first drew attention to the fact that 
 in old dogs and cats a number of Haversian canals in the com- 
 pact bone become obliterated. This investigator observed that 
 the capillary blood-vessel, which represents the last remnant 
 of the medullary tissue within the Haversian canals, is finally 
 transformed into a solid protoplasmic mass, which immediately 
 assumes the character of the bonv basis-substance. The bone- 
 
 * • Uber Riiek- und Neubildung von Blutgefiissen in Knorpel und Knochen," 
 
 Wtriur Mri/irijii.-ic/u' Jiiiirhui'licr.
 
 298 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 corpuscles, which under these circumstances are visible in the 
 center of a Haversian system, are, as a rule, larger than those 
 scattered within the lamell£e of an earlier formation. 
 
 If we consider the pulp-cavity as a medullary space containing- 
 blood-vessels, nerves, and medullary elements, around which are 
 arranged the layers of dentine, enamel, and cementum, we find 
 a coincidence of the formation of bone on the one hand, and of 
 secondary dejitine on the other, in advancing age. In both 
 instances the medullary elements are transformed into basis- 
 substance; the nerves, probably, after having been reduced to 
 medullary elements, also assisting in the formation of secondary 
 dentine; and, lastly, the blood-vessels are solidified. On an 
 average, the older the person the smaller is the pulp-cavity, until 
 at last hardly any trace of the pulp-tissue is left, and the tooth 
 is an almost completely solid mass. 
 
 Opposed to carious destruction of the crown I have repeatedly 
 met with formations of secondary dentine, as described by Salter 
 and Wedl. This occurred, however, only in those forms of 
 caries which have been described by Frank Abbott as chronic. 
 I have specimens which illustrate that such secondary dentine 
 formations, when the carious process has led to the exposure of 
 the pulp and produced pulpitis, are again partially destroyed by 
 the inflammatory process. 
 
 As to the irritation from without, first stated by Salter to be 
 the cause of the ibrmation of secondary dentine, I would add 
 chronic pericementitis, Avhich, when limited to one root or to a 
 portion of the root, leads to the formation of secondary dentine 
 in the pulp-canal of the affected root. There are cases, how- 
 ever, in which neither age nor an external injury accounts for 
 the formation of secondary dentine; and one instance is that of 
 the tooth above described. Here, perliaps, the absence of the 
 fully-developed layer of cementum was the reason for such an 
 extensive premature formation of secondary dentine. 
 
 The coarser anatomical relations of secondary dentine in 
 general are accurately described by C. "Wedl, with whom I fully 
 agree. In analyzing the manifold formations of this kind, I 
 would divide them as follows : 
 
 First. Secondary dentine resembling primary dentine. 
 
 Second. Secondary dentine with a laminated structure. 
 
 Third. Secondary dentine in form analogous to Haversian 
 systems. This latter variety has been termed " osteo-dentine."'
 
 SECONDARY DKXTTXE. 291> 
 
 Secondary dentine, with the essential structure of primary 
 dentine, is evidently of the most frequent occurrence. It never 
 has the regular arrangement of the dentinal canaliculi as seen 
 in primary dentine, but is marked by a lighter color, owing to 
 the large amount of basis-substance and the relatively small 
 number of canaliculi, which at the same time deviate more or 
 less from the direction of the primary canaliculi. In cross- 
 sections of such secondary dentine, — especially in specimens 
 stained with chloride of gold, — we recognize in each canaliculus 
 a central fiber (Fig. 167), from which delicate conical offshoots 
 emanate toward the periphery of the canaliculus. The canaliculi, 
 which as a rule are the wider the nearer to the pulp-cavity, are 
 pierced on their periphery by light interruptions, leading into 
 a delicate light reticulum throughout the whole basis-substance. 
 
 Fiu. 167. 
 
 r-— ■ — ^ - 
 
 I" 
 
 Dkxtixe ok an Aged Person. Ckoss-Section. 
 PD, primary dentine ; XT), secondary dentine. Mngnified 1000 diameters. 
 
 In the reticulum, the presence of living matter is not directly 
 demonstrable, but it must be assumed mainly from the phe- 
 iiomena of inflammation, — viz, caries and pulpitis. The second- 
 ary dentine sometimes remains in an embryonal condition, ex- 
 hibiting roundish fields of basis-substance, such as are visible in 
 the dentine of a nine-months' foetus. The medullary elements 
 being transformed into basis-substance, represent irregular glob- 
 ular bodies, between which the living matter produces the 
 formations known as Toraes's dentinal fibers. 
 
 This much is certain, that the dentinal fibers of secondary 
 dentine are also beaded, and send lateral ofishoots toward the 
 basis-substance, thus indicating the presence of living matter in 
 the latter. (Fig. 168.)
 
 300 THE ANATOMY AND PATHOLOaY OF THE TEETH. 
 
 Formations known as " interglobular spaces" are not infre- 
 quently met with in normal dentine. They are also quite com- 
 mon in secondary dentine, especially on the boundary between 
 primary and secondary dentine. The tooth first described (Figs. 
 163 and 166) furnishes beautiful samples of such formations. 
 Most of these are protoplasmic in nature; nay, some exhibit 
 distinct nuclei. The offshoots are evidently fibers of living 
 matter. Some of these, toward the primary dentine, are in 
 direct communication with its fibers: others run in difl^erent 
 directions toward neighboring kindred formations, with which 
 
 Fig. 168. 
 
 I 
 \ I 
 
 iff 
 
 ('•^ 
 
 
 —IB 
 
 i 
 
 rt 
 
 ■SD 
 
 I' 
 
 Secondaky Dextine, with Gimhulau Formations of the Basis-Substance. 
 
 PI), primary dentine ; SB, secomJary dentine, witli irrogulaily-scattered canaliculi ; IB, 
 globular bodies of secondary dentine, between which the dentinal canaliculi run, all in con- 
 nection with those of the primary dentine. Magnified 500 diameters. 
 
 they inosculate ; others again, after repeated bifurcation, lose 
 themselves in the basis-substance. Exceptionallj^ there occur 
 also protoplasmic bodies without any coarser offshoots. (Fig. 
 166.) 
 
 Higher amplification of these formations plainly demonstrates 
 their minute structures. (Fig- 169.) We see protoplasmic 
 bodies imbedded in lacuufe of thi basis-substance, essentially 
 identical with the so-called " interglobular spaces," the tenants 
 of which never could have been made out in sections obtained 
 from dry teeth. The protoplasmic bodies send in different direc-
 
 SECONDARY DENTINE. 301 
 
 tions into the basis-substance, larger beaded fibers, which are 
 partly in communication with fibers arising from neighboring 
 bodies. Some of the canaliculi I found empty, from Avhich the 
 fibers (evidently in the process of grinding) have been torn out. 
 The protoplasmic bodies on their periphery send conical thorns 
 through the light spaces between the protoplasm and the wall of 
 the lacuna or interglobular space. The pointed ends of these 
 thorns are directed toward the light reticulum, which pierces 
 the basis-substance everywhere. 
 
 The second variety of secondary dentine consists of the for- 
 mation of a lamellated basis-substance, which is traversed by 
 irregular dentinal canaliculi. I have observed in my specimens 
 
 
 
 
 Fig. 
 
 169. 
 
 mm" 
 
 ':nEj?,:^-s^s'3S?..; 
 
 •^?^^ 
 
 .^Rsn- 
 
 d 
 
 
 
 
 
 ^1 
 
 
 
 
 
 t- 
 
 
 
 
 
 
 
 
 
 
 i- 
 
 L 
 
 K 
 
 Secondary Dextixe from Cuspid. 
 
 P, protoplasmic bodies with the reticular structure and offshoots ; B, basis-substance with the 
 light, net-like structure. Magnified 1000 diameters. 
 
 that the lamellated structure begins clo e to the termination of 
 the primary dentine in an almost continuous course. The la- 
 mellee themselves never are very regular, and produce broader 
 and narrower layers, which, as a ^v.]-,, are not strictly parallel to 
 one another. In the interstice < between the laraellfc, here and 
 there, I have met with flat layers of protoplasm. The canal- 
 iculi piercing the lamellated d(mtine are generally very narrow, 
 and run either perpendicular or oblique to the lamellae, with 
 manifold ramifications. They invariably contain delicate beaded 
 fibers of living matter, which send lateral conical ofishoots to- 
 ward the basis-substance, in a much more irregular distribution 
 than we see in primary dentil 'O.
 
 302 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 On the boundiiry between priman' and secondary dentfne we 
 very often succeed in tracing a direct continuity of the canaliculi 
 of the former with those of the latter. 
 
 The figure (Fig. 170) which illustrates the lamellated variety 
 of secondary dentine exhibits a peculiar feature of dentinal 
 canaliculi in the primary dentine, near its connection with the 
 lamellated formation, — viz, bifurcations of the canaliculi of the 
 primary dentine, which otherwise do not occur except on their 
 terminations near the enamel and the cementum. The second- 
 ary dentine shows bay-like excav^ations bordering the pulp-cavity, 
 evidently due to an inilammatory process of the pulp-tissue, which 
 
 Fig. 170. 
 
 PB 
 
 f 
 
 I 
 
 fj ''si 
 
 ■/ ■ 
 
 iifc.. 
 
 Lamellated Variety of Secondary Dentine. 
 
 PD, primary dentine ; SD, secondary dentine ; P, margin toward pulp-cavity, with bay-like 
 excavations, due to pulpitis. The lamellae of the secondary dentine are irregular and pierced 
 by dentinal fibers, some of which are in direct connection with those of the primary dentine'. 
 Magnified 500 diameters. 
 
 has led to the dissolution of the lime-salts. In the specimen 
 from which I have taken the drawing the layer of the lamellated 
 dentine is very broad toward the crown and apex of the root ; 
 while the middle portion of the pulp-cavity, though consifierably 
 narrowed, has a relatively small amount of secondary dentine 
 on its limits. 
 
 The third, and evidently rarest, form of secondary dentine is 
 that known by the term " osteo-dentine." Formations of this 
 kind are either pedunculated, — i.e., connected with the primary 
 dentine by a stem, — or they partly fill the pulp-cavity in the
 
 SECONDARY DENTIN K. 303 
 
 «hap(f of a uniform layer. There is a striking resemblance 
 between osteo-dentine and Haversian systems of bone-tissue. 
 The systems greatly vary in size and shape, and are separated 
 from one another by a tissue kindred to primary dentine, but 
 devoid of dentinal canaliculi. Each system has in its center a 
 medullary canal, containing a certain amount of protoplasmic 
 bodies known as medullary elements; nay, in some of the sys- 
 tems I have met with a central capillary blood-vessel, which has 
 evidently been in direct union with capillaries of the pulp-tissue. 
 Around the medullary canal a system of lamellre is arranged, 
 
 Fig. 171. 
 
 iSi- 
 
 J) 
 
 OSTEO-DENTIXE, THE ThIRD VARIETY OF SeCOXDARY DeNTINE. 
 
 />. primary dentine ; SD, secondary dentine ; SL, system of lamelliB, resembling those of 
 Haversian systems of bone ; MC, medullary canal filled with protoplasm ; BC, small protoplas- 
 mic elements, identical with bone-corpuscles: £P, erosions of osteo-dentine, duo to pulpitis. 
 Magnified 600 diameters. 
 
 sometimes pretty regularly; and the lamella; are traversed by 
 delicate radiating canaliculi, closely resembling those of bone- 
 tissue. Only exceptionally have I seen within the lamellae proto- 
 plasmic formations analogous to bone-corpuscles. The jagged 
 outlines of the lacunae, in which the protoplasmic bodies lodge, 
 are identical with those found in bone; and higher magnifying 
 powers of the microscope, in fact, reveal an open communication 
 of the lacunio with the adjacent canaliculi.
 
 304 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 In the specimen from which I have selected a spot for illustra- 
 tion (Fig. 171), the lamellated systems were developed in a most 
 marked manner ; and the blood-vessels in the center of these 
 systems were so regular that they suggested the query whether 
 or not we had here to deal with vaso-dentine, so common in the 
 teeth of fish. These formations occurred in the apex of the 
 root, — some of them in the midst of regular dentine, — while 
 the lowest systems, without any distinct boundary, were con- 
 nected with the cementum, which latter here and there also ex- 
 hibited medullary canals. 
 
 Fig. 172. 
 
 Secondary Dkntixe of Permanent Molar, Stained with Chloride ofIGold, Decal- 
 cified WITH Acetic Acid. 
 
 F, F, dentinal fibers ; B, B, basis-substance. Magnified 1200 diameters. 
 
 A contribution to the minute anatomy of secondary dentine 
 is published by John I. Hart.* His results were obtained in a. 
 treatment of protracted staining with a solution of chloride of 
 gold: 
 
 " In several of my specimens of permanent teeth, I have'met 
 with secondary dentine toward the pulp-chamber. I have seen 
 
 * "Minute Structure of Dentine." Dental Cosjnos, 1891.
 
 SECONDARY DENTINE. 305 
 
 its two main varieties : tlie one characterized bj the presence of 
 irreguhir and wavy dentinal canaliculi, distributed in the basis- 
 substance in the form of bundles or sheaves, and the other 
 marked by the presence of bone-corpuscles, the so-called osteo- 
 dentine. I must confine my remarks to the former variety, as 
 the latter was seen accidentally, in dead teeth only. (See 
 Fig. 172.) 
 
 " The dentinal fibers are rather large, and supplied with nu- 
 merous vacuoles in their substance. Xumerous coarser lateral 
 offshoots arise from these fibers, apparently more numerous 
 than in primary dentine. Besides, there were seen coarse 
 conical oftshoots springing from the periphery of the dentinal 
 fibers and running into a reticulum, Avhich, in some places at 
 least, was coarser than that of the primary dentine. This re- 
 ticulum also appeared more irregular in the secondary than in 
 the primary dentine." 
 
 II. Secondary Dentine in the Middle of the Pulp-Tissue. — 
 What previous observers have termed " pulp-stones" or " den- 
 ticles" I propose to designate as " dentinification," " eburnifica- 
 tion," and " ossification" of the pulp-tissue. 
 
 It was necessary to invent such terms for the designation of 
 a process which, although known for many years, has never 
 been fully understood. I refer to the new formation of dentine 
 in the middle of the pulp-tissue, independent of the dentine 
 composing the walls of the pulp-chamber. It is the formation 
 of the so-called " pulp-stones" which by some observers are an- 
 nounced as the result of a process of calcification, but by John 
 Tomes, Ulrich, Hold, Bruck, Baume, and Witzel have been 
 described as a variety of secondary dentine. So-called pulp- 
 stones, as is well known, may be found either connected with 
 the dentine proper by means of a peduncule, or loosely im- 
 bedded in the connective tissue of the pulp. ]\Iost of these 
 formations are composed of dentinal tissue in the form termed 
 secondary dentine. Of rarer occurrence are those constructed 
 exclusively of a lamellated bone-tissue. Somewhat rarer still 
 are combinations of both dentine and bone-tissue. The rarest 
 are new formations of dentine strictly identical with primary 
 dentine. 
 
 1. So-called " pulp-stones" of the character of secondary den- 
 tine. The most marked characteristic of these specimens is the 
 presence of dentinal canaliculi irregularly scattered throughout 
 
 21
 
 306 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 the calcified basis-substance. Sometimes the canaliculi assume 
 a tolerabl}' well-marked radiation; in other instances, even 
 large masses of calcified basis-substance are destitute of canali- 
 culi. These, in scanty bundles, are found toward the periphery 
 of the pulp-stone. All the three varieties of secondary dentine 
 are found in these formations. Portions of the l:)asis-substance,. 
 especially toward the periphery, may exhibit delicate concentric 
 laminations. In the midst of an apparently homogeneous basis- 
 substance, small laminated territories ma}^ occur, containing a 
 central corpuscle with branching ofiTshoots, somewhat resembling 
 
 Fig. 173. 
 
 
 Eburnification.— Section of a Pulp-Stone of a Lower Molar. 
 
 X, lamellated secondary dentine, traversed by radiating dentinal canaliculi; C, C, globular 
 masses, exhibiting a concentric striation. Magnified 300 diameters. 
 
 a bone-corpuscle. In sections of one pulp-stone, I have found 
 numerous concentrically-laminated territories, more or less dis- 
 tinct, and either one or two protoplasmic formations in their 
 centers. The tissue between the territories was partly granular 
 and partly composed of secondary dentine, with irregular canali- 
 culi. Here and there medullary spaces were seen traversing 
 the tissue, from which evidently the new formation of the terri- 
 tories had started. This variety is the regular osteo-dentine. 
 2. So-called "pulp-stones" composed of. regularly-developed
 
 SECOXDARY DENTINE. 
 
 307 
 
 laminated bone. I have, as mentioned before, examined pulps 
 composed almost exclusively of a dense fibrous connective tissue, 
 the bundles of which were so interlaced in all directions as to 
 establish a regular cicatricial connective tissue. Scanty nerve- 
 bundles and blood-vessels traverse the dense connective tissue, 
 which in some phices appears to be more or less crowded with 
 medullary or inflammatory corpuscles. In such fibrous pulps I 
 have observed smaller or larger masses of fully-developed bone- 
 tissue, composed of more or less regular lamellaj, or of calcified 
 fibrous lamellae. In these a large number of irrescular branch- 
 
 FiG. 174. 
 
 
 i^t 
 
 \\\ 
 
 Ossification.— Section" of Pulp op Upper Lateral. 
 
 i/, longitudinal, 7", transverse bundle? of cicatricial fibrous connective tissue; £, spicula of 
 lamellated bone. Magnified 500 diameters. 
 
 ing bone-corpuscles are seen, arranged in rows or chains, where 
 the basis-substance shows a more fibrous character. Sometimes 
 the bone-tissue appears in lamellated islands, sharply marke<l 
 from the surrounding fibrous tissue. No formations of second- 
 ary dentine were combined in these cases with the bone-tissue. 
 3. So-called '•puli)-stones" composed of a mixture of regular 
 bone and dentinal tissue. In rare instances I have met with 
 pulp-stones partly composed of secondary dentine and lamel- 
 lated bone in such a wav that irregularlv-bounded masses of
 
 308 
 
 THE ANATOMY AXD PATHOLOGY OF THE TEETH. 
 
 bone contained a few large l)one-corpuscles, alternately sur- 
 rounded by a basis-substance, which contained only irregular, 
 wavy, dentinal canaliculi. 
 
 4. So-called " pulp-stones" composed of dentine with the fea- 
 tures of primary dentine. I have examined a large number of 
 pulp-stones; one of them, a mass about the size of a pea, was 
 built up of dentine. The canaliculi of this dentine are per- 
 fectly parallel, and between these a finely-reticular basis-sub- 
 stance was found, arranged in the same way as in primar}- den- 
 
 FiG. 175. 
 
 m 
 
 
 ■^^ 
 
 Df;NTiNiFiCATiox.— Section of Pllp-Stoxe of Upper Molar. 
 
 PD, primary dentine ; SD, secondary dentine ; 0, irregularly-lamellated bone-tissue ; G, 
 granular layer toward the pulp-tissue. Magnified 500 diameters. 
 
 tine of temporary teeth of children, which teeth are generally 
 poorly supplied with lime-salts. In this specimen, too, the den- 
 tinal canaliculi are wide ; the basis-substance between them, on 
 the contrary, is narrow. The dentinal fibers are relatively 
 bulky beaded formations, with numerous large conical spokes 
 penetrating the peripheral space of the canaliculi. This regu- 
 lar dentine toward the periphery of the pulp-stone is bounded 
 by a slightly-fluted contour, a narrow zone of which exhibits th&
 
 MECHANICAL ABRASION. 309 
 
 structure of canaliculated secondarv dentine. This zone blends 
 with a still narrower one, which is composed of an indistinctly 
 lamellated bone-tissue, wherein l)one-corpuscles, large in size 
 but few in number, are imbedded. This layer is followed by 
 the bounding layer of the specimen. The latter, which has a 
 granular appearance, contains a few angular or spindle-shaped 
 protoplasmic bodies and a few dentinal canaliculi. 
 
 CHAPTER XXYII. 
 
 MECHANICAL ABRASION. 
 
 This term is applied to the process in which the teeth suffer 
 loss by attrition. Mechanical abrasion is a result of imperfect 
 articulation, advanced age, or of an imperfect calcitication of the 
 enamel and the dentine of the teeth. Under normal conditions 
 the cuspid, the bicusi)id, and the molar cusps tit accurately 
 into the depressions of the teeth in the o[)posite jaw. Even u})0u 
 the incisor teeth, when they are first shed, especially on the 
 lower ones, we notice three protuberances, which, through wear, 
 soon disappear. In a normally articulating set of teeth, the 
 cusps of the bicuspids and molars are not easily worn off, and 
 the incisors and cuspids are almost entirely relieved of wear, 
 so that we sometimes meet with persons fifty years of age who 
 still have the enamel upon the cusps of their teeth preserved. 
 As a rule, however, most people lose some of their molar teeth 
 before their thirtieth year. The consequence of the loss of 
 teeth out of the dental arch is a contraction of the jaw, and if 
 one or two of the back teeth be lost from the same side of one 
 jaw, the result will be an imperfect articulation, unless the corre- 
 sponding teeth be removed from the jaw opi)0site. In correct- 
 ing protrusions of either the upper or the lower jaw, it sometimes 
 happens that we need only remove the corresponding two upper 
 or lower first permanent molars. 
 
 Frequently we see that where a few years ago a single molar 
 or bicuspid has been removed from either the upper or the lower 
 jaw, the subsequent contraction of the dental arch has almost 
 closed up the gap. In the displacement of the remaining back 
 teeth, the points of the cusps come in contact with one another.
 
 310 THE AXATOMY AND PATHOLOGY OF THE TEETH. 
 
 and are consequently worn oft"; and correspondingly, as the two 
 jaws come closer together, the upper front teeth are worn out 
 on their lingual surfaces. After the enamel of a molar tooth 
 has been worn oif, the dentine wears away much faster than 
 the enamel does. Where formerly the cusps of the tooth were 
 situated, we now see depressions in the dentine. Later on, 
 again, Avhen the grin ding-surface of the tooth has lost all the 
 enamel of its fissures, the dentine is eroded much faster than the 
 enamel that still surrounds the crown. In such cases a molar 
 tooth presents a cup, the dentine in the center sometimes being 
 worn away up to the pulp-chamber, while the surrounding enamel 
 of the tooth forms a more or less sharp, ragged, high ridge. In 
 a few instances only the enamel of the labial surfaces of the 
 upper incisor teeth is left, while the enamel of the labial surfaces 
 of the corresponding lower incisors is lost. 
 
 Occasionally we see persons who have lost one or two teeth of 
 the upper jaw l)efore the tenth or twelfth year of age, in conse- 
 quence of which the upper jaw is retracted while the lower one 
 continues to develop. In such cases a protrusion of the lower 
 jaw gradually follows, and the teeth then articulate only at their 
 cutting-edges and the points of their cusps. In such an 
 abnormal articulation, the person acquires a habit of using the 
 lower jaw in a rotary movement, by means of the pterygoid 
 muscles. The antagonizing teeth then wear upon one another, 
 so much so that in a few years the cusps disappear, and the 
 incisors sometimes become worn down to the gum, presenting 
 a more or less flat, smooth grinding-surface, similar in shape to 
 that of a worn-off bicuspid. Smokers who use clay pipes, hold- 
 ing them mostly between the same teeth, often exhibit on these 
 teeth abraded notches of a shape fitted to the pipe-stem. 
 
 In mechanical abrasion, much depends upon the hardness of 
 the teeth, as well as the kind of food used by the individual. 
 R. Baume states that some savage tribes add sand to their food, 
 which wears their teeth away in early life. Other persons, and 
 especially highly civilized people, prepare their food in such a 
 manner that the teeth are called upon to do but little mastica- 
 tion, in which case the enamel upon the cusps remains intact to 
 the fiftieth year of age or even longer. Wherever the tooth 
 loses its enamel, it becomes sensitive to the action of weak acids, 
 to thermal changes, and, more or less, to mastication. The 
 degree of the sensitiveness of the abraded surfaces, however,
 
 MECHANICAL AHRASION. 311 
 
 mainly depends upon the chemical composition of the fluids of 
 the mouth. Saliva, when of a distinct acid reaction, always 
 causes consideralde sensitiveness of these surfaces. 
 
 As to the pathology of mechanical abrasion, little can be said. 
 Both ground specimens and those obtained after decalcification 
 in chromic-acid solution show abrupt terminations of the enamel- 
 prisms as well as of the dentinal canaliculi, without a trace of 
 reaction. Occasionally along the border of the al)raded surface 
 a narrow zone of decalcification, parallel to the contour of the 
 abrasion, is seen. In specimens treated with a solution of am- 
 moniacal carmin, tlie decalcified zone assumes a saturated pink 
 color. I have tried to stain a number of ground specimens of 
 teeth afi:ected by mechanical abrasion, with solution of chloride 
 of gold, followed by decalcification in a six per cent, solution of 
 glacial acetic acid. AW these experiments failed, because before 
 the calcified dentine had more than begun to exhibit the details 
 of its structure, the decalcified zone was already of a deep violet, 
 nearly black color, that precluded the study with even medium 
 powers of the microscope. The presence of a decalcified zone 
 close beneath the abraded surface sufficiently explains the inten- 
 sified sensitiveness of the dentine of the affected tooth. 
 
 Of considerable interest is the formation in the pulp-chamber 
 of secondary dentine, always corresponding in site to the abraded 
 surface. In the chapter on secondary dentine the statement has 
 been made that mechanical abrasion is a common cause of the 
 formation of secondary dentine. Here I wish to draw attention 
 to peculiar varieties in the appearance of secondary dentine. 
 Fig. 176 illustrates such a formation of an unusual type. 
 Whereas the upper portion of the pulp-chamber is filled with 
 secondary dentine, scantily supplied with irregular and wavy 
 canaliculi, the lower portion exhibits a zone of secondary den- 
 tine parallel to the primary dentine, but not as yet calcified, as 
 is proven by a deep stain of ammoniacal carmin. The central 
 portion of the pulp-chamber exhibits an ill-calcified peg of 
 secondary dentine, with but scanty canaliculi and granular 
 deposition of lime-salts. 
 
 Fig. 177 shows peculiarities in the arrangement and course of 
 the dentinal canaliculi. In the uppermost layer the secondary 
 dentine is thoroughly calcified and conspicuous only because of 
 the bifurcation and the spindle- and pear-shaped widenings of the 
 dentinal canaliculi. In the following layer we see a formation
 
 312 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 of secondarv dentine, not as yet calcified, but holding a limited 
 number of calcareous globules, the so-called " calco-globine." The 
 fluted contours within this hiver indicate the successive forma- 
 
 FiG. 176. 
 
 
 
 
 Ground Molar. Formation of Secondary Dentine in consequence of Mechanical 
 
 Abrasion. 
 
 A'/'', primary dentine: .S'/^, secondary dentine; iV, non-calcified zone of secondary dentine : 
 C, partly calcified secondary dentine. Magnified 100 diameters. 
 
 tion of the basis-substance in a manner similar to the normal 
 development of dentine in a foetus. The midmost portion of 
 secondary dentine is marked by a devious course of the dentinal
 
 MECHANICAL ABRASION. 
 
 313 
 
 canaliculi, which, in the same field, run obliquely and trans- 
 versely. Around one or several dentinal canaliculi we find 
 lime-salts deposited in such a manner that the nomenclature 
 of territories which we have adopted in our history of the 
 development of dentine once more becomes justified. 
 
 Fig. 178 is taken from another tooth of the same patient. It 
 
 Fig. 177. 
 
 Skcoxdary Dentine in Formation. Ground Bicrspii). 
 
 C, calcified secondary dentine with irregularly-widened dentinal canaliculi ; N, non-calcified 
 secondary dentine, deeply stained with carmin, holding scattered calcareous globules; T, trans- 
 verse section of secondary dentine and its canaliculi ; G, calcareous globules. Magnified 500 
 diameters. 
 
 shows a successive calcification of the basis-substance of the 
 secondary dentine, always in the shape of calcareous globules, 
 partly isolated, partly confluent. The isolated globules are 
 mostly pierced by a dentinal canaliculus, which fact again proves 
 the propriety of our views concerning the production of terri-
 
 314 
 
 THE AXATOMY AND PATHOLOGY OF THE TEETH, 
 
 tories around the dentinal canalieiili. A portion of the second- 
 ary dentine exhibits branching protoplasmic bodies, similar to 
 bone-corpuscles, the offshoots being in this instance dentinal canal- 
 iculi partly in connection with those of the primary dentine. 
 
 A rather unusual occurrence is depicted in Fig. 179. The 
 primary dentine is succeeded by a non-calcified layer of second- 
 
 FiG. 178. 
 
 Secondary Dentine in Formation. Ground Bicuspid. 
 
 PD, primary dentine ; .S^Z*. secondary dentine ; N, non-calcified secondary dentine containing 
 dentinal fibers in bundles ; G, globular deposition of lime-salts, advancing from the primary 
 into the now calcified secondary dentine; jB, non-calcified basis-substance, holding scattered 
 calcareous globules ; C, calcareous globule pierced by a dentinal canaliculus. Magnified 500 
 diameters. 
 
 ary dentine, the most conspicuous feature of which is that its 
 dentinal canaliculi are arranged in groups or bundles, hetween 
 which bundles the basis-substance is altogether devoid of canal- 
 iculi. This is followed abruptly by a layer in which the group- 
 ing of the dentinal canaliculi is shown in a transverse section.
 
 MECHANICAL ABRASION. 
 
 315 
 
 Their bundles are here arranged in fields, branching and inter- 
 connecting, much resembling the protoplasmic net-work of 
 myxomatous connective tissue. The- only difference is that 
 instead of the so-called granules, — or, rather, points of intersec- 
 tion of the reticulum of living matter within the protoplasm, 
 — bundles of dentinal canaliculi have appeared. The basis- 
 
 FiG. 179. 
 
 
 
 W^ :^^M '"^^'i'^ 
 
 Skcon'daky Dp:xtine in Formation. Ghound Bicuspid. 
 
 PB, primary dentine; A^L, non-calcified secondary dentine in longitudinal section ; ST, 
 non-calcified secondary dentine in transverse section ; G. groups of dentinal canaliculi in trans- 
 verse section ; P, protoplasmic spaces, holding dentinal fibers in transverse section ; (7, calcareous 
 globule. Magnified 500 diameters. 
 
 substance filling the meshes of this remarkable reticulum is 
 devoid of canaliculi, holding only a few scattered calcareous 
 globules. This specimen, though anomalous, plainly shows the 
 interchangeability of all varieties of connective tissue. The 
 form may change ; the type remains.
 
 316 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 CHAPTER XXVIII. 
 
 EROSION. 
 
 This term is applied to a process in which the hard dental 
 tissues are eaten or wasted awa}', principally upon the labial 
 surfaces near the cervical margins of the teeth. Some of the 
 older writers have applied the name of denudation to this pro- 
 cess, but at present erosion is universally used. Erosion was 
 noticed as early as 1778 by J. Hunter; but the first investigator 
 who gave a reasonable explanation of it was E. C. Kirk, who, 
 in a paper read before the First District Dental Society of JS^ew 
 York, in 1886,* demonstrated that its origin was from acid 
 mucoid secretions of the mouth. He, however, gives the credit 
 of priority to J. Truman. Much was written on this subject, 
 but without advancing anything new, till E. T. Darby, in a 
 paper read before the New York State Dental Society, ^lay, 
 1892, t stated that erosion is mostly found in teeth of patients 
 who sufl'er more or less from gout. S. G. Perry, in an article 
 read before the New York Odontological Society, 1893,J cor- 
 roborated the assertion of E. T. Darby, and proves from experi- 
 ments made on himself that most cases of erosion yield to an 
 anti-gout treatment. 
 
 In regard to the etiology of erosion, there are three main 
 theories : iirst, that the cause is niechanical action wrought by the 
 too frequent use of the tooth-brush in combination with gritty 
 dentifrices; second, that the cause is local acidiU/ of the mouth, 
 produced by acid beverages; third, that it is constitutional acidity 
 of the mouth as produced in gout. The latter theory is the most 
 generally accepted and most plausible one, although we meet 
 with many gouty patients whose teeth are not aifected by erosion. 
 Again, it cannot be denied that by the too vigorous use of the 
 tooth-brush the cementum, the dentine, and the enamel, espe- 
 cially when softened by an acid, may, to a certain extent, be 
 brushed away. But as we meet with erosion upon the approx- 
 imal and lingual surfaces of the teeth, the mechanical theory 
 cannot be correct. We have therefore to admit that erosion is 
 
 * Dental Cosmos, 1886. 
 
 t "Dental Erosion and the Gouty Diathesis : Are they Usually Associated?" 
 Dental Cosmos, 1892. 
 
 X " Erosion of the Teeth.'' Internat'wnrd Dental Journal, 1893.
 
 EROSION. 317 
 
 not, as yet, explainable in a satisfactory manner. It is generally 
 acknowledged that in gouty diathesis there exists in the system 
 a superacidity, especially of uric acid. This acidity, through tlje 
 circulation of the blood, where it exists in combination with other 
 salts, may be imparted to the secretions of the mouth, in which 
 case the occurrence would be explicable. Gouty conditions of 
 the system may be due to heredity, or they may be produced by 
 improper food and too little exercise in the fresh air. S. G. 
 Perry, in his article {I. c), quotes Dr. J. M. P'othergill, who is of 
 the opinion that a gouty diathesis of the system depends upon 
 imperfect conditions of the liver. Dr. Fothergill distinguishes 
 two kinds of gout : one, when a person who has lived too luxu- 
 riously for a number of years gets rich man's gout; the other, 
 when a person born with an imperfect liver, and not taking 
 exercise enough in the fresh air to consume even a small quan- 
 tity of nitrogenized food, gets poor marl's gout. The writer him- 
 self has observed patients who suffer from both kinds of gout, 
 and who state that whenever their teeth become sensitive they 
 know that they are about to have an attack of this disease. On 
 the other hand, I know of quite a number of patients who suffer 
 from gout, but their teeth do not show erosions. This theory, 
 therefore, although plausible, is by no means a finality. So much 
 is certain, however : that erosion is due to the action of an acid, 
 — probably lactic acid. It was also supposed that the living 
 matter of the tooth could produce the reaction ; but as both 
 living and devitalized teeth are affected in a similar manner by 
 this destructive process, this theory is not tenable. 
 
 There are a number of cases on record of chemical abrasion, so 
 termed, of which the writer has seen two in his own practice. 
 Both had the characteristics of erosion, although the labial sur- 
 faces of the teeth showed but little of this process, while the 
 cutting-edges of the incisors and cuspids, especially the upper 
 ones, were more than half dissolved away. The teeth were 
 similar in appearance to those affected by mechanical abrasion, 
 but as the lower teeth did not articulate with the upper ones, 
 mechanical abrasion in their case was out of the question. 
 
 In regard to the pathological anatomy of erosion, there is but 
 little to say. As the appearances of the eroded dental tissues 
 under the microscope are similar to those affected by mechanical 
 abrasion, I refer the reader to Chapter XXVII, in which that 
 topic is considered.
 
 818 THE ANATOMY. AND PATHOLOGY OF THE TEETH. 
 
 Erosion mostly appears in persons over tliirtj years of age, 
 and starts in one or more small pits, or a slight groove near 
 the cervical margin, in the cement of the neck of the tooth. 
 Usually the attack is upon the labial surfaces; sometimes it is 
 noticed upon the approximal surfaces; but quite rarely on the 
 lingual surfaces of the teeth. The eroded places mostly are 
 smooth, and have a polished appearance. Often these grooves 
 start in the enamel of the lal)ial surfaces of the teeth, a little 
 distance away from the gum, presenting a single, or sometimes 
 a double, furrow which runs parallel to the cutting-edges of the 
 teeth. In rare instances, we notice the greater portion of the 
 enamel of the labial surfaces of the incisors dissolved. All the 
 eroded surfaces are sharply defined ; that is, the boundary is 
 surrounded by a sharp border, whether of enamel or cementum. 
 We also meet with eroded surfaces, the outlines of which, under 
 the microscope, look fluted or slightly bay-like. This appear- 
 ance has induced some writers to believe that the destructive 
 agent of erosion was the so-called Hoicship's lacimce, or gianl-cells. 
 These fluted outlines are mostly found in ill-calcified teeth, and 
 again prove that the dentine and the cementum are dissolved in 
 the same manner in which they are built up, — i.e., by territories. 
 Erosion usually commences on the upper or lower cuspids, 
 probably because these teeth are generally the first that suffer 
 from recession of the gums. It has been stated that erosion 
 occurs below the margin of the gum, but the writer has not 
 met with a single case in which erosion was not preceded by a 
 corresponding recession of the gum. Although there are cases 
 of erosion which are seen to extend beneath the gum-margin, 
 in these instances we always notice an inflammation which has 
 produced a slight tumefaction of the gingival border, thereby 
 overlapping the eroded surface. The cuspids occupy the most 
 prominent position in the dental arch, and consequently are the 
 most subject to irritation by the tooth-brush, which probably 
 accounts for the early recession of the gums on the labial sur- 
 faces of these teeth. The next teeth affected by erosion are 
 most commonly the first and second bicuspids ; then the in- 
 cisors; and, lastly, but not often, the molars. When erosion 
 has affected most of the teeth in the dental arch, usually the 
 cuspids, and especially the upper ones, contain the deepest 
 defects; next the bicuspids; and then the incisors; while the 
 defects upon the buccal surfaces of the molars are rarely large.
 
 EROSION. 
 
 319 
 
 As the eroded surfaces increase in extent, they assume an ap- 
 pearance as though they had been made by means of a small 
 three-cornered or round tile. (See Fig. 180.) The surfaces are 
 generally smooth and bright, but in some few cases dull and 
 rough. The roughness usually is due to the commencement of 
 caries. The color of the eroded tissues, at first, is white or 
 yellowish-white in the enamel, and a light yellow in the dentine 
 and the cementum; but later on it changes in the latter two 
 tissues to a dark yellow or even dark brown. The eroded sur- 
 
 FiG. 180. 
 
 lit :^. 
 
 Ground Section of an Upper Lateral Incisor, with Erosion. 
 E. erosion at the labial aspect of the neck. Magnified 4 diameters. 
 
 faces are usually soon discovered by the patient, especially 
 during the act of brushing the teeth, or when a foreign sub- 
 stance, such as a tooth-pick, a pin, or the nail of a finger, is 
 brought in contact with the erosion. "When this process is 
 active, the affected dentine, the cementum, and sometimes the 
 enamel are extremely sensitive ; while as soon as the secretions 
 of the mouth attain a neutral or an alkaline reaction, the eroded 
 surfaces lose their sensitiveness, and the process comes to a 
 standstill.
 
 320 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 Erosion, therefore, cannot be arrested by the introduction of 
 filling-materials into the eroded cavities ; on the contrary, we 
 frequently observe the gold fillings in the cervical portions of 
 the teeth stand above the level of the enamel for a considerable 
 height. In some instances, however, the eroded surfaces become 
 attacked by caries, in which case the filling of these places 
 becomes a necessity. As stated above, when the eroded surfaces 
 begin to decay, we first notice a roughness, and afterward a 
 softening, which is characteristic of caries. When the carious 
 process is an acute one, the color of the eroded surfaces may 
 remain yellowish-white or even white, and in these cases caries 
 is apt to be confounded with erosion. In the majority of in- 
 stances, however, the caries preceded by erosion is of a dark- 
 yellow or a brown color, and not easily mistaken for erosion. 
 
 CHAPTER XXIX. 
 
 THE REACTION OF THE DENTINE UPON FILLINGS. 
 
 During the past sixteen years, for the purpose of procuring 
 trustworthy data as to the reaction of various filling-materials 
 upon the hard tissues of the teeth, I have made a number of 
 experiments in their introduction, mainly upon the temporary 
 teeth of my own sons. Accurate notes as to conditions and 
 dates were kept, so that the history of each experiment, includ- 
 ing the time the filling remained in the cavity, was complete. 
 I came into possession, also, of a number of teeth from patients, 
 into which fillings had been introduced on account of caries in 
 the ordinary course of my practice. Altogether, there were 
 somewhat more than fifty teeth, of each of which I knew the 
 exact history. 
 
 Some of these teeth were ground into thin slabs under the 
 precautions mentioned in the chapter on dentine, the most im- 
 portant of which is not to allow the slab to become dry, even 
 for a moment, during the process of grinding. Others were 
 placed in a one-half of one per cent, solution of chromic acid, 
 which was renewed daily for about one week. These teeth 
 were kept for several years in separate jars, the solution being
 
 THE REACTION OF THE DENTINE UPON FILLINGS. 321 
 
 changed al)Out three times a year. For some time, about two 
 weeks before cutting, the one-half of one per cent, solution of 
 chromic acid was renewed daily, at the end of which time the 
 teeth had become softened so as to be fit for cuttino- ^vith the 
 microtome. 
 
 The deeper layers of the dentine needed decalcification in 
 most cases, even atKn* imbedding in celloidin. 
 
 The protracted ex[iosure to the decalcifying agent effected a 
 surprising result upon the enamel-tissue, for, whereas in jire- 
 vious years I had invarialdy met Avith failure in 'decalcifying 
 this tissue, I now succeeded in decalcifying the enamel of both 
 temporary and permanent teeth. 
 
 Many of my specimens show varying spaces of thorough de- 
 calcification, but it never involves the enamel in toto. What I 
 have stated with regard to the structure of enamel-tissue in 
 Chapter Xf, I found corroborated in these specimens, made 
 for an entirely different purpose from those of former experi- 
 ments. The mere faet that enamel can be partially, at least, 
 decalcified and preserved, shows plainly the error in the vicAV 
 still held by some, that enamel is not a tissue, but a coat of 
 mail entirely destitute of })roperties of life. 
 
 In analyzing the results of fillings, I wish to draw attention 
 to several possible sources of error wdiich must constantly be 
 borne in mind to prevent faulty conclusions. First, it is not 
 always easy to determine the exact location of the previous fill- 
 ing at the border of the cavity, since crevices sometimes appear 
 in the margin of an aspect resembling that of a previously- 
 filled cavity. The border of the dentine is, as a rule, easily 
 recognizable by the presence of a film of enamel, or, where 
 this is missing, by the bay-like excavations present in the inter- 
 zonal layer between dentine and enamel. A second source of 
 mistake is the presence of [)ortions of dentine decalcified before 
 being placed in the chromic-acid solution. Such fields, in 
 specimens stained with an ammoniacal solution of carmin, are 
 recognizalde by a green color, wdiich is due to the reduction of 
 the chromic acid to chromic oxide. It is considered a legitimate 
 procedure to introduce fillings into caA-ities in the dentine even 
 though the deeper portions of the cavity be slightly discolored, 
 rather than to expose a pulp. Moreover, small carious places 
 in the dentine or enamel cannot always be detected in a cavity 
 of a tooth with the naked eye, or even with a simple magnifying 
 
 22
 
 322 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 lens. In such a case, under the microscope, the impression 
 may be conveyed to the observer that he sees reaction pro- 
 cesses in the dentine where, in fact, only vestiges of the pre- 
 vious })rocess of caries are present. F, B, Fig. 181, affords an 
 illustration of this statement. Along the border of a cavity 
 of the tooth which was tilled with gold April 22, 1889, and ex- 
 tracted on account of pericementitis April 26, 1893, a process 
 is seen, which was first descril)ed by Al>l:)0tt as inflammation 
 
 Fig. 18]. 
 
 Amehtis— Inflammation of Enamel at thf. Border of a Gold-Filled Cavity. 
 
 £, border of cavity ; jp, prisms broken up to medullary corpuscles, enamel-fibers enlarged. 
 Magnified 500 diameters. 
 
 of the enamel, amclitis, due to caries. The enamel-prisms are 
 broken up into small sfpiares, or reduced, as it were, to their 
 embryonal state. More than that, the enamel-fibers between 
 the broken-ui» prisms are slightly enlarged. I cannot reason- 
 ably attribute this change to the presence of the gold filling, 
 since not even dentine shows so pronounced a reaction after 
 the introduction of o-old fillings.
 
 THE REACTION OF THE DENTINE UPON FILLINiiS. 323 
 
 There are two possiblL' L-xplanation^; of tlie amelitis in this 
 case : either we have before us vestiges of primary caries of the 
 enamel, or the enamel has been attacked by secondarv caries. 
 
 A third source of error is found in the fact that practitioners 
 commonlv apnlv to the walls of an excavated cavitv strono" 
 aseptic eoaii-ulants, sueh as i»ure carbolic aeid, creasote, a solu- 
 tion of corrosive sublimate, etc., before introducino; the fillino-. 
 Thus the tissues alonii' tin- iiorder of the cavity are rendered 
 dead to a certain depth. This is shown, under the microscope, 
 by a green color along the border of the cavity and a shriveled, 
 granular appearance of the dentinal fibers to a certain depth of 
 the tissue, when normal fibers again reappear. That under 
 these conditions no reaction of the filling-material can be ex- 
 pected along the border of the cavity is plain enough. 
 
 Having enumerated the points to be ke})t in \iew, I now pro- 
 ceed to tlie analysis of the specimens. 
 
 I. Gutta-percha. — This never showed the sjigiitest reaction at 
 the Ijorder of the cavity in the dentine. The dentinal canaliculi 
 and their tenants terminate alu'uptly toward the cavity. Only 
 liere and there was seen a green discoloration at the border, — 
 due, proltably, to coagulants applied before the introduction of 
 the filling. 
 
 II. Gold. — In some instances no reaction was noticeable in 
 the dentine, only a zone of green color, attributal)le to causes 
 just mentioned under gutta-percha. In other instances, there 
 is a distinct reaction alone; the border, as illustrated in Fig;. 182. 
 The dentine is so thoroughly consolidated in the zone nearest 
 the cavity that this portion shows no dentinal canalieuli. The 
 latter stop short, the ternnnation being evidently due to an ob- 
 literation of the canaliculi, at first partial and finally complete. 
 The solidified zone of dentine is still alive, judging from the 
 slight stain present of the ammoniacal solution of carmin. 
 In still other instances the gold filling has led to a partial ob- 
 literation of dentinal canaliculi similar to that induced by oxy- 
 phosphate of zinc, though never as complete as that which 
 follows the introduction of the last-named filling-material. 
 
 III. Oxyphosphate of Zinc. — The reaction is almost constantly 
 present, and consists of a solidification of the dentine and an 
 obliteration of a number of dentinal canaliculi. The dentinal 
 canaliculi which are obliterated under oxyphosphate fillings 
 first become faint, scarcely traceable, and ultimately disai»pear,
 
 324 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 in consequence of which disappearance the fields of basis- 
 substance between the dentinal canaliculi are considerably 
 broadened. 
 
 The ramifications of some of the denthial canaliculi seen in 
 Fig. 183 are made explicable by tlie presence of lateral ofishoots 
 
 Fig. 182. 
 
 Permanent Tooth, Previously Filled with Gold. 
 
 B, border of cavity, overspread with debris of dentine ; S, zone of consolidation ; D, normal 
 dentine. Magnified 500 diameters. 
 
 of the dentinal fibers, some of which become conspicuous in 
 consequence of irregularity in the process of consolidation. 
 The consolidation is densest along the border of the cavity, 
 where dentinal canaliculi are quite scanty ; but the consolidated 
 dentine extends to a consideral)le depth before it blends with 
 normal dentine.
 
 THE KEACTION OF THE DENTINE UPON FILLINGS. 
 
 325 
 
 IV. Amalgam. — The features that appear after the introduc- 
 tion of this fining depend upon the length of time the material 
 is left in the cavitv. A few months after its introduction a 
 
 Fig. 183. 
 
 Ground Bicispid, Previously Filled with Oxyphosph.vtk of Zinc. 
 
 /?, border of cavity ; />. normal dentinal canaliculi ; 0, obliterated dentinal canaliculi. 
 Magnified 500 diameters. 
 
 pronounced discoloration of the border of the cavity is almost 
 invariably visible. This is due to the penetration of silver or 
 mercuric sul})hide into the dentinal canaliculi. The metallic
 
 326 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 particles are black under the microscope, and therefore easily 
 recognizable. They seem to be carried into the depths of the 
 dentine for some distance, by contractions of the dentinal fibers ; 
 otherwise it would be inexplicable that the most deeply-stained 
 discoloration is seen at some distance awa}^ from the border of 
 the cavity. (See Fig. 184.) 
 
 Fig. 184. 
 
 mmmm. 
 
 Ground Tooth, Previously Filled with Amalgam. 
 
 S, surface of filled cavity marked by large metallic clusters ; B, dentinal canaliculi holding 
 rows of metallic particles, the reticulum quite pronounced in a few places : P, darkly pigmented 
 zone ; Z, slightly pigmented portion of dentine, followed by a darker pigmented portion farther 
 below. Magnified 500 diameters. 
 
 The accumulation of the metallic granules is sometimes an 
 excellent means of rendering visil)le the minute structure of 
 the dentine. In tlie highest degree of infiltration not only the 
 dentinal fibers and their coarser offshoots, but also the finest
 
 THE REACTION OF THE DENTINE UPON FILLINdS. 
 
 327 
 
 rctic'iiliini of tlie living matter in the basis-substance is strongly 
 detined in black. In Figs. 51 and 52, in the chapter on " The 
 Minute Structure of Dentine," this effect upon the reticulum is 
 illustrated. Discoloration after the introduction of amalgam 
 becomes less noticeable in the vicinity of the cavity in propor- 
 
 FiG. 185. 
 
 Dkcalcikiei) Temporary Tooth, Prkviousi.y Fii.lkd \vitii Amai.(;am. 
 
 B, border of cavity ; D, dentinal canaliculi of varying calibers, holding metallic granules; R, 
 reticulum in the basis-substance; C, broad fields of recalcified basis-substance. Magnified 500 
 diameter.'-. 
 
 tion to the lapse of time after its introduction. On the other 
 hand, the body of the tooth in time assumes a dark hue. This 
 fact becomes explicable when we recognize the gradual diffusion 
 of the metallic i)articles throughout the dentine. Tin fillings 
 behave similarly to amalgam, only in a less pronounced degree.
 
 328 THE AN'ATOMY AND PATHOLOGY OF THE TEETH. 
 
 After the lapse of several years the reaction of amalgam upon 
 the adjacent dentine is quite marked. It consists in a consoli- 
 dation of the dentine, due to a partial obliteration of the den- 
 tinal canaliculi and a simultaneous broadening of the fields of 
 the basis-substance. (See Fig. 185.) 
 
 The apparently devious courses of some of the dentinal 
 canaliculi become comprehensible upon the grounds stated in 
 the paragraph concerning oxyphosphate of zinc. Some of the 
 lateral coarse oflshoots of the dentinal canaliculi have been 
 made conspicuous by the preceding decalcification, and have 
 remained unchanged, though many of the main canaliculi or 
 portions of them have become obliterated. That the recalcifica- 
 tion is not a perfect one is best evidenced by the varying cali- 
 bers of the dentinal caualiculi and the presence of the delicate 
 reticulum of living matter in the basis-substance, which is the 
 more conspicuous the nearer it approaches to the border of the 
 cavity. All the formations of living matter in such specimens 
 — the dentinal fibers as well as the minutest reticulum — contain 
 tiny particles of sulphuretted metal, though nowhere in large 
 numbers. 
 
 From tlie above facts we may draw the following practical 
 conclusions : For all teeth in which the hard tissues are 
 much softened, owing to constitutional difficulties, and where 
 irritation of the living matter is to be prevented, gutta-percha 
 will prove to be the best filling-material. Ox;s^3hosphate of zinc 
 will be found preferalde in fairly good teeth which have become 
 softened through caries or temporary illness. Gold produces a 
 reaction in the dentine in some instances; in others it does not. 
 It is best adapted for adult and well-calcified teeth. Amalgam 
 ought to be used in exceptional cases only. Although these 
 rules may hold good for general practice, in the majority of 
 instances the practitioner must be guided by the circumstances 
 of the case and his own experience. It is important, however, 
 to remember the fact that the application of pure carbolic acid 
 mummifies, so to speak, the li\Tng matter in the dentine of the 
 cavity to a slight de]ith. This action will render the dentine 
 less sensitive to thermal changes, and make the walls of the 
 cavity aseptic.
 
 HYPliROSTOSIS OF ROOTS OF TEETH. 329 
 
 CHAPTER XXX. 
 
 HYPEROSTOSIS OF ROOTS OF TEETH.* 
 
 "Under the term liyperostosisf I propose to consider all the 
 forms of pathological new growths of cementum, including -what 
 authors are wont to term osteoma, exostosis, hypertrophy of the 
 cement, etc. 
 
 "As to the cause of this not very infrequent disease, the 
 following points may be enumerated: 
 
 " A. Direct irritation of the pericementum through slight 
 long-standing caries of the crown or neck; or, exposure of the 
 pulp, mainly the result of caries ; 
 
 " B. Localized irritation of the pericementum of constitutional 
 origin, such as from gout and syphilis ; 
 
 " C. Irritation of the pericementum of upper teeth after the 
 removal of their antagonizing teeth of the lower jaw, the result 
 of, or induced by, gravitation. 
 
 " Obviously, irritation of the pericementum is considered by 
 all authors as the cause of outgrowths of cementum. 
 
 " That a chronic irritation of the pericementum, whatever the 
 cause maybe, may result in a new formation of cementum, no- 
 body will doubt; nay, it has been clearly proven by Bodecker 
 that a circumscribed hyperostosis of the cementum may arise 
 from chronic pericementitis. The question, however, is. Can 
 a diifused enlargement of the cementum occur in consequence 
 of pericementitis, either of a local or constitutional origin, after 
 the cementum has once been fully formed ? This question I 
 feel constrained to answer in the negative, and I base my opinions 
 upon microscopical studies of such tumors. My conviction is 
 that hyperostosis of cementum of a diffused character is in most 
 instances afcetal malformation. 
 
 " If a carious tooth be extracted, and the roots be found in a 
 hyperplastic condition, the first impression, of course, would be 
 that the inflamed pulj), in this case, has led to pericementitis, 
 and the latter to hyperostosis of the roots. This undoubtedly 
 
 * Extract from an article hy Frank Abbott. Denial Cosmos, 1886. 
 
 t L. A. AVt'il, in an article, " Ueber Cement-hyperplnsiie, " Oest.-Ung. Viertel- 
 jahi-schrf. ZahnficUlxiinde, III Jahrg., Heft, ii, remarks that the term "hyperos- 
 tosis" would imply a uniform and flat increase of bone-tissue, whereas "exos- 
 tosis" means a circumscribed now formation of this tissue. He prefers the term 
 " hyperplasia of cementum" for the designation of all forms of hyperostosis.
 
 330 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 in some instances may be the case, more especial!}' when the 
 process of caries has attacked a lateral surface of the crown or 
 the neck of a molar, and the root or roots nearest to the point 
 of irritation of the pulp are found to be enlarged ; but if all 
 the roots of a molar are uniformly enlarged, or fused together, 
 we hardly feel justified in stating that caries was the primary 
 and hyperostosis of the roots the secondary cause, or the result 
 of such a primary cause ; for it is possible that the hyperplasia 
 of the roots has been present long before the caries made its 
 appearance. The latter assumption becomes almost a certainty 
 when, upon grinding such teeth for microscopical research, we 
 find either that the caries has not penetrated sutficiently deep to 
 cause inflammation of the pulp, or the dentine is found in a 
 condition which could not be the result of simple ' eburnitis,' 
 but can have been the result only of a malformation at the 
 beginning of its growth in foetal life. 
 
 " After a careful study of a large number of examples of hyper- 
 ostosis, I feel entitled to make the statement that the teeth ex- 
 hibiting it were sound and their pulps alive at the time the bony 
 growth had formed. 
 
 " "Whenever a tooth becomes deprived of its nourishment from 
 the pulp, I doubt the possibility of an osseous new formation 
 upon the cementum; and, further, should such a new formation 
 have existed previously, its* growth has undoubtedly ceased the 
 moment the life of the pulp was gone. Should a dentist extract 
 a sound-looking tooth to relieve excessive pericementitis, or 
 neuralgia suspected to arise from pericementitis, and find the 
 root or roots considerably enlarged, he would hardly be justified 
 in concluding that the pericementitis and neuralgia had caused 
 the growth upon the roots ; but, on the contrary, he would 
 naturally conclude that the growth had been the primary feature 
 and the pericementitis and neuralgia secondary features of the 
 disease. If, for instance, to relieve neuralgia, there be removed 
 from one upper jaw a large number of sound-looking teeth, the 
 roots of all of which are found to be considerably enlarged, we 
 conclude that these roots w^ere malformed at the earliest stage 
 of their development. I have in my possession six upper molars, 
 all removed from the same person's mouth, to relieve neuralgia. 
 The roots of all of them are more or less enlarged ; three have 
 no decay whatever in their crowns, and the other three are but 
 sliirhtlv affected.
 
 HYPEROSTOSIS OF ROOTS OF TEETH. 331 
 
 " Xo growth of any tissue is possible "without its being first 
 partially rodueed to medullary elements. An augmentation of 
 the cementnni is impossible without a preceding augmentation 
 of the medullary tissue, which again is caused by increased 
 nutrition, or, as it is generally expressed, an irritation. 
 
 " I propose to show that cementum, in a pathological (hyper- 
 plastic) condition, is endowed with properties of life the same 
 as in a normal state. Thus it becomes explicable that hyper- 
 plastic cementum itself may become the subject of pathological 
 processes, particularly of inflammation. Hyperplastic cementum 
 may, and often does, become partially destroyed by cementitis 
 and transformed into medullary tissue, from which, evidently, 
 an additional new growth of cementum may start. 
 
 " Since the beginning of the present century, a good many 
 reliable observers have descril)ed and depicted anomalous teeth 
 with hyperostosis in varying degrees of development. Some of 
 these illustrations are striking examples of the excessive growths 
 to which cementum may attain, and still be tolerated by the 
 sufferer. All observers and clinicians, I think, agree that this 
 disease attacks bicuspids and molars only, incisors and cuspids 
 appearing to be exempt; and, again, the teeth of the upper jaw 
 are more frequently affected than those of the lower. 
 
 " Facial neuralgia of the most severe and unyielding char- 
 acter is frequently caused by these malformations. At the same 
 time, the symptoms which point to a diagnosis of hyperostosis 
 of the roots are not very marked. When observable at all, 
 they consist of a slight continued uneasiness in the jaw (as 
 sometimes expressed by a patient, ' I can't call it real pain, but 
 I am coiisiaiiily aware that I have a tootli in that locality'). It 
 is akin to pain, with slight soreness of the tooth or teeth upon 
 biting, while excessive pressure upon it in any direction is pro- 
 ductive of quite severe and prolonged pain. Eventually the 
 soreness becomes more marked, and the pain constant or inter- 
 mittent, and finally terminates in possibly an abscess, severe 
 mental derangement, or the removal of the tooth as a cure. 
 
 " It is not infrequently the case that a patient suffering from 
 neuralgia applies to a dentist to have a certain tooth extracted 
 for relief, the case being to the dentist so obscure that he takes 
 the patient's word for it, and extracts the tootli ; but to his dis- 
 gust the patient, after a few moments, turns to him and says, 
 ' Why, doctor, that isn't the tooth; the pain is just as bad as it
 
 332 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 was before you took it out.' This operation is repeated over 
 and over again with the same result, until finally, perhaps, it is 
 the last tooth in the jaw which when taken out reveals the 
 cause of this long suifering, in a root or roots enlarged from 
 hyperostosis. A peculiar feature in these cases is the long-con- 
 tinued and most distressing pain that follows such extractions, 
 relief coming hut very slowly. 
 
 "As custodian of that portion of the museum of the New 
 York College of Dentistry which pertains to my department, 
 I have come into possession of seventy odd teeth exhibiting 
 hyperostosis of the roots, and this comparatively large number 
 prompts me to try to classify the ditfe rent varieties as they occur 
 to me. I will here add that about one-third of these teeth are 
 sound or very nearly so. Previous authors have simply de- 
 scribed different forms, more or less striking, without observ- 
 ing anv svstem in the arrani^ement. 
 
 Fig. 186. 
 
 Fig. 187. 
 
 " I. Circumscribed Hyperostosis.— Under this title are included 
 osteoma and exostosis of the authors, which are characterized 
 by an outgrowth of bone-tissue from the cementum, of a limited 
 size, varying from that recognizable only with the microscope 
 to that of a lentil or a pea. Their surfaces usually present a 
 nodular appearance, and sometimes they are adjacent to newly- 
 formed cancellous structure of bone, evidently caused by osteitis 
 of the socket. I would subdivide this group into : 
 
 " A. Osteoma on the body of the root (Fig. 186, a, h). 
 
 " B. Osteoma on the apex of the root (Fig. 187, a, h). 
 
 " Either of these appears mostly upon teeth the crowns of 
 which are more or less destroyed by caries, with probably a 
 long-standing exposed pulp, which plainly indicates that their 
 cause is likely to be accounted for in localized pericementitis 
 from tbis source. If, however, we bear in mind that the destruc-
 
 HYPEROSTOSIS OF ROOTS OF TEETH. 333 
 
 tion of the life of the pulp prevents or stops the formation of 
 osteoma on the roots, we must come to the conclusion that such 
 tumors had commenced their formation long before the exposure 
 of the pulp, or this must have remained alive for a very long time 
 after its exposure before it died, causing during this long time 
 a slight but constant irritation, transferred to the pericementum. 
 
 "As soon as severe pericementitis from an exposed pulp sets 
 in, unless vigorous steps for its relief are taken, the pulp is in 
 a fair way to become lifeless very soon. After its death severe 
 pericementitis and its distressing terminations are too well 
 known to practitioners to need mentioning here. In neither of 
 the latter instances would we expect a bony outgrowth on the 
 roots. It is, in my judgment, only an irritation of the perice- 
 mentum while the pulp is living that can result in an increased 
 cementum. 
 
 " In some persons, or conditions of persons, a very sapertieial 
 decay, more particularly upon the necks of teeth, will produce 
 marked pericementitis and neuralgia. We may infer from this 
 fact that in other persons or conditions (or possibly the same), 
 perhaps under the influence of constitutional disturbances, a 
 local irritation of the pericementum is induced, causing exos- 
 tosis, long before exposure of the pulp. 
 
 "II. Diffused Hyperostosis with Roots Separated.— Under 
 this heading a large number of specimens of my collection 
 may be summed up, either of otherwise sound teeth or those 
 decayed or filled. In relation to what I have stated before, I will 
 admit that pericementitis from caries is a cause of hyperostosis 
 only when one root, or two, are involved, others being in a 
 normal condition, and the enlarged root or roots corresponding 
 to the carious cavity either on the neck or crown of the tooth. 
 When all the roots of molars are atfected, without the least 
 symptom of disease upon the exposed portion of the tooth in 
 the mouth, I can see no other correct course than to seek for 
 the cause of malformation in the beginning of the formation of 
 cementum, — to wit, during the first year of extra-uterine life. 
 Hyperostosis of this kind invades the roots from the apex to 
 the middle, to two-thirds their length, sometimes even to their 
 necks. The enlargement is either blending with the crown, 
 without a distinct boundary line, or there is a more or less 
 marked Inilging of the augmented tissue. The enlarged por- 
 tion is either in a more or less horizontal line or is fluted, with
 
 334 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 liere and there irregular prolongations toward the crown. In 
 one instance I have seen a small enamel-nodule corresponding 
 exactly to the summit of a marked conical prolongation of the 
 cementum. Sometimes the bulging of the cementum reaches 
 the crown, and may be distinctly seen overlapping the enamel. 
 Such formations are usually either smooth or slightly nodulated. 
 Sometimes tliey are corroded as if by inflammation ; and, again, 
 upon a comparatively smooth mass there may be found bulging 
 forth an irregular nodule of circumscribed osteoma, evidently 
 the result of an excessive formative pericementitis. 
 
 " In one of my specimens, a left upper second molar, there 
 is upon the anterior surface of the buccal root a pit two and a 
 half millimeters in diameter and one millimeter in depth, the 
 base of the pit l>eing iinely corroded and nodular. On the 
 same surface numerous small nodules are scattered about. On 
 
 Fig. 189. 
 
 the neck the hyperplastic cementum is one millimeter in thick- 
 ness, and terminates all around it in a nearly abrupt line. (Fig. 
 189, a.) 
 
 " On a right upper second molar the palatal root exhibits at 
 its apex a cauliflower-like excrescence, upon a comparatively 
 smooth osteoma, about one millimeter in thickness, occupying 
 the upper two-thirds of the root. The excrescence sends a deli- 
 cate conical offshoot to the mass which cements the buccal roots 
 together. The posterior portion of the crown of this tooth has 
 a carious cavity in it the size of a French pea, with the pulp- 
 chamber opened. (Fig. 189, b.) 
 
 " Roots of this kind look very clumsy and shortened, for the 
 reason that at the place of their union the hyperostosis forms a 
 heavier mass, which has more or less filled the space between 
 them; still, they remain separate to a consideralde extent.
 
 HYPEROSTOSIS OF ROOTS OF TEETH. 
 
 335 
 
 "III. Diffused Hyperostosis with Roots United.— Tliis group 
 mav be subdivided as follows : 
 
 "A. Apices free and straight ; 
 
 " B. Apices free and curved : 
 
 "C. All roots united their entire lengtb. 
 
 " Teeth of the group A are characterized by an osseous out- 
 growth of eementuni uccunudating at the point of junction of 
 the roots, — the roots themselves being either slender and free 
 from osteoma or slightly thickened. An upper wisdom-tooth 
 presenting this anomaly has live roots, three of which are nor- 
 mal at their apices, the fourth being the seat of a difiused hyper- 
 ostosis encircling it, and the fifth root being rudimentary. All, 
 however, are united into a common mass a short distance from 
 their apices, which mass gradually blends with the enamel. 
 (Fig. 190, a.) 
 
 Fig. 191. 
 
 " Teeth of the group B exhibit a union of the roots with 
 markedly devious but slender apices. A left upper second 
 molar of my collection shows this evidently rare anomaly. The 
 palatal root is slightly devious, with an apex arising from the 
 main mass of the root at a right angle. The buccal root (there 
 is but one) shows two curvatures, both at right angles. The 
 osteoma is only moderately large, and on the posterior surface, 
 at the point of junction of the roots, there is -wedged in a sessile 
 oblong nodule, below which is a shallow furrow, indicating the 
 •original point of separation of the two roots. The crown of 
 this tooth is not decayed. (Fig. 190, h.) 
 
 " Teeth of the group C are rather common. In third molars 
 or wisdom-teeth, of both the upper and lower jaws, a union of 
 the roots is quite generally the normal condition. Osteoma, 
 when found upon such roots, is either a clumsy nodular mass
 
 386 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 without any sign of a previous separation, or slight furrows may 
 be visible indicative of such separation of the roots. (Fig. 
 190, c.) 
 
 " Connected with a lower left wisdom-tooth in my collection 
 there is a history that I will give in abstract, feeling that it may 
 be of interest to some who may hear or read it. This tooth 
 exhibits a diiiused osteoma, ridged and nodulated, with a bent 
 apex toward the ramus. It was extracted from the mouth of a 
 lady some years since by my friend. Dr. S. A. Main, of this city, 
 who kindly presented it to me with the following history : For 
 some ten years this lady had suffered most excruciatingly from 
 facial neuralgia. She consulted the best medical talent at home 
 without obtaining the slightest relief. Finally, some three years 
 before the tooth was removed, she went to London, where it 
 was determined by the surgeon who was called to attend her 
 that, in order to afford any relief, it would be necessary to sever 
 the facial nerve upon the side which seemed the most affected, 
 which operation was done, — with, however, only temporary 
 relief. With the hope that the slight cessation of pain would 
 be speedily followed by permanent cure, she went to Paris, 
 anticipating the pleasure of a comfortable tour of the Conti- 
 nent. In a few days the pain returned with renewed energy. 
 In Paris she consulted a surgeon, who decided that the only 
 chance for permanent relief was to have the facial nerve divided 
 upon the other side of the face. The operation was performed 
 with no better results than from the first. Finally she con- 
 cluded to return to her home in New York, there to spend the 
 few days (as she supposed) which she had to live as comfortably 
 as possible. Shortlj- after arriving at her home she consulted 
 her dentist (whom, by the way, she had never thought to con- 
 sult before in reference to her neuralgia), and asked him to look 
 at this tooth, saying at the same time that it often felt quite sore 
 to the touch. (Its antagonist had been taken out many years 
 before.) After examination, she was advised to have it ex- 
 tracted, which was done. Immediately upon its removal the 
 lady realized that the cause of her long-continued, fearfully dis- 
 tressing, and very expensive neuralgia had been found at last, as 
 time proved. 
 
 "IV. Union of Two Teeth through Hyperostosis. — Of this 
 rare occurrence of the osseous union of teeth I have some eight 
 fine specimens. The subdivision suggesting itself is as follows :
 
 HYPEROSTOSIS OF ROOTS OF TEETH. 
 
 337 
 
 " A. Union of the roots at their apices (Fig. 191, a, b); 
 
 " B. Union of the roots at their middle (Fig. 192, a, b); 
 
 •' C. Complete union of the roots (Fig. 192, e). 
 
 '' The first group is characterized by a union of devious roots 
 of neighboring teeth. As both of my specimens show a partial 
 carious destruction of their crowns, the idea may suggest itself 
 that, owing to a destruction of the intervening alveolar wall, 
 and owing to gravitation, the roots became attached to each 
 other through an inflammatory process. At the same time 
 serious objections may be raised against such a view. The main 
 ohjection is that an inflammation of the pericementum sufli- 
 ciontly intense to destroy the alveolus would be very liable to 
 destro} the pericementum itself, to such a degree as to render 
 (juite impossible the secondary new formation of cementum 
 necessary for agglutination of the neighboring roots. Should 
 we assume that tl;ie septum was originally absent, the only way 
 
 of explaining such formations is to suppose that at least one of 
 the germs of the coalesced teeth was malposed at the time of 
 the embrj'onic arrangement. In this view, it will be observed, 
 the alveolar septum did not form at all, and at the time of de- 
 velopment of the roots the mutual pressure was sufficient to 
 cause irritation leading to a new formation. I conclude, there- 
 fore, that the carious destruction of the crowns was merely a 
 coincidence rather than a cause (Fig. 191, a). The roots of one 
 tooth are mere stumps left after carious destruction of the crown 
 and a portion of the roots. Here the hyperplastic cementum 
 of the stumps is jagged and nodular, plainly indicating that the 
 already formed outgrowth of cementum has been destroyed by 
 cementitis in rather a secondary manner. (Fig. 191, b.) 
 
 " Group B shows a concretion of neighboring roots of molars 
 at the middle, upon one side, and at the apices upon the other. 
 (Fig. 192, a.) One of the crowns is slightly aft'ected by caries, 
 
 23
 
 338 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 — by no means, however, to sucli a degree as to account for 
 agglutination of the two teeth, the enlarged cementum of which 
 is mainly smooth. Fig. 192, h, represents two molars grown 
 together nearly the entire length of their roots: both teeth 
 being otherwise sound. One of them shows at its neck an 
 '■ enamel-drop," which feature I consider a further proof of 
 embryonal malformation of such teeth. Some exostoses from 
 the sockets are attached to the roots, which fact, in my judg- 
 ment, proves merely a secondary hyperplastic pericementitis. 
 
 " Group C is represented by but one specimen, — that of an 
 upper cuspid united with a neighboring lateral incisor. This 
 seems to be a case which may be considered an exception to the 
 rule, — viz, that only bicuspids and molars are thus affected. In 
 this case the union is perfect the entire length of the roots, and 
 only shallow farrows on the outer and inner surfaces, reaching 
 nearly to a common apex, indicate the previous separation. 
 The apex presents but one large common foramen. At the 
 necks of both teeth there is shallow carious destruction, — not, 
 however, exposing the pulp-chambers. All these features fur- 
 nish us proof of a foetal malformation. 
 
 " For the purpose of examining this disease microscopically, 
 I have ground quite a large number of specimens from teeth 
 which at the time of extraction were immediately placed in 
 dilute alcohol, in order to keep them constantly wet, and to pre- 
 serve their soft parts. During the process of grinding they 
 were also kept under water. All specimens showed in common 
 a number of features which are represented with a compara- 
 tively low power in Fig. 193. Those to which I wish to call 
 attention are as follows : 
 
 " The dentine in some specimens, perhaps in several localities 
 in the same specimen, was found in a normal condition; and in 
 others it exhibited the so-called interglobular spaces, greatly 
 varying in size and number, indicative of an incomplete calcifi- 
 cation. 
 
 " In some specimens the dentinal canaliculi of the root were 
 arranged in bundles, between which were found areas scantil}^ 
 provided with canaliculi or altogether destitute of them. In 
 these areas are often seen small interglobular spaces, sometimes 
 in direct union with a few canaliculi. 
 
 " The interzonal layer between dentine and cementum invari- 
 ablv exhibited formations known under the name of osteo-den-
 
 HYPEROSTOSIS OF ROOTS OF TEETH. 
 
 339 
 
 tine, or globular deiitiiiG, either as the result of ' eburnitis ' or 
 of incomplete calciiicatiou. It is a condition kindred to that 
 which characterizes the interglobular spaces of Czermak. Such 
 formations, as a rule, extend into the neck of a tooth, — where, 
 liowever, they are more scanty than on the roots. A striking 
 feature is their entire absence at the point of junction of the 
 roots. Here the cementum is found in contact with an irregular 
 formation of dentine (vaso-dentine), which will be described 
 farther on. Wcdl seems to lia\'e been the first to illustrate this 
 formation, — without, however, making an allusion to it in his 
 text. 
 
 Fig. 193. 
 
 
 
 
 
 I '-^ 
 
 -^^ 
 
 l>S^)^y\\\ 
 
 
 ;-^.-^r\;afc 
 
 lillliia 
 
 
 i\ \\H..V. 
 
 '.A;i;»«^i 
 
 Hyi'EKI'lastic Cemkxtum slightly isuloixg TO'n-ARD THE Neck of the Tooth ( Upper 
 Bicuspid). Longitudinal Section. 
 
 Z), dentine; iV, neck : /-", pericementum; 0, globular or osteo-dentine ; 6^, granular layer; 
 //, hyperplastic cementum irregularly lamollated, with irregularly-distributed cement-cor- 
 puscles: .1/, medullary canal. Magnified 150 diameters. 
 
 " ISText to the layer of osteo-dentine invariably a layer is found 
 which, under lower powers of the microscope, looks coarsely 
 granular, and which in consequence I propose to call the granu- 
 lar layer. It is destitute of cement-corpuscles, and, as a rule, is 
 the only layer comprising the cementum of the neck of the tooth, 
 whenever this gradually slopes from the hyperplastic cementum 
 to the enamel. jSText follows the enlarged cementum itself, 
 usually characterized by a large number of irregular lamellae
 
 340 THE AXATOMY AND PATHOLOGY OF THE TEETH. 
 
 more or less concentric to the axis of the root. Some areas may 
 be found destitute of lamelhie; others very richly supplied with 
 them. At the border of the cementum toward the crown, 
 where the former often bulges to a considerable extent, the 
 laraellse are found parallel with the outer periphery of the ce- 
 mentum inosculating with the granular layer at obtuse angles. 
 
 " In thelamellated basis-substance are found scattered cement- 
 corpuscles. The most striking features of these corpuscles are as 
 follows : First, they are far more irregularly distributed in the 
 basis-substance than in normal cementum. In some portions of 
 the hyperplastic cementum such corf»uscles are comparatively 
 few, whether the lamellae be plaiidy marked or not; in other 
 portions they are arranged in groups or clusters apparently with- 
 out any regularity. Second, the cement-corpuscles, as a rule, 
 are smallest near the granular layer, and largest toward the 
 periphery; at the latter boundary their oifshoots are much wider, 
 and more irregular, often piercing the lamelloe rectangularly. 
 J^o constant relation between lamelhe and cement-corpuscles is 
 to be found. Third, occasionally the cement-corpuscles are to be 
 seen in large numbervs clustered together in longitudinal groups. 
 This is probably caused by the previous presence of medullary 
 canals, the tissue of which, at a comparatively late period, has 
 given rise to a large number of cement-corpuscles, and a com- 
 paratively small amount of basis-substance between them. 
 
 " The hyperplastic cementum is often traversed by medullary 
 canals carrying central blood-vessels. These are most numerous- 
 at or near the point of junction of the roots, w^here, as first de- 
 scribed by Tomes, even normal cementum may sometimes con- 
 tain medullary canals. The vessels of these medullary canals, 
 also tirst described by Tomes, with whom I am pleased to agree, 
 are in direct connection, and anastomose with the blood-vessels 
 of the pericementum. In one of my specimens the cementum 
 of the ne'^k exhibits peculiar features. Instead of the coarsely- 
 granular hiyer usually present, and previously alluded to, there 
 is a zone traversed nearly at right angles by bundles of canali- 
 cnli, very broad and in no connection a\ hatever with cement- 
 corpuscles. Aliove this zone lies the ordinary granular zone,, 
 bordered toward the dentine by a thin layer of globular den- 
 tine; then follows the tinely-granular layer of the dentine itself, 
 with very few or no canaliculi, and at last we come to the canali-^ 
 culated dentine of normal development. (Fig. 194.)
 
 HYPEROSTOSIS OF ROOTS OF TEETH. 
 
 341 
 
 " High amplifications plainly reveal the structure of the inter- 
 z(^nal layer between dentine and hyperplastic cementum. The 
 dentine often shows interglobular spaces, which as a rule are 
 filled with granular protoplasm, and serve as the termination of 
 some dentinal canalieuli; especially for their tenants, the fibers 
 of living matter. The interglobular spaces nearest to the 
 cementum sometimes directly inosculate with the interstices 
 between the globular masses of calcified basis-substance, consti- 
 tuting the tissue termed osteo-dentine or globular dentine. The 
 
 Fig. 194. 
 
 mm- 
 
 '-(m 
 
 m G 
 
 Hypkri'lastic Cemen'tum of the Neck of a Molar. Longitudinal Section. 
 N, zone of coarsely-granulated cementum, traversed by bundles of coarse canalieuli: G. 
 granular zone, destitute of canalieuli ; O, zone of globular dentine ; D, dentine with canalieuli 
 stopped short of the cementum. Magnified 500 diameters. 
 
 globules themselves vary greatly in size. They usually, how- 
 ever, correspond with the bulk of one or a limited number of 
 medullary corpuscles present before their transformation into 
 basis-sul)stance. The interstices between the globules also vary 
 in size, and send oft'shoots into the larger globules, subdividing 
 them into incomplete smaller ones. All of them contain granu- 
 lar protoplasm. In the granular zone following the layer of 
 osteo-dentine we sometimes meet with very large and irregular 
 interglobular spaces, apparently in no direct connection with
 
 342 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 the offshoots of cement-corpuscles. In several specimens I have 
 seen arising from the cement-corpuscles very long and slightly 
 wavy offshoots, which, owing to their parallel course, bear a 
 close resemblance to dentinal canaliculi. Formations of this 
 
 Fig. 195. 
 
 Interzonal Layer uetween Dentine and Hyperplastic Cementum of a Molar. 
 Longitudinal Section. 
 
 y^ dentine with small interglobular spaces: 0, osteo-dentine, above which, in the granular 
 layer (?, there is a large irregular interglobular space ; 0, C, cement-corpuscles with long parallel 
 offshoots. Magnified 600 diameters. 
 
 kind occur only in those layers of hyperplastic cementum near- 
 est the dentine, and always lose themselves in the granular layer 
 above the osteo-dentine without directly communicating with 
 the dentinal canaliculi proper. (Fig. 195.) The medullary
 
 IIYPERUSTOSIS (IF HiioTS OF TF^ETH. 
 
 343 
 
 ciinals traversing the enlarged t-enientuni either contain medul- 
 lary corpuscles and capillary blood-vessels, or tliey are tilled with 
 highly-refracting granules and globules of linu'-salts, as described 
 l)y Wedl. Should their canals become obliterated, they give 
 rise to groups of cement-corpuscles between a scantily-calcified 
 basis-substance. 
 
 " At the point of junction of the enlarged roots in several of 
 ray specimens I have met with a peculiar formation of dentine, 
 and as it contains a large number of vascular canals, I propose 
 to term it vaso-dentine. To the naked eye, in the pirepared 
 
 Fro. 19fi. 
 
 \ Ji|ifj|!|^pj^ ) « 
 
 m 
 
 
 
 
 V-U 
 
 -^lakaL 1 >Sb^ ^ 
 
 
 mmi^m 
 
 luv.Bi 'a!.M(i«.^ll:... 
 
 Vaso-Denti.ve from the Junction of the Enlarged Roots op an Upper Molar. 
 Longitudinal Section. 
 
 D, primary dentine; V-D, vaso-dentine traversed by medullary canals in a plexiform 
 arrangement, — the canals contain either blood-vessels or glistening depositions of lime-salts; 
 B, basis-substance of dentine scantily provided with extremely delicate canalieiili, and in 
 some places fan- and fountain-shaped figures of dentinal canaliculi discernible; C, hyperplas- 
 tic cementum lamellatod, and containing a medullary canal. Magnified 50 diameters. 
 
 specimen, a high degree of transparency in the vaso-dentine at 
 once distinguislies it from the neighboring opaque portions of 
 normal dentine, and from cementum. Low powers of the 
 microscope reveal in this dentine a varying number of medul- 
 lary canals, either in a [larallel or plexiform arrangement. The 
 canaliculi contain medullary tissue and capillary blood-vessels, 
 one or two in each canal. Sometimes glistening granules ot 
 lime-salts are found, more especially in dilated portions of the
 
 344 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 canals. Oifshoots of such canals may inosculate wiih very naiv 
 row canals containing granular protoplasm only. The surround- 
 ing basis-substance is scantily supplied with extremely fine cana- 
 liculi, running, without any apparent regularity, in fan-shaped 
 groups, or parallel with the medullary canals, or in the shape of 
 a fountain, encircling the canals in the most beautiful and 
 striking figures. Some portions of the basis-substance may 
 look granular and devoid of canaliculi ; others (and these 
 formed a vast majority) are apparently homogeneous, and scan- 
 tily supplied with extremely minute canaliculi. The ceinentum 
 is directl}' on the border of the vaso-dentiue, without any inter- 
 vening layer of granular dentine, and the cement-corpuscles 
 nearest to the dentine are in direct connection with the dentinal 
 canaliculi themselves. (Fig. 196.) Higher powers of the mi- 
 croscope brought to bear upon the vaso-dentine plainly show 
 the medullary contents of the medullary canals, in which may 
 also be seen one or two capillary blood-vessels. Both the 
 canals and blood-vessels produce loops, as is indicated by their 
 abrupt terminations in vertical sections, and are unquestionably 
 in communication with the blood-vessels of the pericementum 
 (Tomes). A peculiar feature of the vaso-dentine is that por- 
 tions freely supplied with vascular canals contain a consideral>ly 
 larger number of dentinal canaliculi than those devoid of vas- 
 cular canals. 
 
 " The canaliculi in the neighborhood of the vascular canals 
 are very irregular in their course, as before stated, and often 
 loop-shaped, starting from and inosculating with the same vas- 
 cular canal. Again, we find them starting from club-, pear-, 
 spindle-, and irregular-shaped spaces, containing medullar}' cor- 
 puscles, or granular ])rotoplasm, but no blood-vessels. (Fig. 
 197.) I would mention that in all my specimens, as an addi- 
 tional feature of hyperostosis of the roots, the pulp-chamber 
 and often the canals appear considL-rably narrowed by heavy 
 formations of secondary dentine. Besides, the }»ulp-tissue was 
 found to contain formations of secondary dentine known as 
 pulp-stones, or to be crowded with globular calcareous deposi- 
 tions of no definite structure. In the majority of the teeth the 
 enamel also was imperfectly formed, it generally i)resenting a 
 highl^'-pigmented and imperfectly-calcified condition, with 
 enamel-rods very irregular and curly. 
 
 " A striking feature in all microscopical specimens of hyper-
 
 HYPEROSTOSIS OF ROOTS OF TEETH. 
 
 345 
 
 plastic cementum is the great number and large size of the oft- 
 shoots of the cement-corpuscles, the canaliculi, previously so 
 called. The reason for this seems to be that both the corpuscles 
 
 Fio. ]9; 
 
 V-D 
 
 B-n 
 
 VaSO-Den TINE FROM THE PoiNT OF JUNCTION OF THE ENLARGED RoOT OF AN UpPER 
 
 Bicuspid. Longitudinal Section. 
 
 V-D, a porti' n of vaso-dentine with three parallel vascular canals, and very irregular, often 
 looped, canaliuuli, some starting from the vascular canals and others from smaller medullary 
 spaces: B-I), dentine of great transparency, with scanty canaliculi. The boundary line be- 
 tween the two portions is abrupt, with numerous bay-like excavations. Magnified 5i}0 diam- 
 eters. 
 
 (lacunte) and their coarser offshoots (canaliculi) are filled with 
 air, or dirt from the grinding, which causes them to look black.
 
 346 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 If, however, we place a carefully but not completely decalcified 
 portion of this tissue, mounted in glycerin, under a very high 
 power, we are struck w^ith its beautiful and graceful appearance. 
 It is identical in structure with that of normal cementum. The 
 basis-substance forms cavities that contain nucleated protoplas- 
 mic bodies, the cement-corpuscles proper, of a markedly reticu- 
 lated structure. 
 
 "Between the periphery of the cement-corpuscles and that 
 of the lacuna there is a narrow light rim, obviously correspond- 
 ing to a space that serves for the circulation of the nutritive 
 liquids. The lacuna at its periphery is interrupted by numerous 
 
 Fig. 198. 
 
 UJ L-i i-//* A 
 
 Hyperplastic Cemestu.m op an Upper Molar. Cross Section. 
 Magnified 1500 diameters. 
 
 offshoots, wider and more irregular than those of normal ce- 
 mentum. These canaliculi form an extremely delicate reticulum 
 throughout the basis-substance, interconnecting the neighboring 
 lacunse (indeed, all lacunae) of the cementum. 
 
 " Starting from the periphery of the cement-corpuscles, coni- 
 cal otfshoots run into the canaliculi ; the broader, of course, the 
 wider the canaliculus. The coarsest offshoots still exhibit a 
 reticular structure ; whereas the finest are merely beaded threads 
 occupying the middle of the canaliculi. Thus it will be seen 
 that all canaliculi hold filaments of livin": matter in a cobweb
 
 HYPEROSTOSIS OF ROOTS OF TEETH. 347 
 
 arrangement, and thus it becomes [)lain that liyperplastic as well 
 as normal cementum is a living tissue throughout. The reticular 
 structure of the living matter in the corpuscle itseU" is plainly)- 
 visible. The inert basis-substance, iniiltrated at the same time 
 with lime-salts, is located in the meshes of the reticulum of the 
 eanaliculi, and between the basis-substance and filaments of liv- 
 ing matter a slow circulation is going on, the liquid carrying 
 nourishment and taking away the effete material. (Fig. 198.) 
 Thus it is that pathological changes of a pathological tissue 
 become intelligible, and cementitis of hyperplastic cementum, 
 as described and illustrated by Wedl, under the term ' perforating 
 resorption,' is understood. 
 
 " Macroscopically I have already described this condition. 
 Under the microscope it is characterized by the presence of 
 cavities filled with medullary corpuscles, or multinuclear proto- 
 plasmic masses, and bounded toward the unchanged cementum 
 with numerous bay-like excavations. The destruction may 
 iiuolve superficial portions of the tumor only, or the entire 
 mass down to the dentine. As there is little tendency to suppura- 
 tive pericementitis, the termination of the inflammatory process 
 undoubtedly results often in a re-formation of cementum, the 
 same as takes place duiing the process of absorption of the 
 roots of temporary teeth. Under these circumstances the bay- 
 like excavations are refilled with bone-tissue, and the bays are 
 recognizable by sharply-defined lines corresponding to the terri- 
 tories of the cement-corpuscles. Some of my specimens ex- 
 hibit bay-like excavations directly separating the cementum 
 from the dentine, and the bays filled with bone-tissue crowded 
 with cement-corpuscles. In other specimens certain portions of 
 the hyperplastic cementum sliow distinct circular, semicircular, 
 or crescentic lines corresponding to the territory of one or more 
 cement-corpuscles."
 
 348 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 CHAPTER XXXL 
 
 INFLAMMATION.* 
 
 " It is the gift of genius to foresee discoveries even for cen- 
 turies. Such a genius was John Hunter, of London, who 
 toward the end of the last century, merely upon the ground of 
 speculation and ratiocination, made the assertion that inflam- 
 mation is none other than a return of the tissues to embryonic 
 condition. And our present knowledg-e of the process of in- 
 flammation and suppuration is a strong proof, supported b}' 
 careful researches of good pathologists of Germany and Eng- 
 land, that Hunter's theory was the correct one. 
 
 " Since microscopy became a science (a period covered by 
 half a century) the views concerning the intimate nature of the 
 inflammatory process have been greatly at variance. These 
 views largely depend upon the general ground taken by pathol- 
 ogists in reference to the pathological processes at large. We 
 have three marked phases in the development of pathology 
 within the last iifty years. The first is the standard of humoral 
 pathology jiromulgated by the late C. Rokitansky, of Vienna. 
 The second is the phase of cellular pathology established mainly 
 by R. Virchow, of Berlin. The third phase, still in vogue with 
 many pathologists, is the doctrine of emigration of colorless 
 blood-corpuscles or leucocytes, as propounded by the late I. 
 Colin heim, of Leipsic. 
 
 " During the past five years bacteriology has held sway of 
 the minds of the majority of the pathologists, proving what was 
 just stated. To-day no one will be rash enough to neglect the 
 influence of bacteria in producing suppuration. And have we 
 not learned through excellent observers that it is not the micro- 
 organisms themselves, but rather their chemical products, the 
 ptomaines, that play the important role in the causation of sup- 
 puration and possibly of inflammation ? I here allude to the 
 researches of Leber, of Gottingen, who maintains that it is a 
 ptomaine, called by him phhr/estein, that stands in causal relation 
 to inflammation. 
 
 " The task I have undertaken is to review the theories held 
 
 * Much of this chapter is hased upon the investigations of Wm. H. Atkinson : 
 
 "The Origin of Pus," Jcnn^nal of the A^ner lean Medical Association, 1889.
 
 INFLAMMATION. 3-1:9 
 
 ill the last fifty years, closing the historical remarks witli a 
 • lescription of what I consider to be the truth to-day. The 
 review of such a liistory is instructive in many respects. It 
 teaches us that no one, be he of the most gifted talent, is al)le 
 to emanci})ate himself from preconceived ideas and accepted 
 notions. It furthermore teaches us that we are the subjects of 
 general theories extant at the time in which we make our 
 investigations. It teaches the great lesson of modesty and 
 humility. If a man of my age must confess in the seventh 
 decade of his career that he has been misled in his younger 
 days by books and teachers and must try hard to unlearn what 
 he thought he knew before, it is certainly testimony of human 
 fradty, and goes far to prove that wc are obliged to consider 
 the truth to be truth only^^ro tempore, — viz, so long as we do not 
 know l)cttcr. 
 
 '• 111 the fifth decade of our century humoral pathology was 
 thought to hold the full truth in the explanation of inflamma- 
 tion. The older of us will remember what facts the humoral 
 l>atliology was based upon. The web of the foot of a living 
 frog was expanded over a cork ring and ihe web touched with 
 an irritating agent, such as a droplet of ammonia, an acid, or 
 with a pointed, red-hot iron, and the subsequent changes 
 observed under the microscope with the comparatively low 
 powers at the disposal of investigators of the time. They saw 
 around the irritated portion of the web an undulation of the 
 currents of the blood within the vessels, shortly afterward a 
 slacking of the current, and still later a standstill of the stream. 
 The last phenomenon they called ' stasis,' and this stasis was 
 thought to be the essential feature of the inflammatory process. 
 Many and animated controversies arose over the question, What 
 is the stasis due to? Most observers agreed that a paralysis of 
 the capillary blood-vessels, after a few preceding contractions, 
 was to 1)C considered the cause of stagnation. At the same 
 time an inundation was seen to take place in the afiected tissues 
 with a liipiid which of necessity must have come from the 
 general blood-column, and Avas termed ' exudate.' According 
 to the nature of the exudate different varieties of inflammation 
 were set up, such as the ' serous," the ' fibrinous," the ' albumin- 
 ous," and should l)lood have been admixed with the exudate, the 
 ' hfemorrhagic." Corpuscular elements seen in the affected terri- 
 tories and apparently suspended in the exiKfafc were thought to
 
 350 THE AXATOMY AND PATHOLOGY OF THE TEETH. 
 
 have originated from the exudate itself: therefore the pus-cor- 
 puscles would have originated from the exudate, the latter from 
 the blood, hence the definition of pus, ' dead blood.' Xo stress 
 was laid upon the structural changes of the affected tissue itself, 
 except so far as the exudate saturating this tissue was concerned. 
 The ultimate cause of inflammation and suppuration was sought 
 in chemical mixtures of the blood, termed djscrasia, which 
 means bad mixture of the blood. If a person became afl:ected 
 with lobar pneumonia the cause surely was surplus of fibrin in 
 the blood, or fil)rinous dyscrasia. If a person produced a num- 
 ber of abscesses in his organism, the cause was denominated 
 purulent dyscrasia. All diseases Avere, in this dyscrasic view, 
 essentially diseases of the blood. The l)lood in its mixture 
 caused the diseases simply by being overloaded with obnoxious 
 or efiete material. 
 
 " The man who dug the grave of humoral pathology was 
 Virchow, in the beginning of the sixth decade of the present 
 century. To him the phenomena of alterations in the circula- 
 tion of the blood were of secondary importance. The stasis 
 he would not admit as a cardinal symptom of inflammalion, for 
 it would mean rather death of the tissue, gangrene or necrosis. 
 The exudate also played but a secondary role, serving only as 
 a paljulum to tlie living corpuscular elements of the tissues, the 
 so-called cells. Inflammation was, in Virehow"s opinion, a 
 structural cliange of the affected tissue, mainly morphological 
 changes of the cells themselves. The cells being the seats of 
 life, would attract and, as it were, imbibe the exudate, swell up, 
 divide and come to a state of proliferation, in which a number 
 of cells would arise from an oriij:inal sino-le cell, and the laro^e 
 number of newly-formed cells would replace the intercellular 
 substance lost l)y liquefaction. A formation of cells out of a 
 previcms liquid or semi-solid exudate was declared to be impos- 
 sible, since all newly formed cells must have arisen from pre- 
 existing cells. Dyserasias were done away with. The main 
 causes of inflammation were peculiarities of the tissue itself, 
 and a certain weakness of the tissue was i^roposed to explain 
 the predisposition to inflammatory processes. The word sug- 
 gested for this supposed local weakness of the tissue was 
 * diathesis." If a man suffered from articular rheumatism, the 
 cause was said to be ' rheumatic diathesis.' Tuberculous persons 
 were predisposed to cheesy degeneration simply because they
 
 INFLAMMATION. 
 
 351 
 
 were afflieted with (dberealous diathesis. In the same sense 
 heniorrhagic and purulent diatheses were spoken of. The pus- 
 cori)Useles were witliout excejition an ottspring of tlie previous 
 eells (»f tlie tissue, and in this sense pus was considered dead 
 tissue. Celhilar pathology has made a very strong impression 
 
 Fig. 199. 
 
 l)IA(;l{.\.M (IK THK Im I.A.MMATdHY CHANGKS OK CONNECTIVE TiSSlE. CkLI,-1' HOI, IKK K A" 
 TION ACCOUniNCJ TO II. ViRCHOW (1852). 
 
 A, intlnmmatory chnna>-x of rclini/ar cartilage. — a, division of the nucleus of the cartilage- 
 cell ; /', division of the cell into a number of cells ; c, proliferation of cells,— the intercellular 
 substance gradually liquefied. B, iiijluminntor!/ chanpes of fibrous connective tissue. — a, divi- 
 sion of the connective-tissue cell ; b, further advanced division of the connective-tissue cell ; c, 
 high degree of division and proliferation,— the fibrous intercellular substance gradually lique- 
 fied. 
 
 on the minds of ol^servers. Even the stalwart humoral pathol- 
 ogist Kokitanskv yielded to the novel views, and accepted the 
 <loetrine that no cell will grow in an exudate unless previous 
 cells he there. Cellular pathology even in our day governs the 
 minds of most pathologists over the civilized world. Prolifera-
 
 352 THE ANATOMY AND TATHOLOGY OF THE TEETH. 
 
 tion of the cells accounts for all tissue-changes, either neuly 
 formative, the so-called hyperplasia, or destructive, that is, sup- 
 puration. Proliferated cells being present in either of these 
 instances, cellular pathology is at a loss to explain why a certain 
 tissue, owing to proliferation of its cells, becomes augmented 
 and hyperplastic in one instance and is destroyed by suppuration 
 in the other. Still, in spite of all weaknesses of this doctrine, 
 we must consider it an advance in comparison with the teach- 
 ings of humoral pathology. The cell being supposed to be the 
 only center of life, inflammation and suppuration were for the 
 lirst time < onsidered as the phenomena of life, and the idea 
 began to dawn in the minds of pathologists that inflammation 
 and suppuration were morbid processes occurring in tissue- 
 elements endowed with life, the so-called cells. (See Fig. 
 199.) 
 
 " The third period arose in the middle of the seventh decade 
 of our century, when Cohnheim observed a migration of color- 
 less blood-corpuscles through the walls of the capillaries and 
 small veins of an exposed and expanded meseutery of a frog. 
 Several years before S. Str'cker, in Vienna, observed the red 
 corpuscles pass through the walls of the capillaries of the nicti- 
 tant membranes of the live frog, so-called diapedesis. Even in 
 1848 the emigration of leuco(ytes had been seen in England by 
 Walker and Wallace. The facility with which the emigration 
 of leucocytes could be seen under the microscope has induced 
 many German pathologists to accept the view of CohnliLim, 
 that inflammation and suppurati"n are but an emigration of 
 colorless blood-corjiuscles. These accumulating in a tissue 
 whose cells would remain inert and whose intercellular sub- 
 stance would become liquefied and destroyed, furnish a repre- 
 sentation of boih inflamn)ation and suppuration. With this 
 view there was nothing alive in the body but the leucocytes. 
 At first Cohnheim denied the participation of the so-called 
 stable cells in the process of inflammation, but later he admitted 
 that in rep;irative inflammation the tissue-cells do proliferate 
 and furnif^h their share for the benefit of newly-forming tissue, 
 exactly in the sense of cellular pathology. That pus-corpuscles 
 should be emigra'ed colorless blood-corpuscles was intelligible, 
 as isolated corpuscles were nearly identical in appearance. How 
 new tissue could form from leucocytes remained a deeply- 
 shrouded mystery, as no obser\ation has as yet proved that
 
 INFLAxMMATION. 353 
 
 tIiri)Uf;;h coalescence of leucocytes new protoplasmic masses and 
 new tissues can arise. The observation of Ziegler, of Tiibingen, 
 tliat multinuclear bodies, so-called giant-cells, are visible between 
 thin glass plates introduced under the skin of an animal, lacks 
 the proof that such giant-cells arose by coalescence of leuco- 
 cytes. On the contrary, later observations made especially upon 
 deciduous, replanted, and implanted teeth, go far in proving the 
 giant-cells to l)e an oft'spring of the myxomatous granulation- 
 tissue, sprouting in all directions, tilling the bay-like excavations 
 on the deciduous and other teeth and carrying blood-vessels into 
 l)lac'es where there had been none before, leading to the vascular- 
 ization of a new tissue, — seen, for instance, in sponge-grafting. 
 '' S. Strieker immediately sought to overthrow the teachings 
 of Cohnheim. In his investigations he used almost exclusively 
 the cornea (chiefly of frogs, cats, and rabbits), in which he in- 
 duced inHammat'on by introducing a thread. The changes 
 were faithfully watched up to the formation of abscess around 
 the foreign body. The observations enabled him to prove the 
 established views of cellular pathology to be correct, — namely, 
 that these so-called cells divide and subdivide, but also that the 
 coarser otl'shoots of the cornea-corpuscles split up, and by divi- 
 sion produce new corpuscular elements. Strieker also held, up 
 to 1874 (Ashhurst's International Surgical Cyclopedia), that 
 pus-corpuscles were products of proliferation of the cornea- 
 corpuscles and their coarser otl'shoots. Unfortunately, he called 
 all the products of cells originating from proliferation of pre- 
 vious cells pus-corpuscles. Indeed, it was impossible to dis- 
 criminate between intlammatory corpuscles and pus-corpuscles, 
 since all of these appeared isolated under the microscope. 
 Clinically it is well established that every inflammation does 
 not terminate iu suppuration. Particularly do we know of a 
 termination which instead of causing destruction of an affected 
 tissue, as suppuration does, brings about a new formation, an 
 increase of the bulk of the tissue, — the so-called hyperplasia. 
 How shall we explain such marked differences by the theory of 
 cellular pathology, which claims that all corpuscular elements 
 are isolated from the starts However, since 1880 Strieker has 
 been a convert to the views of C. Ileitzmann, established in 
 1873, which doctrine I advocate, having studied specimens, 
 illustrative of inflammation and suppuration, under the micro- 
 sco[)e in that investigator's laboratory. 
 
 24
 
 354 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 " Recent researches of botanists go far to prove that even in 
 the plants there exist no individual cells, hut that the interven- 
 ing cement-substance, or cellulose, is traversed by minute 
 bridges of living matter, rendering the plant an individual from 
 the tips of the leaves to the sporacles of the rootlets. Eecent 
 observers in animal and vegetable microscoj:)}" have drawn atten- 
 tion to the fact that by means of certain reagents the nucleus 
 will be split up into loop-like threads, a process which they 
 consider precedes the division of the nucleus and indirect divi- 
 sion of the protoplasm. This process is termed karyokinesis, 
 or mitosis, — ' iibrillation,' ' thread-making.' This observation is 
 had only with certain reagents, and is not visible in the fresh 
 specimen or in one preserved in a chromic-acid solution. Sus- 
 picion naturally arises that tlie loop-like tigures of the nucleus 
 are artiticially produced, and thereby their connections are ren- 
 dered invisil)le. The threads forming the loops are called 
 ' chromatin,' l)ecause they are readily stained by aniline dyes, 
 whereas the intervening substance and the protoplasm itself 
 stain but little, and therefore are ' achromatin.' Facts ren- 
 dered conspicuous by staining applications only are of doubt- 
 ful correctness. The fact that there are threads and loops in 
 the star-point form arrangement in the nucleus rather proves 
 the latter to be made up largely of living matter, which is 
 known to change shape any moment. Coarse formations of 
 living matter readily stain witli aniline dyes, whereas delicate 
 formations of the same sul)stance will not stain. The connec- 
 tions between the loops of the nucleus and the surrounding 
 radiating reticulum of the protoplasm are plainly visible in 
 fresh specimens, and also those preserved in licpiids which we 
 know will not alter the structure of protoplasm, such as a solu- 
 tion of chromic acid of one-tenth to one-half of one per cent. 
 Alcohol as a preserving iluid is far inferior, owing to the shrink- 
 age it effects. 
 
 '* Whenever irritation is brought to bear upon a living tissue 
 reaction will follow, and this is an inflammatory process. The 
 first step is li((UL'faction of the basis- or cement-substance, 
 probably induced l)y the presence of an acid, likely lactic. 
 Thus the living matter previously concealed (held) in the basis- 
 or cement-substance becomes lil)erated, and the protoplasmic 
 form of the basis-substance reappears. This condition has been 
 observed di recti v bv S. Strieker in the cornea of froffs, as
 
 IXFLAMMATION. 355 
 
 before stated. He saw the basis-sul)stance in motion, changing 
 the eoniiguration of its living matter, under the microscope, 
 laucli like clouds changing on the face of the sky. Next the 
 protoplasm furnishing the substratum of previous basis-sub- 
 stance becomes split up into small bodies, known as medullary, 
 or embryonal, or inflammatory corpuscles. Any portion of 
 living matter of such indifferent bodies may grow to the size 
 of a mu'lous, owing to the presence of an excess of pal)ulum 
 beyond the physiological requirements of these bodies, an ex- 
 cess essential to the inflammation. Not only the original ' cells,' 
 but the intervening basis-substance, will participate in the 
 formation of new elements or inflammatory corpuscles. Here is 
 the distinguishing feature between modern and antique patho- 
 logical views, for according to the latter only the ' cells' them- 
 selves were considered active and capable of proliferation." 
 
 At the beginning of 1892,* P. Grawitz, professor of morbid 
 anatomy at the University of Greifswald, Germany, published 
 an article,t followed by several others, in which he claimed to 
 have discovered that in the process of inflammation not only 
 the eells of the connective tissue proliferate, but the basis-suit- 
 stance likewise furnishes a large number of cells, which he 
 termed sluml)ering cells. Grawitz believes that tlie basis-sub- 
 stance has l)een dcNcloped from cells which remained slumber- 
 ing until again brought to view by an irritative process, such 
 as inflammation. E. 0. Shakespeare, of Philadelphia, in 1882, 
 had previously written of slumbering cells, which he noticed 
 l)uried in tlie basis-substance of the cornea. Quite recently 
 Professor C. Weigert, of Frankfurt, Germany, bitterly attacked 
 Grawitz,;}; calling his discovery " intercellular pathology," in 
 contradistinction to A'irchow's Cellular pathology. He criti- 
 cised Gra^^■itz that the latter had ignored the researches into 
 iuflamiuation during the last twenty years, and quoted Strieker 
 as having flrst discovered that during the process of inflamma- 
 tion the basis-substance likewise produces cells. Weigert, how- 
 ever, still adheres to Cohnheim's emigration theory, and has 
 
 * This and the following paragraph, with the illustrations, are reprinted from 
 "The Doctrine of Intluniination,'" hy C. F. W. Bodeokor. I iifcrnaiional Dental 
 Journal. 1893. 
 
 f Virc/ioiv's ArcJiir. Berliner Wochenschrift. 
 
 XDeidsche Med. Wochenschrift, 1892.
 
 356 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 never admitted that the connective-tissue cells do proliferate. 
 He tries to explain the images of proliferation by stating that 
 the colorless blood-corpuscles, or leucocytes, creep into the 
 tissue-cells, thus producing the appearance of proliferation. 
 
 Fig. 200. 
 
 Diagram of thk Ixklammatory Changes ok Coxnective Tissue. Reduction of Basis- 
 SuBSTAXCE TO Protoplasm accordixg to C. Heitzmaxx (1873). 
 
 A, inflammatory changes of reticular cartilage. — a, increase of the living matter in the cen- 
 tral protoplasmic body, beginning reappearance of living matter in the basis-substance ; 6, 
 territory composed of embryonal corpuscles, after liquefaction of basis-substance ; e, reappear- 
 ance of nuclei in the basis- substance ; d, territory broken up to inflammatory corpuscles. B, 
 inflammatory changes of fibrous connective tissue. — a. original protoplasmic tracts broken up to 
 inflammatory corpuscles ; h, fibrous basis-substance transformed to nucleated protoplasmic 
 bodies,— the "slumbering cells" of P. Grawitz ; c, inflammatory infiltration, all the elements 
 interconnected by threads of living matter. 
 
 Grawitz admits that he is ignorant of these researches. Wei- 
 gert, on the contrary, confesses the knowledge of Strieker's 
 puTdications, but purposely ignores them, because they are 
 adverse to the doctrine of the cellular jjatliology.
 
 INFLAMMATION. 357 
 
 It is romiirkablc tliat the German pathologists have arrived 
 at discoveries wliich Avere made twenty years ago, not by 
 Strieker, as stated, hut l)v Carl lleitzmann, of New York, at 
 that time in Vienna. Strieker himself publicly announced in 
 1880 tliat he became convinced of the correctness of the views 
 of lleitzmann only after six years of hard work. He unques- 
 tional)ly was the tirst in Europe who acknowledged (twelve 
 years ago) the accuracy of Ileitzmann's theory. The discovery, 
 liowevcr, is not his. 
 
 " The sum-total of the newly-formed inflammatory corpuscles 
 is known under the term inflammatory inflltration, which means 
 that a certain amount of a tissue, be it connective, muscular, or 
 nerve tissue, is replaced by and transformed into newly-appear- 
 ing proto[)lasmic bodies in the stage of indiflit'rence, — that is, 
 being purely proto[ilasmic bodies without any distinctive tissue 
 character either as to origin or destiny. So long as the inflam- 
 matory corpuscles remain in continuity by their delicate oft- 
 shoots they represent a tissue, though in a condition of indift'er- 
 ence, or an embryonal state. Such a tissue by new formation 
 of a basis-substance will either return to the previous normal 
 state, terminating the inflammatory condition in 'resolution,' 
 or, l)eing considerably augmented itself, will produce a tissue 
 much greater in bulk tlian the one originally inflamed, and we 
 will have hyperplasia. 
 
 '■'• Hr/'perplasia^ therefore, appears when, in conse([uence of the 
 iiu'rease of the living matter after the new formation of basis- 
 substance, a certain bulk of tissue is formed in excess of its 
 previous normal quantity. In this condition the cells as well as 
 tlie l)asis-substance remain interconnected the same as in the 
 production of a normal tissue. 
 
 "• In neither instance will the inflamed tissue cease even for a 
 moment to be tissue. The tissue which is the bearer of the 
 blood- and lymph-vessels is the connective tissue, and here is 
 the starting-point of inflammation in almost every instance. 
 This we understand from the fact of the rather low status 
 and activity of the connective tissue. We look for the great- 
 est reaction on irritation at the sources of nutrition, obviously 
 tlie blood-vessels. Muscle, nerve, and ejtithelial tissue react 
 in rather a secondary manner on intlanniuition of connective 
 tissue.
 
 358 THE AXAT(3MY AND PATHOLOGY OF THE TEETH. 
 
 " Yircliow proposed the name ' parenchymatous inflammation' 
 for the designation of an inflammatory process which he 
 thought to be primary in epithelial structures. This term may 
 be retained if restricted always to a secondary manifestation 
 upon the primary inflammation of the ' interstitial' connective 
 tissue. A gland, for instance, is a compound organ composed 
 of parenchyma according to Virchow, which is the epithelial 
 glandular tissue. This is surrounded with and accompanied 
 by connective tii^sue bearing many blood-vessels. It is impos- 
 sible that the glandular tissue could be the primary seat of the 
 inflammatory process. This process will be present in the 
 connective tissue first, and more or less rapidly invade the 
 glandular epithelial tissue. 
 
 " If the connections of the inflammatory corpuscles be severed,, 
 we shall have a certain number of isolated medullary or em- 
 bryonal corpuscles suspended in an albuminous liquid, and this 
 we call pus. Pus is therefore the resultant of destroyed tissue^ 
 but quite unfitted for the production of any form of tissue. 
 How much the emigrated blood-corpuscles contribute to the 
 formation of pus may not yet be positively stated. However, 
 we do know positively that upon the approach of suppuration 
 in a certain tissue its blood-vessels are destroyed without excep- 
 tion in the territory involved. The blood-vessels, by outgrowth 
 of their endothelia, become at first solidified and afterward 
 split up into medullary and pus-corpuscles, the same as all the 
 other elemental constituents. Even the smooth muscles of an 
 artery will partake of this pus-forming process. The number 
 of migrated leucocytes cannot be great, considering the loss of 
 the vessels which have supplied them. Pus is destroyed tissue^ 
 first originating in a closed cavity bearing the name of ' abscess'; 
 or, secondly, coming from the walls of physiologically shut 
 cavities, termed 'empyema'; or, thirdly, springing from ex- 
 posed tissue surfaces, viz, such as granulating surfaces of 
 wounds, termed 'pyorrh(ea.' In the two latter instances, 
 namely, empyema and pyorrhoea, the emigration of colorless 
 blood-corpuscles plays, perhaps, a more important role than in 
 the case of ' abscess.' In granulating surfaces of wounds, 
 especially, the source of the pus-corpuscles may be sought 
 mainly in the capillaries, which abound in the myxomatous 
 granulation tissue, producing loops therein, upon the grouping 
 of which depends the raspl)erry look of the so-called ' proud
 
 INFLAMMATION. . 359 
 
 flosli.'* Around an al)8eess a dense layer of fibrous connective 
 tissue is formed very soon, — beautifully displayed in alveolar 
 abscess at tlic apices of diseased roots of teetli. Tliis newly- 
 formed layer re[»resents tlie productive activity of intlanima- 
 tion, beiuii' hyperplastic, fibrous connective tissue, more or less 
 Avell sup}»lie<l with blood-vessels. Old pathologists termed this 
 layer ' mend)rana pyogena,' ■\\hich signifies that the membrane 
 itself produces the ]>us. Tliis view was abandoned long since, 
 and to-day the membrana pyogeiia is known to be a secondary 
 formation in the a|ipearancG of an abscess, as it were, a pro- 
 tective wall to the healthy tissues. After fhe evacuation of the 
 pus from an abscess or an em[»yema, either by spontaneous rup- 
 ture of the covering layer toward the surface, or artificially by 
 knife or caustic, the membrana pyogena changes its character 
 and becomes the seat of an aeute inflammation, which leads 
 to the formation of a free1y-^■asculari/ed myxomatous tissue. 
 This is what is called ' proud tiesh,' or granulation-tissue. In 
 all instances of loss of tissue l)y suppuration, the final result is 
 the formation of a scar. This consists of a dense fibrous con- 
 nective tissue whose bundles freely interlace, and which is, as a 
 nde, scantily supplied with blood-vessels. It is an outcome of 
 myxomatous granulation-tissue, and is covered with epithelium 
 whenever the pus has been discharged through the skin or a 
 mucous membrane, which themselves appear to be covered'in a 
 normal condition with an epithelial layer. 
 
 "Pus, therefore, is a tissue disintegrated and broken up into 
 indifi'erent or medullary corpuscles which are suspended in a 
 licpiid more or less rich in all)umin. The pus-corpuscles 
 remain alive as long as the liquid surrounding them is sufficient 
 for the sujtport of their nutrition. Even fatty degeneration of 
 the pus-corpuscles, as seen in chronic abscesses, will not alto- 
 gether deprive them of their vital phenomena. Such corpus- 
 cles, if transferred upon a slide, remain ameboid, and they die 
 only by exposure to a low temperature, or after the addition of 
 chemical reagents, or within the body by l)eing deprived of 
 their nourishing li(piid. The last condition is noticed in cheesy 
 degeneration of the }ius so often met with in tuberculosis. 
 
 "A question now arises: What is the cause of the formation 
 
 * Recent researches in granulating surfaces of the skin by Louis Heitzmann, 
 Arc/iii: f. DerniKf., 1892, have ])r()V('d that the source of pus is not the caiiillary 
 loops, but the outermost layer of the myxomatous tissue itself.
 
 360 THE ANATOMY AND PATHOLOGY OF THE TEETH, 
 
 of pus ? Ever since the famous experiments of Colmheim and 
 Councilman, who introduced vials tilled with croton oil under 
 the skin of rahhits, with antiseptic jtrecautions, and after heal- 
 ing was complete cracked the vials, suhcutaneously, thus pro- 
 ducing an abscess, this is a much-mooted question. A host of 
 experimenters, who have repeated these trials, have taken views 
 pro and con on the question. I consider the experiments of P. 
 Grawitz and W. deBary, published in Virchow's vlrc/uiT*-, 1887, 
 the most valuable testimony toward settling the question. 
 They found that the sulicutaneous injection of concentrated 
 solution of chloride of sodium in rabbits and dogs was followed 
 by oedema, a swelling of the fascia, but no suppuration. It 
 makes no dift'erence whether the solution contains a large num- 
 ber of staphylococci. Staphylococcus, Avith its three varieties, 
 the Staphylococcus pyogenes aureus, albus, and citreus, first 
 discovered by Kosenbach, was thought to be essential to the 
 production of pus. And even H. Knapp, of New York, main- 
 tained that a small quantity of croton oil mixed with olive oil 
 will not produce suppuration if introduced into the anterior 
 chamber of the eye of the rabl)it, whereas the same mixture if 
 contaminated with pure culture of Staphylococcus aureus will 
 invarial)ly l)e followed l)y suppuration under like circumstances. 
 Grawitz and de Bary, on the contrary, have proved that not 
 only the coccus named, but certain irritating reagents and 
 different products of micro-organisms, not necessarily the sta- 
 phylococcus, ditierent alkaloids, or ptomaines, are productive 
 of pus. Solutions of nitrate of silver, if injected under the 
 skin of dogs, rabbits, rats, and mice, will be harmless if weak, 
 not stronger than .005 of one per cent., but Avhen five per cent, in 
 strength will invariably be followed by abscess in dogs. Neither 
 acids nor alkalies cause suppuration, except the liquor of caustic 
 ammonia, which if introduced in full strength is followed in- 
 variably by suppuration. In neither of these instances were 
 there an}' micro-organisms discoverable in the pus freshly re- 
 moved from the abscess, or transferred upon nutritive gelatin 
 as a culture medium. Oil of turpentine did not induce i»us in 
 rabbits and guinea ['igs, even though injected in large quanti- 
 ties, but only inflammation ; whereas in dogs subcutaneous 
 injection of oil of turpentine, which is a germicide, was alw^ays 
 followed by suppuration. 
 
 " From these experiments it follows that chemical substances
 
 INFLAMMATION. 361 
 
 entirely free from bacteria and cocci tend to induce the suppura- 
 tive process in different animals. On the other hand, it has been 
 experimentally proved that in dogs and rabbits the injection of 
 cultures of staphylococcus into the normal subcutaneous tissue 
 will not induce inflammation or supi»uration. It is necessary 
 that a tissue lirst be irritated to a condition of inflammation, by 
 traumatism or by chemit-al irritants, to have a soil favorable for 
 the development of staphylococcus, which under these circum- 
 stances will produce an abscess. Lately P. Grawitz has shown 
 that the subcutaneous injection of a ptomaine derived from 
 putrescent organic material, cadaverine, will always lead to the 
 formation of an abscess. 
 
 " From the practical stand}>oint it is of the utmost importance 
 to work aseptically, or in other w^ords, with such degree of 
 cleanliness that the introduction of micro-organisms or their 
 ptomaines becomes impossible. It is well established that even 
 open fresh wounds, if ase])tically dressed with gauze saturated 
 with a 1 : 1000 solution of corrosive sublimate and let alone for 
 a few weeks, will kindly heal without one single droplet of pus. 
 Corrosive sublimate and carbolic acid are still most reliable 
 germicides. We are not yet i)repared to assert that micro- 
 organisms alone cause suppuration, since there are irritating 
 chemical substances wdiose introduction into the body may 
 likewise be followed by this process. Recent observers have 
 maintained that there is a marked diiference bet^veen a mere 
 accumulation of leucocytes and an abscess proper. In the first 
 instance there may be present a serous or fibrinous exudate 
 entangled with a number of emigrated leucocytes, without a 
 loss of tissue, without, therefore, suppuration. In the latter 
 instance a certain amount of tissue is destroyed and directly 
 transformed into pus. If this view be correct, it certainly 
 strongly supports our present notions of the process of sup- 
 }»uration herewith laid down.* 
 
 " 1. Inflammation is a disturbance of nutrition of a tissue 
 causing a recurrence of the embryonal condition of the tissue 
 involved. 
 
 * Even to-diiy tlu- (jiiestion whether or not suppuration is dependent upon the 
 presence of staphyk)cocci or their ptomaines is unsettled. All, however, agree 
 that pus devoid ofmicro-t)rganisms is hl'and, harmless, not infectious ; pus, on the 
 contrary, contaminated with miero-organisms possesses infectiinis and jioisonous 
 properties in a high degree.
 
 362 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 " 2. The embryonal condition is established by the breaking 
 up of the tissue into those medullarv or indifferent corpuscles 
 which, at an early stage of normal development, have built up 
 the tissue. 
 
 " 3. The medullarv corpuscles arise not alone from the proto- 
 plasmic bodies of the tissue, the so-called ' cells,' but the inter- 
 cellular or basis-substance is also productive of such corpuFcles, 
 as these have shared in the formation of basis-sul)stance in the 
 process of normal development. 
 
 "' 4. The medullary or indifferent corpuscles will still repre- 
 sent a tissue so long as they remain interconnected and contin- 
 uous. By the reappearance of basis-substance simply the most 
 favorable termination is established, the so-called ' resolution.' 
 
 " 5. If the inflammatory or medullary corpuscles have largely 
 augmented in numbers, thereby remaining in uninterrupted 
 connection, the result will be productive of a newly-formed 
 tissue of increased size, a so-called 'hyperplasia.' 
 
 " 6. Tf the inflammatory corpuscles springing from previous 
 ' cells,' basis-substance, and blood-vessels break asunder and be- 
 come isolated, they will be suspended in an albuminous liquid, 
 and will henceforth represent pus-corpuscles. 
 
 " 7. Pus, therefore, is a destroyed tissue broken up into its 
 constituent elements, and as such incapable of the production 
 of a new tissue, although the single pus-corpuscles will remain 
 alive and amoeboid almost indefinitely as long as they are suffi- 
 ciently nourished. 
 
 " 8. The emigration of colorless blood-corpuscles may par- 
 ticipate in the formation of pus. 
 
 " 9. Suppuration is caused by the presence of certain microbes, 
 mainly the three varieties of staphylococcus, only when a pre- 
 vious inflammation is present in tbe tissue, furnishing a favor- 
 able soil for the development of the before-mentioned microbes. 
 
 " 10. Staphylococcus is not the only antecedent of suppura- 
 tion, it having been proved by experiments that the introduc- 
 tion of certain chemical agents, unfavorable to the development 
 of microbes, may likewise be followed by suppuration."
 
 INFLAMMATION OF THE GUMS,-UL1TIS. 363 
 
 CHAPTER XXXII. 
 
 INFLAMMATION OF THE GUMS-ULITIS. 
 
 To describe all the diseases of the giniis would require a de- 
 lineation of all the lesions that aftect tlie oral mucous mem- 
 brane, or rather of the oral cavity, — a task Avliich far exceeds 
 the plan of this work. I shall therefore confine myself to the 
 description of only those diseases which especially interest the 
 dental practitioner, because in direct relation to the teeth. 
 
 In general ancemkf, or chlorosis, the gums appear bloodless 
 and pale. Kot infrequently they are found in a state of hydropic 
 swelling, — so-called oedema. This condition may be transient, 
 arising from so-called catarrhal stomatitis ; it may last for 
 weeks, as after typhoid fever, or for months, as in pregnancy 
 and after delivery; or, finall}^ it may depend upon a structural 
 change such as is observed in myxoedema of the skin after the 
 destruction or extirpation of the thyroid bod}'. 
 
 Hijpercemia of the gums is caused by poisoning with mer-. 
 cury — salivation — or with dyes, as in the manufacture of arti- 
 ficial flowers, one of the most common offenders in the latter 
 case being picric acid. Sometimes we see the condition in 
 pregnant women. The slightest injury to the hyperfemic gums 
 causes bleeding, which feature, together with a bluish-red color, 
 is symptomatic of scurvy. 
 
 Ulitis (erroneously termed gingivitis, since the Latin word 
 gingiva ouiilit not to be combined with the Greek termination 
 itis) is of fre([ueut occurrence. It is usually caused by meehan- 
 ical injuries, such as the wearing of artificial teeth, especially 
 when mounted on rubber plates. In such cases the pressure 
 upon the gums is assisted by a decomposition of the fluids. of 
 the mouth and the non-conductivity of the rubber. Another 
 fruitful source of ulitis is the accumulation of tartar, or salivary 
 calculus, on the necks of the teeth, which causes pressure upon 
 the border of the gums, resulting ultimately in their recession 
 from the teeth. Decomposing particles of food at the border 
 of the gums and the tartar, in the space between the gum and 
 the neck of the tooth, wdiich space is usually called a pocket, 
 and the accumulation of staphylococci cause a superficial suppu- 
 ration of the gum, which process, by the destruction of the
 
 364 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH, 
 
 alveolar border, hastens tlie recession of the gum and the ex- 
 posure of the necks and roots of the teeth, and induces perice- 
 mentitis. 
 
 The image of acute ulitis under the microscope is rather 
 characteristic. (See Fig. 201.) The iibrous connective tissue 
 building up the main mass of the gums is found crowded with 
 inflammatory corpuscles, usually in nests or roundish foci. These 
 inflammatory corpuscles exhibit greatly varying sizes, from a 
 
 Acute Ulitis. 
 
 CO, row of columnar epithelia ; GU, cuboidal epithelia ; C, C, inflammatory infiltration 
 of fibrous connective tissue ; V, vacuoled epithelia, nucleus dropped out. Magnified 400 diam- 
 eters. 
 
 small solid and homogeneous granule or lump to a vacuoled or 
 even agranular and nucleated protoplasmic body. All these 
 forms are known to be different stages of development of the 
 living matter. We can easily satisfy ourselves that not only the 
 protoplasmic tracts between the bundles have produced inflam- 
 matory corpuscles by a process of outgrowth and splitting up of 
 the lumps of living matter, but the bundles themselves break up
 
 INFLAMMATION OF THE GUMS,-ULITI?. 365 
 
 into rows of inflammatory corpuscles, obviously after the lique- 
 faction of the glue-yielding basis-substance. In consequence of 
 an increase of the living matter, the papilla? at the surface of the 
 connective tissue are considerably enlarged. The blood-vessels, 
 mainly the capillaries and veins, are seen widened and engorged 
 with both red and colorless blood-corpuscles. The stratified 
 epithelial covering of the connective tissue likewise exhibits an 
 outgrowth and a proliferation of the living matter in its proto- 
 plasm. In mild cases, such as the illustration demonstrates, only 
 the row of columnar epithelia and the adjacent cuboidal cpithelia 
 show the proliferation. Frequently the thorns of living matter 
 interconnecting the epithelia by outgrowth and coalescence pro- 
 duce club- or pear-shaped lumps wedged in between the enlarged 
 epithelia (L. Elsberg). In higher grades of acute inflammation 
 not only the columnar but all the cuboidal epithelia are found to 
 be engaged in proliferation. In the latter the serous exudate ire- 
 quently accumulates around the nuclei, which, when they drop 
 out in section-cutting, leave an apparently empty space, — a so- 
 called vacuole. 
 
 Suppuration of the gum is found either superficially along the 
 borders, caused by the accumulation of tartar, or in the shape 
 of a more or less circumscribed abscess in the depth of the 
 connective tissue. Around the abscess the gums are invariably 
 found in a high grade of oedematous sw^elling. The most i're- 
 (juent cause of such abscesses is caries of the teeth combined 
 with }»nrulent pericenR'ntitis. Sometimes foreign bodies, 
 splinters of bone, bristles of the tooth-brush, particles of the 
 cores of apples or pears, etc., cause abscesses of the gum when 
 a simultaneous infection with staphylococci has taken place. 
 
 Ht/perplasia of the gum is always the outcome of chronic 
 [>lasti<' ulitis, and is of frequent occurrence. In its mildest 
 forms only the papillary layer is rendered hyperplastic, the sur- 
 face appearing to the naked eye in the form of lobules like 
 strawberries. Too frequent application of the tooth-brush is 
 suflicient to produce such a pa[»illary hyperplasia. Higher 
 grades of chronic ulitis are often seen along the borders of 
 carious cavities, or covering deeply-seated tumors of the Jaw ot 
 any descrijttion. This process is characteri/A'd by a new forma- 
 tion of myxomatous tissue, rather freely vascularized and re- 
 placing the previous fibrous connective tissue. (See Fig. 202.) 
 The myxomatous tissui' in this instance (hyperplastic gum
 
 366 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 overlapping a cjst) is conspicuous by a large number of proto- 
 plasmic tracts producing the myxomatous reticulum with laro-e 
 spindle-shaped points of intersection. In the meshes in the 
 middle of the myxomatous basis-substance we frequently find 
 
 Fig. 202. 
 
 fe;/; 
 
 
 Chronic Ulitis. 
 
 -1/. myxomatous tissue of papilla; V, V, capillary blood-vessels; CO, CO. row of cok 
 e;>ithelia ; CU, CU, cuboidal epithelia. Magnified 600 diameters. 
 
 protoplasmic bodies. The capillaries of this tissue are con- 
 spicuous by their large calibers and their large-sized endothelia 
 along the walls. Most of these blood-vessels are newly formed. 
 The coluimiar rpitliclia directly covering the myxomatous tissue
 
 INFLAMiAIATIOX OF THE GUMS-ULITIS. 
 
 367 
 
 are still in a state of proliferation, and here and there we like- 
 wise see pear-shaped or branching formations of living matter 
 in the cement-substance. 
 
 The highest grades of hyperplasia of the gum are seen in 
 the vicinity of broken roots left in the sockets, and in the neigh- 
 borhood of large carious cavities. In the former instance peri- 
 cementitis is the cause of chronic ulitis, whereby lobulated 
 tumors in the mucosa are produced sometimes some distance 
 
 Fig. 203. 
 
 Hyperplastic Gum grown into thk Carious Cavity of a Molar. 
 
 K, knob of gum of myxomatous structure in the carious cavity ; 0, outer portion of gum ; F 
 (upper), deep fissure caused by the thin dentinal wall of the cavity ; E, E, stratified epithelium 
 on the surface; V, varicose veins in myxomatous tissue, penetrating into epitliolial layer; /' 
 (lower), fibrous connective tissue. Magnified 100 diameters. 
 
 away from the root. Tumors ma>' even assume the aspect ot 
 cancer, l)ut soon after the extraction of the root they disappear 
 without further treatment. 
 
 When the gums overlap a large carious cavity, or when they 
 penetrate such a cavity through a perforation in the thinned 
 wall of dentine, they produce large lobulated tumors, more or 
 less filling up the cavity. It is not always easy to recognize 
 hyperplastic gums in the carious cavity, especially if the invasion
 
 368 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 has taken place through a perforation in the dentine concealed 
 from the eye. Hyperplastic gums of this description are of a 
 lobulated surface, lively crimson red color, bleeding easily, and 
 occasionally painful. Fig. 203 illustrates such an instance of 
 hyperplastic gums, separated from the outer portion by a deep 
 
 Fig. 204. 
 
 Hypekplastic Gum grown into the Carious Cavity op a Molar. 
 
 H, flat epitholia of horny layer ; CU, cuboidal epithelia ; CO, columnar epithelium in oblique 
 section ; M, myxomatous connective tissue ; V, V, varicose veins penetrating into the epithelial 
 layer. Magnified 500 diameters. 
 
 fissure, evidently caused by a thin layer of dentine bordering 
 upon the perforation, through which the gum found its way 
 into the carious cavity. The portion filling up the cavity is, to 
 a great extent, myxomatous ; in the outer portion the myxoma- 
 tous structure is present only at the surface. A striking feature
 
 INFLAMMATION OF THE GUMS-ULITIS. 3(]9 
 
 of the inner portion is the presence of varicose veins at the sur- 
 face, penetrating into the stratified epithelium. Fig. 204 rejire- 
 sents this rather peculiar occurrence. Here we see that the 
 varicose veins have, b}' a gradual pressure, destroyed a number 
 of ei»ithelia, bulging on the surface and being covered only by a 
 few layers of epitlielia. This fact explains why gums in the 
 condition described bleed so readily and so profusely, sometimes 
 alter the slightest injury. 
 
 Ulceration of the (/ tons in the shape of shallow losses of sub- 
 stance, coated with a whitish exudate, and sharply circumscribed, 
 is not rare. Such ulcers are termed '' (iphthic," popularly canker 
 sores. Their etiology, according to E. Frankl, is based upon 
 an invasion of Staphylococci pyogenes citreus and flavus. In 
 regard to the cause of this trouble but little is known. Some 
 authors believe the disease to be mainly the result of uncleanli- 
 ness, and principally confined to childhood, and to those whose 
 food consists largely of milk. It is certain, however, that derange- 
 ments in the digestion, anaemia, rhachitis, as well as pregnancy 
 and the menstrual period, greatly enhance a predisposition to 
 the infection. The writer has a patient who, almost every month 
 shortly before the appearance of her monthly periods, for several 
 years was troubled with a[)htha3. These patches are most com- 
 monly observed upon the gums in the vicinity of the apices of 
 the roots of cuspids and bicuspids, where the mucous membrane 
 of the cheek joins that of the gums. They are also seen under 
 the tongue on either side of the frtenum. In the beginning we 
 notice them as one or more roundish spots, about the size of a 
 pin-head. These spots at first are separated from one another 
 by a dark red line encircling each place. In later stages the 
 small patches unite into one, usually assuming a more or less 
 oblong shape. The patients frequently complain of great pain 
 during mastication and deglutition, according to the location of 
 the trouble. 
 
 S^/philis likewise causes ulcers upon the gums, especially in 
 its later stages, when shallow ulcers, much resembling aphtha?, 
 sometimes appear symmetrically. Such ulcers, which likewise 
 are characterized by pains in the ingestion of acid foods, may 
 indeed be mistaken for aphthiv. Even their causation by syphi- 
 lis is in many cases doubtful. The dark-red border around the 
 ulcer is said to be characteristic of a syphilitic origin. The 
 scars left after the ulcers have healed, so-called kucoplahla^ 
 
 25
 
 "S70 THE A.NATOMY AND PATHOLOGY OF THE TEETH. 
 
 likewise in many instances present an appearance which makes 
 the origin of the trouble dubious. Intense salivation, following 
 the misuse of mercury in previous years, has often led to an 
 ulcerative destruction of the gums. To-da}', however, when 
 mercury is administered under great precautions, and saliva- 
 tion is not allowed to pass beyond its initiative stages, such an 
 occurrence is rare. 
 
 Scun\ij in its highest grades ma}' produce ulcers on the gums, 
 characterized by a bluish-red base and easy bleeding. The 
 (Edematous swelling around scorluitie ulcers is always intense. 
 
 Diphtheritic ulcers of the gums, caused by a specific bacillus 
 (Klebs-Lotiler), are rarities ; so are tuberculous ulcers, which are 
 caused by the tubercle bacillus (Koch). 
 
 Gariqrme of the gam is caused either by noma or by stomatitis. 
 It rapidly destroys large masses of tissue, mainly at the buccal 
 surface of the oral cavity. The micro-organism causing this 
 disease is probably the same as that of splenic fever. In intense 
 salivation due to overdoses of mercury, and in high degrees of 
 scurvy, gangrene of the gum has likewise been observed. 
 
 CHAPTER XXXIII. 
 
 IXFLAMMATIOX OF DENTINE -EBURXITIS.* 
 
 It is a well-known fact that dentine becomes the seat of an 
 inflammatory reaction by caries, as well as through the gradual 
 destruction of the roots caused by alveolar pyorrhoea, whereby 
 {in the latter instance) first the cementum and afterward the 
 dentine are destroyed. Another instance of an inflammatory 
 invasion of dentine is observed during pulpitis, where first the 
 secondary and afterward the primary dentine are destroyed by 
 an inflammation of the pulp-tissue. Aside from these secondary 
 forms of inflammation, there occurs a primary inflammation 
 in dentine, independent of pulpitis or pericementitis, running 
 its course in the middle of the dentinal tissue, and leading, as 
 
 *" Inflammation of Dentine." By C. Heitzniann and C. F. W. Bodccker. 
 
 IndepoiiJcni Pmctlfiom-r, 1886.
 
 INFLAMMATION OF DENTINE-EIJURNITIS. 371 
 
 all inflammatory processes do, either to a new formation or to 
 ilestruction bv suppuration. This primary inflammation of den- 
 tine is the subject of this cha[»ter. 
 
 As to the causes of " eburnitis," as we propose to term this 
 process, there are a small number of cases in which nothing can 
 be observed that would account for an inflammatory reaction in 
 the dentine, which, although alive, is far away from the blood- 
 vessels throughout. In a few specimens we observed nothing 
 anomalous in the soft parts surrounding the root of the tooth, 
 nor in the pulp-tissue. Some preparations exhibited a slight 
 degree of pericementitis, with the characteristic superficial 
 erosions of the cement-tissue. In other cases we noticed a 
 layer of secondary dentine, indicative of an increased activity 
 of tlie pulp-tissue, although no pulpitis was visible. In all cases 
 of eburnitis, however, we observed in the dentinal tissue itself 
 a striking feature : an incomplete calcification of the dentine, 
 and a great abundance of interglobnlar spaces, signifying a 
 malformation and an incomplete calcification of the basis-sub- 
 .stance. This accounts for its greater vulnerability and suscepti- 
 bility to irritative processes. The enamel, in ground specimens, 
 will likewise show abnormalities, such as pigmentation, stratifi- 
 cation, or insufiicient deposition of lime-salts. 
 
 Far greater are the number of instiint-es in which traumatism 
 has led to an inflammation of the dentine. It is evident that 
 any surgical interference, such as burring or excavating, will in 
 an otherwise normal dentine produce irritation sutficient to 
 result eventually in an inflammatory reaction. If, in addition 
 to excavating, a caustic is applied or a filling inserted, which 
 may exert a certain amount of irritation, inflammation of the 
 dentine may follow. 
 
 'We know, from practical experience, that when a caustic in 
 the form of an oxychloride or an oxyphosphate filling is applied 
 to very sensitive dentine, this tissue, in the course of time, will 
 become less sensitive through the partial obliteration of the 
 canaliculi in the dentinal wall of the cavity. The filling-material 
 in this manner e.xcites an irritation, which in the course of 
 months or years results in a new formation of dentine around 
 the filling, and tliis is often denser than the original dentine. 
 This hardening, as the most fiivorable result of traumatism, is 
 the consecpience of a reaction of the dentine, known under the 
 term of consolidation. On the other hand, instances are not
 
 372 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 rare in which the insertion of an oxyphosphate, oxychloride, or 
 a goUl filling has given rise to excruciating pain, sometimes 
 even necessitating the removal of the filling. The latter result 
 is clue to intense irritation of the dentine, manifested probahlj 
 through the medium of the dentinal fillers encroaching upon 
 the pulp-tissue. Such unfavorable results are met with mainly 
 in patients whose teeth are badly calcified, or in tempi>rary 
 teeth, in which the amount of living matter is much greater 
 than in the average permanent teeth. 
 
 The best known example of the effects of traumatic injuries 
 upon dentine is seen in the elephant's tusk in which a bullet 
 has lodged. The remarkable changes of the dentine around 
 the bullet are well known to scientists as well as mechanics. As 
 early as 1798, the great German poet and philosopher, Goethe, 
 investigated the subject of diseased ivory from the elephant's 
 tusk, resulting from the impaction of iron or leaden balls : the 
 process appeared to him to be a sort of coagulation (Gerinnung) ; 
 he also mentions the occurrence of exostosis upon the wall of 
 the pulp-cavity, in cases where a ball entered the posterior, weak 
 and hollow portion of the tooth. 
 
 In order to realize the structural changes in inflammation of 
 the dentine, let us remember that it, like bone, is a living tissue. 
 The analogy between these two tissues is clearly established by 
 the fact that in the development of bone-tissue we observe 
 globular territories, the same as in the formation of dentine. 
 In the former instance every territory contains one or more 
 bone-corpuscles, witli their offshoots (lacunae and canaliculi), 
 whereas in the dentine the territories are pierced by the canali- 
 culi and their tenants, the dentinal fibers. The basis-substance 
 in both these tissues is traversed by a large amount of living- 
 matter, in the shape of a delicate reticulum, the meshes of 
 which are filled with the calcified basis-substance proper. The 
 study of the history of development of bone and dentine reveals 
 a striking similarity in the formation of l)oth of these tissues. 
 The osteoblasts are preliminary formations in developing bone- 
 tissue, in the same manner as are the odontoblasts at the 
 periphery of growing dentine. All attempts to explain the 
 development of dentine directly from tlie odontoblasts have 
 proved unsuccessful, as neither the formation of the basis-sub- 
 stance nor that of the dentinal fibers could ever be brought in 
 accordance with the elongated odontoblasts, whereas the-
 
 INFLAMMATION OF DENTINE-EBURNITIS. 
 
 373 
 
 developniont of the dontine becomes pUiiii if we take the 
 ground thjit tlie odoiitoblastH break up into medullary corpus- 
 cles, between which the dentinal libers are formed. If the 
 odontoblasts should calcity directly, we would be at a loss to 
 understand the formation of globular territories in fully-devel- 
 oped dentine. If, on tiie contrary, Ave accei)t the formation of 
 basis-substance from medullary corpuscles, the appearance of 
 globular territories becomes plain. Nothing is required Imt a 
 groui» of me(billary corpuscles, which are transformed into 
 
 Fig. 205. 
 
 Eiu'KN'iTis. Neck of Tooth. 
 
 6', coiiientum, with shailnw excavations at its periphery, caused by poricementitis ; 7>. den- 
 tine in the beginning of dissolution of limp-salts; E. pr .toplasmic masses in globular territories. 
 Magnified 20U diameters. 
 
 basis-substance, while the larger threads of living matter, 
 known as Tonies's fibers, traverse the rows of medullary cor- 
 puscles, taking their course between ihem. Six years" study of 
 the history of development of the teeth, especially of specimens 
 of the sixth month of iiitrii-iiterine life, when dentine begins to 
 form, has k'd to the eonvic ion stated above. 
 
 Inflammation causes a solution of the lime-salts, and after- 
 Wiird a licjuefaction of the b;isis-sii])stance, l»oth in bone and 
 dentinal tissue. The result will be the ai)]iearance of globular
 
 374 THE ANATOMY AND PATHOLOUY OF THE TEETH, 
 
 spaces, or bay-like excavations, wliicli, instead of being filled 
 with basis-substance, exhibit medullary corpuscles, or multinu- 
 clear protoplasmic masses, corresponding to the embryonal 
 stage of the inflamed tissue. (See Fig. 205.) The excavations 
 of the dentine are identical with those seen in the process of 
 absorption of the dentine of temporary teeth, and those of sec- 
 ondary dentine in the neighborhood of an inflamed pulp. The 
 diagnosis of primary ebnrnitis becomes established, not by the 
 appearance of such excavations, but by their presence in the 
 middle of the dentine without any connection with the surface^ 
 or with the pulp-chamber of the tooth. 
 
 The earliest feature of eburnitis under the microscope is the 
 appearance in the middle of the dentine of bay-like excavations 
 of varying sizes, and separated from one another by glistening 
 ledges. At first the dentinal canalicnli and their tenants (the 
 Tomes fibers) remain recognizable within the basis-substance. 
 In the next stage only dentinal fibers remain discernible, the 
 contours of the canaliculi being lost, while the basis-substance 
 itself looks irregularly granular. The diiference in the refi'ac- 
 tion of light of these globular spaces, as compared with normal 
 dentine, indicates a dissolution of lime-salts within them. In a 
 still later stage the entire basis-substance is transformed into a 
 granular mass, which is easily stained by an ammoniacal solu- 
 tion of carmin. The globular spaces appear to be filled with 
 multinuclear protoplasmic masses, or with a number of medul- 
 lary corpuscles, more or less coarsely granular, and flattening 
 each other to some extent. These features, therefore (as men- 
 tioned;, are identical with those observed in absorption of tem- 
 porary teeth, the only difference being that the latter process 
 starts from the periphery, whereas eburnitis begins in the mid- 
 dle of the dentine, w^ithout any direct connection with the outer 
 surface or the pulp-cavity of the tooth, and often at the border 
 of cavities that have been previously filled. (See Fig. 206.) 
 
 The origin of the globular fields of dissolution in temporary- 
 teeth, in some instances, may be questioned, since it is admitted 
 that they are simply the results of the dissolution of the lime- 
 salts, while their filling in with medullary corpuscles may be 
 caused by immigration from without. But in most of the speci- 
 mens of eburnitis which we have examined, no doubt was left 
 as to the primary origin of the spaces and their contents within 
 the dentine, for many of them were isolated, and sometimes far
 
 INFLAMMATION OF DENTINE-EIU KN ITIS. 
 
 375 
 
 apart from the oriii-inal seat of inflanmiation and far from the 
 pnlp-eliamber as well as the periphery of tlie tooth. In connec- 
 tion with ebnrnitis we have noticed frequently that the crowns 
 of teeth tlius affected were surrounded hy defective enamel. 
 There can be no doubt that the medullary corpuscles present in 
 these spaces have really grown from dentinal tissue, respectively 
 from the living matter of the dentinal libers and of the l)asis- 
 substance. 
 
 Fig. 20G. 
 
 -: \ks/ 
 
 EiuKMTis. Crown or Molak. 
 
 Ii, boginning dissolution of lime-salts in the niiddlo of dentine ; .I/.' medullary corpuscles fill- 
 ing the globular spaces that have arisen from inflamed territories of dentine; '', cavity in the 
 dentine, whose contents had been dragged out. Magnified 500 diameters. 
 
 Ill some of the specimens, es|)ecially in the central portions 
 of somewhat larger cavities, the medullary tissue had been 
 removed by the process of grinding or cutting. Where, how- 
 ever, they had been left in sihi^ the me(hillarv corpuscles 
 appeared interconnected by means of delicate offshoots, repre- 
 senting an embryonal tissue; or no distinct boundary lines were 
 seen between the medullary corpuscles, the whole filling of a 
 globular territory being a uniformly granular protoplasmic 
 mass, with interspersed nuclei. We cannot deny the possibility
 
 376 THE ANATOMY AND PATHOLOOY OF THE TEETH. 
 
 that by tlie breaking apart of these medullary corpuscles pus 
 may be formed in the middle of the dentine, thus representing 
 an abscess independently of the pulp-tissue. Wedl and Al- 
 brecht take the presence of blood-vessels, presumably grown 
 into the dentine from the pulp, for an absolute necessity in 
 cases of abscess of the dentine. Such a presumption is super- 
 fluous, in our opinion, for we assert the dentine to be a living 
 tissue, and as such capable of primary inflammation, nay, sup- 
 puration, without the direct co-operation of blood-vessels. We 
 fully believe in the possibility tliat a so-called pyogenic mem- 
 brane could even form around the abscess without a direct sup- 
 ply of blood-vessels. If it is claimed that an abscess in the 
 dentine must form originally in connection with the pulp-tissue, 
 and afterward be separated from the laiter, we deny any such 
 necessity, since we claim the possibility of the formation of a 
 primary abscess in the dentine, independently of the pulp-tissue. 
 
 Far more common than suppuration, however, is the healing 
 process of eburnitis, the results of which may be either a new 
 formation of dentine, closely resembling secondary dentine, or a 
 dentine which is destitute of canaliculi, representing what some 
 authors have termed osteo-dentine. AVe meet with places in 
 the dentine, more especially in the neighborhood of fillings of 
 some years" standing, wherein the dentine is largely composed 
 of calcified basis-substance, and the dentinal canaliculi are 
 arranged in bundles more or less separated, but of a normal 
 appearance. It is obvious that here the recalcification of the 
 previously inflamed dentine was most perfect, producing a 
 tissue which is harder and richer in lime-salts than the original 
 dentine. 
 
 In another instance, the newly-formed tissue closely resembles 
 secondary dentine, with few, irregularly-scattered, wayj canali- 
 culi, and large territories of calcified basis-substance, destitute 
 of canaliculi. Sometimes the basis-substance may be uniform 
 in structure, or composed of globular fields or territories. The 
 tissue as such under the microscope could not be distinguished 
 from secondary dentine ; the fact, hoAvever, that it is found far 
 from the pulp-chaml)er, in the middle of otherwise normal den- 
 tine, proves that it is the result of a previous inflammatory 
 process of the dentine. Here the calcification still attained a 
 high degree of perfection, so desirable from the practical stand- 
 point, although morjihologically not as perfect as in the first
 
 INFLAMMATION OF DENTINE -EHURNITIS. 
 
 377 
 
 instance. Fig. 207 illustrates this form of healing process in 
 eburnitis. Here the cavity, whose soft medullary contents had 
 been dragged out in the process of grinding, is surrounded by 
 a tissue bearing all the characteristics of secondary dentine. 
 
 Another result of eburnitis is the re-formation of the basis- 
 substance, composed of small globular masses, between which 
 are visible irregular and widened canaliculi. It is obvious that 
 calcification in this instance is deficient, and consequently the 
 newly-formed dentine is less consistent than normal dentine. 
 In one of our specimens, dentine of a temporary tooth, we 
 
 Fig. 207. 
 
 nil 'I vv I 
 
 ' c 
 
 tUil >i 
 
 Healing of Ebuknitis. Ckowx ov Iuolak. 
 
 C. empty cavity ; 3/, medullary tissue, at the border of the cavity, partly calcified; 6'. sec- 
 ondary dentine, with scanty and irregularly-scattered canaliculi. Magnified 100 diameters. 
 
 observed not far apart two spots, one of which shows a large 
 amount of basis-substance, with scanty and narrow canaliculi, 
 whereas another spot was in the condition before descril)cd, — 
 A'iz, imperfectly calcified. The latter portion exhibited well- 
 marked globular territories all around a cavity, which probably 
 contained medullary ti.ssue, before subjection to the process of 
 grinding. Some territories contain numerous and wide canali- 
 culi, others scarcely any. Crystals of Imematoidin indicate the 
 inundation of the infiainod tissue with blood, in the acute stage.
 
 378 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 As this cavity was near the pulp-ehamber, the saturation of the 
 tissue in consequence of a hemorrhage is explicable. (See Fig. 
 208.) 
 
 In a fourth instance of eburnitis the healing process is rather 
 poor. No new canaliculi are formed, but the whole field is 
 traversed by irregular, angular, branching spaces, with numer- 
 ous radiating offshoots, bearing a close resemblance to bone- 
 corpuscles. The presence of such spaces gave rise tO' the term 
 " osteo-dentine," applied by previous authors. AV e would agree 
 
 Fig. 208. 
 
 Healing of Eburnitis. Crown of Bicuspid. 
 
 C, cavity bounded by globular territories, between which there are uncalcified interglobular 
 spaces; S, secondary dentine; M, crystals of rust-brown htematoidin. Magnified 500 diameters. 
 
 with this term if the restriction be added, that in these instances 
 no regular bone-tissue is combined with dentine, but only a 
 tissue resembhng bone. The spaces are filled either with medul- 
 lary corpuscles, or a homogeneous basis-substance, or highly re- 
 fracting globular masses, the result of a recent but rather imper- 
 fect deposition of lime-salts. The basis-substance between these 
 spaces is likewise composed of globular calcified masses, between 
 which we observe branching offshoots of the spaces. The
 
 ixflam:^[ation of dentine -eburxitis 
 
 379 
 
 periphery of a spot of healed eburnitis may show small spaces 
 scantily scattered in the basis-substance, whereas the central 
 portions may exhibit very large spaces and comparatively little 
 basis-substance. Fig. 209 illustrates such a termination of ebur- 
 nitis, one portion showing a tolerably well-developed secondary 
 dentine, other portions a poorly-calcitied, so-called osteo-dentine, 
 in which the peripheral zones are decidedly richer in lime-salts 
 than the central ones. Evidently the healing process of eburnitis 
 
 Fig. 209. 
 
 Healing Process of Erukxitis. Root of Molar. 
 
 //, secondary dentine, with scanty canaliculi and a globular basis-substance; 5, spaces re- 
 sembliDK bono-corpuscles. with very irregular, branching offshoots; (7, globular depositions of 
 lime-salts in the basis-substance. Magnified 500 diameters. 
 
 is poorest in the last instance, leading, as it were, to the ibrma- 
 tion of a comparatively soft, brittle, and crumbling dentine, 
 lacking the elasticity of the original tissue, and not entitled to 
 the name of dentine proper. From the description given of 
 healed eburnitis around gun-balls in elephants* tusks, it is ob- 
 vious that the mass, as described as a result of "consolidation" 
 or "coagulation," etc., is sych a poorly-calcified dentine, or 
 osteo-dentine.
 
 380 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 . CHAPTEK XXXIY. 
 
 PULPITIS IN ITS CLINICAL ASPECTS. 
 
 Many disturbances, such as certain forms of pericementitis, 
 necrosis, etc., are the result of primary pulpitis that has caused 
 the death of the dental pulp. The pain which usually accom- 
 panies pulpitis is, as a rule, severe, though not always localized. 
 The dental pulp being richly supplied with nerve-fibers and 
 blood-vessels, at the same time inclosed in an unyielding wall 
 of dentine, is unable to swell.' Even a comparatively slight 
 inflaujmation may cause considerable pressure upon the nerve- 
 fibers, — pressure which manifests itself either as pain in the 
 affected tooth, or as neuralgia in other parts of the nervous 
 system. The severity of the pain in pulpitis is not so much 
 dependent upon the changes occurring in the pulp-tissue, as 
 upon external influences and constitutional peculiarities of the 
 patient. We often meet with pulps in which the inflammation 
 is slight, while the pain caused thereby is severe. On the other 
 hand, we observe cases in which even an extensive pulpitis 
 causes comparatively little or no pain. Occasionally we see 
 patients, most of whose teeth are broken and decayed, who de- 
 clare, nevertheless, that they have never had toothache, while 
 in other instances patients suffer pain as soon as the caries has 
 penetrated the enamel of the tooth. 
 
 The etiology of pulpitis may be classified under the following 
 I head.^ : 
 
 Dental cai-ies ; 
 
 Invasion of the pulp by micro-organisms (staphylococci and 
 streptococci) ; 
 • Pressure of filling-materials placed too near the pulp: 
 
 Mechanical violence, or traumatism ; 
 
 Fracture of the tooth; 
 
 Pericementitis; 
 
 Xew formations in the pulp-tissue ; 
 . Constitutional disturbances; 
 
 Sudden thermal changes ; 
 
 Electrical shock. 
 
 The exciting cause of jiulpitis may be one of the above cate- 
 gory of causes, or a combination of several of them. The 
 most frequent is unquestionably caries. In the process of caries
 
 PULPITIS IN ITS CLINICAL ASPECTS. 381 
 
 micro-organisms in tlie dental canaliculi enter in advance of 
 the zone of decalcification, and this explains the occurrence 
 of inflammation in pulps which are not as yet exposed. In 
 many instances we find that the dentine covering- the pulp in a 
 carious cavity is quite hard, and one-half of one millimeter, or 
 even more, in thickness. Nevertheless, should the tooth be 
 extracted, we may meet with an inflamed pulp in it. In this 
 instance the exciting cause is an invasion of micro-organisms 
 into the pulp-tissue through the portion of the dentine covering 
 the pulp in the vicinity of the carious cavity. Sometimes this 
 layer of dentine is, though thin, quite healthy, and a gold filling 
 hammered into the cavity may produce inflanimalion of the 
 pulp, not only by reason of the pressure exerted in the intro- 
 duction of the filling, but also through the thermal changes 
 resulting from the contact of the metal with the thin layer of 
 dentine covering the pulp. The same may be the result after 
 the introduction of an amalgam filling under the above condi- 
 tions. The irritation, however, will be much greater should the 
 filling-material be oxychloride or oxyphosphate of zinc. In the 
 latter instance, as soon as the filling is introduced, the patient 
 usually experiences considerable pain, which may last from one 
 hour to one or two days, or until the filling-material is removed. 
 
 Exceptionally we may induce pulpitis in the process of regu- 
 lating teeth, when the force employed has been too great or 
 too rapid. Pulpitis may be the result of a heavy or too long- 
 continued malleting in the introduction of gold fillings, or of 
 the driving of wooden or metallic wedges between the teeth. 
 We also observe pulpitis in consequence of traumatisms, when 
 portions of the crown of a tooth are broken ofl", and the pulp 
 becomes more or less exposed. New formations of bone or 
 dentine — so-called pulp-stones — sometimes become a source of 
 irritation to the pulp-tissue. As a rule, so long as these newly- 
 formed tissues are developed upon the walls of the pulp-chamber 
 in contact with the primary dentine, they do not cause irrita- 
 tion. Quite dift'erent, however, is the outcome of new forma- 
 tions of bone or dentine, when they originate in the middle of 
 the pulp-tissue, in which situation they often produce pulpitis. 
 They nuiy give rise to neuralgia which freiiuently is obscure 
 and more pronounced in other parts of the nervcnis sy^tcm than 
 in the aft'ected dental pulp. 
 
 Constitutional disturbances, esi)ecially those interfering with
 
 382 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 the circulation of the blood, occasionally produce pulpitis. 
 Among these I would mention anaemia as the most frequent. 
 In circumscribed pericementitis the inflammatory infection may 
 reach the apex of the root of a tooth, and thus induce pulpitis. 
 Heat, cold, and electricity are remedial agencies frequently em- 
 ployed to abate inflammation, but when applied to the teeth in 
 higher degrees, or suddenly, they also may produce pulpitis. 
 
 To the dental practitioner it is of the utmost importance to 
 be able to make a correct diagnosis of the diseases of the pulp, 
 that he may decide upon the proper mode of treatment. First 
 of all, it will be necessary to classify the diseases, in order to 
 ditterentiate between them. For this purpose most of the 
 classiflcations of pulpitis are rather unsatisfactory. From a 
 pathological point of view, we have to consider only two prin- 
 cipal forms of inflammation, — viz, the acute and the chronic. 
 From a clinical standpoint, on the other hand, it is advisable 
 to formulate a more definite classification of the diseases of 
 the dental pulp. Adolph Witzel* distinguishes varieties of 
 pulpitis in the following manner: 1. Irritation of the pulp, or 
 primary hyper^emia; 2. Partial pulpitis; 3. Total pulpitis with 
 abscess; 4. Suppuration and fatty degeneration of the pulp; 
 5. Inflammatory gangrene of the pulp. The classification of 
 J. Arkovy,t in Europe, has been accepted by several of the 
 later writers. He was the first to state that most of the dis- 
 eases of the pulp originate independently, while formerly it was 
 believed that all chronic forms of pulpitis developed from a 
 primarj^ acute inflammation. Arkovy's classification is as fol- 
 lows: I. Acute pulp if U. 1. Septic superficial acute pulpitis ; 2. 
 Partial acute pulpitis; 3. Total acute pulpitis; 4. Purulent 
 partial acute pulpitis ; 5. Acute traumatic pulpitis. 11. Chronic 
 pulpitis. 1. Chronic parenchymatous pulpitis; 2. Chronic total 
 purulent pulpitis; 3. Chronic hypertrophy of the pulp: a, gran- 
 ular, 6, sarcomatous; 4. Gangrene of the pulp; 5. Total gan- 
 grene of the pulp : 6. Chronic idiopathic pulpitis (.?. concre- 
 mentalis). 
 
 The pathology of the process of irritation has l)een dwelt 
 upon in Chapter XXV, without reference to its clinical aspect. 
 
 * '• Die Antiseptisdie Belianilluiii;- der Pulpakrankhfiteii.' Berlin. 1879; and 
 •' Cnnipendiiini der Pathologii' imd Therapiedor Pulpakrankheiten." Hagen in 
 
 ^\., 1886. 
 
 t '• Diagnostik dur Zahnkrankheiten." Stuttgart, 1885.
 
 PULPITIS IN ITS CLINICAL ASPECTS. 383 
 
 "While, from a pathological point of view, we cannot embrace 
 this process in the chapter on pulpitis, clinically considered it 
 belongs in the latter chapter. Arkiivy and Rothmann classify 
 irritation of the pulp as pulpitis, and call it " arule septic supn-fi- 
 eial pulpitis.'' I cannot agree with them, as the word pulpitis 
 implies a process in wliieh the i)ulp-tissue undergoes marked 
 changes, visible under tbe microscope. The process which both 
 these authors describe as acute septic superficial pulpitis does 
 not, according to their description, exhibit any tissue-changes in 
 the pulp, but merely an invasion of micro-organisms, and is, 
 therefore, in strictness, nothing but an irritation of the i»ulp. 
 I therefore agree with "Witzel and Baume as to this point, and 
 will call this disturbance " irritation of the pulp," though for 
 convenience in a clinical consideration, I shall classify it with 
 pulpitis. According to general princi}iles in morbid anatomy, we 
 will classify diseases of the pulp under the following headings: 
 
 I. Irritation of the Pulp. 
 
 II. Acute Pulpitis. 
 
 1. Xon-purnlent. 
 
 a. partial. 
 
 b. total. 
 
 2. Purulent. 
 
 a. partial. 
 
 b. total. 
 
 III. Chronic Pulpitis. 
 
 1. Hyperplastic. 
 a. partial. 
 
 h. total. 
 
 2. Purulent. 
 a. partial. 
 h. total. 
 
 IV. Gangrene of the Pulji. 
 
 a. moist. 
 
 b. dry. 
 
 V. Degenerations and Atrophies of the I'ulp. 
 
 <i. calcitications. 
 
 b. eburnitication and ossification. 
 
 c. sclerotic atrophy. 
 i1. reticular atrophy. 
 c. fatty degeneration. 
 /". pigmentation.
 
 384 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 I. IRRITATION OF THE PULP. 
 
 When caries approaches the pulp-chamber, irritation of the 
 pulp ensues. A tooth may decay, and the process reach a 
 small portion of the pulp-chamber, yet the pulp may not react 
 beyond the stage of irritation. The same conditions some- 
 times occur in teeth affected by mechanical abrasion and erosion. 
 Fracture, mechanical violence to the teeth, or pericementitis 
 may likewise irritate the pulp. Quite frequently this trouble 
 originates from eburnification and ossification of the pulp- 
 tissue, the pathological anatomy of which is described in Chap- 
 ter XXVI. Constitutional disturbances also are known to have 
 the same effect upon the pulps, and sometimes even in teeth 
 without mechanical abrasion, erosion, or carious defects. 
 
 Diagnosis. — The affected teeth may be slightly sensitive in 
 mastication; if decayed, the cavity rarely extends to the pulp- 
 chamber, the layer of dentine interposed between pulp and 
 carious cavity, although quite thin, being usually hard. In rare 
 instances the pulp may be exposed on one of its horns by caries, 
 and apparently but irritated, when, nevertheless, slight pressure 
 upon it by means of a piece of cotton produces but momentary 
 pain. 
 
 The subjective jjhenomena of irritation of the pulp are char- 
 acterized by intermittent, sub-acute, drawing pain, mostly last- 
 ing a few minutes at one time. The pain usually originates 
 suddenly, when the tooth comes in contact with anything hot, 
 cold, salty, sweet, or sour, or when foreign substances are 
 pressed into the carious cavity. The crowns of teeth not being 
 affected by caries, erosion, or mechanical abrasion, the pulps 
 being irritated by pulp-stones, or in consequence of constitu- 
 tional derangements, the patients mainly complain of a sensa- 
 tion of uneasiness in all the teeth or the jaw of the affected side. 
 This sensation may sometimes be associated with slight neuralgic 
 pains in other parts of the nervous system. 
 
 Differential Diagnosis. — There are two diseases of the pulp 
 showing symptoms somewhat similar to those of.irritation of the 
 pulp, — viz, acute partial pulpitis, and sclerotic atrophy of the palp. 
 Acute partial pulpitis, however, rarely exists unless the pulp be 
 exposed by caries, except when irritation is due to pulp-stones 
 or constitutional disturbances, which tiH'(|uently occur in other- 
 wise sound teeth. In the latter case, it is not always possible to 
 state, with any degree of certainty, whether a pulp be merely
 
 PULPITIS IN ITS CLINICAL ASPECTS, 385 
 
 irritated, or whether slight partial acute pul})itis be present. 
 When the affected tooth contains a carious cavity, it should be 
 carefullv examined, especially in the vicinity of the horns of 
 the i>ulp, which will nsnally lead to the proper diagnosis. 
 
 Sclerotic atrophy of the ]nilp also raaj' be confounded with 
 irritation of the pulp, but clinically we are unable to differen- 
 tiate between these two diseases. 
 
 The prognosis of irritation of the pldp is quite favorable in 
 carious teeth, as the removal of the cause, by disinfecting and 
 tilling the cavity, always effects a cure, although Arkcivy men- 
 tions that sometimes after filling teeth whose pulps have l)een 
 irritated, partial or total gangrene may follow, — a result which 
 the writer never has observed. 
 
 II. ACUTE PULPITIS. 
 
 1. Non-Purulent. — a. Partial Acute Pulpitis. — Diagnosis. — 
 In a pulp slightly exposed, an acute partial inflammation usually 
 results. After the removal of the carious dentine from the 
 cavity of the tooth, we can easily ascertain if the pulp has be- 
 come exposed in a small place, the exposure usually being 
 situated over one of the horns. In a few instances the pulp 
 may still be found covered by a very thin layer of comparatively 
 healthy dentine. The slightest pressure upon this thin layer of 
 dentine, even with a round instrument, will yield considerable 
 pain. In these instances, therefore, it is advisable to introduce 
 into the cavity of the tooth a small piece of cotton, upon which 
 slight pressure may be exerted without danger of injuring 
 the pulp. AVhen, in the examination of a tooth affected with 
 partial acute pulpitis, the pulp becomes wounded, bright-red 
 blood flows from the pulp-chamber. Percussion will sometimes 
 elicit a sound slightly different from the normal in a tooth af- 
 fected with partial acute pulpitis, but does not increase the pain 
 during a paroxysm. 
 
 Suhjcctirc Phenomena. — The pains produced in partial acute 
 inflammation of the pulp are of an intermittent character. The 
 attacks last from Ave minutes to an hour, but during the intervals 
 the tooth feels comfortable, though slightly sensitive to thermal 
 changes, especially to cold. The paroxysms of pain mostly 
 occur once or twice in twenty-four hours, and usually not until 
 five or seven o'clock p.m., unless during mastication food has 
 become pressed into the cavity of the tooth. When the tooth
 
 '386 THE ANATOMY AND PATHOLOGY OF TUE TEETH. 
 
 has been subjected to extreme thermal changes or other irritat- 
 ing agents, the pain is often quite acute, but soon ceases upon 
 the removal of the irritant. In this form of pulpitis the patient 
 usually is able to locate the paiu in the affected tooth ; and reflex 
 phenomena in other parts of the nervous system rarely accom- 
 pany the malady. 
 
 Differential Diarpiosis. — Partial acute pulpitis may be con- 
 founded with total acute pulpitis, but in the latter instance the 
 pulp is usually exposed largely or in more than one place. If 
 the pulp-cavity of a tooth affected with total acute pulpitis be 
 opened, the blood oozing forth will have the color not of arterial 
 but of venous blood. The paroxysms of pain are more frequent, 
 and last longer than in partial pulpitis. In total acute pulpitis 
 the tooth is more sensitive to hot than to cold substances; per- 
 cussion of the tooth elicits a distinctly dull sound, and is slightly 
 painful. 
 
 With partial acute pulpitis, gangrene of the pulp may be con- 
 founded, as the subjective symptoms of both diseases are similar, 
 although in gangrene of the pulp we notice a characteristic foetid 
 odor as soon as the pulp-chamber is opened. 
 
 The procpiosis in partial acute pulpitis is usually favorable for 
 the preservation of the pulp, provided the inflammatory process 
 has existed only a short period, and has only extended over a 
 small area of the pulp-tissue. 
 
 b. Total Acute Pulpitis. — TJiagiiosis. — In this form of pulpitis 
 the tooth generally is much decayed, and the pulp largely ex- 
 posed in one or more places. Sometimes we find the pulp not 
 <piite exposed, though the carious cavity is large. In these 
 instances, if a total acute inflammation be present, the dentine 
 between the pulp and the carious cavity is found quite soft and 
 thin. If the carious dentine l^e removed from the cavity and 
 the pulp-chamber opened, dark venous blood flows from the 
 pulp-chamber. Percussion upon the affected tooth always elicits 
 a somewhat dull sound, and is at the same time slightly painful. 
 
 Suhjective Symptoms. — The pain in total acute pulpitis is inter- 
 mittent but severe, the paroxysms lasting from one to six hours 
 at a time, and the painless intervals, as the disease progresses, 
 becoming shorter, in the same ratio as the pain during the par- 
 oxysm's is increased. Irritants, or pressure into the carious 
 cavity, produce severe pain, lasting an hour or more. The patient 
 usually complains of pain on the whole side of the face, and is
 
 PULPITIS IN ITS CI.IXKAL ASPECTS. 387 
 
 unable to locate it. Often reflex phenomena in other parts- of 
 the nervous system of the affected side are present. AVhen one 
 of the wisdom-teeth, especially a lower one, becomes affected 
 with total acute pulpitis, reflex pain in the ear, the larynx, the 
 shoulder, and even in the lungs is frequently complained of. 
 In the latter instance the jiatient is subject to great difhculty in 
 breathing. If, however, the affected tooth is in the u]i[»er jaw, 
 the reflex pain may affect the nerves of the supra- and infra- 
 orbital region, the eye, and the nose. In exceptional cases the 
 pain is located by the patient in teeth of the opposite jaw, 
 although these maybe quite sound. Sliould the pulp of a tooth 
 affected with total acute pulpitis be left without treatment, the 
 pain after five to eight days becomes less acute, and the inflam- 
 matory process gradually assumes a chronic character. If the 
 carious cavity of an affected second or third molar tooth is 
 situated in one of the approximal surfaces, it sometimes becomes 
 difficult to tell which tooth causes the pain. In such an emer- 
 gency either percussion, transillumination, or separation by 
 wedges will assist the practitioner in making the diagnosis. 
 After two or three days of pain from total acute pul}>itis, the 
 trouble is usually localized in the afi'ected tooth. 
 
 DifereiiVal Diagnosis. — Total acute pulpitis may easily lie con- 
 founded with other diseases of the pulp, — viz, chronic purulent 
 pulpitis, and gangrene of the pulp. Chronic purulent pulpitis 
 difters from total acute pulpitis principally in its reaction upon 
 the pericementum. In the former disease the tooth becomes 
 quite sensitive to pressure and percussion after the first day of 
 inflammation, whereas in the latter the aj)parent elongation of 
 the tooth and its sensitiveness to })ercussion and pressure arc not 
 marked in so high a degree, and do not apjiear till the third or 
 fourth day after the beginning of the total acute pulpitis. 
 
 The sul»jective and objeetive phenomena of gangrene of the 
 pulf) are quite similar to those of total acute i>ul}>itis. AVe are, 
 therefore, unable to difierentiate between these two diseases. 
 
 ]*ro(ino.'<is. — It is not advisable to attem[tt to save a i>ulp that 
 has become the seat of total inflammation. The only way to 
 preserve the tooth })ernianently is completely to extirjtate the 
 pulp, and thoroughly to disinfect and fill the pulp-canal. When 
 this has been successfully accomplished, the tooth may last as 
 long as though it had a living pulp. 
 
 2. Acute Purulent Pulpitis. — The pathological description c)f
 
 388 THE ANATOMY AXD PATHOLOGY OF THE TEETH. 
 
 this disease is divided under the heads of 'partial and total pul- 
 pitis. Clinically, however, a diiierentiation is neither possible 
 nor important. I shall therefore describe acute purulent pul- 
 pitis under one head. 
 
 Diagnosis. — When the carious dentine is carefully removecL 
 from the cavity of a tooth aft'ected with acute purulent pulpitis,^ 
 we always find the pulp exposed, at least at one of its horns. 
 The exposed portion of the pulp does not He close up to the den-' 
 tinal wall of the pulp-chamber, but recedes somewhat from it 
 at the orifice. As soon as the pulp-chamber is opened, pus oozes 
 out, whereupon the patient is instantly relieved from pain. Pres- 
 sure through a piece of cotton or a blunt instrument upon the 
 exposed portion of the pulp, before the pulp-chamber has been 
 opened, does not increase the pain instantly, but after a few 
 seconds; and if then the pus l)e allowed to escape, the pain 
 ceases altogether. Percussion upon a tooth affected with in- 
 cipient acute purulent pulpitis produces no pain, although its 
 sound may be slightly didl. After the second or third day the 
 tooth will be sensitive to percussion, and its sound will l)e dis- 
 tinctly dull. 
 
 Subjective Phoiomena. — In acute purulent pulpitis the pain is 
 pulsatory, but seldom as severe as in the foregoing forms of 
 pulpitis. The paroxysms of pain are protracted, usually from 
 four to twelve hours, and as the disease proceeds the painless 
 intervals are progressively shortened, until the pain becomes 
 continuous. In those cases where the pulp is still covered with 
 a layer of softened dentine, the tooth is extremely sensitive to 
 heat, but the pain is relieved upon the application of cold. The 
 pain in the affected tooth produced by the heat is due to the 
 expansion of gases accompanying the pus in the closed pulp- 
 chamber. As gases are greatly expanded by heat, the result is 
 obvious. In some instances, and especially in weakly-constituted 
 persons, acute purulent pulpitis is accompanied by an elevatii)n 
 in the temperature of the jiatient, which begins as soon as pus 
 forms. 
 
 Differential Diagnosis. — Acute purulent pulpitis may be con- 
 founded with three other diseases of the pulp, — y\z, partial acute 
 pulpitis, chronic purulent pulpitis, and gangrene of the palp. In 
 partial acute })ul}iitis the pain is more intermittent, and when 
 the carious portion is lemowd from the cavity of the aft'ected 
 tooth, the pulp almost protru(h's, and if wounded will yield
 
 • PULPITIS IX ITS CLINICAL ASPECTS. 389 
 
 bright-red blood; whWv in acute purulent pulpitis the pulp is 
 somewhat retracted at the exposed horn, is very sensitive to 
 heat, and when the [tulp-chamber is opened pus instead of 
 blood oozes out. The piiiicipal diiference between acute and 
 chronic purulent pulpitis is that in the latter the pulp is exposed 
 quite larij:ely, or in several places, the pain is much less severe, 
 and the tooth aches l)ut litth' upon application of heat. Gan- 
 grene of the I'ulp also may l)e mistaken for acute purulent pul- 
 pitis, but when the puli»-chamber of a tooth atfected with the 
 former disease is ojjcned we observe in it a g-rayish or brownish 
 fluid, with the characteristic odor of gangrene. 
 
 The profinosis for pulps of teeth atfected with acute purulent 
 pulpitis is ahvays unfavorable. In these instances the sooner 
 the pul}> is removed, and the pulp-canal disinfected and filled, 
 the better. This, successfully accomplished, will usually save 
 the tooth. 
 
 III. CHRONIC PULPITIS. 
 
 1. Hyperplasia. — a. Partial. — Clinically considered, there are 
 two varieties of partially hyperplastic pulps, — the rayxotibrous 
 and the sarcomatous. But as the latter belongs to the tumors, 
 I shall consider it in the chapter on that subject. 
 
 Diagnosis. — Under the head of partial hyperplasia we will 
 consider such pulps as are found in teeth largely decayed in 
 their entire grinding-snrface, and exposed at one or all of their 
 horns. The pulps have grown out of the pulp-chamber, and 
 their surface presents a lobulated appearance, of a crimson hue. 
 These little tumors of the pulp vary in size from that of the 
 head of a pin to that of a pea, or even more. They occur 
 mostly in tlie molar teeth; sometimes they are seen in the 
 bicuspids and cuspids, exceptionally in the incisors. This dis- 
 ease, when it afiects the pulp of an upper molar, starts usually 
 from the lingual root, while hyperplasia of the lower molars 
 commonly originates in both roots. Pul}»s atfected with par- 
 tial hyperplasia are not very sensitive to mastication, nor to the 
 touch of an instrunient. Even a probe introduced along the 
 wall of the pulp-chamber for a little distance produces no pain, 
 thougli it will usually start a profuse hemorrhage. The hyper- 
 plastic portion is connected with the unchanged pulp within 
 the pulp-chamber or the canals by means of a constricted stem 
 or pedicle.
 
 390 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 The suhjective jjhenoinena of partial hyperplasia are quite few, 
 and beyond a sensation of uneasiness in the affected teeth no 
 pain exists, unless pronounced thermal changes or mechanical 
 injury affect the pulp. 
 
 D'tjf'erential Diagnosis. — Partial hyperplasia of the pulps may 
 sometimes be confounded with granuloma of the gums, or the 
 pericementum which occasionally occurs when, besides the 
 cavity in the grinding-surface, a tooth also contains a carious 
 cavity in the neck under the gum communicating with the 
 pulp-chamber. In these cases the gum or the pericementum 
 may grow into the pulp-chamber and appear in the cavity on 
 the grinding-surface of the tooth. Their vulnerability renders 
 an examination difl&cult, and the best way to arrive at a correct 
 diagnosis is to insert a piece of cotton saturated with carbolic 
 acid as far into the pulp-chamber as possible, leaving it for about 
 twenty-four hours. Then we are usually able to make the 
 examination. 
 
 Tlic prognosis for the preservation of the pulp is bad ; but the 
 tooth can be saved if the pulp be extirpated and the canals 
 filled, which in partial hyperplastic conditions of the pulp is 
 usually easy to accomplish. 
 
 6. Total Hyperplasia. — Diagnosis. — This disease is more 
 common in teeth whose pulps are largely exposed by caries, 
 but is met with in some instances, where the pulp is still covered 
 by softened dentine. Pressure upon the dentine in the vicinity 
 of the pulp is not painful, except when foreign substances enter 
 the pulp-chamber. When the softened dentine is removed from 
 the carious cavity, and the pulp exposed, we are able to enter it 
 for some distance with a tine instrument, and sometimes we 
 even touch the periphery of the pulp without producing pain. 
 But the pulp in this condition bleeds easily and profusely upon 
 the slightest injury. The tooth is acutely sensitive to thermal 
 changes, and an injection of hot or cold water into the cavity 
 causes pain. The pain, however, does not start of a sudden, 
 but gradually, lasting from one to ten minutes. As a rule, the 
 tooth is somewhat loose, though not sensitive under pressure 
 nor during mastication unless these irritate the pulp directly. 
 Percussion upon the affected tooth is answered with a slight 
 dullness in the sound, and also detects a tenderness, whicli proves 
 that the chronic inflammation of the pulp lias reacted upon the 
 pericementum.
 
 ITLI'ITIS IX ITS CLINICAL ASPECTS. 391 
 
 Su/tjective PJicnomena. — In chronic hyperplasia of the pulps we 
 rarely observe severe pain, unless the inflammatory process 
 should enter an acute stage. The first warning the patient has 
 of the trouble consists of an uneasy sensation, which he is 
 usually able to localize in the affected tooth. This may continue 
 from fifteen minutes to three or four hours, followed by abso- 
 lutely painless intervals of a day, a week, or even of months. 
 The paroxysms of pain arc usually produced by irritating sub- 
 stances brought in contact with the exposed pulji, although 
 in some cases constitutional derangements are apt to bring on a 
 paroxysm of pain, oftentimes acute. Whenever the pulp of 
 such a tooth becomes disturbed, either by constitutional or local 
 irritants, the tooth begins to ache severely and exhibits all the 
 phenomena of a total acute pulpitis, lasting from two to four 
 days. When the patient suffers from such an acute attack, we 
 usually observe reflex pains in other parts of the nervous system, 
 similar to those experienced in total acute pulpitis, when pro- 
 duced l)v eburnification and ossification of the pulp. Usually 
 after that the tooth is comfortable for several weeks or months. 
 Every attempt at destroying, by means of arsenions acid, a pul[) 
 affected with total hvjierplasia will result in an excruciatingly 
 painful paroxysm, and in a failure to accomplish devitalization. 
 The character of the pain in such an acute paroxysm is mostly 
 dependent upon the area of the exi»osure of the pul}i. In cases 
 ■where the pulp is largely exposed and not covered by softened 
 dentine, the pain will be considerably less than in cases where 
 the exposure of the pulp is small, or the pulp is still covered by 
 softened dentine. 
 
 Differential Diar/nosis. — Three diseases of the pulp maybe con- 
 founded with total hyperplasia of the pulp : total acute pulpitis, 
 fjangrcne of the pulp, cburinji cation and ossification of the pulp. 
 The principal difference between total acute pulpitis and total 
 hyperplasia of the pulp is in the reaction produced upon the 
 pericementum, which in the former instance is but slight; in 
 the latter, (juite noticeable. Another characteristic feature of 
 hyperplastic pulps is their behavior upon the application of 
 carbolic acid, campho-phenique,phenate of cocaine, aconite, etc., 
 which in this disease never give ready relief when applied 
 during an acute paroxysm of pain, wheieas they act instantly 
 in cases of total acute pulpitis, (iangrene of the pulp can be 
 distinguished from its total hy[»er[)lasia, although the subjective
 
 392 THE ANATOxMY AND PATHOLOGY OF THE TEETH. 
 
 and the objective gymptonis of both diseases are similar. In the 
 former, when the pulp-chamber is opened we observe the char- 
 acteristic smell of gangrene, which never is present in total 
 hyperplasia of the pulp. Quite different, however, is the t ase 
 when the tooth is so sensitive that we are unable to open the 
 pulp-chanil)er. In such an instance a correct differentiation 
 between tbese two diseases cannot be made. Total hyperplasia 
 of the pulp may also be confounded with eburnitication and 
 ossification of the pulp, the more so as most of the hyperplastic 
 pulps in time partially degenerate into dentine and bone. More- 
 over, the degeneration into dentine and bone, as spoken of in 
 the next chapter, principally occurs in teeth not affected by 
 caries. Whether this exists or not can be ascertained by careful 
 examination. 
 
 2. Chronic Purulent Pulpitis. — The morbid anatomy of 
 chronic purulent pulpitis, like that of acute purulent pulpitis, 
 admits of two forms of the disease under consideration. As 
 it is of little importance to the practitioner whether a pulp is 
 affected by partial, or by total chrcmic purulent pulpitis, I shall 
 discuss the disease in one [laragi-aph, especially since the 
 term total purulent pulpitis, as usually applied, is a misnomer. 
 So soon as all the pulp-tissue has been transformed into pus, 
 there is no longer any pulpitis, but a pulp-chamber filled with 
 pus instead. In the majority of instances, however, we still 
 find remnants of pulp-tissue, as evidenced in the chapter on the 
 morbid anatomy of [lulpitis. 
 
 Diagnosis. — Chronic ])urulent pulpitis is found in tcctli with 
 large carious cavities, whereby the i»ulp has been exposed largely 
 or in several places. The dentine covering the exposed portions 
 of the pulp is always quite soft, and frequently such a deteriora- 
 tion extends over • the greater portion of the pulp-chamber. 
 This form of pulpitis is easily recognizable by the quantity of 
 pus eliminated upon the opening of the pulp-chamber, in cases 
 where this has remained covered by softened dentine. Usually 
 but a few drops of pus appear, but in exceptional cases the pulp- 
 chamber, on l)eing opened, yields about a teaspoonfiil of pus or 
 even more. In such instances there is present, additionally to 
 the pulpitis under consideration, an acute or chronic purulent 
 pericementitis. In general, however, in this disease, when the 
 pulp-chamber is found open, most of the pus has already 
 escaped, and upon examinaliou we only find one or two drops
 
 PULPITIS IX ITS CLINICAL ASPECTS. 893 
 
 of it in the pulp-chamber. A probe may be introduced into the 
 .pulp-chamber for some distance without producing either pain 
 or hemorrhage. Indeed, when an instrument enters the pulp- 
 chamber of the tooth, causing the evacuation of the pus, the 
 patient is instantl}' relieved. Pressure upon the softened dentine 
 in the vicinity of the pulp-chamber elicits no reaction, except in 
 those rare cases where the pulii-chamber is still inclosed by soft- 
 ened dentine. A characteristic feature of this form of pulpitis 
 is the })resence of pericementitis, which in the earlier stages of 
 chronic purulent pulpitis is acute. In those instances,' on the 
 contrary, in which the pulp-chamber has been largely perforated, 
 and chronic purulent pulpitis has existed for four weeks or more, 
 it is associated with chronic purulent pericementitis. Percus- 
 sion as well as slight pressure upon the affected tooth will be 
 quite painful, and the former will elicit the characteristic dull 
 sound. 
 
 Subjective Phenomena. — In chronic purulent pulpitis, the patient 
 complains of moderate throbbing and shooting pain in the 
 aftected tooth, w'hich, owing to the inflammatory process set 
 up in the pericementum, is quite sensitive upon mastication. 
 When the perforation in the pulp-chamber is small, and most 
 or all of the pus retained in the puli)-chamber, the tooth is 
 extremely sensitive to heat, which, however, is not the case 
 when the perforation of the pulp-chamber permits the evacua- 
 tion of the pus. Usually, whenever pus is formed, the patient 
 is attacked by a chill followed by more or less fever, the severity 
 of which depends upon the quantity of pus accumulated in the 
 pulp-chamber and the pericementum, as well as upon the con- 
 stitutional peculiarities of the patient. 
 
 Differential Diagnosis^. — Chronic purulent pulpitis may be con- 
 founded with four diseases, — viz, acute purulent pulpitis, acute 
 total pulpitis, ganjirenc of the pulp, and acute alveolar abscess. 
 Acute purulent pulpitis differs from the chronic form principally 
 in the inflammatory reaction which the latter always produces, 
 while in the former it is scarcely noticeable. Other character- 
 istic features of chronic purulent pulpitis are the large extent of 
 the carious cavities, and the quantity of pus eliminated upon 
 opening the pulp-chamber; whereas in acute purulent pul}>itis 
 the pulp is, as a rule, exposed only at one of its horns, and but 
 one or two drops of pus are seen at the iicrforation of the pulp- 
 chamber. Total acute pulpitis diflers from chronic purulent
 
 394 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 pulpitis principally in that when the pulp-chamber is opened 
 blood oozes forth, and pressure in the vicinity of the pulp- 
 chamber produces intense pain ; whereas in chronic purulent 
 pulpitis pus is present, and no pnin is experienced upon pressure 
 in the neighborhood of the pulp-chamber. In its latter stages 
 chronic purulent pulpitis may easily be confounded with acute 
 alveolar abscess, while in its beginning we always find traces 
 of sensitive pulp-tissue in some parts of the pulp-chamber or 
 root-canal. 
 
 Frofpiosis. — In chronic purulent pulpitis the death of the pulp- 
 of the tooth is inevitable, and the earlier the pulp be extirpated 
 the better is the chance of preventing the formation of an acute 
 alveolar abscess. When pericementitis has but slightly developed, 
 and great care is exercised in the removal of the pulp, by absolutely 
 aseptic instruments, the canals after a thorough preparation and 
 disinfection may at once be filled and no trouble will follow, pro- 
 vided micro-organisms have not already entered the pericemen- 
 tum during the process of pulpitis. If, however, the pericemen- 
 titis has progressed to the stage of tenderness or fluctuation 
 above the end of the root, the pulp-canal cannot be filled at once, 
 though by skillful treatment the preservation of the tooth is 
 possible. 
 
 IV. GANGRENE OF THE PULP. 
 
 a. Moist. — This disease is most common in carious teeth, the 
 pulp-chambers of which are still covered with softened dentine. 
 The extent of the carious cavities in the teeth affected with 
 moist gangrene seeais to have no influence upon the infection of 
 the pulp. In some instances we meet with carious cavities 
 representing an almost straight tube-like canal, not much larger 
 in diameter than a stout nerve-broach ; in others we see almost 
 the whole crown of tlie tooth lost, betore the pulp is attacked 
 by moist gangrene. This process usually starts at one of the 
 horns of the pulp, lapidly destroying it in the direction of the 
 root. For this reason an examination by means of a probe, 
 when handled carefully, is painless to the patient, even in the 
 first stages of moist gangrene. At the same time the examina- 
 tion of the pulp-cliamber of such a tooth will leave no doubt as 
 to the correctness of the diagnosis, because the instrument em- 
 ployed will inevitably be tainted with the characteristic «dor 
 of gangrene. In perforating the pulp-chamber of a tooth, the
 
 PULPITIS IN ITS CLINICAL ASPECTS. 395 
 
 pulp of which we suspect to be gangrenous, care must he exer- 
 cised not to exert too much pressure, as in the beginning of the 
 process only the horn is destroyed, and the instrument might 
 enter the yet unaffected pulp-tissue, an exceedingly painful acci- 
 dent. In many instances, however, we are enabled to pass the 
 broach almost to the apex of the root without producing i)ain. 
 In these cases, when an infection of the pericementum has 
 occurred, the gangrenous process has advanced nearly to the 
 apex of the root; or it will do so as soon as a broach reaches the 
 apical foramen of the roots of the tooth, unless the pulp-canal 
 had been previously made aseptic. It is therefore advisable 
 during the examination of a pulp-canal never to enter the root- 
 canals of a tooth by instruments. One of the most characteristic 
 signs of both moist and dry gangrene is the discoloration of the 
 tooth, especially marked in the incisors and cuspids. Before 
 other instruments are employed, transillumination, either by 
 reflected or electric light, will greatly assist in making the diag- 
 nosis. The color of such teeth depends upon the acuteness 
 and the stage of the process. At the beginning of gangrene, 
 when only a part of the coronal portion of the pulp has been 
 destroyed, there is seldom any discoloration visible. In further 
 stages, however, when most of the coronal portion of the pulp 
 has been devitalized, the tooth changes its color, at first to a 
 slightly grayish-blue, gradually becoming darker, until it assumes 
 a dirty brownish or even blackish shade. In some instances, 
 when in the process of acute pulpitis a blood-vessel had rup- 
 tured, and the pulp dies, the tooth rapidly changes its color, at 
 first to a light pink, and after one or two weeks to a dark brown. 
 The discoloration in all instances, however, will be slight, or 
 even not noticeable at all, when the pulp has been removed before 
 it is wholly destroyed by the gangrenous process. 
 
 Tlie sabjedire phenomena of moist gangrene are quite severe 
 intermittent pains, which in the first stages last from a few 
 minutes to half an hour. In the later stages, however, a parox- 
 ysm may last over one hour. The pain mostly arises spon- 
 taneously, and does not seem to be started nor aggravated by 
 thermal changes. A tooth affected with moist gangrene is 
 never quite free from pain. Even between the paroxysms the 
 patient complains of an uneasy feeling or slight pain, that 
 increases in severity as the gangrene advances. In the latter 
 stages of the process the tooth, up to that time comfortable,
 
 396 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 begins to get sore in mastication, and becomes elongated in its 
 socket, — a characteristic sign of the infection of the peri- 
 cementum and its inflammation. 
 
 Diff'ereritial Diagnosis. — Moist gangrene of the pulp may be 
 confounded with the majority of the diseases of the pulp, but 
 especially with acute partial, acute total, acute purulent, and chronic 
 p undent pulpitis. The principal characteristic symptoms of gan- 
 grene of the pulp are usually a sensitiveness to pressure upon 
 the softened dentine of the pulp, and, when the instrument 
 enters the pulp-chamber, the gangrenous odor. 
 
 Prognosis. — In the first stages of moist gangrene of the pulp 
 "u^e may, in some instances, succeed in amputating the coronal 
 portion of the pulp, and thus save the pulp-stumps; but this 
 success must be regarded as exceptional. The best procedure 
 to preserve the tooth is the complete extirpation of the pulp and 
 filling of the root-canals as soon as the diagnosis of gangrene of 
 the pulp has been made. The earlier this is accomplished the 
 better will be the color of the tooth, and the less is the probability 
 of a succeeding pericementitis. 
 
 t>. Dry Gangrene. — Diagnosis. — While moist gangrene is of 
 frequent occurrence, dry gangrene of the pulp is not so often 
 observed. Dry gangrene of the pulp usually occurs in teeth the 
 crowns of which have not been attacked by deep-seated caries. 
 The teeth usually show a grayish-blue discoloration, and often 
 this has been noticed for years before such teeth have given pain 
 or discomfort. Percussion upon a tooth affected with dry gan- 
 grene will produce no pain, but often a slightly dull sound. 
 
 Subjective Phenomena. — Besides the discoloration of the tooth, 
 there is no symptom to inform the patient of the existence of 
 the disease. 
 
 Differential Diagnosis. — Dry gangrene may, perhaps, be con- 
 founded with moist gangrene of the pulp, although in the latter 
 disease the patient has suftered more or less pain before the 
 tooth became discolored, and when the pulp-chamber is opened 
 the cliaracteristic smell is present. Teeth affected by dry gan- 
 grene are not decayed, and when the pulp-charnber is opened 
 we find a grayish-white filamentous substance, perfectly dry. and 
 with no perceptible odor. Some teeth affected with dry gan- 
 grene remain so perfect in color that a difterentiation between 
 them and the teeth with living pulps is almost impossible. In 
 such instances an application of the chloride-of-methyl spray
 
 .MORBID AXATOMY OF I'ULl'ITIS. 397 
 
 ought to be made as near to the neck of the tooth as possible, 
 with the precaution to adjust the rubber-dam ou the tooth to be 
 sprayed. If the tooth does not react upon the spray, the pulp 
 is dead; whereas a living pulp will ache considerably upon the 
 use of the chloride-of-methyl spray. 
 
 The ■prognosis of a tooth affected with dry gangrene is always 
 favorable, and when the tooth is bleached by pyrozone, the dis- 
 coloration usually does not return. 
 
 CHAPTER XXXV. 
 
 MORBID ANATOMY OF PULPITIS. 
 
 I. Acute Pulpitis. — In accordance with the classification of 
 pulpitis laid down in the previous chapter, I propose to consider 
 first the acute non-purulent form. 
 
 a. Acute Non-Purulent Pulpitis. — This may be either partial or 
 total, the former being far more common than the latter. 
 Partial pulpitis is usually found in the crown portion, starting 
 from its surface and due to an irritation brought to bear upon 
 the pulp-tissue, commonly by the approach of a carious process. 
 It is much less frequently met with in the root-portion of the 
 pulp, having for its origin an irritation transferred from peri- 
 cementitis. 
 
 Acute superficial pulpitis is illustrated with a low power in 
 Fig. 210. In this example only the surface of one horn of the 
 crown portion has been attacked. We may infer that this same 
 horn had been previously attacked by a slight plastic inffam- 
 rnation which led to fibrous hyperplasia, and a deposition of 
 lime-salts in the shape of osteoid tissue (0). The later acute 
 attack has, however, led to an acute inflammation even of the 
 fibrous portion. A peculiar feature observable in this pulp, and 
 one with wliidi we fre([uently meet in pulpitis, is the general 
 dissemination of the infianimatory foci {F), which are usually 
 established around larger blood-vessels. 
 
 Specimens of this type, if carefully [trescrved in dilute chromic- 
 acid solution and sliced by the microtome, ati'ord excellent 
 opportunity for the study of the process of pulpitis, with medium
 
 398 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 and high powers of the microscope. (See Fig. 211.) The spot 
 selected for illustration exhibits three grades of acute pulpitis, 
 passing from a quite intensely-inflamed region to a slightly- 
 
 FiG. 210. 
 
 AcuTK Pulpitis in the Coronal Portion. 
 
 /.intensely-inflamed horn; 0. osteoid tissue; F, apparently isolated inflammatory focus. 
 Magnified 10 diameters. 
 
 inflamed one. In the former, the myxomatous structure of the 
 palp-tissue is nearly destroyed, and in its stead we see a large 
 number of lumps of living matter, m_ostly clustered, in varying
 
 MOIIBID ANATOMY UF PULPITIS. 
 
 399 
 
 phases of development, from a minute granule of compact 
 li^'ing matter to a distinctly outlined, coarsely-granular proto- 
 plasmic body. We trace the development of such lumps, not 
 only from previous lym[)h-corpuscles by a process of splittino- or 
 
 Fig. 211. 
 
 Acute Pim-itis. 
 
 7, intensely-inflamed portion ; M, moderately-inflamed portion ; ^S". slightly-inllamod portion ; 
 JV, JV, small bundles of meJullatod nerves, intensely inflamed ; B, larsfo bundle of nieduUated 
 nerTOs, slightly inflamed ; T, nerve-bundle in transverse section ; ]'. vein, engorged with red 
 and colorless blood-corpuscles ; (', capillary, engorged and widened. Magnified 500 diameters. 
 
 division, but also from the tral)e('ula' of the myxomatous net- 
 work and from the protoplasm or myxomatous substance filling 
 the meshes of the myxomatous net-work. Since the develop- 
 ment of these so-called intlammatory i-orjiusclos is so easily
 
 400 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 traceable, as originating from all the components of the pulp- 
 tissue, we again are placed in position to emphatically deny the 
 emigration of leucocytes according to J. Cohnheim's theory. 
 True it is that the capillaries and small veins within the inflam- 
 matory focus are engorged with red and colorless blood-corpus- 
 cles, the latter being accumulated mainly along the walls of the 
 vessels. True it is, also, that the leucocytes creep through the 
 walls of the capillaries and small veins; but this occurs in the 
 preliminary stage of inflammation in hyperfemia, and is by no 
 means an essential feature of inflammation. 
 
 Fig. 212. 
 
 Acute Pulpitis. 
 
 S. secondary dentine; B, bay-like excavations filled with medullary or inflammatory corpus- 
 cles; F, transverse section of a blood-vessel ; il/, multinuclear body. Magnified 300 diameters. 
 
 The nerve-bundles break up into inflammatory corpuscles. 
 First the perineurium, next the m3'elin investment, then after the 
 disappearance of the myelin, lastly the axis-cylinders themselves 
 take part in the production of inflammatory corpuscles. This 
 transformation easily explains the severe pains caused by an acute 
 though only superficial pulpitis. 
 
 Should an acute inflammation start in a pulp around which 
 secondary dentine had been formed, the latter would likewise 
 be afl[ected, its lime-salts being dissolved out in bays similar to
 
 MORBID ANATOMY OF PULPITIS. 401 
 
 those seen in intlamed cementum and bone-tissue, filled with 
 multinuclear protoplasmic bodies or inflammatory corpuscles. 
 (See Fig. 212.) 
 
 There are two ways of explaining this feature, — /.t'., the 
 inflamed tissue itself may have caused the liquefaction of the 
 basis-substance of the secondary dentine and grown into the 
 bays thus produced; or the living matter belonging to the sec- 
 ondary dentine may have grown up to inflammatory corpuscles 
 and so-called giant-cells. The latter view seems to me to be the 
 most probable. 
 
 All the tissue-changes described become less pronounced the 
 nearer we approach the healthy portion of the pulp, and frequently 
 the border-line between the inflamed and normal portion is 
 quite abrupt. 
 
 Among recent authors, Arkovy and Rothmann describe a 
 septic superficial pulpitis due to an invasion of the pulp by 
 streptococci. Rothmann depicts this alleged form of pulpitis; 
 but in his figure only normal pulp-tissue is seen, together with 
 a few streptococci. Whether or not such a partial septic pulpitis 
 exists I am unable to say from my own observation, and I fully 
 concur with A. Witzel in the view that in such cases we have 
 no right to speak of pulpitis, but only of irritation of the pulp. 
 
 Should the entire pulp be attected, which is very rare, it will 
 be found crowded with inflammatory corpuscles. The outcome 
 of this form of pulpitis seems to be invariabl}' suppuration, or, 
 through the complete destruction of all blood-vessels, gangrene 
 of the pulp, 
 
 b. Purulent Pulpitis. — So long as the inflammatory corpuscles 
 remain interconnected, inflammation of the pulp is always non- 
 purulent. So soon, on the contrary, as the connections of the 
 corpuscles are torn, we have as a result the appearance of pus- 
 corpuscles. Again, the formation of pus may be limited to one 
 horn of the crown, or may aftect all parts of the pulp. In the 
 former instance, the trouble is known as abscess of the pulp ; in 
 the latter as suppuration of the pulp. 
 
 An instance of acutely-formed abscess is illustrated in Fig. 
 213. Luckily, the pus-corpuscles have remained in situ in this 
 specimen, i)crhaps owing to its being imbedded in celloidin. 
 A well-defined border line is seen between the inflamed and the 
 suppurating portions of the })ulp. The former takes the stain of 
 ammoniacal carmin, the latter does not. In tlic vicii'.ity of the 
 
 27
 
 402 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 abscess most of the blood-vessels are obliterated by being trans- 
 formed into longitudinal clusters of inflammatory corpuscles. 
 It is reasonable to assume that the disintegration of the inflamed 
 
 Fig. 213. 
 
 AcL'TK Sui'PURATivK Pulpitis in thk Coronal Portion. 
 
 /, intonselyinflaiued horn; ^.abscess; F, blood- vessels engorged with blood; .S'. superficially- 
 inflamed horn ; iV, nest of inflammation. Magnified 10 diameters. 
 
 tissue, notwithstanding the presence of enormous numbers of 
 staphylococci, is due to the destruction of the blood-vessels. 
 Should this disintegration take place throughout the entire
 
 MORBID ANATOMY OF PULPITIS. 
 
 403 
 
 pulp, suppuration will follow everywhere, and in such a case 
 the whole pulp-cliamljer will be transformed into an abscess- 
 cavity. Such a termination of acute purulent pulpitis seems to 
 be exceedingly rare. Far more commonly, the coronal portion, 
 or one or several root portions, are transformed into pus, while 
 one or more root portions remain in the stage of acute pulpitis 
 without l>eing destroyed by suppuration. 
 
 II. Chronic Pulpitis. — Modern writers claim that chronic pul- 
 pitis is not inevitably the outcome of primary acute pulpitis. 
 This holds good in my experience for a certain number of cases. 
 Unquestionably, however, the outcome of a slight acute process 
 must be the form which I propose to term hyperplasia. In the 
 light of late researches we must admit that any particular form 
 
 Fig. 214. 
 
 Left Upper Mol.\r with Paktial Hyperplasia of the Pulp. 
 Magnified 2 diameters. 
 
 of tissue, before its transmutation into another form, will have to 
 be reduced to an intermediate state of indiiference, its embry- 
 onal or medullary condition. Acute pulpitis furnishes such an 
 intermediate stage of indiiference. Since the term inflammatory 
 corpuscles is synonymous with that of embryonal or medullary 
 corpuscles, the result of the production of a new tissue is 
 termed hyperplasia. Such hy])erplasia may yield a tissue 
 kindred to the originally inflamed one, the result being a new 
 formation of myxomatous tissue ; in other instances, the result 
 will be the transmutation of the myxomatous ]ym[th-tissue into 
 fibrous connective tissue. 
 
 In many instances, an exposed and consequently inflamed 
 pulp at the bottom of a large carious cavity, instead of perish-
 
 404 
 
 THE ANATO:HY AND PATHOLOGY OF THE TEETH. 
 
 ing by suppuration, produces so-called ^'- proud fesh,'' known to 
 the pathologist as granulations. (See Fig. 214.) Such granula- 
 tions are often pediculated, starting from the narrow root por- 
 tion and freely expanding over tlie open cavity. They are 
 known to sprout out wherever a wound on the surface of the 
 body heals by suppuration. Similarly the exposed pulp pro- 
 
 FiG. 215. 
 
 ^ ^ ' "'^V/^-^^-r) 
 
 Hyperplastic Myxomatous Pulp, ■which Filled a Carious Cavity. 
 
 M, lobules made up of papillae of a myxomatous structure, rich in capillary and venous 
 blood-vessels ; G, calcareous globule ; E, epithelial cover of papillfc. Magnified 10 diameters. 
 
 duces crimson-red, slightly lobulated granulations, with a con- 
 tinuous though slight discharge of pus. 
 
 Under the microscope the granuhition-tissue is seen with low 
 powers to consist of myxomatous (.'onnective tissue freely sup- 
 plied with blood-vessels, but lacking nerves. (See Fig. 215.) 
 The size to which such an outgrowth may expand is almost
 
 MORBID AXATO.MY OF PULPITIS. 405 
 
 unlimited, a circumstance due to the continuous outgrowth ot 
 myxomatous tissue with an equally continuous new formation 
 of eapillary blood-vessels hy means of sprouts of the capillary 
 blood-vessels, which are at lirst solid, and afterward vacuoled 
 and hollowed out. The layer of the myxomatous tissue nearest 
 to the surface is broken down into protoplasm, and furnisln's the 
 source of suppuration. (L. Heitzmann.) 
 
 There can be no doubt as to the origin of the peculiar forma- 
 tion illustrated in Fig. 215 from previous pulp-tissue, since a 
 calcareous globule is present which obviously could have been 
 formed only in a pulp. 
 
 Not infrequently the granuloma filling a carious cavity does 
 not suppurate on its surface. In such a case, the surface is 
 found covered with an incompletely stratified epithelium, to the 
 presence of which Arkovy first drew attention. Xay, it may 
 occur that a portion of the granuloma yields pus, while another 
 portion is covered with epithelium, as is seen in Fig. 215. 
 
 Considerable interest attaches to the covering epithelium 
 found at the surface of a tissue-formation, sprung from pulp- 
 tissue which lacks epithelia altogether. (See Fig. 216.) There 
 are two possibilities for the explanation of this peculiar fact. 
 Those who adhere to the theory of the mesoblastic origin of 
 connective tissue will deny the possibility of an epiblastic tissue, 
 such as epithelium is, taking its origin from connective tissue. 
 For these investigators there exists but one possibility, — viz, a 
 transplantation of epithelia from any portion of the oral mucosa 
 to the surface of the granuloma. Arkovy himself takes this 
 view. Those who admit the possibility of an interchange of 
 tissues of mesoblastic and epiblastic origin, as A. Kolhker did 
 in previous years, will also concede that a transformation of 
 connective tissue into epithelia may occur. I myself have 
 strongly advocated the idea of the change of the epithelium of 
 the original enamel-cord into myxomatous connective tissue of 
 the enamel-organ. On the other hand, I cannot object to the 
 view that connective tissue may be changed into epithelia. 
 "When we closely observe the row of columnar epithelia at the 
 surface of a granuloma of the pulp, with medium powers of the 
 microscope, we are struck with the elongated feet of a majority 
 of these bodies, blending with the fibers that constitute the 
 reticulum of the myxomatous granulation-tissue. (See Fig. 
 216.)
 
 406 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 The final answer to the question under consideration has, 
 however, not as yet been reached. 
 
 Far more frequently the outcome of pulpitis is the production 
 of dense fibrous connective tissue. (See Fig. 217.) This tissue- 
 change may involve either the entire pulp, or it may be confined 
 
 Fio. 216. 
 
 Hyperplastic Myxomatucs Pulp. 
 
 .1/, mj-xomatous granulation-tissue; G, cluster of small homogeneous corpuscles; C, capil- 
 lary blood-vessel in transverse section ; T, vein in transverse section ; E, E, rows of irregular 
 columnar epithelia, overlapped by cuboidal epithelia. Magnified 500 diameters. 
 
 to a part, not infrequently even to a small superficial portion. A 
 feature of fibrous pulps is that they easily lead to the pro- 
 duction of bone-tissue to a varying extent. Indeed, I have 
 never met with spiculte of bone in pulps which were not fibrous.
 
 MORBID ANATOMY uF IMI.l'lTIS. 
 
 407 
 
 If the fibrous tissue-change involves only a peripheral portion 
 of the pulp, the new formation of bone will take place along 
 the wall of the pulp-chamber, as in the case illustrated. Excep- 
 tionally, instead of bone, a tissue allied to it — i.e., osteoid tissue 
 — will make its api^earance. (See Fig. 218.) This is the only 
 
 Fig. 21' 
 
 
 
 l<:;.^ i\ v\ .^..„.,, , , 
 
 Fibrous Root Porttox of Pn.p with Ossification along the Dentinal Wai.i,. 
 
 D. primary dentiue: iV, nock-like formation of bone-ti?suo ; B. 77, faintly lamellated bone- 
 tissue ; F, fibrous pulp with scanty blood-vessels, bundles interlacing; E, bay-like excava- 
 tions in the bone-tissue. Magnified 200 diameters. 
 
 instance where I have seen such osteoid tissue, which as to 
 structure is evidently between calcification and ossification. 
 
 Should pulpitis again attack a fibrous pulp, the latter will be 
 reduced to medullary tissue, and we j^hall see bay-like excava-
 
 408 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 tions corroding the periphery of calcified m.asses, or of newly- 
 formed spiculaB of bone-tissue, the excavations being filled with 
 multinuclear protoplasmic bodies. In the transmutation of 
 myxomatous lymph-tissue into fibrous connective tissue the 
 
 Frc 21^. 
 
 OsTKOiD FoRMATiDNS IN THE PiT.p. (From Fig. 210.) 
 
 L, ledges of calcareous deposits along the border of the pulp : G, globular calcareous terri- 
 tories with central prutoplasniio bodies: .1/. fibrous connective tissue crowded with medul- 
 lary corpuscles ; /', fibrous connective tissue the result of chronic plastic pulpitis. Magnified 
 500 diameters. 
 
 nerves seem to participate actively in the tissue-changes, ^^•hich 
 would explain the fact that fibrous pulps, or fibrous portions ot 
 the pulp, lack nerves altogether. 
 
 Chronic Purulent Pulpitis. — This, again, may appear in two
 
 ^rORBID ANATOMY OF IHLPITIS 
 
 409 
 
 forms, — partial and total suppuration. A chronic abscess is 
 not infrequently found in the coronal portion of the pulp. It 
 is, of course, invariably the outcome of an acute abscess. 
 
 Fig. 219. 
 
 CHROXIf SlPin-RATIVK PlI.lMTIS TKH MIXATIXG IX C.V Lfl FIC.V T lOX 1)F TIIK PlS AXli AtKOI'HY 
 
 OF THE PlLP. 
 
 .4', larger abscess, filled with calcified pus: A", abscess at the periphery of the pulp ; A^, A', 
 small longitudinal al>rces3os, all calcified ; N, calcified ncrvc-bumllo : (', ('. calcareous deposi- 
 tions in the fibrous pulp-tissue : /'. P, pigment clusters from previous luMiinrrliage. Magnified 
 10 diameters. 
 
 While in the latter form there is no distinct boundarv-line at 
 the border of the diseased territory, when the abscess has per-
 
 410 
 
 THE AXATOMY AST) PATHOLOGY OF THE TEETH. 
 
 sistecT for some length of time it becomes encapsulated by a 
 layer of newly-formed fibrous connective tissue, the so-called 
 " memhrana pyogena'^ of older writers. Then the boundary-line 
 is conspicuous, especially when the pus crumbles away in the 
 process of section-cutting. As soon as the abscess has become 
 chronic, the pus-corpuscles undergo fatty degeneration, the same 
 as the contents of all chronic abscesses in the body. Still later 
 the fatty pus becomes the seat of a deposition of lime-salts, and 
 thus it is rendered harmless, since all micro-organisms are de- 
 stroyed b}' this process. (See Fig. 220.) 
 
 Fig. 220. 
 
 Segment of Abscess of Pulp, holding Calcified Prs. (From Fig. 219.) 
 
 ir, wall of abscess crowded with micro-organisms : P, calcified pus- corpuscles ; C, calcareous 
 masses ; M, bundle of micro-organisms. Magnified 500 diameters. 
 
 Chronic total purulent pulpitis is, according to recent re- 
 searches (Arkovy and Kothmann), a process not necessarily de- 
 pending upon a preliminary stage of acute suppuration ; just as in 
 the case of acute total purulent pulpitis the chronic form com- 
 monly aflects only parts of the coronal and root portions of the 
 pulp, other portions almost always escaping destruction and 
 remaining alive. (See Fig. 219.) In this figure we observe a 
 large number of purulent foci of greatly varying size scattered 
 throughout the entire substance of the pulp-tissue. The re-
 
 MORBID ANATOMY OF PULPITIS. 411 
 
 maiiulcr of tlie living pulp-tissue has become fibrous, erecting 
 walls around each abscess. As these are crowded with micro- 
 organisms, it is probable that, with each newly-applied irrita- 
 tion, the micro-organisms induce suppuration again, and so a 
 successive production of abscesses may go on almost indefi- 
 nitely. The fibrous portions of the pulp may cause either a 
 new growth of bone-tissue or the appearance of calcareous 
 globules, as in the case illustrated. A fresh attack of purulent 
 inflammation always leads to a partial dissolution of the lime- 
 salts and the appearance of the bay-like excavations at the 
 borders of both calcified and ossified tissues. Since, as stated 
 before, change of the pulp to a fibrous tissue leads to a destruc- 
 tion of the nerve-l)undles, it is reasonable to assume that chronic 
 suppuration of the pulp is not accompanied with as much pain 
 as is the acute. 
 
 If we examine the contents of a chronic abscess of the pul[), 
 we invariably find the pus-corpuscles in a state of fatt}' degen- 
 eration, — i.e., crowded with fat-granules. Occasionally the con- 
 tents of a chronic abscess are pus-corpuscles in a high degree ot 
 calcification, owing to the deposition of lime-salts. (See Fig. 220.) 
 This process renders each pus-corpuscle a glossy, indistinctly- 
 granular and irregularly-contoured body, glued to its neighbors 
 and intermixed with larger caked calcareous masses and groups 
 of inert micro-organisms. The calcareous metamorphosis of 
 pus exiilains why, in sections of pulps affected with chronic 
 purulent pulpitis, the contents of the abscesses i-emain in situ. 
 
 III. Gangrene of the Pulp. — This process is invariably the 
 outcome of acute pulpitis, when certain micro-organisms, as 
 the Streptococcus septicus, obtain access to the inflamed i)ulp. 
 In most cases of gangrene the pulp is transformed, in a short 
 space of time, into a dark grayish-brown, pulpy, and fietid mass, 
 almost diffluent, not oflering any reason for its preservation. 
 The fd'tid odor is due to the production of the gases of putretac- 
 tion. It has been asserted that the accumulation of such gases 
 in the pulp-chamber has, by their expansion, led to a bursting 
 of the crown of the tooth, the explosion being accompanied 
 by a report resembling that of a pistol-shot. jS'o certain data 
 about sucli an accident have ever been recorded. 
 
 By an almost total stopping up of the caliber of the afler- 
 ent artery, as, for instance, by an emliolus, death of the pulp- 
 tissue may ensue in the shajte of so-called </n/ f/nnf/rnie. In this
 
 412 THE AXATOMY AND PATHOLOGY OF THE TEETH. 
 
 process, the pulp, so far as my own experience teaches, is trans- 
 forraed into a grayish-white, dry mass, devoid of odor, mummi- 
 fication of the pulp-tissue, with an imperfect preservation of its 
 constituent elements. To this process I shall devote a separate 
 chapter, dwelling upon artificial mummification or coagulation- 
 necrosis of the [tulp-tissue. 
 
 CHAPTER XXXVI. 
 
 DEGENERATIONS AND ATROPHIES OF THE PULP. 
 
 I PLACE the above diseases of the pulp in a separate chapter, 
 because these retrogressive tissue-changes are by no means 
 always the outcome of pulpitis. ITaving examined a large 
 number of pulps containing so-called pulp-stones, I can say that 
 these are, as a rule, the result of irritation, but not of inflamma- 
 tion. True it is that they are frefjuently the cause of pulpitis. 
 
 a. Calcification. — Calcification occurs in two forms, z.c, within 
 the basis-substance of the myxomatous connective tissue, and in 
 the nerves and blood-vessels. 
 
 Calcification of the basis-substance of the myxomatous con- 
 nective tissue is of quite frequent occurrence, and seems to be 
 more common in the pulps of teeth which have stood in crowded 
 dental arches, the wisdom-teeth being especially prone to it. 
 The age of the patient apparently does not influence calcifica- 
 tions of the pulp, as the writer has found them in the pulps of 
 teeth- of quite young, as well as old people. From external 
 appearances, or subjective phenomena, we are unable to diagnose 
 this form of calcification of the pulp, as it never causes trouble. 
 The aspects are quite difterent, however, when calcifications 
 occur in the blood-vessels or nerves of the pulp. 
 
 Diagnosis.— Hho, latter form of calcification occurs onlv in 
 teeth aft'ected with chronic marginal pericementitis which has 
 existed more than one year. The gums in the vicinity of the 
 inflamed pericementum during a paroxysm of pain in the pulp 
 appear acutely inflamed, and are somewhat sensitive to pressure. 
 The tooth is raised from its socket, slightly loose, and sensitive 
 to percussion and pressure. Tiie characteristic features of this 
 painful disease are, that the tooth is of a normal color, and ex-
 
 DEGENEKATIONS AND ATROPHIES OF THE I'ULI'. 41;^ 
 
 tremely sensitive to thermal changes, especially cold. The ^iib- 
 jevO've phenomena of calcilications of the blood-vessels and nerves 
 of the pulp are characterized in the beginning of the process by 
 slight intermittent pain. The process commences with acute 
 marginal pericementitis, a so-called blind abscess, which after be- 
 coming chronic gradually affects the pulp of the tooth. The 
 l)ain in the pulp usually begins two or three months after the 
 tirst appearance of the pericementitis, in paroxysms, lasting at 
 first a few hours, but in later stages they may continue for four 
 days or even more. Such paroxysms of pain are usually induced 
 by a depressed state of the general health. When the pain is 
 over, the tooth continues to feel sore for two or three days, 
 though usually the pain does not recur for a month or two. 
 With every renewal of the attack, however, the pain becomes 
 more severe and the paroxysms last longer. When such a tooth 
 contains a cavity, or a gutta-percha filling, which is situated near 
 the pulp-chamber, w^e may be able to relieve the patient from 
 the terrible suffering which the disease produces in pronounced 
 stages. 
 
 Differential Diagnosis. — Calcifications of the blood-vessels and 
 nerves of the pulp may be confounded with an acute apical 
 alveolar abscess, although in the latter instance the tooth is 
 usually discolored and not sensitive to thermal changes. In this 
 respect, a characteristic feature of teeth affected with calcifica- 
 tions of the blood-vessels and nerves of the pulp is the suiter- 
 sensitiveness of the dentine to the bur. 
 
 Prognosis. — Teeth whose pulps are afi'ected by a calcification 
 of the blood-vessels and ner\'es are usually lost, unless the pulp 
 can be extirpated, which is barely possible in the advanced 
 stages of this process, on account of the great sensitiveness of 
 both the pul}) and the dentine. 
 
 b. Eburnification and Ossification of the Pulp. — On account 
 of the obscurity of their diagnosis, these disturbances of the 
 pul[t cause great trouble. The w^riter has met with patients who 
 for months or even years have suftered intensely from what was 
 supposed to be neuralgia of the face, arms, and the chest, the 
 trouble subsequently localizing itself in the pulp of a tooth, and 
 the pains ceasing instantly and never returning after the extir- 
 pation of the aftected pul[). Tn order to emphasize the impor- 
 tance of this subject, I will bricfiy relate three characteristic 
 cases met with in my practice.
 
 414 THE AXATOMY AND PATHOLOGY OF THE TEETH. 
 
 I. For Miss S., aged fourteen years, I filled, on November 
 25, 1872, the second lower molar with amalgam. The cavity 
 was situated on the buccal, near the mesial surface, and w^as 
 rather extensive. The tooth, alter the filling had been inserted, 
 remained sensitive to thermal changes for a long time, but 
 otherwise gave no trouble. In December, 1879, the tooth 
 became decayed on its mesial surface, but in trying to prepare 
 this cavity I found the dentine so extremely sensitive that the 
 patient, being at the time in bad health, would not submit to 
 it. June 3, 1880, I saw the tooth again, when the decay had 
 reached the pulp-cavity. It had never given very much trouble, 
 except when food, during mastication, was pressed into the 
 cavity. I found the dentine sensitive as before, and concluded, 
 therefore, to devitalize the coronal portion of the pulp, and 
 made an application of arsenious acid. The next day, when 
 the patient entered my otfice, she told me she felt better than 
 for many months. When I removed the dressings and exam- 
 ined the state of the pulp, I found a large so-called " pulp-stone" 
 lying toward the amalgam filling. The patient, since that time, 
 has had no more neuralgia, has grown quite strong and vigorous, 
 and the molar, with the coronal portion of the pulp amputated, 
 does good service, and has not given any further trouble. 
 
 II. On September 3, 1881, Mrs. E., aged twenty-two, came 
 to me with excruciating pain in the left upper lateral, contain- 
 ing a large gold filling in its mesial surface wdiich had been 
 inserted several years previously. About a year before the 
 patient first noticed lameness of the left arm, which, after some 
 weeks, had terminated in more or less constant neuralgia, 
 affecting, at times, the entire left side of the body; but no pain 
 was observed in this tooth previous to the 1st of September, 
 two days before the patient applied to me for relief. I opened 
 the pulp-chamber from the lingual surface of the tooth, and 
 found the pulp in a state of acute total pulpitis, which had 
 extended somewdiat into the pericementum. An application of 
 carbolic acid, tannin, and morphia was made, which greatly 
 relieved the patient. About one hour later I renewed the 
 application, and after a few minutes introduced "arsenious acid, 
 and then dismissed the patient, w^ho felt greatly relieved. The 
 next day I extracted the pulp by means of a broach, and im- 
 mediately immersed it in a very weak solution of chromic acid. 
 A section of this is exhibited in Fig. 174. The patient, who at
 
 DEGENERATIONS AND ATROPHIES OF THE PULP. 415 
 
 that time lived in the country, came back two days afterward 
 to thank me for the cure of her neuralgia, which, up to this 
 time, has not recurred. 
 
 III. On June 1, 1878, I inserted for Dr. H. an oxyehloride 
 filling in the right upper first molar, which had previously l>een 
 filled with amalgam. The cavity was large, involvino: the distal 
 and grinding-surfaces, with half of the lingual wall broken off. 
 On August 21, 1880, I restored the lost portion of the tooth 
 with gold, but left much of the oxychloride cement over the 
 pulp-cavity. The walls of the cavity were quite sensitive under 
 the bur, so much so that my patient, who in all other opera- 
 tions I had previously performed for him never said a word of 
 the pain produced by excavating, in this instance remarked 
 that the drilling in some places was very painful. There had 
 been no pain whatever previous to the introduction of the 
 gold, but about a week after the operation was completed 
 the tooth became sensitive upon percussion and mastica- 
 tion, without signs of pulpitis. About two weeks later my 
 patient was suttering from an acute alveolar abscess situated 
 above the buccal roots of this molar tooth. I immediately 
 tried to open the pulp-chamber, but could only go a little way 
 into the dentine, when the patient informed me that the drill- 
 ing caused him severe pain, analogous to the excavating of a 
 sensitive tooth. I abstained from drilling any further, filled 
 the small hole with gutta-percha, and began the treatment of 
 the abscess through the gum at the buccal surfece, but with no 
 success. The abscess was continually discharging until the 
 beginning of December, when 1 removed the gutta-percha, and, 
 with a sharp drill, perforated the pulp-chamber, but, to my sur- 
 prise, found the pulp alive and bleeding freely. I then, as quickly 
 as possible, capped the pulp in the usual way, and filled the outer 
 portion of the drill-hole, which had been widened with a larger 
 bur up to the cap, with oxyphosphate cement, concluding to 
 wait a few weeks longer, and then, if the abscess did not heal, to 
 devitalize the pulp. On January 23, 1881, I removed the fill- 
 ing, together with the cap, in order to destroy the pulp, but 
 found that the pulp had died recently, as there was no smell of 
 putrefaction present in the pulp-chamber. I took out a large 
 filling in the mesial surface of the tooth, and from this situation 
 thoroughly exposed the pulp-chamber, from which I extracted 
 a very large so-called " pulp-stone" of the size of a small pea,
 
 416 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 occupying the neighborhood of the buccal roots. This is the 
 specimen which I have illustrated in Fig. 175, " so-called 
 ' pulp-stones' composed of dentine with the features of primary 
 dentine." The canals of the tooth were then examined, and I 
 found the two buccal canals in a very putrid condition, but the 
 lingual canal contained its recently-dead portion of the pulp 
 without laro-e calcified or eburnified masses. After the disin- 
 fection and filling of the pulp-canals the abscess began to heal, 
 and the tooth to-day is as serviceable and comfortable as any 
 other tooth in the mouth. 
 
 Diagnosis. — As stated before, to differentiate clearly between 
 cases of true neuralgia and those depending upon eburnifications 
 and ossifications of the pulp is sometimes impossible, although in 
 most instances we are successful in localizing the origin of the 
 trouble. The crowns of the teeth producing such reflex pains 
 are sometimes perfectly sound, or they have previously been 
 filled. In the latter case it is likely that a large metallic or oxy- 
 phosphate filling has been placed too near the pulp. In these 
 cases the diagnosis is usually made by the application of hot and 
 cold water, taking the precaution to separate the suspected tooth 
 either with the rubber-dam, napkins, or bibulous paper. Ther- 
 mal changes always produce great pain, and the sudden appli- 
 cation to the seat of the trouble of agents wdiich produce them 
 often enables us to locate the oftender. Quite different, how- 
 ever, are those cases in wdiich the crowns of the affected teeth 
 have never been filled, and are apparently healthy. While in 
 the former instance the disease is usually limited to the tooth 
 that had previously been filled, in tlie latter instance the 
 trouble often originates more or less from two or more teeth on 
 the same side, in which event all the teeth of the affected side 
 will react upon the application of hot or cold water, although 
 sometimes this reaction may be wanting. In such cases per- 
 cussion has proved of great service to the writer. In the per- 
 cussion test, however, we must carefully exclude all devitalized 
 teeth, which are sometimes sensitive to percussion while the 
 patient is affected with neuralgic pains, although their peri- 
 cementum may be healthy. Teeth the pulps of which are 
 affected by eburnifications or ossifications are a trifle loose in 
 their sockets, and yield, upon percussion, a sUglitly dull sound. 
 
 The subjeciire phenomena connected with eburnifications or 
 ossifications of the pulp-tissue are marked by great pains of the
 
 DEliEXERATIOXS AND ATROPHIES OE THE PL'Ll'. 417 
 
 attcH'ted side, whieli are seldom localized in the pulp of the tooth 
 prodiu'iiig the disturbance, but are usually more pronounced in 
 neighboring parts of the nervous system. The attected nt-rves, 
 in the beginning of the process, are slightly sensitive to sudden 
 thermal changes, which sensitiveness lasts, as a rule, not over 
 one minute. But with eve'rv attat'k the pain increases in 
 severity, and although seldom lasting longer than from one to 
 three minutes at a time, is most excruciating. One patient 
 described these pains to be similar to that of a strong interrupted 
 current of electricity going through the teeth and face. The 
 paroxysms of pain may occur once or twice in tAventy-four 
 hours, or they may return every five minutes. When the patient 
 has suttered for some time, we ofren observe a lameness of the 
 muscles of the affected region, which in some instances even 
 become sore to the touch. Such an attack ma^- last a week or 
 a month, and the duration and recurrence of the pain seem to 
 be influenced by changes in the weather as well as by locaHty. 
 Damp and cold weather is apt to bring on an attack of pain, 
 while dry and warm weather is said to postpone it. 
 
 Diferenlial D/'at/iwsis. — From what has been stated above it is 
 evident that most of the teeth, the pulps of which are affected 
 by eburnifications or ossifications, contain no deep-seated carious 
 cavities. Teeth, therefore, exhibiting large or deep-seated 
 carious cavities, reaching the vicinity of the pulp, are to be 
 excluded from this category of pulp-diseases. There is, how- 
 ever, one form of pulpitis, total hyperplasia, the subjective symp- 
 toms of which are somewhat similar to those of eburnifications 
 and ossifications of the pulp. The similarity in the pain of 
 these two diseases is explained by the fact that upon examination 
 with the microscope we always find the pulps to be composed 
 more or less of fibrous connective tissue, which easily gives 
 origin to new formations of bone or dentine; the difference, 
 however, being that a pulp suffering from total hyperplasia is 
 more or less exposed, and the patient usually is able to localize 
 the pain. 
 
 Hyperostosis of the Roots of the Tfeth has sometimes 
 been confounded with eburnification or ossification of the pulps, 
 both indeed often presenting the same symptoms. In one in- 
 stance observed by the author, a patient about thirty years of 
 age, whose dental arches were much crowded, had suffered inter- 
 mittently from severe neuralgia, sometimes on one, sometimes 
 
 28
 
 418 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 on both sides of the face. The teeth were not affected hy 
 thermal changes nor hy alterations in the weather, and upon the 
 extraction of the four wisdom-teeth the pain ceased and never 
 returned. Unerupted lower wisdom-teeth, when the arch is too 
 small to accommodate all the teeth, may give rise also to pain, 
 which maybe confounded with ossifications or eburnitications of 
 the pulp. Theso, however, are easily recognized by the inflam- 
 mation thev usuallv produce in their surroundino;s. "SViien the 
 seat of the trouble is thought to be in a tooth, the only method 
 to give relief and make the diagnosis certain is to open the tooth 
 and devitalize the pulp. 
 
 Prognosis. — When the seat of the trouble is discovered, the 
 pulps extirpated and the root-canals filled, the severe pains will 
 never return. In many instances, however, patients during 
 their paroxysms of pain have had the teeth extracted without 
 discovering the one containing the eburnifications or ossifications, 
 which was left in the mouth, the pains of course continuing. 
 The writer once met a genileman who, upon the advice of his 
 physician, had all his posterior teeth removed, first those of the 
 upper, then those of the lower jaw, but the pain persisted for 
 about eighteen months longer, when it localized itself in an 
 upper cuspid. This tooth was opened, the pulp devitalized and 
 extirpated, and the canal was filled, since which time the pains 
 have never returned. Upon examination, I fi^und the pulp to 
 be crowded with small eburnifications. 
 
 c. Atrophies of the Pulp are of rare occurrence, and little is 
 known of them so far as clinical observations are concerned, as 
 in most instances Ave are unable to make a correct diagnosis 
 from the external appearances of the affected teeth. J. Arkovy 
 mentions four forms of atrophy of the pulp, — viz, simple, scle- 
 rotic, reticular, and total atrophy. As, however, simple and 
 total atrophies of the pulp, from a clinical as well as from a 
 histological point of view, are of little importance, I shall con- 
 fine myself to the description of the two most important dis- 
 eases of this type, — viz, sclerotic atrophy and reticular atrophy. 
 
 Sclerotic Atrophy of the Pulp. — Diagnosis. — This disease 
 is met with in apparently sound teeth, as well as in those whose 
 crowns have been the seat of caries. The filling of the cavity 
 of a tooth apiKirently has no influence over this disease of the 
 ]»ulp. From the external appearance of a tooth the ]iulp of 
 which is affected with sclerotic atrophy, we are unal)le to make
 
 DEGENERATIONS AND ATROl'lIIES OF THE PULP. 419 
 
 a correct diaii-nosis. When this disease occurs in teeth with 
 deep-seated caries that does not quite reach the pulp-chamber, 
 there is usually an uneasy sensation in the tooth, simihir to that 
 in irritation of the pulp, A ditterential sign is that when the 
 cavity of a tooth, the pulp of which is affected with sclerotic 
 atrophy, is disinfected and filled, the sensitiveness remains, 
 while in one with an irritated pulp it will usually cease after 
 one or two days. 
 
 The prognosis of })ulps with sclerotic atrophy seems to be fair, 
 as a pulp so affected may live for many years without causing 
 severe disturbance. Tlie author has observed one case, a risfht 
 lower first molar, in the mouth of a healthy lady. In May, 
 1880, the tooth was somewhat sensitive at times, and upon ex- 
 amination I found a carious cavit}' in its mesial surface, whicli 
 was prepared, disinfected, and filled with gutta-percha, without 
 any subsequent change in the sensation of the tooth. In Sep- 
 tember, 1893, the lady had a fall which loosened the cuspid, the 
 two bicuspids, and the molar teeth, and as they pained consider- 
 ably, she insisted upon having them removed. Upon opening 
 the molar, I found that a portion of the pulp was affected by 
 sclerotic atrophy. 
 
 Reticular Atrophy of the Pulp. — Diagnosis. — This peculiar 
 disease of the pulp occurs most commonly in teeth which have 
 not been attacked by caries, although they may have been pre- 
 viously filled, tlje filling reaching the vicinity of the pulp-cham- 
 ber. Teeth usually attacked by reticular atrophy stand alone 
 in the dental arch, or articulate with tlieir antagonists in such a 
 manner that they are inclined either to the lingual or to the buc- 
 cal side of the mouth. In such a case the pericementum is irri- 
 tated every time the antagonizing tooth comes in contact with 
 it. We also meet with this process in patients who have worn 
 tlieir incisors, by mechanical abrasion, nearly down to the pulp- 
 chambers, and also in the teeth of aged persons. In color, very 
 little or no difference is detectable between the teeth affected and 
 those containing normal pulps. We also find some teeth in 
 the later stages of pyorrluca that contain pulps affected with 
 reticular atrophy. The apices of their roots are usually slightly 
 absorbed, but this is frequently observed in other teeth, the 
 pulps of which are affected by reticular atrophy. Thermal 
 changes exert no iiifiueuce on sueh teeth. Most of them suffer 
 more or less from chronic apical pericementitis. Percussion will
 
 420 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 yield a dull sound, although we meet with many cases in which 
 no pericementitis is demonstrable from external appearances. 
 "When the pulp-canal of a tooth the pulp of which is atfected 
 with reticular atrophy is opened, the pulp appears like a quite 
 thin flattened thread of catgut. 
 
 Suhjective Phenomena. — Teeth whose pulps have been the seat 
 of reticular atrophy do not cause any pain as such, except that 
 sometimes, as is the case in pyorrhcea alveolaris, apical perice- 
 mentitis may assume an acute form. 
 
 Differential Diagnosis. — This disease maybe easily confounded 
 with dry gangrene of the pulp, the only difference being that the 
 apices of the roots of the teeth, the pulps of which have died of 
 dry gangrene, are seldom affected by chronic pericementitis. 
 
 The prognosis of teeth the pulps of which have died from 
 reticular atrophy is always good, as the filling of the root-canals 
 is rarely followed by acute pericementitis. 
 
 CHAPTER XXXVII. 
 
 MORBID ANATOMY OF ATROPHIES AND DEGENERATIONS OF THE PULP. 
 
 a. Calcifications. — According to C. Wedl, small nodular cal- 
 careous concretions of the pulp may be produced either by a 
 calcification of cells, or by a direct impregnation of the organic 
 substance with calcareous salts. The frequent occurrence of 
 such nodules in the pulp is by no means confined to old age 
 and the period of absorption of temporary teeth, but is not 
 rarely met with in teeth of young men and women. Altogether 
 calcareous depositions in the pulp, in the shape of both nodules 
 and irregular needles or spiculse, are frequently found (Witzel, 
 Baume), but the cause of their formation is as yet unknown. 
 A pronounced case is illustrated in Fig. 221. The slightly- 
 lobulated calcareous globules are concentrically striated around 
 one or several centers, which latter, judging from a slight stain 
 with ammoniacal carmin, are not so intensely calcified as are 
 their peripheral portions. 
 
 The age of the person apparently has nothing to do with 
 the calcification of the pulp. Some very good ol)servers have
 
 MORBID ANATOMY OF ATROPHIES AND DEGENERATlnx-;. 421 
 
 described it as the result })riiicipally of caries or loss ot sub- 
 stance of the tooth by mechanical means. I have a great many 
 specimens of pulps prepared from bicuspids and first and third 
 
 Fig. 221. 
 
 PiTLP WITH Coxckxtrkwm.y-Stri.vtkd C.vLCAUEons Gloiiules, so-callku Pulp-Sto.nk.s. 
 C. C. calcareous globules ; L, lymph-vessel ; N, N, bundles of moduUated nerves. Magnified 
 lu diameters. 
 
 molars of young- persons, which had to be extracted on account 
 of irregularity or want of room, and most of them are exter- 
 nally perfectly sound. Some of the wisdom-teeth were removed
 
 422 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 when only one or two of their cusps had pierced the gum, hut 
 with only one exception all of these pulps exhibit greater or 
 less quantities of calcific deposits as well as eburnifications. 
 The same conditions I have observed in pulps derived from the 
 teeth of old persons. 
 
 I extracted an unerupted wisdom-tooth from beneath the 
 gums of a youth fifteen years of age, the pulp of which I 
 found crowded with such calcareous globules. A rare in- 
 stance of calcification of blood-vessels is drawn in Fig. 224. 
 Here we notice a large portion of the blood-vessels of the 
 
 Fig. 222. 
 
 Calcificatiox.— Pulp of a First Lower Molar of a Healthy Young Max Eighteex 
 Years of Age, Extracted ox accouxt of Irregularity. 
 
 C, calcified masses composed of irregular lumps, rrobably former medullary corpuscles ; 31, 
 medullary corpuscle unchanged; P, central plastid, free from infiltration ; /'.capsule of fibrous 
 connective tissue. Magnified 300 diameters. 
 
 pulp, mainly the arteries and capillar'ies, transformed into 
 calcified solid rods of a markedly brown color. With medium 
 powers of the microscope, we can easily ascertain that the 
 majority of the vessels are solidified, only a few being choked 
 with red blood-corpuscles. Xo doubt the primary cause 
 of this calcification was an embolism of micrococci of an 
 unknown nature in the arteries and capillaries, which did not 
 cause pulpitis. Next, stagnation of the blood followed, and a 
 number of red blood-corpuscles were transformed into caky, 
 yellow-brown masses, which later became the scat of calci-
 
 MORBID .ANATOMY OF ATROPHIES AND DEGENERATIONS. 423 
 
 fication. Some of the vessels look homogeneous; others con- 
 tain a number of caky masses, freely intermixed with micro- 
 cocci. The veins have escaped calcification ; only a few exhibit 
 clusters of ditfusely-pigmented cakes, evidently of the' same 
 origin as those in the arteries and capillaries. 
 
 Pulps containing a larger number of calcified spicuhe, as a 
 rule, exliibit more fil)rous connective tissue than myxomatous. 
 Invariably around the calcified masses a dense layer of fibrous 
 connective tissue has formed, ensheathing the calcified nnisses. 
 Where these masses have fiillen out an empty fibrous sac is left 
 behind, in which there are neither endothelia, so characteristic 
 of blood-vessels, nor oblong nuclei, which we see in the exter- 
 nal perineurium of the Inindles of medullated nerve-fibers. 
 The presence of this envelope may convey the idea (especially 
 if the calcified masses are elongated and appear like small 
 lobulated sausages) that an obliteration has first occurred in 
 the blood-vessel by a process which in other vascular systems, 
 mainly that of the lungs, is known as " fatty embolism." The 
 application of different reagents, especially osmic acid, has, 
 how^ever, convinced me that neither of these formations is a fat- 
 embolism, and I am unable to observe any positive connection 
 between the blood-vessels and the calcified masses. Sometimes 
 it looks as if a capillary blood-vessel were attached to the space 
 containing the calcified mass, or it may occur that a capillary 
 vessel is suddenly dilated like a small aneurism, and in this 
 widened portion we notice pieces of a calcified mass. The 
 idea that the plasma of the blood laden with lime-salts accu- 
 mulates in the capillaries of the pulp, and, unalde to escape 
 behind, deposits its lime-salts, I do not accept. 
 
 (). Eburnification and Ossification. — In one root of the right 
 lower second molar of a [ihysician about thirty-eight years old, 
 circumscribed chronic pericementitis eventuated in chronic 
 plastic pulpitis, with the new formation of fibrous connective 
 tissue, and the formation of bone along the wall of the root- 
 canal. (See Fig. 217.) In the other root of this tooth I found 
 most of the bundles of the medullated nerves calcified, in appear- 
 ance similar to Fig. 226. So intense was the pain caused by 
 the .calcification of the nerves, that the tooth had to be removed. 
 Eburnification and ossification have been further dwelt upon in 
 Chapter XXVI, on the so-called pulp-stones (secondary den- 
 tine), to which the reader is referred.
 
 424 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 e. Sclerosis. — A peculiar metamorphosis is sometimes met 
 with in the pulp-tissue, termed sclerosis, which is closely allied to 
 waxT degeneration. 'Whether or not this process is the outcome of 
 pulpitis I am unable to state. This much, however, is certain, 
 that the unchanged tissue in the vicinity of a sclerotic portion is 
 not infrequently seen inflamed. (See Fig. 223.) Sclerosis trans- 
 
 FiG. 223. 
 
 Waxy Degkxeratiox of Pule, with Acute Pclpitis. 
 
 U^ waxy homogeneous mass; M, M, medullated nerve-fibers, broken up to inflammatory cor- 
 puscles ; V^ vestiges of medullated nerve ; P, myxomatous pulp-tissue, slightly inflamed ; N, 
 medullated nerve-fibers: ^, acute inflamiuation of pulp-tissue. Magnified 500 diameters. 
 
 forms the pulp-tissue into a horny-looking, nearly homogeneous 
 or faintly granular mass, holding scanty atrophied nerves, but 
 no blood-vessels. It difters from waxy degeneration in so much 
 as sclerotic portions are not stained by ammoniacal carmin 
 solution, which is invariably the car^e in waxy degeneration.
 
 MORBID ANATOMY OF ATROPHIES AND DECJENERATIOXS. 425 
 
 d. Reticular Atrophy. — C. Wedl* first drew ntteution to this 
 condition. Sucli atrophied pulps are ret-ognizable witli the 
 naked eye by their flattened, shriveled appearance and lincly- 
 indcnted outer surfaces. Their color is liirhter or darker, 
 grayish-yellow or reddish-brown, according to the amount of 
 
 Fig. 224. 
 
 A^fV 
 
 
 Calcakkots EMiioLis.\t OF Caimli.ariks of TiiK Pllp. 
 Ry R, inci|)ient reticular atrophy ; (', C, arteries and capillaries choked with emboli ; V, vein, 
 holding a pigmented I'oaguluin. Magnified 10 diameters. 
 
 necrotic blood present. The }»ulps have a dry appearance, are 
 brittle, and of a consistence similar to parchment. Wedl at- 
 tributes this atrophy to a withering of the reticulated connective- 
 tissue cells, together with the peripheral blood-vessels and nerves. 
 
 * " Pathology of the Teeth," 1872, page 237.
 
 426 
 
 THE AXATOMY AND PATHOLOGY OF THE TEETH. 
 
 In Fig. 224 this process is illustrated in its incipient stage at 
 the surface of both the coronal and root portions. This pulp 
 contains a number of blood-vessels, mainly arteiies and capil- 
 laries filled with calcareous masses of a yellow-brown color, 
 which have obviously taken their origin from coagulated and 
 disintegrated blood. The nerve-bundles are conspicuous by their 
 small size. 
 
 In the highest degrees of this atrophy the pulp-tissue is trans- 
 formed into a myxomatous reticulum, lacking lymph-corpuscles 
 
 Fig. 225. 
 
 Reticular Atrophy of the Pulp (Wedl). 
 
 .b', surface of pulp, overspread with fine offshoots ; R, myxomatous reticulum, with nuclei at the 
 points of intersection ; N, fibrous bundles, a previous bundle of nerves. Magnified 500 diam- 
 eters. 
 
 in its meshes, while the points of intersection show nuclei. (See 
 Fig. 225.) The cause of this form of atrophy is a serous infil- 
 tration of the pulp-tissue, in consequence of which first a 
 hvdropic swelling, followed by a dissolution of the constituent 
 elements, takes place. In the highest degree of such a serous 
 infiltration, the entire pulp may be dissolved. In rare cases we 
 find the pulp-chamber empty. This process is termed " dissolu- 
 tion of the pulp."
 
 MORBID AXATOMY OF ATROPHIES AND 'dECEX KR ATION<. 427 
 
 c. Atrophy of the Nerves of the Pulp.— Atrophy of the 
 meduUated nerves api)eiirs in tliree varieties,— /.f., simple 
 
 Fm. 226. 
 
 Atrophy ok Mf.duli.atkd Nerves ix a Living Puli> of ax Upper Moi-ar of a 
 Person Twenty-fivf, Years ov Age. 
 
 B, bundle of nerves; M, vestiges of medullary corpuscles ; //, nearly lioinoKenoous sclerotic 
 basis-substance. Magnified 1200 diameters. 
 
 atrophy, transformation into fibrous connective ti.-<sne, and cal- 
 ciiication. In sclerotic pulps we frequently meet with simple
 
 428 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 atrophy of medullated nerves, both siiigle and arranged in 
 bundles. (See Fig. 226.) The nerves are much reduced in 
 their bulk, being at the same time varicose in some places, 
 
 Fto. 227. 
 
 
 'kilt .: '',.■' \ '■>',:<■'■ < 
 
 feSSitoii»fekft 
 
 Transformatiox of Bundles ok Medui-lated Nerves into Partly-Calcified Bundles 
 
 OF Fibrous CoxxECTivE Tissue. Formation of Calcareous Globule. Crown 
 
 Portion of Pulp. 
 
 //, A', partly-calcified bundlos of fibrous connective tissue, previous meilullated nerves; G, 
 calcareous globule, embracing a number of fibrous bundles; t', thoroughly-calcified point of 
 globule, directed toward the surface of the tooth ; P, P, pulp-tissue crowded with cocci. Magni- 
 fied 500 diameters. 
 
 where the myelin has not perished altogether. The double 
 contour of Schwann's sheath is still recognizable even in the 
 narrowest portions of the nerve-libers, where myelin does not
 
 MORBID ANATOMY OF ATROPHIES AND DEGENERATIONS. 429 
 
 exist. I have been uiial)lo to liiid axis-cylinders in such atropine 
 nerves, not even in their transverse sections. The internal peri- 
 nenrium between the single nerve-fibers is invariably augmented. 
 
 Fro. 228. 
 
 Calcified Bl-.\i)lf. of Medullated Nerves. ^Froin Fig. 217.) 
 .V. calcifioa rod of a previous mo.lullatod nerve; A. calcified amylaceous corpuscle, from pre- 
 vious myelin : /, indamod connective tissue, crowded with granules of lime-salts. Magnified 
 izuu uiamcters. 
 
 Fibrous degeneration of the nerves is of rare occurrence, as it 
 seems, and is generally combined with the formation of calcar-
 
 430 
 
 THE AXATOMY AND PATHOLOGY OF THE TEETH. 
 
 ecus globules. (See Fig. 227.) An example of this degenera- 
 tion is also depicted in the figure of the reticular atrophy of the 
 pulp. The bundles of medullated nerves become transformed 
 
 Fig. 229. 
 
 ^^-^'^''^''^^^?lfcii4iif 
 
 Tkasskormatios of Bu.vdles of Medullated Nerves into Partly-Calcified Bundles 
 
 OF Fibrous Connective Ti.s.sue. Incipient Formation of a Calcareous Globule. 
 
 KooT Portion of Pulp. 
 
 11. B. partly -calcified bundles of fibrous connective tissue, previous medullated nerves ; G, 
 globule made up of finely-striated basis-substance: S, calcified nucleus of globule ; li, calcified 
 rim of globule toward the apex of the root; /^ P. pulp-tissue, crowded with cocci. Magnified 
 SOU diameters. 
 
 into bundles of fibrous connective tissue, which latter can be 
 traced even through the calcareous globule. The myxomatous 
 tissue of the pulp is apparently unchanged.
 
 MORBID ANATOMY OF ATROPHIES AND DEGENERATIONS. 431 
 
 Calcareous degeneration of the nerve-bundles seems to invade 
 the medullated nerves after their transformation into fibrous 
 connective tissue, thoiigh this preceding stage is not always 
 traceable. Fig. 228 shows a calcified bundle of nerves, from 
 a pulp affected with chronic purulent iniiammation, abounding 
 in calcareous deposits, 
 
 A combination of fibrous and calcareous degeneration is 
 occasionally met with in pulps otherwise normal, or in a state 
 of slight inflammation. Fig. 229 shows such a combination, 
 and is valuable for demonstrating the devious course of nerve- 
 bundles around a future calcareous globule, which for the present 
 is made up of dense concentric layers of fibrous connective ti?sue, 
 and is calcified only in a small portion .of its center. 
 
 /. Fatty Degeneration. — According to Wedl, fatty degen- 
 eration is of frequent occurrence. A fatty pulp appears cloudy, 
 and under the microsco}»e crowded with fat-granules in all its 
 constituent elements, including the nerves. Fatty degeneration 
 is sometimes observed in the pulps of temporary teeth, wdiile 
 their roots are undergoing the process of absorption. Owing to 
 the process of imbedding our pulps in celloidin, made liquid by 
 ether, I have had no opportunity to observe this degeneration. 
 
 (J. Pigmentation. — ^One of the rarest forms of degeneration 
 of the pulj»-tissue \s pif/mentation. In Fig. 219 there are depicted 
 clusters of pigment, richest in one horn of the coronal portion 
 of the pulp. These clusters appear rust-brown where seen in 
 tliin layers, and jet-black where they have accumulated in heavy 
 masses. Unquestionably tliis pigmentation is the outcome of a 
 [»revious hemorrhage, the more explicable since the pul}) under 
 consideration, besiiles showing calcareous deposits, is aft'ected by 
 chronic purulent pulpitis. In Fig. 224 diffuse pigmentation of 
 the emboli in the blood-vessels is observed, likewise arising from 
 the coloring-matter of the blood. 
 
 h. Colloid Degeneration. — C. Wcdi {I.e.) has observed colloid 
 corpuscles in the pulp. The author has had no opportunity to 
 see such corpuscles in s})ecimens of his own collection.
 
 432 THE ANATOMY AND PATHOLOGY OF THE TEETH, 
 
 CHAPTER XXXYIII. 
 
 PERICEMENTITIS IN ITS CLINICAL ASPECTS. 
 
 In regard to the classification of the diseases of the root-mem- 
 brane and the alveohar process, many systems have been published ; 
 but to find one which from both pathological and clinical point of 
 view is absolutely satisfactory has proved well-nigh impossible. 
 
 Albrecht* was the first to give the subject some attention. 
 He, however, classified the diseases with reference to their clinical 
 aspect only. Magitot,t in 1882, published another and more 
 extensive classification of pericementitis, adding many important 
 points. In 1885, J. Arkovy| gave quite a detailed and good 
 system of the diseases of the pericementum and the alveolar 
 process. Several other classifications have been issued since; 
 but neither of them being satisfactory to the writer, he attempted 
 to formulate a new one. Although, as mentioned above, not 
 free from objections with reference to its clinical aspect, the 
 author hopes it may meet with approval. 
 
 yon-Purulciit — 1. Acute marginal pericementitis; 
 
 ■2. Acute circumscribed pericementitis; 
 
 3. Acute apical pericementitis; 
 
 4. Acute dift'use pericementitis ; 
 
 5. Chronic hyperplastic partial perice- 
 
 mentitis; 
 
 6. Chronic hyperplastic diftuse perice- 
 
 mentitis; 
 Purulent. — 7. Acute apical pericementitis; 
 
 8. Acute diffuse pericementitis ; 
 
 9. Chronic marginal pericementitis ; 
 
 10. Chronic circumscribed pericementitis; 
 
 11. Chronic apical pericementitis; 
 
 12. Chronic difi:use pericementitis. 
 Secondary Forms. — 13. Chronic alveolar abscess; 
 
 14. Cementitis and eburnitis; 
 
 15. Periostitis, osteitis, and osteomyelitis; 
 
 16. Lymi)hadenitis, necrosis of the jaw- 
 
 bones, empyema of the antrum. 
 
 * "Die Krankheiten dcr Wurwlhaut ik-r Zalinc." Berlin, 1860. 
 t " Dictionnairc Encyclopediriuc dcs Sciences Medicales." Par Duchanibre 
 Paris, 1882. 
 
 X "Diairnostik der Zahnlvnuikheitcn." Stuttixart, 1885.
 
 PERICEMENTITIS IN ITS CLINICAL ASPECTS. 433 
 
 I. Acute Non-Purulent Marginal Pericementitis. — This form 
 of pericementitis occurs around the necks of the teeth, and is 
 produced by chemical or mechanical irritants. The chemical 
 irritation often is due to the decomposition of food left between 
 the teeth, or forced under the gum in mastication. The majority 
 of cases of this form of pericementitis, however, are caused by 
 mechanical insults, — viz, fine pieces of bone, a part of a tooth- 
 pick, the bristles of a tooth-brush, etc., which have entered the 
 pericementum ; badly-fitting clasps of artificial dentures, parti- 
 cles of oxyphosphate cement encroaching upon the perice- 
 mentum; crowns and bridges; filling-materials protruding 
 above the cavities ; pieces of rubber-dam or floss-silk ligatures 
 left under the margin of the gum more than twenty-four hours. 
 Quite frequently this disease originates from salivary calculus, 
 manifesting itself by a bluish ring upon the gums around the 
 necks of the teeth. The inflammation in this form of perice- 
 mentitis seldom extends beyond one- fourth part of the length of 
 the root, and is mostly observed in the pericementum of the 
 approximal surfaces of the roots of tbe teeth, except when due to 
 an accumulation of salivary calculus, in which case it is mostly 
 seen upon the lingual or labial surfaces, though sometimes 
 encircling the entire neck of the tooth. 
 
 Diagnosis. — Acute non-purulent marginal pericementitis is 
 characterized by the bright-red color of the gum covering the 
 inflamed pericementum. The gum appears more or less de- 
 tached from the neck of the tooth, and an instrument may 
 easily be passed under it. An instrument coming in contact 
 with the inflamed pericementum causes pain and more or less 
 hemorrhage. Salivary calculus, as before mentioned, causes a 
 bluish color of the gum around the neck of the tooth. It can 
 readily be detected by an instrument which, passed over salivary 
 calculi, will impart to the fingers the sensation of roughness 
 characteristic of this substance; while, in absence of tartar, 
 the neck of the tooth appears smooth. The tooth usually is 
 somewhat sensitive upon percussion in the direction of the in- 
 flamed portion, at the same time eliciting a somewhat dull sound. 
 
 Subjective Phenomena. — Acute non-purulent marginal perice- 
 mentitis seldom produces acute pain, but rather an uneasy, 
 anno^-ing sensation. The tooth is sensitive to mastication and 
 pressure, and usually to thermal changes. When produced by 
 salivary calculi, the patient scarcely exi»eriences much sensation, 
 
 20
 
 434 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 except in an aggravation of the inflammatory process by particles 
 of food lodged under the gums. 
 
 Differential Diagnosis. — Although in the majority of instances 
 the patient is able to localize the disease in the root-membrane, 
 there is a possibility of confounding acute non-purulent marginal 
 pericementitis with irritation of the }iul}>. In some instances we 
 find small, deeply-seated carious cavities under the margin of 
 the gums, which likewise may produce an inflammation of the 
 marginal portion of the gum. In most cases, however, a fine 
 exploring instrument will readily enter the carious cavit}'. 
 Should the latter be situated in the approximal surfaces of one of 
 the second or third molars, especially in short teeth, where the 
 necks are almost as large as the crowns, this procedure may 
 become difficult. 
 
 Prognosis. — After the removal of the irritant and the disin- 
 fection of the mouth, the inflammation in the gums and perice- 
 mentum soon abates, unless the general health of the patient be 
 much impaired, in which case the inflammation tends to become 
 chronic. 
 
 II. Acute Non-Purulent Circumscribed Pericementitis. — This 
 form of pericementitis mostly involves one side of the root, or 
 may encircle the entire root about its middle, without, however, 
 aflfecting the apical portion of the pericementum. The area of 
 inflammation seldom extends over the entire root, unless the 
 process has become chronic. 
 
 Arkow)^, who gives a good description of this disease, mentions 
 two forms : " periodontitis acuta circumscripta consecutiva,"' and 
 " periodontitis acuta circumscripta idiopathica." Since both forms 
 are identical, except in their origin, I shall describe them under 
 one head. Arkovj- furthermore claims that acute non-purulent 
 circumscribed pericementitis arises from acute total pulpitis. 
 My specimens and clinical observations show, on the contrary, 
 that the pulpitis is the result of the pericementitis, as in most 
 instances I have observed a new formation of bone or secondary 
 dentine in the pulp-chamber, corresponding to the inflamed 
 pericementum on the outer surface of the root, especially in 
 cases due to constitutional disturbances. 
 
 Acute non-purulent circumscribed pericementitis may origi- 
 nate either from mechanical violence or constitutional disturb- 
 ances. Among the former I will enumerate hard biting, or a 
 blow applied in a more or less oblique direction to the root.
 
 PERICEMENTITIS IX ITS CLINICAL ASPECTS. 435 
 
 Teeth standing isolated have more freedom of motion than 
 those closely approximated by others ; thus we observe acute 
 non-purulent circumscribed pericementitis mostly in such teeth. 
 J. Foster Flagg* was the first to draw attention to the fact that 
 this disease sometimes is produced by constitutional derange- 
 ments, an assertion which fully concurs with my own observa- 
 tions. 
 
 Diagnosis. — Teeth affected by acute non-purulent circum- 
 scribed pericementitis do not appear looser in their sockets than 
 the other teeth in the mouth, nor longer when they articulate. 
 Since the disease attacks both sound and decayed teeth, the etiol- 
 ogy must be carefully considered in order to establish a diagnosis. 
 It mostly lasts from one to three days, except when caused by con- 
 stitutional disturbances, in which case chronicity is apt to ensue. 
 The teeth, during the first two or three days of the affection, are 
 but little sensitive to cold, while warmth will produce no altera- 
 tion. The main characteristic w^hich will aid us in the diagnosis 
 of acute non-purulent circumscribed pericementitis is percussion 
 and pressure upon the crown of the affected tooth, if possible 
 in at least three directions, — viz, upon the grinding-surface, 
 respectively the cutting-edge; upon the labial, respectively the 
 buccal surface ; and upon the lingual surface. When the peri- 
 cementitis is localized mainly or exclusively upon the lingual 
 portion of the root, which happens in the majority of instances, 
 percussion upon the labial respectively the buccal surface of the 
 tooth will yield a slightly dull sound and be somewhat sensitive. 
 Percussion or pressure upon the affected tooth in the other two 
 directions mentioned will elicit neither pain nor dullness. 
 
 Subjectice Phenomena. — Acute non-purulent circumscribed 
 pericementitis, when produced by mechanical violence, causes 
 but little annoyance to the patient, except when pressure or 
 percussion is applied in the manner described above. When, 
 however, the disease has originated from constitutional derange- 
 ments, the subjective symptoms are more pronounced, at the 
 same time affecting two, or even more, teeth. In almost all 
 cases I have seen, I have noticed, besides the acute non-purulent 
 circumscribed pericementitis, more or less erosion, and an acid 
 reaction of the saliva. The teeth are quite sensitive to cold, but 
 I could not ascertain whether this was due to the pericementitis or 
 to the erosion. Sometimes, especially in teeth standing isolated, 
 
 * Dental Cosmos, 1878.
 
 436 THE ANATOMY AXD PATHOLOGY OF THE TEETH. 
 
 the inflammatory process extends to the neck of the tooth, and 
 often becomes chronic and purulent, presenting the features of 
 a so-called "blind abscess" (chronic purulent circumscribed 
 pericementitis). 
 
 Differential Diagnosis. — The only disease with which acute 
 non-purulent circumscribed pericementitis could be confounded 
 is chronic jiurulent circumscribed pericementitis. The latter is 
 characterized by the soreness upon pressure with the finger on 
 the gum over the root of the afiected tooth, whereby a small 
 quantity of pus may be seen to exude at the neck of the tooth. 
 The latter symptom is never observed in acute non-jnindent cir- 
 cumscribed pericementitis. 
 
 The prognosis of teeth aft'ected with acute non-purulent cir- 
 cumscribed pericementitis as the result of mechanical violence is 
 always good: while, on the contrary, cases depending upon con- 
 stitutional trouble sometimes ibecome chronic. In the latter in- 
 stance the pericementitis induces chronic hyperplastic pulpitis, 
 followed by calcification of the blood-vessels and nerves of 
 the pulp, usually terminating in the loss of the tooth. 
 
 III. Acute Non-Purulent Apical Pericementitis. — This type of 
 pericementitis is of frequent occurrence, and is mostly produced 
 by pulpitis and by mechanical and chemical irritants. Among 
 the forms of inflammation of the pulp that may induce acute non- 
 purulent apical pericementitis are the following : acute total 
 pulpitis, acute purulent pulpitis, chronic total hyperplasia of the 
 pulp, and moist gangrene. The last-named disease, if rapidly 
 progressing, is the most frequent cause of acute non-purulent 
 apical pericementitis, which, in this instance, is prone to involve 
 the entire }>ericementum of the tooth. Apical pericementitis 
 may be induced by chemical irritants, such as filling-materials, 
 which during the process of filling the pulp-canal have been forced 
 through the apical foramen of the root of the tooth. The same 
 untoward result may occur when chemical irritants, such as cor- 
 rosive sublimate, chloride of zinc, pure carbolic acid, iodine, 
 etc., employed in the disinfection of the root- canal, have come 
 in contact with the pericementum through the apical foramen. 
 We also observe this form of pericementitis after extensive 
 oj»erations in restoring large portions of teeth with gold. The 
 protracted or too severe nialleting upon a tooth, as well as a 
 protruding filling, a crown, a bridge, or an artificial tooth that 
 causes more pressure upon its antagonist than normal, often
 
 PERICEMENTITIS IN ITS CLINICAL ASPECTS. 437 
 
 produce an acute non-[)urulent apical pericementitis. This may 
 likewise result from too rapid regulating, wedging, or anything 
 that will force the teeth out of their normal position, especially 
 when the force is applied in the direction of the apex of the 
 tooth. 
 
 Diagnosis. — Acute non-purulent apical pericementitis is easily 
 recognized by slight percussion, either with an instrument or 
 with the finger-nail. In teeth possessing but one root, the dull- 
 ness as well as the soreness elicited upon percussion in the direc- 
 tion of the apex of the root are quite marked ; while in teeth 
 having two or three roots, both dullness and soreness upon per- 
 cussion are not so pronounced, unless the vibrations are produced 
 in the direction of the apex of the affected root. The same will 
 be the result upon pressure which, in the direction of the apex 
 of the affected root, produces slight pain, while when applied 
 laterally to the affected tooth it is painless. Acute non-purulent 
 apical pericementitis does not raise the teeth out of their sockets, 
 consequently they are not looser than the other teeth in the 
 mouth. As this disease frequently occurs in teeth which either 
 have been filled or contain carious cavities, a careful examination 
 must be made in regard to pul[»itis, or the particulars in regard 
 to the filling of the carious cavity or the pulp-canal of the tooth. 
 
 Subjective Phenomena, — Acute non-purulent apical pericemen- 
 titis usually becomes noticeable from ten to twenty-four hours 
 after the irritation. The pain, in most cases starting instanta- 
 neously during mastication, is localized by the patient in the 
 affected tooth. The tooth does not appear elongated, but is 
 sensitive in mastication. The pain may last from one to three 
 days after the removal of the irritant. 
 
 Diferential Diat/nos/s. — By carefully considering the etiology, 
 the diagnosis, and the subjective symptoms of acute non-puru- 
 lent apical jtcricementitis, it is barely possible to confound this 
 disease with any other form of pericementitis. It may, how- 
 ever, sometimes be mistaken for chronic ]»artial hyperplastic or 
 acute purulent apical pericementitis. 
 
 Chronic partial hyperplastic pericementitis is characterized 
 by being quite sensitive to pressure upon the gum in the region 
 of the apex of the root of the affected tooth, which pressure 
 will yield negative results in the case of acute non-purulent 
 apical pericementitis. Acute purulent apical pericementitis 
 may be differentiated by the rapidity with which it develops,
 
 438 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 the severe pulsating pains, as well as the elongation of the 
 tooth, all of which phenomena are absent in acute ?io?z-purulent 
 apical pericementitis. 
 
 Prognosis. — According to the origin of acute non-purulent 
 apical pericementitis, the prognosis of this disease is either 
 quite favorable or not. If the disease has arisen from external 
 violence, such as too heavy or too long-continued malleting, 
 too rapid regulating, fillings, crowns, or artificial teeth left too 
 high, or wedging, the inflammation upon the removal of the 
 irritant will usually subside in from one to three days. If, on 
 the contrary, acute non-purulent apical pericementitis is pro- 
 duced by acute purulent pulpitis, by gangrene of the pulp, or 
 by filling-materials or other foreign substances pushed through 
 the apical foramen of the root, the prognosis becomes unfavor- 
 able. In some instances the disease assumes a chronic hyper- 
 plastic character; in others it may develop into an acute puru- 
 lent apical pericementitis, the prognosis of which is stated in 
 the respective }>aragraphs of this chajjter. 
 
 IV. Acute Non-Purulent Diffuse Pericementitis. — This disease 
 usually extends over the greater portion of the root-membrane, 
 although we seldom find the cervical portion of the perice- 
 mentum involved. Arkovy states that this form of pericemen- 
 titis is accompanied by a considerable degree of tedema of the 
 involved portion of the pericementum. Acute non-purulent 
 diffuse pericementitis mostly occurs in consequence of pulpitis, 
 traumatism, mechanical or chemical irritation at the apical fora- 
 men, and sometimes constitutional derangements. Of the dis- 
 eases of the pulp, only those of a quite acute character Avill pro- 
 duce this form of pericementitis, — viz, acute total pulpitis, or 
 moist gangrene. In a traumatic way the disease may be pro- 
 duced by a heavy blow, a fixll, the too rapid wedging or regu- 
 lating of the teeth. Sometimes it occurs that in the treating 
 or filling of pulp-canals severe chemical irritants are pushed 
 through the apical foramen of the root or enlarged dentmal 
 canaliculi; furthermore, pieces of filling-materials, either metallic 
 or non-metallic, or a broken nerve-instrument protruding through 
 the apical foramen, may lead to an acute non-purulent difi"use 
 pericementitis. 
 
 D'utgnosis. — As we always notice considerable swelling of the 
 pericementum, the affected tooth will be found quite loose in its 
 socket, and the crown raised considerably above the level of the
 
 PERICEMENTITIS IN ITS CLINICAL ASPECTS. 439 
 
 other teeth. Slight percussion upon the afl'ected tooth yields a 
 very dull sound : at the same time the tooth is quite sensitive to 
 pressure, especially in the direction toward the apex. The cor- 
 responding gum usually exhibits some redness, and is sensitive 
 to pressure, without indication of fluctuation. When this dis- 
 ease occurs in teeth with living pulps, an irrigation of cold 
 water produces pain, which symptom always calls for a careful 
 examination of the pulp-chamber. 
 
 Subjective Phenomena. — The pain of acute non-purulent diffuse 
 pericementitis develops gradually about twenty to thirty hours 
 after the irritation, at least in cases originating from mechanical 
 or chemical violence. The pain in the latter instances is acute 
 and drawing. When, however, the disease originates from acute 
 total pulpitis or gangrene of the pulp, the patient complains of 
 severe throbbing pain, not only in the affected part, but over the 
 whole side of the face. As the tooth is raised out of its socket 
 considerably above the level of the other teeth, mastication, or 
 even the closure of the mouth, is rendered impossible. This 
 state may continue for three or four days, and sometimes may 
 last a week, when the inflammation either gradually abates or 
 becomes chronic. The pain usually is much more severe toward 
 evening, especially when the patient occupies a recumbent posi- 
 tion, or after taking alcoholic stimulants or active bodily exercise. 
 
 Differential Diagnosis. — Acute non-purulent diffuse perice- 
 mentitis may be confounded with acute or chronic purulent 
 difllise pericementitis. Acute purulent difl'use pericementitis is 
 principally characterized, in contradistinction to acute non- 
 purulent diffuse pericementitis, by the former never being sen- 
 sitive to cold applications; the presence of fever; besides, upon 
 slight pressure on the gums pus will be eliminated. The gums 
 in the purulent form are seldom attached tightly to the neck of 
 the tooth; they are considerably swollen, and at the same time 
 fluctuating. 
 
 Chronic purulent diffuse pericementitis principally differs 
 from the acute non-purulent diffuse form in the character of 
 the subjective phenomena, which in a chronic disease are never 
 intense. 
 
 The prognosis of acute non-purulent dift'use pericementitis, in 
 the majority of instances, is favorable for the preservation of 
 the tooth, although in cases where chemical irritants or foreign 
 bodies pushed through the apical foramen have produced the
 
 440 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 inflammation, the prognosis is not so favorable. In the latter 
 instances, as well as in those originated from gangrene of the 
 pulp, an invasion of strepto- and staphylococci takes place, fol- 
 lowed by purulent pericementitis. 
 
 V. Chronic Hyperplastic Partial Pericementitis. — Under this 
 head I propose to classify the growths of the pericementum 
 occurring around the cervical portion and sometimes lodging in 
 carious cavities about the necks of the teeth. In this situation 
 they may easily be confounded with a hyperplastic pulp, espe- 
 cially when in a largely-decayed molar the pericementum has 
 grown through a perforation at the bifurcation of the roots. 
 This disease, however, is not exclusively found in carious teeth, 
 but also in those with apparently sound crowns. The etiology 
 is not perfectly clear in all cases. The author, however, has 
 frequently found it to be the result of chronic purulent marginal 
 pericementitis (pyorrhoea alveolaris). 
 
 Diagnosis. — In most instances chronic hyperplastic partial 
 pericementitis is readily recognized by the presence of granula- 
 tion-tissue. The latter appears knob-shaped at one side of the 
 neck portion of the pericementum in varying sizes. "When 
 these growths occupy carious cavities, they seldom surpass the 
 size of the head of a pin or that of a pea. Exceptionally we meet 
 with granulations the size of a walnut or even larger, mostly 
 occupying the labial, respectively buccal surface of otherwise 
 sound teeth. The tumor in the latter cases is attached by means 
 of a pedicle and lobulated upon its upper surface, while the 
 lower one resting upon the gum usually is smooth. The so- 
 called granulomata are richly supplied with capillary blood- 
 vessels, and therefore bleed profusely when wounded. The teeth 
 are not looser in their sockets than the other teeth in the mouth, 
 and percussion elicits a dull sound only in the direction of the 
 diseased portion of the pericementum. 
 
 Subjective Phenomena. — Chronic hyperplastic partial perice- 
 mentitis does not jiroduce pain as such, except when the growth 
 becomes irritated in mastication or by exposure to pronounced 
 thermal changes. 
 
 Diferential Diagnosis. — When chronic hyperplastic partial 
 pericementitis occurs in teeth the crowns of which are largely 
 decayed at their cervical portion as above mentioned, it may 
 easily l)e confounded with granuloma of the gum or partial 
 hyperplasia of the pulp. lu such instances the granuloma of
 
 PERICEMENTITIS IX ITS CLINICAL ASPECTS. 441 
 
 the pericementum grows into the carious cavity, and sometimes, 
 in devitalized teeth, may even occupy the pulp-chamber. A 
 thorough examination is not always possible at once, since the 
 granulations of the gum and the pulp, as well as those of the 
 pericementum, bleed profusely. It is advisable to insert a piece 
 of cotton, saturated with pure carbolic acid, into the cavity of 
 the tooth, which after twenty-four hours will enable us to make 
 a clear diagnosis. When chronic hyperplastic partial perice- 
 mentitis occurs in teeth in the early stage of pyorrhea alveo- 
 laris, the disease under consideration is easily recognizable. 
 Here it sometimes happens that the granulations have destroyed 
 small portions in the neck or the root, which latter appear in the 
 form of cup-shaped excavations. 
 
 Prognosis. — So long as chronic hyperplastic partial perice- 
 mentitis occurs in places accessible to removal of the granuloma, 
 and prevention of its recurrence by the application of strong 
 escharotics, the tooth need not be sacrificed. When, on the con- 
 trary, the granulations have absorbed portions of the root, the 
 prognosis becomes doubtful. The sharp edges of the excavations 
 on the root irritate the pericementum even after the granulations 
 have been destroyed, and usually give rise to an incessant new 
 formation thereof. 
 
 VI. Chronic Hyperplastic Diffuse Pericementitis. — This form 
 of pericementitis embraces the new formations occurring in the 
 pericementum below the margin of the alveolus. They mostly 
 are built up of granulation-tissue, gradually absorbing the roots of 
 the teeth as well as the alveolus of the jaw-bone. This form of 
 pericementitis predominates in teeth of young patients, especially 
 when the roots were not fully formed at the time of death of 
 the pulp. We also notice it in teeth the pulp-canals of which 
 have been filled with gold wire. No pus is noticed in hyper- 
 plastic pericementitis unless it is accompanied by a purulent 
 form of pericementitis. 
 
 The diai/nosis of chronic hyperplastic diflfuse pericementitis 
 cannot always be established with certainty. Although such 
 teeth are loose, and appear considerably elongated, the gums 
 around their necks may be normally attached, and a probe can- 
 not be easilv introduced alons; the root of the tooth. When, 
 however, the gum encircling the neck has lost its attachment to 
 the tooth, the granulomata in some instances can be distinctly 
 felt by means of a probe. The latter feature mostly prevails
 
 442 THE AXATOMY AND PATHOLOGY OF THE TEETH. 
 
 in diffuse cases ; when the granuloma involves only the apical 
 portion of the pericementum, an examination bv the probe is 
 impossible. The gum in the vicinity of the affected root usually 
 appears almost normal. 
 
 Sabjectire Phenomena. — Chronic hyperplastic pericementitis 
 seldom causes pain or much discomfort to the patient. Teeth 
 thus affected are quite loose and somewhat elongated, although 
 the surrounding gum shows little or no signs of inflammation. 
 Pressure upon the tooth in the direction of the apex of the root 
 usually is painful. 
 
 Differential Diagnosis. — Chronic non-purulent diffuse perice- 
 mentitis may easily be confounded with chronic purulent apical, 
 as well as with chronic purulent diff'use pericementitis. In fact, 
 in both of these forms where the inflammatory process has lasted 
 for some time, we often observe new formations of fibrous con- 
 nective tissue and bone-tissue in the vicinity of the inflamed 
 pericementum. The characteristic features of the disease in 
 question are not well marked. 
 
 The jorognosis of teeth affected with chronic non-purulent 
 diffuse pericementitis is always bad, since the root gradually 
 becomes absorbed, and the tooth, unless extracted, in course of 
 time falls out. 
 
 VII. Acute Purulent Apical Pericementitis. — As every puru- 
 lent inflammation depends upon an infection of the tissue with 
 staphylococci, sometimes combined with streptococci, acute puru- 
 lent partial pericementitis never occurs unless an infection with 
 the above-named micro-organisms has taken place. The disease 
 under consideration frequently is induced by gangrene of the pulp; 
 also by acute or chronic purulent total pulpitis; eventually by 
 septic nerve-instruments introduced into the pulp-canal or 
 through the apical foramen. With regard to the aseptic condi- 
 tion of instruments, I would advise the utmost care; although I 
 must admit that an absolute aseptic treatment in the mouth is 
 next to an impossibility, even though the rubber-dam be applied. 
 Bacteria are organisms so minute that they can only be detected 
 by the microscope with a magnifying power of at least 600 
 diameters. The human mouth is crowded with micro-organ- 
 isms, and they will adhere to everything coming in contact with 
 it. Our fingers will transfer them to the handles of instruments, 
 the hand-piece of the dental engine, napkins, towels, cotton, etc. 
 Bacteria may even enter a pulp-canal although the instrument
 
 PERICEMENTITIS IX ITS CLINICAL ASPECTS. 443 
 
 used was sterilized, and the hands after the application of the 
 rubber-dam have been thoroughly washed. I am convinced 
 that everything in the office coming in contact with the fingers 
 of the operator is more or less infected with micro-organisms. 
 If, therefore, a nerve-instrument touches a napkin, a towel, the 
 rubber-dam, or anything which has been in contact with our 
 hands, before they were thoroughly washed again, an infection 
 of the pericementum may be the result. It is evident that an 
 aseptic treatment of a pulp-canal without the application of the 
 rubber-dam to the affected tooth is impossible. This fact no 
 doubt explains the origin of many occult cases of acute purulent 
 apical pericementitis. 
 
 Dkifinoms. — Acute purulent apical pericementitis never occurs 
 unless the pulp of the tooth be affected by total purulent inflam- 
 mation, by gangrene, or in a devitalized tooth. The gum 
 around the root of the tooth usually is but little swollen or altered 
 in color, and unyielding, though somewhat painful to pressure. 
 The tooth appears but little higher, and is only partially sensi- 
 tive in mastication. Slight percussion upon the tooth, especially 
 in a labio-lingual direction, is quite painful, and elicits a distinctly 
 dull sound. Such teeth are seldom looser than the other teeth 
 in the mouth. 
 
 Siihjcctioe Phenomena. — When a tooth becomes aifectecl with 
 acute purulent apical pericementitis, the patient notices soreness 
 of the tooth about eight to twelve hours after the infection of 
 tlie pericementum. This is followed by gradually increasing 
 pain, which after about twenty-four hours becomes severe and 
 of a pulsating character. The tooth now is extremely sensitive 
 to cold, and even the inhalation of cold air produces pain. The 
 affected side of the mouth feels quite hot, especially the gum in 
 the neighborhood of the root of the diseased tooth. Toward 
 evening the patient usually is attacked by fever, the severity of 
 which, however, depends upon his constitution. The pains are 
 much aggravated in the recumbent position, by active bodily 
 exercise, or alcoholic stimulants. 
 
 Differential Diafinosis. — Acute purulent apical pericementitis 
 may be confounded with acute non-purulent partial pericemen- 
 titis, although the pulsating character of the pain always present 
 in the former disease is never noticed in pericementitis, not 
 terminating in suppuration. 
 
 The prognosis of teeth attacked by an acute purulent apical
 
 444 THE AXATO.MY AND PATHOLOGY OF THE TEETH. 
 
 pericementitis, as a rule, is favorable, although much depending- 
 upon the constitution and the age of the patient, the shape of 
 the pulp-canal, and the position of the tooth. TVhenever the 
 practitioner is able to obtain entrance through the apical fora- 
 men, by means of a fine l:)roach, into tlie abscess, and thereby 
 evacuate the pus, the pain will almost instantly cease. The 
 tooth and pulp-canal, after proper treatment, may then be filled,, 
 which when successfully accomplished will preserve the tooth; 
 
 VIII. Acute Purulent Diffuse Pericementitis.— This disease 
 is almost invariably the outcome of the one before described, 
 its etiology being similar. 
 
 Diarjnosis. — A tooth affected with acute purulent diffiise peri- 
 cementitis is extremely sensitive to the touch with the finger,, 
 or even the tongue. It is quite loose in its socket, and appears 
 considerably elongated above the level of the other teeth, so 
 much so that the patient is unable to eat or even to close his 
 mouth. The corresponding cheek or lip becomes oedematous, 
 producing a marked disfigurement, and sometimes complete 
 closure of the eyelids. The gum in the vicinity of the affected 
 tooth always is swollen, and painful to pressure with the [loint 
 of a finger. In some instances, upon pressure more or less pus 
 will be eliminated around the cervical portion of the tooth. 
 According to the severity of the process the inflammation is 
 imparted to the alveoli and the pericementum of the neighbor- 
 ing teeth, to such an extent that only the characteristic color 
 of the dead tooth will indicate the original seat of the abscess. 
 Thermal changes, especially cold applications, are quite pain- 
 ful. Slight percussion, which ought to be applied gently, is 
 extremely painful, and produces a dull sound. Should the 
 neighboring alveoli be involved in the inflammatory focus, the 
 tooth wdiich is the original seat of the pericementitis will 
 always elicit the comparatively dullest sound. 
 
 Subjective Phenomena. — The pain before the appearance of 
 the cedema caused by acute purulent diffuse pericementitis, is 
 stated to be among the severest of human sufferings. Its 
 character is pulsating, affecting the wdiole side of the face, and 
 is materially increased by the recumbent position, by bodily 
 exercise, and alcoholic beverages. Although there are no 
 intermissions of pain, it usually is worse toward evening, or at 
 night. The f»ain steadily increases from hour to hour, until it 
 becomes almost uiibt,'aral)le. A severe cliill indicates that jtus
 
 PERICEMENTITIS IN ITS CLINICAL ASPECTS. 445 
 
 has formed. AYitli still increasing pain fever sets in; the 
 patient's tem}»eraturo is elevated, the pulse accelerated, the 
 a}»petite lost, and the tongue becomes thickly coated. The 
 sufiering continues from one to five days, when at once an 
 oedema of the face makes its appearance, whereby the patient 
 is relieved, the pain now assuming a more or less dull and 
 intermittent character. 
 
 Differential Diaqnosis. — Acute purulent diffuse pericementitis 
 may he confounded with acute diffuse non-purulent, or chronic 
 jiurulent diffuse pericementitis. The principal characteristic 
 feature of acute purulent diffuse pericementitis is its initiation 
 l)y a chill followed by fever, which never occurs in the non- 
 purulent form. 
 
 Chronic purulent diffuse pericementitis may easily be dis- 
 criminated from an acute one by the character of the pain and 
 the absence of fever. In an acute inflammation the pains are 
 severe, pulsating, and steadily increasing, Avhile in chronic 
 inflammation the pain is not severe, of a more intermittent and 
 drawing character. 
 
 The ijrognosis of teeth affected with acute purulent cliflTuse 
 pericementitis is almost as good as that of teeth attacked by 
 the a[)ical form. 
 
 The same rule is applicable in both instances, — viz, when- 
 ever we are al)le to evacuate the pus from the alveolus, either 
 by incision through the gums or by means of a fine broach 
 through the [lulp-eanal, or both ways combined, the tooth 
 may l)e saved. To accomplish this, however, the pulp-canal 
 as well as the tooth, after the disappearance of the abscess, 
 must be thoroughly disinfected and filled. The greatest obsta- 
 cles to treating such a tooth are both its looseness and the pain 
 produced by the opening of the pulp-canal. This, nevertheless, 
 in most instances can be accomplished by fastening the tooth to 
 a ligature and pulling it l)y the string against the drill. In 
 severe cases, the tooth, besides iK'ingligated, must be held with 
 two fingers by an assistant, while the canal is opened by a 
 drill. 
 
 IX. Chronic Purulent Marginal Pericementitis, so-called 
 " Pyorrhoea Alveolaris."— This disease has also been termed 
 " pyorrhcea alveolo,'" Toirac by Desirabode ; " cemento-perios- 
 titis," by Magitot; " gingivitis expulsiva," by Marchal de Calve; 
 "alveolitis infectiosa,"' by A. Witzcl ; -'Blennorrhoe der Alveo-
 
 446 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 len," by Steinberger : and Riggs's Disease. The last name was 
 coined in honor of Dr. Riggs, who was the first to give this 
 disease special attention. 
 
 In regard to the etiology of the disease under consideration, 
 few positive facts are known ; but hypothetical speculations 
 about it are quite abundant. Prior to the time of Riggs (1867), 
 pyorrhoea alveolaris was believed to be a disease of the gums. 
 Riggs himself was of the opinion that the disease was a necrotic 
 condition of the alveolar border. In 1873 Magitot proved that 
 the trouble was situated in the pericementum. C. Tomes first 
 made the statement that pyorrhoea alveolaris was not due to 
 deposits of salivary calculi, which, up to his time, was believed 
 to be the cause. Tomes furthermore called attention to the fact 
 that tartar is of secondary importance, and in many cases no cal- 
 culi are present. Since that time nmch has been said and written 
 on the subject, without, however, advancing anything of impor- 
 tance, except that many practitioners agreed in that the disease 
 was not primarily due to a deposition of salivary calculi, but 
 rather to systemic derangements. J. Arkovy calls this disease 
 " caries alveolaris," and maintains that its origin is a necrotic 
 process in the margin of the alveolus, which in later stages is 
 transferred to the pericementum and cementum of the tooth. 
 C. N. Peirce, in a paper read before the Xew York Odontological 
 Society, I^ovember, 1893,* expressed the view that pyorrha-a 
 alveolaris is principally due to a gouty diathesis of the system, 
 and defines two forms of this disease. He says, " In one form 
 of pericementitis the origin of the calcic salt is the saliva, and 
 in the other form the blood. The former I shall designate a 
 ptyalogenic calcic pericementitis, expressive of the idea that in its 
 origin it is local, peripheral, and salivary. The latter I shall 
 •designate as hcematogenic calcic pericementitis, expressive of 
 the idea that in its origin it is constitutional, central, and asso- 
 ciated w^ith some modifications of the normal composites of the 
 blood-plasma. 
 
 " Calcic 'pericementitis may have its origin at the yinyical borders, 
 the tartar acting as a local and mechanical irritant, with the train of 
 concomitant erils, such as irritation, inflammation, formation of pus, 
 and absorption of gum and cdreolar process. 
 
 " We have three distinct, abnormcd conditions affecting the gums, 
 pericemental or alveolo-cemental membrane, and alveolar process. 
 
 * The Internafiomd Denial Journal, 1894.
 
 PERICEM-ENTITIS IN ITS CLINICAL ASPECTS. 447 
 
 Thejirst is gum ivjiamwation and (kstniciion, caused bg a mechanical 
 irritant. Second, ivfarnmation of the gingival borders without the 
 presence of tartar. The third is a pericemental irritation commencing 
 at or near the apical extreniitg of the root, due to the presence of some 
 morbid composite of the blood, exuded icith the plasma and infiltrating 
 the alveolo-cemental membrane, and frec^uentlg deposited or precijyitated 
 upon the root of the tooth near its apex. This latter 1 designated true 
 pyorrhoea alveolaris, or hamatogcnic pericementitis, and so intimately is 
 it associated with some other local manifestcdion of a gouty diathesis, 
 that I have believed and do now bdiere it to be but another local 
 expression of that systemic condition." 
 
 While the views of Peirce have many followers, among whom 
 are Edwin T. Darby, S. G. Perry, K. R. Andrews, A. P. Bru- 
 baker, and others, the contradictory opinions seem to be just 
 as strong, as expressed by S. H. Guilford, M. L. Rhein, James 
 Truman, R. Ottolengui, G. S. Allan, as well as the writer, and 
 others. It cannot be denied that a superabundance of uric acid 
 in the system may assist in producing pj'orrhoea alveolaris; but 
 it will not exert more influence in this direction than consump- 
 tion, anaemia, nephritis, hepatitis, diabetes, arthritis, syphilis, 
 typhoid, chronic diseases of the nervous system, etc., which are 
 often found associated with pyorrhea alveolaris. Furthermore, 
 it is an established fact that sometimes uric acid is present in 
 the system without producing either gout or rheumatism. We 
 must therefore admit that the cause of the disease under con- 
 sideration principally is a more or less chronic general ailment, 
 and not due to any particular forru. At the same time, we meet 
 with many cases of pyorrha-a alveolaris which can be attributed 
 to nothing but heredity. The disease is mostly hmited to middle 
 age, although exceptionally we see it in persons under twenty 
 years. 
 
 Diagnosis. — Chronic purulent marginal pericementitis begins 
 as an acute or a subacute inflammation in the cervical portion, 
 soon becoming purulent and afterward chronic. In the early 
 stages the gum is yet of a normal color, and detached from the 
 neck of the tooth only in a small area, — as a rule, upon the labial 
 surface. Salivary calculi seldom are seen in those places where 
 the gum is found detached from the neck of the tooth, although 
 it may be present upon the lingual or the approximal surfaces of 
 the teeth. Exceptionally we meet with patients suflering from 
 pyorrhoea alveolaris, in consequenceof rheumatism, who have an
 
 448' THE AXATOMY AND PATUOLO(n' OF THE TEETH. 
 
 abundant accumulation of calculi above the gum-margin. Some- 
 times we meet with pyorrhoea alveolaris in which the calculary 
 deposit encircles the entire necks of the teeth; but in these 
 instances the tartar had formed previously to the development 
 of the disease under consideration. The deposits below the 
 gum-margin which later accumulate upon the roots of the aifected 
 teeth usually have been called " seruminal tartar," in contradis- 
 tinction to that found upon the teeth above the gum-margin. 
 The former deposits are of a dark-brown or black color, and, as 
 the disease progresses, gradually extend toward the apex of the 
 root. In some instances the middle portion of the pericemen- 
 tum of the root remains intact, and at the first glance it appears 
 as though the deposit at the apex of the tooth were in no con- 
 nection with that found upon the neck. Closer examination 
 with a magnifying lens, however, shows that the deposits in one 
 or more narrow routes have obtained access to the apical por- 
 tion. In the incipient stage of the disease the affected teeth are 
 not looser than the others in the mouth, and the only symptom 
 indicative of pyorrhoea alveolaris is the presence of pus upon 
 pressure around the neck of the tooth. At first the quantity of 
 pus eliminated is small, seldom more than about one drop in 
 ten or twelve hours. The pus can be best exhibited by pressure 
 upon the gum, gradually extending toward the cutting-edge, 
 respectively the grin ding-surface of the tooth. In advanced 
 stages, however, the pus may fiow continually from the sockets, 
 causing a peculiar odor of the breath of the patient. "With the 
 progress of the disease the pericementum is destroyed by degrees, 
 and the so-called pocket between the gum and the neck of the 
 tooth becomes deeper. In some instances we notice the margin 
 of the gum to be thin and sharp ; in others the gum appears 
 thick and almost hypertrophied, which fact seems to have little 
 to do with the stage of the disease, as both conditions are 
 noticed in deep as well as in shallow pockets. As the destruc- 
 tion of the pericementum advances, the gum recedes from the 
 necks of the teeth, especiallv the labial surfaces, which, as a 
 rule, become sensitive to thermal changes, particularly to cold. 
 The teeth by degrees lose their firm hold in the alveolus, due to 
 the absorjition of the cementum and the socket. This enables 
 us to. introduce a probe, sometimes more than half-way between 
 the alveolus and the root of the tooth, without pain. Pyorrhoea 
 alveolaris is not uncommon in front teeth which have lost their
 
 PERICEMENTITIS IN ITS CLINICAL ASPECTS. 449 
 
 proper antagonism. c'S[>C'cially when eitlier the upper or the 
 lower jaAV protrudes. As the disease [)roceeds toward the apex 
 of the root the socket is destroyed, sometimes only on one 
 side, but often in the entire extent of the root of the tooth. In 
 such instances the pulp of the tooth often becomes devitalized, 
 mostly without the knowledge of the patient. The affected 
 teeth seldom are discolored, and I have seen instances wdiere 
 transillumination gave but negative results. When the inflam- 
 matory process has existed for a long time, granulation-tissue 
 is formed, which usually absorbs portions of the root and the 
 alveolus. A. AVitzel holds the 0]>inion that the granulations 
 [irineipally spring from the medulla of the alveolus. Such 
 new formations may be seen around the cervical as well as the 
 xipical portion of the root, and always induce a ra[)id loosening 
 of the tooth. 
 
 Subjective Phenomena. — Pyorrhoea alveolaris in its beginning 
 usually is not noticed by the patient, and even in its later stages 
 causes no pain. The patient complains, however, of an uneasy, 
 annoying sensation in the teeth and jaws. There may be loss of 
 appetite, although this can be attributed to constitutional causes 
 as well as to the local disease. The teeth in advanced stages, 
 even though quite loose, are tolerably comfortable in mastica- 
 tion so long as the roots have not been absorl>ed l)y granula- 
 tions. "When, however, this hapi)ens, the tooth becomes sensi- 
 tive to pressure and percussion. Such a tooth, if subjected to 
 mechanical violence, usually reacts by a painful acute attack of 
 purulent difl^usc pericementitis. Should the pulp of a tooth 
 become devitalized in consequence of pyorrhoea alveolaris, the 
 patient has no ])ain whatever from this source. 
 
 Differential Diagnosis. — Pyorrhoea alveolaris might be con- 
 founded with a deposition of salivary calculi, which in some in- 
 stances gives rise to symptoms similar to those of true pyorrhoea 
 alveolaris. The principal characteristic of pyorrhea caused 
 by salivary calculi is that it yields to local treatment in a com- 
 paratively short space of time, and usually does not return so long 
 as the necks of the teeth are kept free from calculary deposits. 
 
 Another disease which might be mistaken for pyorrhoea alveo- 
 laris is chronic hyperplastic diffuse pericementitis, which some- 
 times is accompanied by a purulent inflammation. As the latter 
 disease mostly occurs in devitalized teeth, and generally is con- 
 lined to one tooth, the diagnosis becomes comparatively easy. 
 
 30
 
 450 THE ANATOMY AXD PATHOLOGY OF THE TEETH. 
 
 A process in many respects similar to the one under consider- 
 ation is '■'■ senile atrophy of the jaw-hones.'' This, as a matter of 
 course, is found in old persons, although exceptionally we meet 
 with it in middle age. The characteristic feature of this process 
 is a gradual wasting of the alveolus, and, if the person is other- 
 wise healthy, no pus wall be visible around the necks of the 
 teeth. The gums are generally of healthy appearance, although 
 sometimes they may be slightly inflamed. In the early stage 
 of senile atrophy of the jaws, the necks of the front teeth 
 become denuded of their gums, first upon the labial surface. 
 In the molars, especially the upper ones, the lingual surfaces are 
 affected first, and w^e often see the lingual roots of these teeth 
 entirely bare. The same atrophy is noticed after the extraction 
 of the molars on one side of the jaw. The teeth in the oppo- 
 site jaw having lost their normal antagonism, on account of the 
 absorption of the alveolus, apparently elongate, and subse- 
 quently fall out. This process in a healthy person usually makes 
 but little progress, especially when all or most of the teeth are 
 present in the dental arch. When, on the contrary, the system 
 is attacked by a chronic, wasting disease, we soon notice chronic 
 purulent pericementitis, more or less pronounced, around the 
 loose teeth. Almost the only characteristic of senile atrophy in 
 this form is that the calculary deposits seldom are seen beneath 
 the alveolar border. In such a complication, senile atrophy of 
 the jaws exhibits the picture of pyorrhoea alveolaris, and yet 
 senile atrophy combined with pericementitis, even though the 
 system be impaired, yields to proper treatment. Such teeth, as 
 a matter of course, are loose and will remain so, but they may 
 be serviceable and be preserved for many years. 
 
 The prognosis of pyorrhoea alveolaris depending upon constitu- 
 tional derangements is not altogether hopeless, provided the 
 sreneral disturbance can be combated, althouii;h, in most 
 instances, when the calculary deposits have extended beyond 
 the middle portion of the root, the saving of the tooth becomes 
 doubtful. In such a case the prognosis is the worse the older 
 the patient; while the disease, if occurring under thirty years 
 of age, is mostly curable. When the disease has lasted for 
 some time, granulation-tissue often arises, which, if situated 
 around the neck of the tooth, and accessible to treatment, may 
 not prevent the tooth from being saved. Should, on the con- 
 trary, granulomata develop at the apex of the root, the prognosis
 
 PERICEMENTITIS IN ITS CLINICAL ASPECTS. 451 
 
 'of the tooth becomes doubtful. Although we must admit that 
 pyorrhcea alveolaris is a disease not always amenable to treat- 
 ment, we ought not to sacrifice the teeth unless they cause 
 trouble. The author not infrequently has seen teeth so loose 
 that they might have been removed by the fingers, the calculary 
 deposits besides being present more than half-way toward the 
 apex of the root, and yet they have, under proper treatment, 
 grown firmer in their sockets. 
 
 X. Chronic Purulent Circumscribed Pericementitis, so-called 
 "Blind Abscess." — This form of [(ericementitis is mostly the 
 outcome of repeated attacks of an acute non-purulent circum- 
 scribed pericementitis, more especially when due to constitu- 
 tional derangements. It is also known to arise from foreign 
 bodies, such as bristles of a tooth-l>rush, fine fish-bones, etc., 
 when ol)taining access into the pericementum. In a healthy 
 person the presence of a foreign body in the pericementum 
 usually leads to an acute inflammation, while in poorly-consti- 
 tuted patients such an irritation may lead to a chronic suppur- 
 ative inflammation. It seems that the staphylococci intro- 
 dueed into the depth of a tissue cause suppuration easier in 
 the latter than in the former instance. 
 
 Diagnosis. — Besides chronic purulent circumscribed perice- 
 mentitis, there is often present chronic hyperplastic pulpitis, 
 the more pronounced the longer the blind abscess has existed. 
 In the beginning the abscess causes but little discomfort to the 
 patient, except that occasionally the afi^ected tooth is sensitive 
 to thermal changes. From time to time the patient notices a 
 swelling of the gum corresponding to the diseased portion of 
 the pericementum. The swelling upon the evacuation of the 
 pus soon disappears, and with it the tooth is comfortable, until 
 another subacute attack sets in. These paroxysms of pain last 
 from two to four days, while the intervals between the attacks 
 may last from one to six months. The disease is met with 
 both in sound and carious teeth, though the latter process in 
 this form of pericementitis never extends to the pulp-chamber. 
 The color of the afl'ected teeth always is normal, and trans- 
 illumination will yield l)ut negative results. The tooth is 
 somewhat loose in its socket, and quite painful to pressure, 
 especially in the direction toward the inflamed portion of the 
 pericementum. Cold water or the inhalation of cold air pro- 
 duces excruciating pains lasting from ten minutes to half an
 
 452 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 hour. Pressure upon the gum over the inflamed pericemen- 
 tum is painful, at the same time causing the oozing forth of pus 
 from the ahscess, the pus making its appearance between 
 the neck of the tooth and the surrounding gumi. Percussion 
 upon the afl^'ected tooth is painful, and elicits a distinctly dull 
 sound, especially when directed toward the inflamed portion 
 of the pericementum. 
 
 Suhjecticc Phenomena. — The pain in chronic purulent circum- 
 scribed pericementitis is principally due to pulpitis. In all 
 cases that have come under my observation, chronic hyper- 
 plastic pulpitis was present, which by an additional irritation, 
 such as an accidental hard bite or extreme thermal change, 
 assumed an acute character. The pain is of throbbing char- 
 acter and excruciating. Articulation is impossible, because the 
 tooth is raised in its socket. Upon attempting to open the pulp- 
 chamber we find the dentine abnormally sensitive, often induc- 
 ing a paroxysm of almost unbearable pain. Chronic purulent 
 circumscribed pericementitis sometimes may be accompanied by 
 a slight rise of temperature, which usually occurs toward evening. 
 
 Differential Diagnosis. — Chronic purulent circumscribed peri- 
 cementitis may be confounded with acute purulent difltuse peri- 
 cementitis. The principal characteristic of the former disease 
 is that the tooth is of normal color and contains a living pulp, 
 while the pulp of a tooth attacked by acute purulent diffuse 
 pericementitis is always devitalized and in most instances dis- 
 colored. 
 
 The prognosis of teeth affected by chronic purulent circum- 
 scribed pericementitis as such, would be quite favorable, if by 
 some means we were able to extirpate the diseased pulp. 
 Aside from the dentine being extremely' sensitive to the action 
 of the bur, the pericementitis renders the tooth painful to 
 pressure, and consequently such teeth are usually lost. 
 
 XI. Chronic Purulent Apical Pericementitis. — Under this head 
 I propose to describe a form of chronic abscess principally con- 
 fined to the apices of the roots of the teeth. This disease is 
 always the outcome of an acute or sometimes subacute non- 
 purulent apical [)ericementitis, mainly depending upon the con- 
 stitutional peculiarities of the patient. The better the constitu- 
 tion, the more acute and severe will be the pericementitis; on 
 the other hand, the poorer the constitution, the less acute (sub- 
 acute) and the more chronic the inflammatory process will be.
 
 PERICEMENTITIS IN ITS CLINICAL ASPECTS. 453 
 
 Diagnosis. — A tooth affected witli chronic |)iiriilent apical 
 pericementitis is somewhat loose in its socket, although the 
 gum around the neck of the tooth is firmly attached and appears 
 comparatively healthy. This disease most frequently occurs in 
 teeth the pulps of which have been largely exposed and subse- 
 quently died from moist gangrene or chronic purulent pulpitis. 
 The pus, therefore, has had an opportunity to escape from the 
 abscess through the apical foramen, whereby the chronic inflam- 
 mation usually remains limited to the apical portion of the root. 
 The teeth usually are much discolored. The oral mucosa in the 
 vicinity of the apex of the affected root may be slightly swollen 
 and sensitive to pressure, or may appear normal. Percussion 
 and pressure upon the tooth in the direction of the apex of the 
 affected root always is more or less painful, and the former will 
 elicit a distinctly dull sound. The principal characteristic of 
 such teeth is that as soon as the opening of the i)ulp-canal be- 
 comes temporarily obstructed by particles of food or a piece of 
 cotton, severe pain is the result. When a tooth attacked by 
 chronic purulent apical pericementitis is extracted, we some- 
 times find attached to the apex of the root the abscess inclosed 
 in a more or less spherical bag. In other instances the sac is 
 torn in the extraction of the tooth. 
 
 Subjective Phenomena. — As long as the pulp-canal remains open 
 and the pus is able to escape freely, chronic purulent apical 
 pericementitis produces but little pain, though the tooth may be 
 tender in mastication. Thermal changes applied to such teeth 
 have no effect. 
 
 Dip'erential Diar/nosis. — The only disease with which chronic 
 purulent apical pericementitis might be confounded is chronic 
 purulent difi'use pericementitis. In the latter disease^ however, 
 pus usually is eliminated when pressure is applied upon the gum 
 in the vicinit}' of the affected root. Besides, the gum in the 
 latter disease never is attached to the neck of the tooth, and 
 the obstruction of the pulp-canal by food or cotton usually will 
 produce no trouble, whereas in cases of chronic purulent apical 
 pericementitis such an obstruction is followed by severe pain. 
 
 The prognosis of teeth aflected with chronic purulent apical 
 pericementitis much depends upon the constitution of the 
 patient and upon his toleration to pain. Another fact has to 
 be taken into consideration, — viz, the condition of the apex 
 of the root of the affected tooth. When the disease has existed
 
 454 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 for some time, granulation-tissue will arise, partially absorbing 
 the root, whereby usually the tooth becomes lost. The prog- 
 nosis of chronic purulent apical pericementitis may be expressed 
 in short as follows : If the disease has not lasted long enough 
 to affect the apex of the root, and we are able to destroy the so- 
 called pyogenic membrane and afterward thoroughly disinfect 
 and fill the pulp-canal, such a tooth may be saved. If, on the 
 contrary, the end of the root has been absorbed by granula- 
 tions, or the patient will not submit to the destruction of the 
 pyogenic membrane, the tooth should preferabh' be extracted. 
 
 XII. Chronic Purulent Diffuse Pericementitis. — In most in- 
 stances the disease under consideration originates from acute 
 non-purulent diffuse pericementitis, or chronic purulent pulpitis. 
 It may also develop after the death of the pulp by gangrene. 
 
 Diagnosis. — A tooth affected with purulent diffuse perice- 
 mentitis is quite loose in its socket, and can be moved laterally 
 as well as perpendicularly without causing much pain. Articu- 
 .lation, on the contrary, is always painful. The tooth usually is 
 discolored, indicative of the devitalization of its pulp. The 
 mucous membrane around the root of the affected tooth is more 
 or less inflamed, tumefied, and soft to the touch. The color of 
 the gum is dark red, often exhibiting a bluish ring around the 
 neck of the tooth. The gum has lost its attachment to the 
 neck, and often we are able to pass a fine probe between the 
 tooth and the gum, even for some distance into the perice- 
 mentum, without producing either hemorrhage or pain. 
 
 Pressure upon the gum with the point of the index finger is 
 somewhat painful, and will always be followed by an evacuation 
 of more or less pus. In advanced stages the affected tooth 
 sometimes becomes extremely sensitive to pressure in one or 
 more directions. This indicates that an absorption of the root, 
 or a new formation of bone-tissue, either in the hyperplastic 
 pericementum or upon the walls of the socket, is present. Per- 
 cussion upon the crown of a tooth affected by chronic purulent 
 diffuse pericementitis always is painful, and elicits the dullest of 
 all sounds produced by percussion of teeth in the mouth. 
 
 Siihjccth'e PJieiiomcna. — With the exception of pain in nuistica- 
 tion, the patient experiences but little discomfort from a tooth 
 attacked by chronic purulent difi'use pericementitis. 
 
 Diferciiiial Dia'/nosi.^. — The disease under consideration may 
 be confounded with chronic hyperplastic diffuse, with chronic
 
 PERICEMENTITIS IN ITS CLINICAL ASPECTS. 455 
 
 purulent apical pericementitis, with alveolar abscess, and with 
 necrosis of the jaw-bones. 
 
 Chronic hyperplastic diffuse pericementitis can hardly be dif- 
 ferentiated from chronic purulent diffuse pericementitis, espe- 
 cially since, in advanced stages, the former disease always is 
 associated with the latter. 
 
 Chronic purulent apical pericementitis is characterized by the 
 ffum beins: closelv attached to the neck of the affected tooth; 
 while in chronic purulent diffuse pericementitis the gum always 
 is found detached, emitting pus upon pressure. Alveolar abscess 
 may be differentiated from chronic purulent diffuse perice- 
 mentitis by the ix'dema of the fiice, which, in the majority of 
 cases, is present in the former disease. Another characteristic 
 of alveolar abscess is the fistula in the mucous membrane, com- 
 municating with the abscess, which never is found in chronic 
 purulent diffuse pericementitis. 
 
 Necrosis of the jaw-bone is recognized by the denuded sur- 
 face of the bone presenting a roughness when a probe is passed 
 over it. Here we always find the periosteum more or less 
 detached from the surface of the bone. In cases where the 
 necrosis originated from chronic purulent pericementitis, it 
 usually is limited to the surrounding alveolus of one tooth. 
 "When, on the contrary, the necrosis is of sj-philitic or phosphoric 
 origin, it may involve many teeth simultaneously, although in 
 such an instance the teeth may still be alive. 
 
 The prognosis of teeth affected with chronic purulent diftuse 
 pericementitis mainly depends upon the constitution of the 
 patient and the stage to which the disease has advanced. As 
 long as it is not associated with diftuse hyperplastic perice- 
 mentitis, and the constitution of the patient is not impaired, the 
 prognosis is fair. The presence of hj'perplastic new formations 
 in the pericementum is indicated by pains when even slight 
 pressure is brought to bear upon the tooth. In such cases it 
 ouglit to be removed. On the other hand, when granulations 
 are absent and the pulp-canal is carefully disinfected, and, after 
 the cessation of the formation of pus, is thoroughly filled, such 
 a tooth might be saved. 
 
 XIII. Chronic Alveolar Abscess. — Under the foregoing heads 
 I have described the morbid changes in the pericementum 
 alone; in the following I propose to dwell upon the secondary 
 processes subsequent to pericementitis.
 
 456 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 When purulent perieemeatitis has lasted for some time, the 
 inflammation spreads to the neighboring bone-tissue, which 
 process, though secondary to pericementitis, must be regarded 
 as a disease of the jaw-bones. Among the forms of inflamma- 
 tion of the root-membrane principally causing chronic alveolar 
 abscess, I would mention chronic purulent dift'ase and chronic 
 hyperplastic pericementitis. 
 
 Diagnosis. — In the early stage of a chronic alveolar abscess the 
 mucous membrane over the aliected root is considerably swollen 
 and softened, similar in appearance to that found in chronic 
 purulent diflfuse pericementitis. In later stages, almost invari- 
 ably a fistulous communication with the abscess is present, due 
 to an ulcerative destruction of the mucosa. In quite chronic 
 cases the fistula becomes closed from time to time, thus pro- 
 ducing the formation of a parulis (so-called " gum-boil"). This 
 formation is characteristic of chronic alveolar abscess when the 
 periosteum is neither much thickened nor detached from the 
 bone. Should the pericementum be hypertrophied or detached, 
 no gum-boil is found, the opening of the fistula is not obstructed,. 
 and the disease has advanced to a further stage, — /.(., periostitis, 
 or necrosis of the jaw-bone. In slowly-progressing cases we 
 sometimes see around the parulis a growth of granulation-tissue^ 
 in shape and size of a pea. In rare instances, especially in the 
 teeth of the upper jaw, the fistula does not break open through 
 the mucous membrane, but the pus is evacuated around the 
 neck of the affected tooth. Exceptionally the fistulous oj^ening 
 is not seen in the vicinit}' of the affected root, but some distance 
 from it, in which instance it may be ditficult to find the tooth. 
 It occurs, though rarely, that the fistula of one of the upper 
 front teeth opens at the border of the hard palate. The fact 
 that the disease under consideration always is caused by a devi- 
 talized tooth will assist us in clearing the diagnosis. Further- 
 more, pressure and percussion upon the affected tooth are 
 always sensitive, though such a tooth may not be elongated or 
 loose in its socket. In (juite chronic cases, where the granulations 
 have absorbed portions of the root and the alveolus, the tooth 
 is markedly sensitive to pressure and percussion. In such 
 cases we not infrequently find the alveolar process of both 
 neighboring teeth lost, which loss oiten can be distinctly detected 
 by the point of thei ndex finger. 
 
 Subjective Phenohtena. — Chronic alveolar abscess, in its incipi-
 
 PERICEMENTITIS IN ITS CLINICAL ASPECTS. 457 
 
 ent stage, when osteitis sets in, is accompanied by drawing paii.s, 
 and sometimes by fever. During this period, which usually 
 lasts from one to three days, the tooth is sensitive to the touch 
 and to mastication. In time the process assumes a less acute 
 course, and when the gum-boil becomes established, the patient 
 suffers no more pain. Only the rupturing of the parulis, from 
 time to time, indicates the existence of a chronic alveolar 
 abscess. 
 
 Differential Diagnosis. — In most instances a chronic alveolar 
 abscess is easily recognized. Where no fistulous opening is 
 present, it might, however, be confounded with chronic puru- 
 lent diffuse or circumscribed pericementitis, as well as chronic 
 purulent hyperplastic pericementitis. Hyperplastic and diffuse 
 pericementitis are so similar to a chronic alveolar abscess with- 
 out a fistula, that a correct difierentiation is not always possible. 
 Chronic purulent circumscribed pericementitis, however, is char- 
 acterized by the living pulp the tooth mostly contains, while 
 chronic alveolar abscess occurs only in devitalized teeth. 
 
 T/ic prognosis of teeth afiected with chronic alveolar abscess, 
 on an average, is good, especially in cases which have not existed 
 long enough to develop granulations at the end of the root. 
 The rule here, as in the treatment of teeth afiected with chronic 
 purulent pericementitis, is that so long as the root has not been 
 absorbed the tooth can be saved. The success of the treatment, 
 however, depends upon the ability of the operator and the form 
 and accessibility of the pulp-canal of the afiected tooth. If the 
 pulp-canal can be thoroughly disinfected and filled, and no fill- 
 ing-material has been pushed through the apical foramen of the 
 root, the tooth is usually saved. 
 
 XIV. Cementitis and Eburnitis. Inflammation of the Cemen- 
 tum and Dentine. — As already mentioned, wherever a chronic 
 infiammatory process has existed for some time, granulation- 
 tissue develops, leading to a gradual destruction of the root of 
 the tooth, by cementitis and eburnitis. These processes, under 
 the microscope, are characterized by bay-like excavations in the 
 hard tissues, often filled with multinuclear protoplasmic bodies. 
 In some instances even new formations of bone are met with 
 in the adjacent tissues. 
 
 Dia<jiiosis; — To the naked eye the roots of teeth affected by 
 cementitis and eburnitis present deep and irregular cup-shaped 
 excavations, between which shar}» projections are left. When
 
 458 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 pressure is exerted upon the crown of a tootli affected by 
 cementitis and eburnitis, the sharp projections irritate the adja- 
 cent pericementum, thus causing more or less pain. The gum 
 in the vicinity of the affected root is in some instances inflamed, 
 in others normal, depending upon the condition of the perice- 
 mentum. 
 
 The only subjective •phenomenon of cementitis and eburnitis is 
 indeed, as mentioned before, that pain is produced on pressure 
 upon the tooth. 
 
 Diferentkd Diagnosis. — A diagnosis of this disease cannot be 
 made with any degree of certainty until the tooth has been 
 extracted. 
 
 27«e j9?'o^nos/.y of teeth affected with cementitis and eburnitis 
 always is unfavorable, since the sharp projections of the denuded 
 root continually keep irritating the pericementum. Such teeth 
 are usually lost. 
 
 XV. Periostitis, Osteitis, and Osteomyelitis. — As these dis- 
 eases usually are associated with, and the outcome of, puru- 
 lent pericementitis, I shall consider them under one head. 
 Occasionally they occur in consequence of mechanical violence, 
 — i.e., by a hard blow; in difficult eruption of the wisdom-teeth, 
 especially the lower ones; or in tearing of the gum in extract- 
 ing badly-decayed roots. These diseases always arise by an 
 infection, sometimes accomplished by the use of septic instru- 
 ments or unclean tooth-picks, pushed under the gum. 
 
 Diagnosis. — The inflammatory process attacking the perios- 
 teum extends over the bone, either in the form of osteitis, osteo- 
 myelitis, or necrosis. Periostitis in the beginning always is 
 acute, and causes swelling of the mucous membrane, and some- 
 times considerable oedema of the lip and cheek. When this 
 occurs in the lower jaw, the swelling soon involves the sub- 
 maxillary gland, and often spreads down to the shoulder. To- 
 gether with the periostitis, usually there is a swelling and rigid- 
 ity of the muscles of mastication, whereby the patient is unable 
 to open the mouth. Periostitis, when a sequel of pericementitis, 
 mostly is preceded by osteitis and osteomyelitis, in which case 
 the inflammation first attacks the bony socket, before its peri- 
 osteal covering becomes involved. In cases of traumatic origin, 
 however, as a rule, the periostitis is the primary process, while 
 the osteitis, osteomyelitis, or necrosis are secondary occurrences. 
 Periostitis in an acute stage mav exist alone; but subacute or
 
 PERICEMENTITIS IX ITS CLINICAL ASPECTS. 459 
 
 chronic cases are always accompanied Ijy more or less osteitis, 
 osteomyelitis, or necrosis of the jaw-bones. In the majority of 
 instances an inflammation of the alveolar periosteum is the 
 result of a devitalized tooth, which may be easily recognized 
 by its dark color. The extent of the area of the affected alveolus 
 greatly varies. In some cases it. is only as large as a pin's 
 head, while in others the process may involve the alveolar pro- 
 cesses of four or five teeth in a comparatively short space of 
 time. When purulent periostitis, osteitis, or osteomyelitis are 
 present, as a rule, one or several fistulous openings are seen in 
 the gums. Sometimes, however, the pus is evacuated along the 
 necks of the teeth. In quite severe and chronic cases, espe- 
 cially those of the lower jaw, the pus, after perforating the bone, 
 makes its appearance on the outer surface of the skin. When 
 the diseases under consideration originate in consequence of 
 difficult eruption of the lower wisdom-teeth, the swelling and 
 the formation of pus may be copious, especially in acute cases, 
 while those of a more chronic type seldom exhil)it much swell- 
 ing or pus. The gum over the affected periosteum usually is 
 spongy to the touch, and, according to the stage the inflamma- 
 tory process has advanced, is characterized by more or less red- 
 ness and heat. Not infrequently periostitis, osteitis, and osteo- 
 myelitis, when present in the upper jaw, extend into the antrum, 
 or even the nasal cavities, on which emergencies I shall dwell 
 more fully in a separate chapter. When chronic pericementitis 
 becomes diftuse, it may be accompanied by the formation of 
 fistulse and abscesses in the neighboring tissues. The writer 
 has seen patients who, in consequence of a neglected chronic 
 alveolar abscess, suffered from secondary abscesses in several 
 places of the neck, near the clavicle. There are even fatal cases 
 on record in which the pus found its way into the mediastinum, 
 producing secondary abscesses, purulent pleuritis, or oedema of 
 the lungs. 
 
 Sahjedice PJienomeno. — In periostitis, osteitis, and osteomye- 
 litis, much depends upon the constitution of the individual. The 
 better the general health of the patient, the more acute is, as a 
 rule, the inflammatory process, and the greater will be the suf- 
 fering, especially in diffuse inflammation. In such instances 
 these diseases always are accompanied by more or less fever and 
 other derangements of the system, the more severe the greater 
 the number of deep-seated abscesses formed in the neighbor-
 
 460 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 hood of the iuflaraed parts. The majority of cases of perios- 
 titis, osteitis, and osteomyelitis, however, do not become diffuse, 
 but remain localized to a comj^aratively small area. Then, 
 should the trouble be caused by pericementitis, the patient ex- 
 periences but little pain from the periostitis, while osteitis and 
 osteomyelitis are acconi}ianied by excruciating pains. As soon, 
 however, as the alveolar process is perforated by the pus the 
 }>ain subsides, and periostitis, in itself not very painful, as stated 
 before, takes issue. 
 
 Differential Diagnosis. — Periostitis in either its localized or 
 diffused form cannot easily be mistaken for another disease, 
 while osteitis and osteomyelitis may sometimes be confounded 
 with necrosis of the jaw-bones, the more so since it mostly is 
 associated with the former. The distinguishing peculiarities of 
 necrosis are the roughness and hardness of the exposed surface 
 of the bone to the probe. The periosteum is detached, and be- 
 tween it and the bone a considerable amount of pus is continu- 
 ally formed, freely escaping upon pressure. Inflamed bone ap- 
 pears softened to the touch of the probe; its surface, wdien 
 exposed, looks red, its periosteum is hy}iertruphied and more 
 or less firmly attached to the diseased bone. 
 
 Prof/iiosis. — Periostitis, osteitis, and osteomyelitis, occurring 
 in consequence of mechanical violence, usually yield to antisep- 
 tic treatment in a comparatively short space of time, and with- 
 out the loss of teeth. When, however, these diseases are due 
 to purulent pericementitis, the loss of the tooth, together with 
 a portion of the alveolar process, cannot be avoided. When 
 secondary abscesses have formed in the region of the neck or 
 the mediastinum, these diseases l)ecome quite serious, as a rule^ 
 and sometimes even endanger life. 
 
 XVI. "Lymphadenitis," Inflammation of the Lymph- 
 Ganglia. — The naiiK- •• lynqihadfiiitis," though generally used, 
 is erroneous, since it means inflammation of a lym[)li-gland, 
 whereas the lymph-follicles and lymph-ganglia are not glands, 
 lacking epithelial structure altogether. Inflammation of the 
 lymph-ganglia is most common in the submaxillary region, 
 always due to a transmission of infectious material through the 
 lymph-vessels into the lymi>h-ganglia. There are persons who, 
 upon the slightest non-puriilent inflammation of the pulp or 
 the pericementum, react with a swelling of the submaxillary 
 ganglia. Purulent pul|iitis and pericementitis, with all the
 
 PERICEMENTITIS IN ITS CLINICAL ASPECTS. 461 
 
 inflammjiton' complications dependent upon tlicm, are invari- 
 aVjly accompanied by a swelling- and hardening' of the lymph- 
 ganglia. Gangrene of the pulp is prone to cause this trouble. 
 All tliis holds good only for infectious diseases of the teeth of 
 the lower jaw, while those of the upper jaw but rarely affect 
 the lymph-ganglia in the submaxillary region. It seems that 
 this disease is more common in youths under ten years than in 
 persons more advanced in age. In adults it frequently occurs 
 during difficult eruptions of the wisdom-teeth, or after their ex- 
 traction. In some instances lymphadenitis makes its appear- 
 ance after an attempted extraction of a tooth or a root, in wliich 
 case, however, the symptoms never are severe. 
 
 Dwijnosis. — In the l)eg-inning- of tlie process the submaxillary 
 ganglia swell and l)ecome hard. The covering skin is rendered 
 tense and hot, and the enlarged knot immoval)le. The slight- 
 est pressure upon it is painful. The swelling in mild cases 
 attains the size of a walnut, while in severer ones it may reach 
 the size of a man's fist or more. There is great rigidity of the 
 muscles of the jaAv, so much so that the mouth can only be 
 opened by means of instruments. The principal characteristic 
 of this disease is that there usually are no fistulous openings 
 present in the gum. Although, as a rule, the inflammatory 
 infiltration soon abates, in rare instances the ganglia suppurate, 
 indicated by a red spot upon the skin covering the ganglia, 
 and by the fluctuation. These symptoms usually are accom- 
 panied by more or less fever. 
 
 S'lhjecfive Phevomeva. — In tlie beginning of the process the 
 patient experiences Init little pain, unless something comes in 
 contact witli the swollen ganglia. In the milder forms this dis- 
 ease does not cause pain, but only discomfort ; while the severer 
 cases, accompanied by fever and the formation of an abscess, 
 are quite distressing. Real pain commences as soon as the 
 submaxillary ganglia verge to suppuration. 
 
 Differential Diagnom. — -Taking into consideration the sub- 
 jective symptoms, and what has been stated concerning the 
 diagnosis of the disease in question, it cannot easily be mis- 
 taken for another disease. 
 
 Profpiosis. — In lymphadenitis much depends upon the con- 
 stitution of the patient. Otherwise healthy persons, when at- 
 tacked by the disease, seldom sufter mucli, nor are the ganglia 
 apt to suppurate except in a so-called lynipliatic constitution.
 
 462 THE ANATOMY A>D PATHOLOGY OF THE TEETH. 
 
 Some very acute cases may become annoying, more by tbe 
 protracted swelling of tbe neck and tbe disfigurement, often 
 lasting for weeks, tban otbers in wbicb suppuration bas taken 
 place. 
 
 CHAPTER XXXIX. 
 
 MORBID ANATOMY OF PERICEMENTITIS. 
 
 According to tbe severity of tbe irritation, and tbe constitu- 
 tional peculiarities of tbe individual, pericementitis presents 
 itself as acute or cbronic, eitber of wbicb may be non-purulent 
 or purulent. Acute pericementitis is not infrequently confined 
 to tbe region of tbe neck of tbe tootb. As in any otber acute 
 inflammatory process, it may issue in a bemorrbage, especially 
 in so-called bsematopbiles or bleeders, wbo upon tbe sligbtest 
 injury bleed profusely, botb from open wounds at tbe surface of 
 tbe body and from a comparatively sligbt inflammatory process, 
 such as ulitis or marginal pericementitis. In my collection of 
 microscopical specimens, wbicb embraces tbousands of objects 
 from pathological teetb, are several obtained from tbe neck of 
 a tooth in which I observed the presence of a large number 
 of clusters of hrematoidin crystals in tbe neck layer of tbe ce- 
 mentum as well as in tbe subjacent so-called granular layer of the 
 dentine. (See Fig. 230.) This condition maybe termed apoplexy 
 or hiEinorrJiotjic infarctui- of tbe bard tissues of the teetb. In my 
 judgment, it is impossible to explain the presence of hfematoidin 
 in the cementum and the dentine without a previous sufi'usal of 
 these tissues with blood. Tbe fact that tbe cementum of tbe 
 neck is rich in protoplasmic bodies and tbe granular layer of tbe 
 subjacent dentine rich in living matter, arranged in tbe shape of 
 a coarse reticulum, aftbrds an explanation of this remarkable 
 condition. 
 
 Acute Non-Purulent Pericementitis, in its mildest degree, 
 with lower powers of the microscope, is recognizable by the 
 presence of nests, tilled witb medullary elements, in tbe midst 
 of tbe connective-tissue bundles. Tbe shape of these nests is, 
 as a rule, oblong, corresponding to the longitudinal direction of 
 the connective-tissue bundles, or roundish, in accordance witb 
 the cross-section of bundles. The scantier these nests, the
 
 MORBID ANATOMY OF PERICEMENTITIS. 
 
 463 
 
 milder is the inflammatory process. With high magnifying 
 powers of the uiicroseope we learn that the earliest stage of the 
 inflammation consists in a transformation of the connective-tissue 
 fibers into protoplasm. With the knowledge of the normal 
 structure of the pericementum we are enabled to comprehend 
 that a mere liquefaction of the basis-substance is sufficient for 
 the reproduction of the protoplasmic condition of the basis-sub- 
 stance. Such a reproduction occurs in the shape of streaks in 
 
 Fig. 230, 
 
 
 
 'if 
 
 Cl.lSTERS OP H.EMATOIDIX IN THE CeMEXT AND I>KNTINE OF TUE NeCK. 
 
 T, decalcified tartar ; C, cementum of neck with numerous clusters of haematoidin ; J), 
 granular dentine of neck ; IT, clusters of haematoidin in dentine. Magnified 500 diameters. 
 
 the midst of a bundle, independently of the original protoplasmic 
 bodies, — the formerly so-called connective-tissue cells. (See 
 Fig. 231.) 
 
 According to the spindle shape of the elementary fields of the 
 basis-substance, spindle-shaped protoplasmic bodies have ap- 
 peared, wholly identical with the normal protoplasmic bodies 
 within the fibrous connective tissue. All these bodies are 
 separated from one another by light rims, and connected with 
 each other by the delicate threads of living matter traversing
 
 464 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 those rims. The tinely-granular newly-appeared protoplasmic 
 bodies soon afterward become coarsely granular, which means 
 that the living matter therein has increased in bulk. A liquid 
 exudation as "such is never visible under the microscope, but 
 we infer its presence both from the liquefaction of the basis- 
 
 FiG. 231. 
 
 AcfTE Pericementitis of a Moderate Degree. 
 
 F, fibers of pericementum unchanRed ; R, li, rows of inflammatory or embryonal corpuscles; 
 V, capillary blood-vessel obliterated; B, bundles of pericementum implanted into cementum ; 
 C, C, cement-oorpuacles ; S, basis-substance of cementum. Magnified 500 diameters, 
 
 substance and the increase of living matter, which latter can 
 only be due to-an increased afflux of nourishing material. These 
 changes take place in the newly-appeared as well as in the 
 original protoplasmic bodies, the nuclei of wdiich invariably
 
 MORBID ANATOMY OF PERICEMENTITIS. 
 
 465 
 
 become shining, homogeneous, and enlarged, owing to the same 
 cause which led to the enlargement of the points of intersection 
 of the reticulum of living matter. 
 
 We see next that a number of granules — the points of inter- 
 section of the reticulum — have increased in size to such an 
 extent that they resemble small nuclei, and from these foci new 
 
 Fig. 232. 
 
 Intense Pericemkntitis, veiujinc; on Suppu'ratkix (Zone 2) of Fig. 242. 
 
 T, T, tracts of fibrous connective tissue much reduced in bulk ; N, N, nests of inflammatory 
 corpuscles crowded with stsiphylocoeci ; S. S. clusters of staphylococci: B, R. rows of inflam- 
 matory corpuscles in broad tracts of fibrous connective tissue. Magnified 500 diame' ers. 
 
 protoplasmic elements are formed, partly shining and homo- 
 geneous, partly reticular in structure. After the originally solid 
 lumps of living matter have split into a reticulum, many of the 
 newly-formed elements contain solid nuclei. All elements are 
 uninterruptedly connected with each other by delicate threads 
 
 31
 
 466 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 of living matter. Thus, the inflammatory infiltration is estab- 
 lished at first in the shape of scattered nests, the centers of 
 which correspond to the capillary blood-vessels. In later stages 
 almost the whole amount of the connective tissue is transformed 
 into medullary elements to such a degree that only scanty 
 bundles of the original connective tissue are left. (See Fig. 
 232.) 
 
 The changes in the wall of the capillary blood-vessels are of 
 considerable interest. Doubtless the largest accumulation of the 
 inflammatory elements takes place in the immediate neigh- 
 borhood of the blood-vessels, for in the midst of many nests 
 capillaries can be traced. We readily understand that in the 
 immediate vicinity of the source of nutrition the inflammatory 
 process must be the liveliest. This fact has been taken up as an 
 
 Fig. 283. 
 
 RICKMKNTLM IX AN" EaRLY 
 
 ^, capillary bloocl-vc?;'el, the endothelia of which are coarsely granular and proliferating; 
 B, medullary or inflammatory elements, imbedded in a finely-gi-anular basis-substance : C. C, 
 spindle-shaped elements. Magnified lOUO diameters. 
 
 aro-ument by those who assert that the inflammatory nests are 
 altogether due to an emigration of colorless blood-corpuscles. 
 I am strongly opposed to this opinion, because my observations 
 show that the majority of the inflammatory elements are origi- 
 nally connected with one another by delicate threads, therefore 
 representing a tissue. The endothelia of the capillaries share in 
 the inflammation, b}'' being transformed into coarsely-granular, 
 irregular protoplasmic bodies, which, by division, also produce 
 new medullary elements, partly nucleated, partly devoid of 
 nuclei. By the new formation of inflammatory elements from 
 the endothelia, the capillary is first considerably narrowed in 
 caliber, and afterward completely obliterated. (See Fig. 233.)
 
 MORBID ANATOMY OF PERICEMENTITIS. 467 
 
 An exuberant growth of the endothelia will, as a rule, result in 
 the destruction of the capillaries by suppuration, and will prob- 
 ably give rise to formations which I shall presently describe. 
 
 In most of my specimens of inflamed pericementum I have 
 met with a singular formation. A number of medullary 
 elements coalesce into globular masses, greatly varying in size, 
 and in some instances surrounding a central polyhedral space, 
 evidently made by the compression of the former blood-vessel. 
 The globular masses are either composed of medullary elements, 
 shining, homogeneous, and split into smaller lumps of living 
 matter, or they are continuous masses of a coarsely-granular 
 protoplasm in wliich varying numbers of nuclei are seen. There 
 is scarcely an}" doubt that the latter formations have arisen from 
 the former ones through confluence of the single medullary 
 elements. On the boundary very often concentric layers of 
 round or spindle-shaped, finely-granular elements are present. 
 In specimens stained with a solution of chloride of gold the 
 concentric layers are of a pale violet, w^hile the protoplasmic 
 masses inclosed therein exhibit a dark-purple color. Formations 
 of this kind are well known in inflamed periosteum and medulla 
 of bone ; they have been termed m^'eloplaxes, myeloid bodies, 
 giant-cells, etc. All the well-known hypotheses as to their sig- 
 nificance disagree with what I have seen, — viz, the formation of 
 territories of bone-tissue from these clusters. 
 
 My specimens show plainly that in the so-called plastic inflam- 
 mation of the pericementum all inflammatory elements remain 
 connected with one another, and thus represent a medullary, 
 embryonal, or inditFerent tissue. In slight degrees of inflamma- 
 tion the morbid process may yield to what has been termed 
 " the resolution of inflammation." ISTothing is required but the 
 re-formation of the basis-substance, and the normal condition is 
 re-established, sometimes so completely that no trace of the 
 former inflammation is noticeable. More severe forms of plastic 
 pericementitis, or repeated recurrences of the inflammatory 
 process, will result in a new formation of the connective tissue, 
 the so-called hyperplasia. Higher degrees of plastic pericemen- 
 titis are invariably accompanied by inflammation of the gum, 
 the cemcntum, and the bony alveolus. 
 
 Cementitis is shown under the microscope by the presence of 
 bay-like excavations on the periphery of the cementum, and 
 sometimes also beneath the surface. These excavations are filled
 
 468 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 with medullary elements or multinuclear protoplasmic bodies. 
 On an average, the excavations are deeper and more numerous in 
 proportion to the intensity of the original inflammatory process. 
 To their presence is due the peculiar corroded appearance of 
 the cementum in teeth extracted during an attack of peri- 
 cementitis. (See Fig. 234.) 
 
 Fig. 234. 
 
 #^^.^va^ 
 
 
 Intense Acute Cemextitis and Pericemextitts. 
 
 P. pericementum much inflamed; P', inflamed pericementum detached from cementum; 
 />, dissolution of lime-salts in territories along the border of cementum ; A, A, advanced reduc- 
 tion of cementum ; E, i?, enlarged cement-corpuscles. Magniliod 500 diameters. 
 
 Osteitis of the Ijone of the alveolus is manifested in its incipi- 
 ent, form by a dissolution of the basis-substance of the bony tis- 
 sue, in' the shape of bay-like excavations, corresponding to the 
 territories of the bone-tissue. Within the decalcified territories
 
 MORr.ID ANATOMY OF PERICEMENTITIS. 
 
 469 
 
 coarsely-granular Ijone-corpuscles are seen, many of which are 
 distinctly enlarged, sending forth numerous hifurcating off- 
 shoots. The territory itself is reduced to its protoplasmic 'con- 
 dition, indicated by a fine and uniform granulation. In many 
 
 Fig. 2.35. 
 
 Incipient Osteitis op Alveoll's. Dissolution of Lime-Salts. Reappearance of 
 
 Tekritories. 
 
 /', still calcified framework at the borJers of the territorie? : (',(', enlarged and coarsely-gran- 
 ular bone-corpuscles; /*, P, reappearance of protoplasm within the territories : E. cluster of 
 embryonal or inflammatory corpuscles ; />. divided bone-corpuscle : B, empty bays, the 
 inflammatory corpuscles dragged away ; //, large empty bay, a so-called Howship's lacuna. 
 Magnified 500 diameters. 
 
 places, however, clusters of coarse granules are .^een, some of 
 which have considerably increased in size, approaching thatjof 
 medullary corpuscles, the inflamed bone thus appearing to be 
 provided with far more V)one-corpuscles than the normal bone.
 
 470 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 This appearance is due partly to the enlargement of the old 
 bone-corpuscles, parti}' to their splitting up into two or more 
 protoplasmic bodies, and partly to the formation of new proto- 
 plasmic bodies. If the basis-substance melts completely, the 
 entire existing bone-tissue is rendered protoplasmic, and by a 
 
 ¥w. 236. 
 
 Acute Osteitis in Ai.veolah AVai.l. 
 
 N,fN, normal bone-corpusoles : Ji, territory roLlueed to iirotoplasm : /, bono-corpuscles 
 increased in size and number ; Z, A, enlarged bone-curpusclos; A', Z7, medullary spaces much 
 enlarged; C, normal medullary canal ; ^1/, muUinudear protoidasmic body. Magnified 400 
 diameters. 
 
 new formation of medullary cor}iuscles from the living portion 
 of thejprotoplasm medullary or inflammatory corpuscles arise 
 filling the"bay-like cxcavatitms, which have been originated by 
 a. fusion'^of the dccalcitiod territoiies. Such bay-like excava-
 
 MOKIJID ANATOMV Ul- I'KltJrE.MENTITI.S. 471 
 
 tions appear empty when specimens made from dry bone are 
 examined, or if, in cutting the section, the medullary tissue is 
 dragged away. They are known to pathologists as Howship's 
 lacuna. (See Fig. 235.) 
 
 When intense acute inflammation begins in the bony socket 
 of the alveolus, the image under the microscope is somewhat 
 different. No regular territorial decalcification takes place, but 
 a rapid dissolution of the lime-salts in circumscriVjed nests 
 occurs independently of Haversian canals. The previous bone- 
 corpuscles and the living matter spread throughout the basis- 
 substance of the bone lead to the rapid appearance of inflam- 
 matory or medullary corpuscles, either scattered singly in a 
 myxomatous basis-substance or in clusters termed myeloplaxes. 
 In the center of such an inflammatory nest, as a rule, a newly- 
 formed capillary blood-vessel makes its appearance. At the 
 periphery of the inflamed nest decalcification is indicated by 
 more or less crescentic fields, imperfectly marked as to territory, 
 such as we frequently see in the developing bone-tissue of 
 embryos between the third and sixth months of intra-uterine life. 
 The decalcification invades the bone-tissue diffusely, as we maj* 
 infer from the fact that we see many enlarged and split-up bone- 
 corpuscles without the reappearance of territories. In a thor- 
 oughly-calcified basis-substance such changes of the bone-cor- 
 puscles would be impossible. (See Fig. 236.) 
 
 This process is invariably combined with osteomyelitis, and 
 the result of both processes is the transformation of the hard 
 bony tissue into a soft medullary or inflammatory tissue. In 
 some of my specimens of osteitis this change is exhibited to a 
 very high degree, so that (fiiiy small islands of bony tissue are 
 left as remnants of the former wall of the alveolus. 
 
 Chronic Hyperplastic Pericementitis. — An intense plastic peri- 
 cementitis, (jr repeated attacks of a so-called subacute inflamma- 
 tory process, will lead to a new formation of connective tissue, 
 cementum,and bone. Xew formations due to a distinct inflam- 
 matory process are termed hyperjilasia or hypertrophy, in dis- 
 tinction from those new formations that arise without prom- 
 inent inflammatory symptoms and are generally termed 
 "tumors." 
 
 Hyperplasia of pericementum occurs whenever a large num- 
 ber of inflammatory elements are newly formed and remain in 
 connection with one another, thus not ceasing to be a tissue.
 
 472 THE ANATOMY AXD PATHOLOGY OF THE TEETH. 
 
 The inflammatory elements in certain districts become elong- 
 ated, and, after having split into narrow spindles, are trans- 
 formed into a solid basis-substance, which means a new forma- 
 tion of connective-tissue bundles. Such bundles differ from 
 those of normal pericementum in their greater density and 
 their verv irregular arrangement. Hypertrophied pericemen- 
 tum is occasionally augmented in its entire bulk, and is built 
 up of coarse bundles of connective tissue, between which, in the 
 earlier stages of the hyperplastic process,' more or less numer- 
 ous nests of inflammatory elements are still seen. In other 
 instances, the entire pericementum is transformed into a dense 
 cicatricial connective tissue, whose bundles are very small, and, 
 by crossing one another in all directions, produce a feltwork. 
 Hyperplastic pericementum, as a rule, holds fewer blood-vessels 
 than the normal. 
 
 Sometimes scattered nests of the inflammatory elements 
 exhibit a high refracting power, which evidently is due to a 
 deposition of lime-salts in them, the so-called ealcilication. 
 This process is entirely difterent from ossification, though the 
 former apparently precedes the latter. Scattered nests of 
 inflammatory elements may be transformed also into clusters 
 of fat-granules, which are recognizable by their peculiar refract- 
 ing power, and by remaining unstained by either carmin or 
 chloride of gold. Irregularly-distributed fat-globules are very 
 often seen in hyperplastic pericementum. Whether these glo- 
 bules are identical with the original fat-globules in normal peri- 
 cementum, or are formed after the inflammatory process has 
 abated, I am unable to say. 
 
 Localized hyper])lasia of the pericementum is sometimes 
 observed at the neck of the tooth, in the shape of rather broad 
 nodules, either pediculatcd or sessile, freely vascularized, and 
 therefore of a deep-red color to the naked eye. The tissue of 
 such a nodule, under the microscope, appears as a combination 
 of fibrous and my.xomatous connective tissue, richly supplied 
 with capillary blood-vessels. (See Fig. 237.) 
 
 Nodules of this type are allied to granulation-tissue, the 
 admixture of fibrous bundles being attributable to the original 
 fibrous structure of the pericementum. Such nodules are prone 
 to penetrate the cementum to varying depths. They cause the 
 appearance of jiits in the cementum of the neck of the tooth as 
 well as the roots. Often they are transformed into pus at their
 
 MORBID ANATOMY OF PERICEMENTITIS. 
 
 473 
 
 surface, though suppuration is seldom profuse in this form of 
 marginal pericementitis. Intense suppuration, combined with 
 formations of myxomatous granulomata, is of not infrequent 
 occurrence along the root, leading to an almost complete pitted 
 absorption of the roots of the affected teeth. This process 
 is invariably accompanied by intense cementitis and eburnitis. 
 
 Fio. 237. 
 
 ^ 
 
 Q^f^m^^^ 
 
 
 
 Hyperplastic Myxdfihruus Pkiuckjikxtuii Gkanui.o.ma at thk Neck of a Molar. 
 
 F, F, remnants of bundles of fibrous connective tissue ; M, M. myxomatous granulation- 
 tissue between the fibrous bundles ; (', C, capillary blood-vessels ; P, P, zone of suppuration. 
 Magnified 500 diameters. 
 
 Xew formation of cementum is observable in two forms : 
 either as re-formation in the Ijay-like excavations, or as a new 
 formation on the outer surface of the cementum. 
 
 Re-formation of the cementum is always characteri;^ed by a
 
 474 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 deposition of lime-salts in the territories of the cement-corpus- 
 cles, previously dissolved by the inflammatory process. The 
 bay-like excavations remain unchanged in their configuration, 
 even after new cementum has formed. The difference between 
 normal and newly-formed cementum is that in the latter cement- 
 corpuscles are larger, more numerous, and irregular. In the 
 basis-substance we not infrequently recognize the inflammatory 
 elements (osteoblasts), the infiltration of which, first with a gluey 
 basis-substance, afterward with lime-salts, has caused the new 
 formation of cementum. In the cementum of both the neck 
 and the root I have met with such sharplj'-circumscribed. islands 
 of newly-formed cementum, apparently wnth no connection with 
 the outer surface. Nay, in some of my specimens such an island 
 has formed in the cementum, covering the neck of the tooth, 
 and, w^hile the latter shows a normal structure, and is devoid of 
 cement-corpuscles, the newly-formed cementum penetrates the 
 dentine deeply, and exhibits a large number of irregular cement- 
 corpuscles. 
 
 The inflammatory new formation on the surface of the cemen- 
 tum appears in the shape of either a continuous layer of cement- 
 tissue, distinctly bounded toward the normal cementum, or 
 jagged on the outer surface, with manifold elongations and 
 erosions, filled with newly-formed connective tissue. Sometimes 
 relatively large globular formations appear on the outer surface 
 of the cementum as the result of pericementitis. 
 
 There are globular bodies in connection with the cementum 
 by means of a pedicle, which closely resemble those in the pulp- 
 cavity attached to the dentine. These peculiar formations exhibit 
 a distinctly concentric lamination. They are surrounded by a 
 layer of spindle-shaped medullary elements, and hold in their 
 centers a radiating protoplasmic mass, resembling a bone-cor- 
 puscle. As to their origin, there can be scarcely any doubt that 
 they arise from clusters of medullar}- elements or multinuclear 
 protoplasmic bodies as above descril)ed, one of which is seen in 
 Fig. 238, in the immediate neighborhood of the globular forma- 
 tion. We readily understand that a transformation of the 
 medullary elements into bony basis-substance will lead to the 
 formation of a laminated cement-globule; the ditficulty is only 
 to understand the origin of the central protoplasmic body. 
 Perhaps this body is a former blood-vessel solidified, the like of 
 which we can often trace in the midst of a multinuclear proto-
 
 MORBID ANATOMY OF PERICEMENTITIS. 475 
 
 plasmic cluster. All new formations on the surface of the 
 cementum caused by an inflammatory process may be properly 
 denominated " exostoses of the cementum." 
 
 I have repeatedly seen true bony new formations in hyper- 
 plastic pericementum. They appear in the shape of irregular 
 islands or elongated spiculfe within the iibrous connective tissue, 
 sometimes so near to the cementum that no doubt is left about 
 their formation in the midst of the pericementum, indepen- 
 dently of the bony alveolus. These formations bear a close 
 resemblance to embryonal bone, — viz, contain a large number 
 
 
 
 ^-^4^; 
 
 Globular Body, Result of Peuiceme.ntitis. 
 
 G, concentrically-striated mass, surrounded Vjy small spindle-shaped elements, holding a star- 
 shaped protoplasmic body in its center; t\ cementum ; M, multinuclear body, so-called myelo- 
 plax, from which a globular body may originate ; IE, inflammatory elements, crowded in the 
 pericementum. Magnified 200 diameters. 
 
 of irregular bone-corpuscles, Avith broad offshoots, and a relatively 
 small amount of bony basis-substance. 
 
 Lastly, true bony new formations may occur on the wall of 
 the alveolus, which, after repeated attacks of pericementitis, as 
 clinical observation teaches, is sometimes supplied with thorny 
 new formations of bone. These exostoses originate on the 
 socket of the tooth from the medullarv tissue, in the same 
 manner in which exostoses grow on any other bone as sequelae 
 of periostitis and osteitis. In the highest degree of development 
 these exostoses of the socket replace the pericementum to such
 
 476 THE ANATOMi' A^'D PATIIOLOaY OF THE TEETH. 
 
 an extent that only traces of the pericementum are left. No 
 instance, however, at least to my knowledge, has been observed 
 of a complete fusion of the socket with the tooth. 
 
 Purulent Pericementitis. — This form of inflammation is invari- 
 ably the outcome of an acute process with supervening infection 
 with staphylococci, at least according to the most modern 
 bacteriological views. The invasion is explicable, if the micro- 
 organisms have access to the inflamed pericementum through a 
 carious cavity or a broken root of a tooth. 
 
 Numerous cases are, however, on record in which teeth with 
 living pulps have become afiected by suppurative pericementitis. 
 In such cases we surmise that the staphylococci were carried into 
 the pericementum by some foreign body accidentally pushed 
 into the socket below the gums and the neck of the tooth. 
 
 The possibility cannot be denied that staphylococci may 
 circulate temporarily in the blood and then settle down in the 
 inflamed pericementum, causing suppuration. 
 
 The disease is either acute or chronic, and may appear in 
 either of these forms at the neck of the tooth as marginal, or in 
 a limited portion of the pericementum as circumscribed, or at 
 the apex of the root as apical pericementitis or as alveolar abscess. 
 The first-named form is usually termed pyorrhoea alveolaris. 
 Either of the forms named, though originally limited to a por- 
 tion of the pericementum, may become diffuse, affecting most 
 of the tissue, and may run an acute or a chronic course. 
 
 Marginal Purulent Pericementitis is usually termed pyorrhea 
 (dreolai-is. In this, as in any other suppurative process, a certain 
 amount of the tissue involved is destroyed. 
 
 Under the microscope, the first stages of suppurative perice- 
 mentitis are identical with those of the plastic form, — viz, there 
 are nests of inflammatory elements between bundles of unchanged 
 connective tissue. (See Fig. 232.) The less, therefore, of this 
 connective tissue is left, the more numerous the inflammatory 
 elements are, the nearer is the tissue to suppuration. 
 
 "With high magnifying powers of the microscope we see 
 that the inflammatory process goes on in exactly the same way 
 as in plastic pericementitis. The bundles of connective tissue 
 are transformed <lirectly into inflammatory elements, which at 
 first are all united with one another. This union of the inflam- 
 matory elements is recognizable in relatively large nests also, in 
 which there are but scanty capillary blood-vessels left. It is
 
 MOKBID ANATOMY Of PERICEMENTITIS. 477 
 
 only after the mutual connection of these elements is broken 
 that the bodies, now isolated, deserve the name of pus-corpuscles, 
 which are suspended in an albuminous fluid, and fill a cavity 
 termed an "abscess," This, it' finding exit to the surface 
 around the neck of the tooth, exhibits the typical pyorrhoea 
 alveolaris. After the elimination of the pus, the surrounding 
 inflamed tissue grows in the form of so-called " proud flesh" or 
 granulations, which we not infrequently meet at the neck as 
 well as on the roots of teeth extracted durinir an attack of sup- 
 purative pericementitis, being especially well develo})ed in the 
 bifurcations between the roots of molars. Such granulations are 
 built up by a myxomatous connective tissue, which is freely 
 vascularized, and after having filled the cavity of the abscess, is 
 transformed into dense fibrous connective tissue. Such repara- 
 tive tissue is termed a " cicatrix." Suppurative pericementitis 
 will invariably heal by cicatrization. 
 
 The morbid anatomy of pyorrhoea alveolaris has been studied 
 by Wm. H. Atkinson* on the teeth of a cat, his conclusions 
 being shown in the following abstract : 
 
 " Whether suppuration must be present before deposition of 
 lime-salts can only l)e settled by a study of proper micro- 
 scopical specimens in the very earliest stage of the disease. 
 The deposit was formerly called tartar, but is now known to be 
 a deposit of lime-salts, phosphate of lime, with some carbonate 
 of lime, entangled with leptothrix, a growth which is rather 
 comman around the teeth of almost every person. If a speci- 
 men be placed in a solution of chromic acid, the lime-salts will 
 be dissolved, not only of the hard tissues of the tooth, such as 
 dentine, enamel, and cementum, but also from the deposit erro- 
 neously called tartar; and ultimately, under the microscope, 
 nothing will be seen but aheap of leptothrix, more or less firmly 
 attached to the neck of the tooth. 
 
 '' In one specimen, the epithelial covering of the gums has 
 taken a bright pink, the connective tissue a pale pink, the den- 
 tine remaining a bright green from the reduction of the chromic 
 acid, and the bone of the socket a dark green for the same 
 reason. Blood-vessels filled with blood retained their original 
 color, not being affected by the carmin. I have to add that 
 neither the horny layer of the epithelium nor the growth of 
 
 '^ Dental Cosmos, 1888.
 
 478 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 leptothrix has been influenced by the carmin, as they retained 
 a slight brownish-green color. All micro-organisms are known 
 to resist the dye of carmin ; whereas they eagerly take up all 
 
 Fig 2'^9 
 
 Temfukary Molar of a Kitten Six Wekks Old, rsHowiNW the Earliest Stages 
 
 OF PYOliRIHEA ALVEOLARIS. 
 
 P, pulp-tissue with capillary blood-vessels; Z?, bony socket ; T', fibrous connective tissue, 
 producing upward the stroma and the papillte of the gum, downward the pericementum and the 
 periosteum ; E, epithelium ; D, cluster of leptothrix deprived of its lime-salts : L-, cluster 
 of leptothrix upon an eroded neck of tooth and entangled with pus-corpuscles ; A, cavity filled 
 with pus in continuity with the pericementum. Magnified 50 diameters. 
 
 sorts of anilin dyes. Thus a single specimen shows a variety 
 of colors, which serves as assistance for the discrimination of 
 otherwise not well-marked tissues.
 
 MORBID ANATOMY OF PERICEMENTITIS. 
 
 479 
 
 "For low powers of the microscope, just sutHcient for 
 obtaining topographical views, a molar was selected, in which 
 the features I am about to explain are beautifully marked. 
 (See Fig. 239.) The specimen is taken for illustration because 
 on one side of the neck of the tooth the recession of the gum 
 and the growth of leptothrix is marked, without apparent sup- 
 puration ; while on the other side the growth of leptothrix has 
 
 Fig. 240. 
 
 Formation of Pis from Coxxective Tissue axd EprriiEi.ruM ix Pyorrhcea 
 Alveola Ris of a Kittex Six Weeks Old. 
 
 £, epithelium of gum with iiroliferating nuclei; ^P, epithelium in transformation to pus- 
 corpusclos ; P, pus-corpuscles sprung both from epithelium nnd connective tissue ; C, connective 
 tissue of gum ; /?, B, blond-vessels filled with corpuscles ; N, cemontum of neck of tooth ; D, 
 dentine. Magnified 600 diameters, 
 
 led to marked structural changes in the cementum of the neck, 
 in the epithelium of the gum, and in that portion of the peri- 
 cementum in contact with the uppermost portion of the neck, 
 which by anatomists has been called ligamentum dentium.
 
 480 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 " 1^0 sign of trouble below the pouch, or pocket, is seen on 
 the right side of the specimen, except a slight hyperpemia, marked 
 by slightly-dilated blood-vessels filled with blood-corpuscles. We 
 see in the connective tissue, furnishing the papillae as well as the 
 pericementum, a gradual transition from basis-substance to pus- 
 corpuscles. At first the connective tissue appears granular; 
 later granular or solid lumps make their appearance; and at last 
 the basi8-sul)stance has almost completeh' disappeared, being 
 replaced by a number of so-called inflammatory corpuscles. As 
 soon as the latter become isolated the}^ represent pus-corpuscles, 
 which invariably are intertwined in smaller lumps and scattered 
 granules, probabl}^ from a disintegration of some pus-corpuscles. 
 (Fig. 240.) Here we observe a gradual increase of the living 
 matter of the epithelia from a mere division or splitting of the 
 nuclei to a considerable increase of lumps within the epithelia, 
 and to their breaking up into isolated lumps or corpuscles,— 
 viz, pus-corpuscles. 
 
 " In epithelial laj^ers the cement-substance between epithelial 
 bodies holds a good deal of living matter in the shape of con- 
 necting filaments, previously termed the thorns. Close observa- 
 tion shows that these thorns at first increase in bulk; afterward 
 coalesce into solid cord-like formations; farther on swell up to 
 pear- or club-shaped formations, which themselves split up into 
 pus-corpuscles, thus adding to those visible in an abscess. The 
 pus-corpuscles sprung from previous epithelia are in no way 
 difi'erent from those originated from previous connective tissue. 
 
 " To-day it is an established fact that suppuration will not take 
 place either in connective tissue or in epithelium, without the 
 presence of certain micro-organisms which are known as staphy- 
 lococcus, or Streptococcus pyogenes aureus, albus, or citreus. 
 It is a great question yet to decide whether it is micro-organisms 
 themselves penetrating the protoplasm, thus inducing disinte- 
 gration of the tissue, or whether it is the chemical product of 
 the micro-organisms, the ptomaines, that induce the suppura- 
 tion. However this may be, the specimens here presented 
 furnish conclusive proofs that, so long as the horny or pavement 
 epithelium is present as a protective layer, no invasion of micro- 
 cocci will occur. As soon, however, as this protective coat is 
 lost, the micro-organisms may penetrate both epithelium and 
 connective tissue, at once inducing mischief. 
 
 '• On the right side of Fig. 239 the pouch between the tooth
 
 MORBID ANATOMY OF PERICEMENTITIS. 
 
 481 
 
 and the gums is lined all around by flat epitlielia; there is a 
 marked hypersemia of the connective tissue, but no marked 
 inflammation or suppuration. On the left side, on the contrary, 
 the pavement epithelium is lost at the bottom and the sides of 
 the pouch, and suppuration has started at once. Whether or 
 not the growth of leptothrix alone is sufiicient to excite inflam- 
 mation or suppuration is not settled, but we can easily conceive 
 
 Fig. 241. 
 
 Cemen'titis induced by a Growth of Leptothrix on the Neck op the Tooth 
 OF A Kitten Six Weeks Old. 
 
 i, leptothrix ; C, ceinontum of neck ; i*, dentine of the neck destitute of canaliculi ; P, pus 
 partly entangled with leptothrix. Magnified 600 diameters. 
 
 of a possibility that together with the leptothrix other micro- 
 organisms are carried along, being ready for the invasion of the 
 formed tissues as soon as the protective horny layer is lost. 
 
 " Attention has been given to the morbid changes of the 
 cementum at the neck, wherever they come in contact with the 
 leptothrix. (See Fig. 241.) 
 
 32
 
 482 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 " Some observers claim that even a simple inflammatory pro- 
 cess may be produced by the presence of micro-organisms. 
 This assertion I am not able to sustain from the study of my 
 specimens, or any that I have seen. True, wherever leptothrix 
 has encroached upon the hard tissues of the tooth, a melting 
 down of the lime-salts of such tissue will be the result. In the 
 milder forms of such a decalcification (so-called) we observe bay- 
 like excavations, partly containing isolated protoplasmic bodies, 
 clearly the offspring of the perfected tissue present even in the 
 hard tissues of the tooth. But the number of such corpuscles 
 is never sufiiciently large to warrant the diagnosis of inflam- 
 mation; all we could claim is a reduction of the hard tissue 
 into soft protoplasm, probably corresponding to a juvenile or 
 embryonic stage of that very tissue. On the left side of Fig. 
 239 bay-like excavations are discernible, penetrating not only 
 the cementum of the tooth, but also the dentine; still, there is 
 nowhere a symptom of inflammation or caries. Here our micro- 
 scopical finding again agrees with clinical experience, which 
 teaches us that in pyorrhoea alveolaris the exposed roots of the 
 teeth very rarely become carious, usually exhibiting only a 
 slightly roughened surface." 
 
 Alveolar Abscess. — This is a peculiar form of suppurative 
 inflammation on the apices of the roots of teeth. 
 
 Examinations of microscopical sections through the root, the 
 socket, and the alveolar abscess, demonstrate that the latter is 
 either unilocular or multilocular, — viz, separated into two or 
 several chambers, all tilled with pus. 
 
 In acute alveolar abscess both the main wall and those of the 
 compartments are crowded with inflammatory corpuscles to such 
 an extent that with low powers of the microscope no vestige of 
 the original fibrous connective tissue of the pericementum is 
 recognizable. At the periphery of the inflamed zone we see a 
 moderately-inflamed layer of pericementum, holding a variable 
 number of brown clusters, obviously remnants of extravasated 
 blood, verging on the formation of pigment. The central por- 
 tion of a unilocular alveolar abscess is found empty the same as 
 the compartments of a multilocular abscess, because the pus, not 
 being a tissue, is dragged away in the process of section-cutting, 
 both from the inflammatory nests of the pericementum and 
 from the contents of the abscess-cavitv. Numerous clusters of
 
 .MORUII) ANATOMY OF PERICEMENTITIS. 
 
 483 
 
 staphylococci can be seen with higher powers of the microscope. 
 (See Fig. 242.) 
 
 If such an abscess has existed for several weeks or months, 
 it becomes chronic, and then the aspect under the microscope 
 is different from that seen in the acute stage. As a rule, the 
 
 
 AcuTK Alveolar Abscess.— Ixcipiext Suppuration is Compartments 
 
 C, compartments from which the pus has been removed by the microtome ; Z^, outermost 
 zone, the mo ierately-inflameJ pericementum ; Z'-, middle zone, the intenselj'-inflamed perice- 
 mentum ; ZK zone in approaching suppuration. Magnified 103 diameters. 
 
 walls of the compartments have perished by being transformed 
 into pus. A chronic abscess, therefore, will usually appear 
 unilocular. 
 
 The tissue bordering directly upon the abscess is a broad
 
 484 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 layer of the myxomatous type, intermixed with dehcate bundles 
 of fibrous connectivej tissue. In this layer a scanty number of 
 newly-formed capillaries are met with. (See Fig. 243.) 
 
 This layer has been overlooked by previous observers, and 
 even Virchow termed it " crude pus." To-day we know that 
 it is just the myxomatous tissue which at its innermost portions 
 
 Fig. 243. 
 
 Wall op Chronic Alveolar Abscess. 
 
 M, myxomatous portion of wall ; F, fibrous portion of wall (so-called membrana pyogena) ; 
 /*, periosteum slightly inflamed ;|1 (7, pus-cavity, pus-corpuscles removed by section-cutting. 
 Magnified 100 diameters. J , 
 
 breaksjup into pus-corpuscles, thus augmenting the size of the 
 pus-cavity. (See Fig. 244.) 
 
 We know also that after the evacuation of the pus it is the 
 myxomatous layer which, by a luxuriant growth, furnishes the 
 richly- vascularized granulation-tissue.
 
 MORBID ANATOMY OF PERICEMENTITIS. 
 
 485 
 
 At the periphery of the myxomatous wall of the abscess we 
 notice a dense layer of newly-formed iibrous connective tissue, 
 the wall proper of the abscess, which by old surgeons was 
 termed " membrana pyogena." That this layer is newly 
 
 Fig. 244. 
 
 iil»^K^fffi 
 
 InniJrmost Portion of Wall of Absckss. Myxomatous Tissue. 
 
 /?, 7?, partly protoplasmic, partly fibrous reticulum; B, B, myxomatous basis-substance ; 
 P, P, protoplasmic bodies in various stages of development ; G, capillary blood-vessel. Mag- 
 Bified 500 diameters. 
 
 formed, appears clearly from the fact that its bundles run a con- 
 centric course around the abscess, noticeably different from 
 those of the original pericementum. (See Fig. 243.) 
 
 As a matter of course, an intense purulent pericementitis will 
 easily affect the periosteum. It is not infrequent that, owing
 
 486 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 to complete destruction of the blood-vefsels of the peripsteum 
 and the medulla, serving for the nutrition of the bone, this 
 latter becomes necrotic. (See chapter on Necrosis.) 
 
 When the inflammatory process has lasted for months, the 
 newly-formed connective tissue assumes a distinct tibrous struc- 
 ture, and between the bundles there are interspersed nests ot 
 inflammatory elements. These may be partly transformed into 
 fat-granules, or produce opaque layers in fatty degeneration. 
 If, on the contrary, the alveolar abscess be of a more recent 
 date, the fibrous structure of the sac is plainly marked on its 
 periphery only, while the central portions bear the character ot 
 a myxomatous granulation-tissue. The strings or the septa, 
 traversing the abscess, may eventually, in accordance with the 
 duration of the disease, be found either of a fibrous or myxo- 
 matous structure. In both instances we often meet with a large 
 number of newly-formed capillary blood-vessels. The inner 
 surface of the sac is not smooth, but largely provided with 
 irregular protrusions, or papillary outgrowths of a myxomatous 
 structure, crowded with inflammatory elements. The sac con- 
 tains inspissated pus, which, upon the cutting of microscopical 
 sections, crumbles away. 
 
 Ceraentitis and osteitis always accompany an alveolar abscess. 
 Cementitis leads to a destruction of the cementum in the shape 
 of deep, irregular, bay-like excavations, which exhibit all stages, 
 from the liquefaction of the basis-sul)stance up to the trans- 
 formation of the living matter into pus-corpuscles. Sometimes 
 the excavations penetrate the dentine. In the highest degrees 
 of pericementitis the apex of the root, inclosed in the alveolar 
 abscess, is transformed into a thin, jagged, and corroded stump, 
 with but scanty remnants of the former cementum. 
 
 Osteitis (inflammation of the wall of the alveolus) is an inevit- • 
 able result of the formation of an alveolar abscess. The portion 
 of the socket in contact with the sac of the abscess is widened, 
 its surface being eitlier smooth or jagged. Examination with 
 the microscope leaves no doubt that the inflammatory elements, 
 sprung from the bony tissue after dissolution of its lime-salts 
 and liquefaction of its gluey basis-substance, become spindle- 
 shaped, and share largely in the formation of the wall of the 
 abscess. 
 
 In higher degrees of osteitis the wall of the alveolus is re- 
 duced to irregular, eroded trabecular of bone, the outer surface
 
 MORBID ANATOMY OF PERICEMENTITIS. 
 
 487 
 
 of which is lined l)y a dense, newly-formed connective tissue, 
 identical with that of the wall of the abscess. The neighboring 
 medullary spaces are enlarged and crowded with inflammatory 
 elements. 
 
 Considerable interest attaches to the healing process of peri- 
 
 FiG. 245. 
 
 Healing Process op Pericementitis and Cementitis. 
 
 P, pericementum consisting ' of newly-formed fibrous connective tissue ; B, border of 
 cementum with bajj-like excavations; T, zone of cementum with faintly-marked territories ; 
 C, unchanged cementum ; /, /, islands of territories of cementum ; M, medullary space. 
 Magnified 400 diameters. 
 
 cementitis and cementitis, such as we are able to observe in 
 chronic alveolar abscess, after the subsidence of the inflamma- 
 tory symptoms. (See Fig. 245.) We observe a transformation 
 of the inflamed pericementum into irregular tracts of fibrous
 
 488 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 connective tissue, still plentifully supplied with globular and 
 spindle-shaped protoplasmic bodies. In this tissue we find 
 inclosed irregularly recalcified territories of cementum, with 
 faintly-marked central cement-corpuscles. The border-zone of 
 the cement is conspicuous by its deep, bay-like excavations, 
 filled with newly-formed pericementum. At some distance 
 from the border, the outlines of the recalcified territories of the 
 cement-corpuscles are still recognizable. In this zone we notice 
 apparently isolated medullary spaces, which probably are in 
 continuity with the surface of the cementum and have escaped 
 recalcification. After the accomplishment of the latter process, 
 the cement-corpuscles have resumed their original shape, 
 though many of them appear a trifle larger and more irregular 
 than the original cement-corpuscles. 
 
 CHAPTER XL. 
 
 CARIES OF THE TEETH. 
 
 The modern views in regard to the origin of caries of the 
 teeth are based upon bacteriological researches. Previous to 
 1882, before bacteriology became a systematized science, the 
 origin of caries was thought to be a mere decalcification of 
 enamel and dentine, accompanied by a growth of micro-organ- 
 isms. But even at that time much valuable work was accom- 
 plished. The proof that the living tissues of the teeth, if 
 attacked by the process of caries, react by an inflammatory 
 process, was then a great step in advance, a fact which has 
 altogether been neglected by bacteriologists. In order to do 
 justice to both parties, I deem it advisable to give the views 
 held by Frank Abbott* and those announced by W. D. Miller, 
 of Berlin. t The former was published in ante-bacteriological 
 times, the latter is founded entirely on bacteriological research. 
 I am convinced that only by a combination of both the inflam- 
 matory and the bacteriological doctrines the full truth will be 
 reached. 
 
 * Dental Cosmos, 1879. 
 
 t " The Micro-Organisms of the Human Mouth," 1890.
 
 CARIES OF THE TEETH. 489 
 
 Frank Abbott's Views.* — " Etiolofiy. — The first lesion under 
 all circumstances is due to the action of an acid, which in a 
 merely chemical way dissolves out the lime-salts from the 
 enamel. No doubt quite a strong acid is necessary for decalci- 
 fication of so solid a tissue as the enamel of a tooth. And the 
 question next arises, Where does this acid come from ? 
 
 *' First let us take into consideration the starting-points of the 
 morbid process. I fear no contradiction on the part of my pro- 
 fessional brethren when I say caries never begins on the smooth 
 surfaces of a tooth, which are exposed to the friction of masti- 
 cation, but always starts on points which, owing to their ana- 
 tomical structure, form receptacles for food, etc., or on points 
 between the teeth where, owing to want of cleanliness, decaying 
 material can accumulate. It is therefore not to the friction 
 between the single teeth (Salter), which, as we know, is possible 
 to a certain extent in the normal condition, but to the acid 
 generated from the decaying material retained between the two 
 flat or concave surfaces which the teeth present to each other, 
 that the beginning of the destruction of enamel is due. 
 
 " That this decaying material may be sought for and found in 
 the food, I think will hardly admit of a doubt; and, as it occurs 
 to me, mainly in such kinds of food as through their decompo- 
 sition are apt to produce an acid, not very strong, perhaps, in 
 itself, but possessing a high degree of afl&nity for lime-salts, — 
 viz, lactic acid. 
 
 " First among the varieties ot food ranks meat, which by 
 putrefaction may produce free lactic acid ; next are the sac- 
 charine materials; and last the amylaceous, which being con- 
 verted into dextrine by the action of the saliva, may be trans- 
 formed, if brought in contact with putrefying meat, into lactic 
 acid. There is no doubt that the organic portion of teeth, 
 as it advances to the stage of decomposition in the process of 
 caries, plays a very important part in the formation of this acid. 
 
 " Perhaps the sour decomposition is assisted locally by the 
 action of micrococci and leptothrix; although these organisms 
 are known to prosper only in alkaline, and not in acid fluids. 
 These vegetable organisms are present in innumerable quanti- 
 
 *This was first published in 1879. Professor Abbott has been kind enough to 
 furnish me, especially for this book, with his present views, as expressed in the 
 conclusions of his original paper The headings I, II, and III of the results of 
 his studios are changed by himself.
 
 490 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 ties on the healthiest gum ; tartar is crowded with them. And 
 even in the highest degrees of development of tartar caries is 
 absent. In fact, when decayed cavities in the teeth become 
 filled with tartar, the carious process is as effectually stopped as 
 it is possible for it to be when such cavities oxe filled in the most 
 perfect manner with gold or any other favorite material. Hence 
 I do not consider the views of those authors correct who claim 
 that micrococci and leptothrix play any important part in pro- 
 ducing, or even supporting, the carious process. 
 
 " I fully concur, however, with the views of those who claim 
 that the resistance of the teeth against caries, owing to their 
 amount of lime-salts, greatly varies in different people. The 
 hue of the teeth, as is well known, is indicative to some extent 
 of their amount of lime-salts. The microscope shows a con- 
 siderable variety, wdth regard to the presence or the degree of 
 density, of that layer of the basis-substance surrounding the 
 dentinal canaliculi. E. Keumann first drew attention to this 
 layer, wiiich sometimes is so dense and so well defined, owing 
 to its greater refracting power than that of the basis-substance 
 between the canaliculi, that it may be regarded almost as a 
 protecting sheath to the living matter Avithin the canaliculi. 
 This layer is well marked even in fossil teeth ; it resists some- 
 what the action of strong acids and alkalies, but it is almost 
 completely absent in a number of carious teeth which I have 
 examined. I have also remarked that different teeth, treated 
 exactly in the same manner with chromic-acid solution, become 
 soft in a markedly shorter space of time than others. The 
 general health or constitution may have considerable influence 
 upon the quantity of lime-salts deposited in the basis-substance 
 of the teeth. 
 
 " Nations of high civilization, which inevitably leads to bodily 
 and mental depravation, as a rule have a greater percentage of 
 carious teeth than those of a low degree of culture, or with no 
 culture at all. 
 
 " However this may be, the fact that caries of the teeth begins 
 as a chemical process scarcely will, in my opinion, be ques- 
 tioned. On a dead tooth, natural or artificial, as well as on 
 teeth manufactured from the dentine of the elephant or the 
 hippopotamus, the process will remain, under all circumstances, 
 a chemical one, assisted only by the putrefying remains of the 
 organic material of the tooth ; while on a live tooth either
 
 CARIES OF THE TEETH. 491 
 
 acute or chronic reaction-changes take phice, which I intend 
 presently to consider. 
 
 '■'■Caries of Enamel. — The clinical phenomenon of caries, in 
 its very origin, consists essentially in a discoloration of the 
 enamel. A whitish or grayisli spot on the surface of the 
 enamel is indicative to an experienced eye of the beginning of 
 decay, which spot proves, when touched with an instrument, 
 to be soft and crumbly. Often a brown spot is visil)le on the 
 enamel as a sign of the softening process. The less pigmen- 
 tation present, the more rapid is the process of decay. On the 
 contrary, the more distinct tlie discoloration, the slower is the 
 softening process, N^ay, dark-brown spots may be present in 
 the enamel for many years without being followed by softening. 
 The brown discoloration, as such, cannot be considered as an 
 essential feature of caries of enamel, but it usually accompa- 
 nies the carious process, and does so the surer the slower the 
 morbid process runs. On microscopic specimens we meet with 
 decayed pits in enamel without any discoloration of this tissue. 
 On other specimens we have a very marked orange or brown 
 hue on the decayed part as well as in its neighborhood, and 
 sometimes scattered specks are to be seen some considerable 
 distance from the diseased part. The brown discoloration is 
 located in the basis-substance of the enamel-rods, the outlines 
 of which are much more marked than when in a healthy condi- 
 tion. The interstices between the rods here are plainly visible 
 even with a magnifying power of only 500 diameters. This 
 power will reveal delicate beaded fibers of living matter within 
 the interstices, which in healthy enamel can be seen distinctly 
 with a power of 800 to 1000 only. Besides the discoloration, 
 no material changes are seen in the enamel-rods. 
 
 " What process the pigmentation of the enamel is due to I 
 cannot say, but it occurs to me that we have no right to look 
 upon this process as a merely chemical reaction upon the basis- 
 substance of the rods. That in fact it is the basis-substance 
 holding the pigment, and not the lime-salts deposited therein, 
 is proven by specimens from which the lime-salts have been 
 extracted to a considerable extent by chromic acid, and which 
 still show the brown stain. I dare say that this brown dis- 
 coloration is a strong proof of the presence of life in the 
 enamel, as in teeth where the pulps are dead such stains never 
 appear, nor can they be produced by artificial means. The
 
 492 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 process of decay in the enamel can best be studied on superficial 
 erosions of the same, a sample of which I have illustrated. In 
 this instance the brown discoloration of the decayed part was 
 but trifling, and entirely absent in its vicinity, so that we have 
 to consider it as a case of acute caries. 
 
 " We see at E, Fig. 246, the unchanged enamel partly de- 
 prived of its lime-salts. Toward the periphery a zone appears 
 in which the enamel-rods are spotted, evidently owing to their 
 partial decalcification. Close to this and immediately below 
 the decayed part a zone is visible in which the enamel is 
 granular, and looks precisely like normal enamel from which, 
 
 Fig. -246. 
 
 ^kA'-^-^i A^^tm-^m^A 
 
 Acute Caries of Enamel. 
 
 E, unchanged enamel ; .S", enamel deprived of its lime-salts ; M, enamel broken down to 
 medullary corpuscles; Z), medullary corpuscles indistinctly marked ; iV, flat epithelia. Magni- 
 fied 1000 diameters. 
 
 by a somewhat stronger solution of chromic acid, the lime-salts 
 have been dissolved out. Here the protoplasmic condition of 
 the enamel is re-established simply by disorganization, and 
 there is no doubt that this is the very condition of the enamel 
 by which the white spot is produced upon the surface while the 
 tooth is still in the jaw. On the boundary of the enamel 
 we see a shallow depression filled with protoplasmic bodies, 
 which represent either complete enamel-prisms or lumps of 
 such prisms. All these protoplasmic formations are united 
 with one another by delicate threads; they exhibit but a slight
 
 CARIES OF THE TEETH. 493 
 
 T3rown discoloration, they readily imbibe earmin, and if the 
 specimen be stained with a half per cent, solution of chloride 
 of gold these bodies assume a dark-blue tinge, while the 
 unchanged enamel is but little affected by this reagent. On 
 the outermost layer we see several flat epithelial bodies 
 attached to the protoplasm, which in the transverse section 
 look irregularly spindle-shaped, and are evidently the remnants 
 of the so-called J^asmyth's membrane, or enamel-cuticle, 
 sunken down with the decaying protoplasm. On the level of 
 the enamel we also recognize such flat epithelia. Beneath 
 them on the right side of the drawing there is present a zone 
 of decalcified enamel, while on the left side the division into 
 protoplasmic bodies is fully accomplished. 
 
 " ]^ot a trace of micrococci or of leptothrix is visible in or 
 above the decayed pit of the enamel, which again proves that 
 these organisms do not play any important part in the process 
 of caries ; at least, do not materially interfere with the tooth in 
 its normal condition. 
 
 " The way in which the caries proceeds downward is plainly 
 shown by the figure. There are small, irregular, bay-like 
 excavations on its boundary, and in the midst of the decayed 
 part a wedge-shaped elongation is running downward into 
 the softened enamel. The shape in which caries appears in 
 the enamel is, however, greatly varying. Besides the wedge 
 shape as illustrated in the figure, the forms in which caries pro- 
 ceeds are shallow or conical excavations, with abrupt walls, 
 fissures, and grooves. On the bottom of the main excavation 
 we sometimes see a smaller cavity, it being in a narrow or 
 wide communication with the main decayed mass. 
 
 " Besides the peculiar medullary elements forming the con- 
 tents of a carious cavity of the enamel in its initial stage, I not 
 very rarely have met with dark-brown, irregularly-shaped clus- 
 ters tilling the whole cavity. How such changes of medullary 
 corpuscles are produced I am unable to say, although it seems 
 to be kindred to the so-called colloid or hi/aloid metamorphosis 
 which we observe in other tissues, the only difterence being 
 that in caries the colloid clusters are deeply saturated with a 
 uniform brown pigment, the origin of which, as mentioned 
 above, is unknown. 
 
 " Caries of Dentine. — Upon examining a large number of 
 teeth with carious dentine, we are struck by conditions to the
 
 494 
 
 THE ANATOMY AXD PATHOLOGY OF THE TEETH. 
 
 presence of which no observer has as yet drawn attention. 
 Sometimes the dentine, attacked by caries, looks but little 
 changed on its periphery. A narrow zone of yellowish color 
 forms the boundary toward irregular, shallow excavations (see 
 Fig. 247). At other times, besides the bay-like excavations on 
 the periphery, there are visible elongations, cylindrical, conical, 
 pear-shaped, or leaf-like, passing down into the dentine in 
 varying depths (see Fig. 247, 0). There is no doubt that this 
 form of decay of the dentine occurs with the least preliminary 
 changes of the tissues ; it evidently runs a slow course, and I 
 think I am justified in calling this form of caries chronic. It 
 seems evident that decay of a tooth assumes an acute or chronic 
 form just in proportion to its perfect or imperfect calcification. 
 
 Fig. 247. 
 
 Chronic Caries of Dentine. 
 
 D, dentine ; 0, the process of decay penetrating into dentine in the shape of short offshoots ; 
 C, decayed mass. Magnified 200 diameters. 
 
 Dead teeth in which the pulps have been destroyed either by 
 necrosis as a natural process, or by artificial means with caus- 
 tics, very frequently run this kind of slow or chronic decay. 
 The decay of artificial teeth, either human or ivory, in all 
 probability runs either an acute or a chronic course, according 
 to the amount of lime-salts infiltrated into the glue-yielding 
 basis-substance. 
 
 " I have examined apiece of a hippopotamus tooth which, for 
 a period of about one year, was worn in the mouth of a patient,^ 
 and a spot became decayed about the size of a hemp-seed. I 
 softened this piece with chromic-acid solution, imbedded it in 
 paraffin and wax, and cut thin sections with a razor. On the 
 bottom of the decayed pit numerous conical spots appeared
 
 CARIES OF THE TEETH. 495 
 
 runuiuii' dowiiAvard into tlie dentine, characterized by the 
 absence of coloring-matter in specimens stained with carmin. 
 'No material change besides was observable; even the dentinal 
 canaliculi did not look enlarged. The bottom of the carious 
 cavity was covered with a layer of linely-granular, evidently 
 disintegrated organic material, and above this the ordinary 
 masses filling carious cavities in teeth, — viz, micrococci and 
 leptoth rix, — were visible. 
 
 " In chronic caries merely a chemical process takes place, 
 assisted by putrefaction of the organic constituents of the tooth. 
 Here first the solution of the lime-salts of the dentine takes 
 place, either along the bay-like excavations or in the shape of 
 longitudinal depressions. No reaction whatever follows this 
 process. The glue-yielding basis-substance being deprived of its 
 lime-salts shows a yellow discoloration, and only traces of the 
 dentinal canaliculi. The basis-substance then breaks down into 
 an indi-^tinct granular mass, which is immediately filled with a 
 new growth of low vegetable organisms, — viz, micrococci and 
 leptothrix. 
 
 " My specimens plainly show that these organisms are not the 
 advance guard in the process of decay. The first change that 
 takes place is exposure of the basis-substance by the chemical 
 action of some acid, independent of the named organisms, which 
 come to view only after complete disintegration of the basis- 
 substance. I never have seen the penetration of these organisms 
 into the dentinal canaliculi before a thorough decalcification of 
 the basis-substance had taken place. No doubt, however, the 
 decayed mass itself may be crowded with such organisms which 
 they seem to form with. In the great majority of my specimens 
 I have met with formations on the diseased boundary of the den- 
 tine which demonstrate a considerable degree of reaction, pro- 
 duced by the irritating power of the same agent, to which the 
 lime-salts of the dentine yield. In fact, this was the case in all 
 teeth which were alive when attacked by the carious process, or 
 rather when removed from the jaws. On the boundary of this 
 process we see irregularly-shaped elongations running a certain 
 depth into the tissue of the dentine. The more superficial the 
 elongations are, the surer the morbid process may be termed a 
 slow one ; and, on the contrary, the deeper the elongations, the 
 more certain we may be that the morbid process has advanced 
 rapidly. The elongations mainly have the shape of fissures
 
 496 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 filled ^'itli a dark granular material, if viewed witli a low power. 
 These fissures run independently of the direction of the dentinal 
 canaliculi; nay, very often cross them. (See Fig. 248.) In 
 the specimens they look, as a rule, as if communicating with 
 each other, and also directly or indirectly with the decayed outer 
 surface. Sometimes the fissures appear completely isolated, 
 though we may assume that they are separated from the com- 
 munication with analogous and more superficial formations only 
 by the method of preparation, — viz, cutting into thin lamellae. 
 " On the surface of the carious portion of dentine we see 
 
 Fig. 248. 
 
 Acute Caries of Dextixe. 
 
 E, E, fissures in which the decay penetrates into the dentine ; /, small islands of unchanged 
 ■dentine. Magnified 200 diameters. 
 
 irregular cavities filled with the same granular mass that is 
 present in the fissures, consisting evidently of debris of the 
 fi)rmer tissue, together, perhaps, with micrococci, and very often 
 fine thread-like leptothrix. The more rapidly the destruction 
 of the dentine has advanced, the more irregular islands of 
 dentine are left on the surface. 
 
 " In our figure the decay evidently has proceeded rapidly ; 
 hence the remnants of the former dentine, recognizable by the 
 presence of the canaliculi, are very small and irregular on the 
 outer periphery of the dentine.
 
 CARIES OF THE TEETH. 497 
 
 "The outermost portion of the decayed part is, as a rille, 
 biittle, and crumbles away in chromic-acid specimens. Where 
 it is left it shows a crowd of leptothrix and micrococci, without 
 any distinctly recognizable remnants of the former tissue. On 
 the boundary of the carious portion we, as mentioned above, 
 meet with a yellow discoloration of the dentine, evidently pro- 
 duced by an inflammatory reaction, which flrst breaks down the 
 organized constituents of the lime-salts and in turn liquefies the 
 glue-yielding basis-substance. In live teeth the yellow discolora- 
 tion usually takes place in the shape of longitudinal strings of 
 diflerent diameters, running mainly parallel with the longi- 
 tudinal direction of the dentinal canaliculi. Nay, we often see 
 single yellow strings running from the bottom of a carious cavity 
 in the enamel through the whole depth of the dentine to the 
 pulp-chambers. (See Fig. 248, E, E.) The best method for 
 demonstrating these strings is doubtless the staining of chromic- 
 acid specimens in an ammoniacal solution of carmin. While 
 the unchanged dentine readily takes up the carmin, the strings, 
 the deep yellow color of which is undoubtedly due to the action 
 of the chromic acid, remain unstained. 
 
 "With a power of about five hundred diameters, we recog- 
 nize under the microscope, in longitudinal section of the dentine, 
 that sometimes the yellow discoloration has taken place only 
 within the limits of a few dentinal canaliculi, while at other times 
 quite a number of these have undergone discoloration. Still 
 sharper defined is the yellow discoloration in transverse sections. 
 Here we see that mainly the canaliculi and their immediate 
 neighborhood have taken up the yellow color in the shape of 
 sharply-circumscribed dots, which are the larger the nearer they 
 approach to the periphery of the decayed part. The basis-sub- 
 stance between these yellow spots has taken up more or less 
 carmin. Let us examine such a cross-section with a magni- 
 fying power of 1000 diameters under the microscope. 
 
 " At a certain distance from the decay the canaliculi look 
 unchanged, and each contains the central transverse section of 
 the dentinal fiber with its delicate radiated offshoots. (See Fig. 
 249.) iSTearer to the decay we meet with moderately-enlarged 
 canaliculi, the center. of which is occupied by a cluster of proto- 
 plasm, the granules and threads of which have readily taken 
 up the carmin. One step fiirther we find the canaliculi consid- 
 erably enlarged, to double or treble their original size, and filled 
 
 33
 
 498 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 with yellow protoplasm, plainly exhibiting the net-like arrange- 
 ment of the living matter. The most peripheral grannies send 
 delicate conical offshoots throngh the snrroundmg light space 
 toward the unchanged basis-substance. In some of tlie enlarged 
 canaliculi accumulations of living matter are seen fully in the 
 shape of nuclei; sometimes two or more such nuclei maybe 
 seen surrounded by a varying amount of protoplasm. Still 
 nearer to the decay the canaliculi are enlarged to ten or fifteen 
 
 Fig. 249. 
 
 Caries of Destine. 
 
 J^, unchanged dentinal fiber; P, enlarged dentinal canaliculi, filled with protoplasm; H, 
 medullary corpuscles in considerably widened dentinal spaces ; G, complete transformation of 
 dentine into medullary corpuscles. Magnified 1000 diameters. 
 
 •times their original diameter, and the cavities thus produced 
 are all filled with a partly-nucleated protoplasm. Between the 
 roundish cavities we meet with longitudinal cavities, arising 
 from the confluence of several cavities in one main direction. 
 The cavities continue increasing in size, and form large spaces, 
 with rounded, bay-like boundaries, between which only scanty 
 traces of unchanged basis-substance are left. Lastly, the basis-
 
 CARIES OF THE TEETH. 
 
 499 
 
 substance has entirely disappeared, and only protoplasm is visible 
 in its place, either in the shape of multinuclear layers or of ir- 
 regular so-called medullary elements with rather faint marks of 
 division. Nearest to the periphery the protoplasm does not 
 exhibit any form elements, but looks like a disintegrated granu- 
 lar mass, probably intermixed with or replaced by micrococci. 
 T say probably, inasmuch as all good histologists agree, nowa- 
 days, that the diagnosis of micrococci is possible only when they 
 
 Fig. 250. 
 
 ^-^>-^ 
 
 ^ 
 
 f 
 
 '3 
 
 
 Caries of Dkntine. Oblique Section. 
 
 P, widened dentinal canaliculi, containing protoplasm; N, spaee containing medullary cor- 
 puscles; Af, transformation of dentins into protoplasm; C, trace of dentinal canaliculus con- 
 taining an enlarged fibril. Magnified 1000 diameters. 
 
 are clustered together, which is not always demonstrable even 
 in the thoroughly-decayed mass. 
 
 " We have a series of changes of the dentine fibers, and the 
 surrounding basis-substance of the dentine before us, which T 
 have not the least doubt is the normal procedure of the trans- 
 formation of dentine Ijy the carious process. 
 
 " Fig. 250 is an oblique section, and illustrates exactly the 
 same changes from]a tooth attacked by a less acute caries, per-
 
 600 KIE AXATO.MY AND PATHOLOGY OF THE TEETH. 
 
 haps owing to its greater solidity or more perfect calcification. 
 Here a relatively small number of dentinal canaliculi are en- 
 larged and tilled with protoplasm. The center of the proto- 
 plasmic bodies is occupied by one or two nuclei, which look as 
 if they originated from the former dentinal fiber. On the per- 
 iphery of the dentine there are regular nests filled with proto- 
 plasmic formations of the above description, partly broken 
 down into medullary elements. In other parts, on the con- 
 trary, the transformation of the basis-substance into protoplasm 
 has even preceded the changes of the dentinal fibers. The cana- 
 liculi are not noticeably enlarged ; the dentinal fibers are either 
 unchanged or slightly swollen, and more granular than in the 
 normal condition; while outside these we have a thoroughly 
 decalcified and liquefied basis-substance, which means a reap- 
 pearance of the net-work of the living matter. 
 
 " Caries of Cement. — So long as the gums are in their normal 
 condition and position, caries does not begin in the cement; but 
 if the gums have receded from any cause, thus exposing the 
 cement which covers the necks of the teeth, it may then begin 
 to decay. I never have had an opportunity of examining 
 primary caries of cement under the microscope, but of caries 
 of this tissue advanced from within — viz, from decayed dentine 
 — I have several specimens. The microscope reveals in these 
 specimens a more or less advanced decay, which in its essential 
 features is fully analogous to caries of the dentine when in a 
 live condition; in other words, it is an inflammatory process. 
 On the l)Oundarv of the cai'ies we see, besides unchanged cement- 
 corpuscles (see Fig. 251), those which have been enlarged and 
 transformed into medullary or inflammatory elements, i^ay, I 
 have observed that the lacunte holding the protoplasmic body 
 were partly unchanged, while a part participated in the inflam- 
 matory process. 
 
 " The enlargement of the cement-corpuscles is evidently not 
 due to a direct swelling of the protoplasm itself, but to a lique- 
 faction of the surrounding basis-substance, in which the proto- 
 plasmic condition, and with this also the medullary elements 
 which have participated in the formation of the basis-substance, 
 reappear. The inflamed portions of the cement look granular 
 with lower powers of the microscope, but high powers reveal 
 the n€t-like structure of the living matter, and the formation of 
 irregular polyhedral elements which are separated from one an-
 
 CARIES OF THE TEETH. 501 
 
 other by u light, narrow seam, this being traversed by extremely 
 delicate uniting threads. 
 
 " The history of development of l)one demonstrates that this 
 tissue originates from medullary elements, the so-called osteo- 
 blasts, which partly remain unchanged, and as such form the 
 bone-corpuscles, while their greater part is transformed into 
 basis-substance (Waldeyer). The liistory of the development 
 of the cement has not as yet been studied, but we have good 
 reasons for assuming that it develops in a way identical with 
 
 Fio. 251. 
 
 1 
 
 •p 
 
 
 
 f^ 
 
 Cemkntitis due to Cakies 
 
 C, unchanged cement-corpuscles; /, space filled with medullary corpuscles; /', cement-cor- 
 puscles partly unchanged, partly transformed into medullary corpuscles; Ai, the cementum 
 wholly transformed into medullary corpuscles. Magnified 1000 diameters. 
 
 that of bone, as both tissues are identical in their structure, and 
 exhibit identical results when inflamed. 
 
 " Dr. C. Ileitzmann has drawn attention to the fact that the 
 protoplasm of the medullary elements, when transformed into 
 glue-yielding basis-s\djstance, does not altogether perish. It is 
 only the fluid, non-living part of the protoplasm which, by 
 chemical changes, is transformed into glue; the living part of 
 the protoplasm, on the contrary, remains unchanged, and is
 
 502 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 siijiply concealed by tlie refracting power of the ghie-yieldmghas\s- 
 substance. That this view is a correct one the investigator 
 named has proven by the appearances in inflamed bone, and I 
 can fully corroborate his views from my observations on in- 
 flamed cement. 
 
 " Virchow's view that the bone-corpuscles swell and divide 
 into inflammatory elements by being converted into prolifer- 
 ating mother-cells, is, in my opinion, wrong. No proliferation 
 is demonstrable in the earliest stages of inflammation of the 
 cement. Nothing but a liquefaction of the glue-yielding basis- 
 substance takes place, in order to bring to view the very same 
 medullary elements which once have shared in the formation 
 of the cement. The inflammatory reaction in the cement- 
 corpuscle itself may be so slight that (as mentioned above) 
 a part of the protoplasm may look almost unchanged, while 
 another part toward the decalcified basis-substance gives an 
 appearance identical with that of the surrounding liquefied 
 basis-substance. The result of this process is a transformation 
 of the tissue of the cement into medullar}^ or inflammatory 
 elements. These remain in connection with one another by 
 delicate threads of living matter, but at last become disinte- 
 grated, and furnish, together with micrococci and leptothrix 
 threads, a decayed mass, just as well as enamel and dentine. 
 
 " Results. — After having examined the teeth attacked by the 
 carious process, microscopically, from the mouths of over thirty 
 different persons, I can sum up the results of my researches in 
 the following aphorisms : 
 
 "I. In enamel, caries in its earliest stages is a chemical pro- 
 cess. After the lime-salts are dissolved through the inflamma- 
 tory reaction, and the basis-substance liquefied, the protoplasm 
 reappears and breaks apart into small, irregularly-shaped, so- 
 called medullary or embryonal bodies, and subsequently the 
 lime-salts are dissolved by acids or washed away. 
 
 " II. Caries of dentine consists of a dissolution of the lime- 
 salts in the intertubular substance by the inflammatory reaction, 
 a melting down of the glue-yielding basis-substance (matrix) 
 around and between the canaliculi. The living matter con- 
 tained in the canaliculi proper is transformed into nucleated 
 protoplasmic bodies, which, together with protoplasmic bodies 
 originating from the living matter in the basis-substance, form 
 the so-called indiflerent or inflammatory tissue.
 
 CARIES OF THE TEETH, 503 
 
 " III. Caries of cement exhibits first all phenomena known to 
 1)0 present in the early stages of inflammation of bone. The 
 protoplasmic cement-corpnscles, together with the basis-sub- 
 stance, after its liquefaction, produce indiiierent or inflamma- 
 tory elements. 
 
 " IV. The inditterent elements originating through the carious 
 process from enamel, dentine, and cement do not proceed in 
 new formation of living matter, but become disintegrated and 
 transformed into a mass crowded with micrococci andleptothrix. 
 
 "V. Caries of a living tooth, therefore, is an inflammatory 
 process, which, beginning as a chemical process, in turn reduces 
 the tissues of the tooth into embryonic or medullary elements, 
 evidently the same as during the development of the tooth have 
 shared in its formation; and its development and intensity are 
 in direct proportion to the amount of living matter which they 
 contain, as compared with other tissues. 
 
 "VI. The medullary elements, owing to want of nutrition 
 and to continuous irritation, become necrosed, and the seat of 
 a lively ne^v growth of organisms common to all decomposing 
 organic material. 
 
 " VII. Micrococci and leptothrix by no means produce caries ; 
 they do not penetrate the cavities in the basis-substance of the 
 tissues of the tooth, but appear only as secondary formations, 
 owing to the decay of the medullary elements. 
 
 " VIII. In dead and artificial teeth caries is a chemical pro- 
 cess, assisted only by the decomposition of the glue-yielding 
 basis-substance of dentine and cement." 
 
 W. D. Miller's Views.* — " Physical Phenomena of Dental 
 Decay. — a. Decau of Enamd. — As the first indication that the 
 process of destruction has begun on the external surface of the 
 enamel, we notice that it has lost its normal polish and trans- 
 parency ; then a white (not black) spot of chalky color appears; 
 a sharp instrument {cg.^ the point of a needle) will not easily 
 glide over the surface, but will readily detect the presence of a 
 slight roughness, caused by a softening or disintegration of the 
 enamel, by which it is gradually changed into a soft, cheesy 
 powder. This dissolution of the enamel may be best observed 
 when decay advances from the dentine upon the inner surface 
 
 *"Tlie Miom-()ri,'iini>ms ..f the Human Muutli."' 1890.
 
 504 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 of the enamel (secondary decay); here the broken-down enamel- 
 prisms cannot be washed away, so that quite a thick layer of a 
 perfectly white cheesy substance may often be found. 
 
 " In primary decay the disorganized enamel-prisms are soon 
 mechanically washed away, whereby an excavation or cavity is 
 formed. The form of the cavity depends upon various circum- 
 stances, — among others, upon the breadth of surface of contact 
 with the adjacent tooth, also in a high degree upon the struc- 
 ture of the enamel. It is sometimes flat and broad with scarcely 
 distinguishable margins, sometimes narrow and deep with sharp 
 ragged margins. Soon after the commencement of decay, a 
 more or less pronounced discoloration sets in. In my opinion, 
 the view held by some, that the discoloration is to be regarded 
 as the first sign of decay, is based on an error which is to be 
 explained only on supposition that the advocates of this view- 
 have not examined decay in its earliest stages. . . . Dis- 
 coloration appears in very different grades; when the decay 
 proceeds very rapidly (caries acutissima), it is slight or wholly 
 wanting (white decay). In other cases only the margin of the 
 enamel is colored brown to black, while the center of the 
 cavity remains white. "When the decay proceeds very slowly, 
 — that is, when it is of long standing (caries chronica), — the 
 greater part of the affected tissue is deep brown or black. 
 This is also the case when the progress of the decay has been 
 interrupted", as is often observ^ed on the approximal surfaces of 
 teeth which have been exposed by extraction of an adjacent tooth. 
 Such cases are usually designated as caries nigra (black decay). 
 This badly-chosen term must, however, not mislead us to sup- 
 pose that we have to do here with an especial form of decay. 
 As a matter of fact, we are scarcely entitled to speak of such 
 places as decay at all, any more than we are to say that a man 
 with a pockmarked face has got the smallpox, because they do 
 not indicate that the process of decay is going on at the time 
 being. They are simply degenerated tissue, which, in the 
 course of time, has become discolored by oxidation, precipita- 
 tion, or other processes of this nature. Decay-marks would be 
 a much better name for such spots. 
 
 " h. Decay of Dentwe. — By the progress pf the above-described 
 process, the destruction of the enamel spreads until the surface of 
 the dentine is reached. Here the disease takes on a very differ- 
 ent form, inasmuch as we no longer find the tissue being
 
 CARIES OF THE TEETH. 505 
 
 changed into a soft, cheesy mass, hut into a tough, cartilaginous 
 suhstanee, which does not readily fall to pieces or yield to the 
 slightest friction, as does the decayed enamel, but may retain its 
 form for some time. This stage is designated as softening of 
 dentine, and is conditioned, as will be seen below, by a more or 
 less complete decalcification of the dentine. This softening 
 spreads in all directions in the dentine, with a rapidity depend- 
 ent upon the intensity of the fermentation processes present in 
 the mouth and the physical and chemical constitution of the 
 dentine. 
 
 " The softened mass may be easily cut or peeled off with a 
 sharp instrument; upon pressure, it discharges a small quantity 
 of a liquid which, in the great majority of cases, will be found to 
 redden blue litmus paper, — i.e., to have an acid reaction. 
 
 " The thickness of the softened layer varies considerably in 
 different cases. Yery soon after the softening of the dentine, 
 its disintegration or dissolution begins, leading to the formation 
 of a cavity in the dentine. The surface no^ appears uneven, 
 soft, and porous, infiltrated and contaminated with particles of 
 fermenting food, masses of bacteria, etc. 
 
 " The discoloration of the dentine is brought about by the 
 same causes as that of the enamel; it also shows the same 
 variations in acute and chronic decay, and all shades from the 
 natural color of dentine to black 
 
 " c. Deccuj of Cement. — Decay of cement frequently occurs at 
 the neck of the tooth. The layer of cement is, however, so thin 
 here that the characteristic phenomena of cement-caries scarcely 
 become apparent. Caries of the cement of the root occurs only 
 when the latter is exposed, and is therefore comparatively rare. 
 
 '' The roots of molars which are laid bare by the recession of 
 the gum and destruction of the periosteum show the greatest 
 preference for decay. Such roots are often covered with thick 
 white or yellowish-white deposits, consisting of food-particles, 
 dead epithelium, mucus, and fungus-masses, and not infrequently 
 present cases of typical decay of the cement. 
 
 " The first symptom of cement-decay is an abnormal rough- 
 ness or softness of the cement-surface, which may be easily 
 penetrated or scraped off with an excavator. 
 
 " This Y>henomenon, which is also nothing but the softening 
 of the cement, is followed by a loss of the surface substance ; 
 thus a cavity is produced, or rather a dei»ression, since it has
 
 506 THE AXATOMY AND PATHOLOGY OF THE TEETH. 
 
 little similarity with the cavities of the crown. Deep bulb- 
 shaped cavities are hardly ever formed; they are, for the most 
 part, shallow, widely-extended excavations, without a distinct 
 margin. 
 
 " This is due to the fact that there are no circumscribed 
 points of retention or foci of decay on the roots, from which 
 alone the destruction could proceed. It therefore seldom 
 happens that decay, beginning at the root, spreads from the 
 cement to the dentine, and destroys the latter to such an extent 
 that the root-pulp is exposed. 
 
 " A natural retention-center is formed at the point of bifur- 
 cation of the molar roots, where it has been exposed by recession 
 of the gums, and penetrating decay is consequently not seldom 
 found here, . . 
 
 " Accompanying Phenomena of Dental Decay. — As concomitant 
 phenomena of dental decay, I designate certain processes which 
 manifest themselves either immediately or some time after the 
 appearance of decay, and which, in my opinion, have been 
 erroneously denominated as characteristics of it. 
 
 "These processes are: (1) transparency; (2) the pigmenta- 
 tion or discoloration of the decayed tissue. 
 
 " Coincident with the development of the opacity and the 
 pigmental degeneration in the commencement of the carious 
 affection of the dentine, an increased translucency is observed, 
 frequently, in portions adjacent to the boundary of the carious 
 portion. With reflected light these portions have a horny 
 appearance, similar to that found in senile roots, and ^vith 
 transmitted light they present hyaline bands and spots. The 
 focus of the caries is surrounded by a diaphanous halo. The 
 opaque, carious dental cone, therefore, is invested by a trans- 
 lucent zone, extending from the periphery toward the center; 
 around a more spherical, carious portion of the dentine a cres- 
 centic diaphanous halo is sometimes met with. (Fig. 252.) The 
 light portions, finally, vary exceedingly in respect to their out- 
 lines, according to the form in which the carious limits are 
 extended, being radiated, kidney-shaped, etc. (Wedl.) 
 
 " A true picture of transparency can be obtained only where 
 softening and pigmentation of the dentine have not yet taken 
 place ; that is to say, where there is as yet no decay. 
 
 " The transparent portion here forms a cone whose apex 
 points toAvard the pulp, and whose sides run parallel with the
 
 CARIES OF THE TEETH. 
 
 507 
 
 dentinal tubules. In most cases the transverse sections of these 
 cones are, as far as my observations go, bounded by two opaque 
 
 '^''-^Under the microscope the dentinal tubules within these 
 stripes are seen to be filled with irregular, angular granules or 
 oblong particles. 
 
 Fig. 252. 
 
 a)' .. -■■ •■ ■■■' ''■/" 
 
 «f».r>".«* 
 
 
 h,.-^^^wm 
 
 §ii ' V i:-:^ \'''f 
 
 4^5 
 
 y 
 
 % 
 
 B-\ 
 
 1% 
 
 
 '^t 
 
 ^-m 
 
 
 m 
 
 
 -^-<^ .^■'' 
 
 :>/- 
 
 1 
 
 % 
 
 «i\ifv>l 
 
 I 
 
 Portion of a Longitudinal Ground Section through the Crown of a Molar. 
 Showing two cavities of decay, with the transparent zone at c. (After Gysi.) 
 
 « Pigmentation of the Tissue In Dental Decay.— "Ih^ pigmen- 
 tation or discoloration usually attending decay of enamel or 
 dentine is another secondary process, which has erroneously been 
 viewed as a stage of decay. Every degree of discoloration may 
 be observed, from the normal color of the tissue to a yellow-
 
 508 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 isli, yellow, yellowish-brown, dark brown, black. In the very 
 first appearance of decay no discoloration is visible. This ab- 
 sence of discoloration is especially remarkable in secondary caries 
 of enamel, the tissue being converted into a perfectly white 
 powder. 
 
 " ITor does rapid caries show any, or but very little, discolora- 
 tion in the deeper parts, while chronic caries always exhibits a 
 dark color, dark brown to black ; in other words, the intensity of 
 the discoloration is in inverse proportion to the rapidity of the 
 progress of the disease. Besides, the discoloration of dentine 
 does by no means occur in decay only. Wlierever the dentine is 
 laid bare, it maybe more or less discolored in time. The black 
 discoloration is especially common in worn-off teeth, and, in- 
 deed, not only in the case of smokers, but also of non-smokers, 
 nor is it rare for the teeth of dogs to show a deep brown to 
 black discoloration. 
 
 " Most authors concur in the view that the pigment arises 
 from without, and is conditioned by causes which have nothing 
 to do with the decay itself. 
 
 " In my judgment, the cause of discoloration in dental caries 
 is exactly the same as that of the discoloration of any other 
 organic substance which is decomposed by micro-organisms. 
 
 '■'■ Decaii of Enamel. — Microscopic examination of decayed 
 enamel brings to light in many preparations nothing more than 
 a depression (a loss of substance), with uneven margins (Fig. 
 253), a more or less pronounced pigmentation of the enamel in 
 the vicinity of the depression, and a distinct appearance of the 
 transverse striation of the enamel-prisms. In other better-pre- 
 pared specimens the depression is seen to be filled with masses 
 of micro-organisms which readily take on coloring matter; the 
 margin of the cavity is indented, the enamel cracked, the 
 prisms falling to pieces. The spaces between the loosened 
 prisms are, in these cases, often filled with the same fungal 
 masses, whereas the latter never penetrate between the prisms 
 of normal enamel. In grinding, the masses of bacteria, as well 
 as the loosened prisms, are generally torn away. 
 
 " After the enamel has once been perforated by decay, its 
 further destruction proceeds principally from the inner surface. 
 This statement may at first seem strange, but will be found on 
 closer examination to be in accordance with the observed facts. 
 The remains of food accumulating in every dental cavity do
 
 CARIES OF THE TEETH. 
 
 509 
 
 not, of course, attack the external, l)ut the internal surface of 
 the enamel. We will tind, furthermore, in nearly all large 
 cavities the decay extending from the dentine upon the inner 
 surface of the enamel. 
 
 "This latter form of decay, which we designate as secondary 
 enamel-decay, is in many respects better suited for study than 
 the primary, inasmuch as the diseased tissue is not torn away 
 
 Tig. 253. 
 
 Undeumim.nu Enamel-Decay. 
 a, masses of bacteria lining the cavity. Magnified about 50 diameters. 
 
 by mastication, etc., and not contaminated from without by 
 foreign bodies. 
 
 " Sections of enamel in secondary decay often show the bac- 
 teria forcing their way between the loosened prisms. About 
 the same result is obtained where normal enamel is treated 
 with diluted acids. The destruction of the enamel as it occurs 
 in decay must be regarded as essentially a parasitico-chemical 
 process. The loosening of the enamel-prisms is caused by acids, 
 concerning whose origin there can be no doubt; they arise in
 
 510 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 the mouth by fermentatioii of carbohydrates. The prisms thus 
 loosened are sometimes mechanically removed; sometimes they 
 remain on the spot, as in the case of secondary enamel-decay, 
 until an opening is formed through which they escape. The 
 bacteria directly participate in the process, inasmuch as they in- 
 vade the broken-down enamel, perhaps drive the prisms farther 
 apart, and destroy the remnant of organic matter. Micro-organ- 
 isms do not exert a direct influence on normal enamel; their 
 action upon the enamel in the first stage of decay is therefore 
 indirect, — ^that is, they act b}' means of the acids which they pro- 
 duce. In the later stages of the process they exert also a direct 
 action upon the diseased tissue. 
 
 '-'■ Decaii of Dentine. — Ajjpearances under the Microscope. — 
 Preparations colored with fuchsin, when examined under very 
 
 Fig. 254. 
 
 
 ■? 
 
 ^e / 
 
 
 Interglobular Spaces filled with Micrococci. 
 Magnified about 400 diameters. 
 
 low power or even with the naked eye, show that the bacteria 
 are not equally distributed throughout the mass of softened 
 dentine. Sections parallel to the dentinal tubules (longitudinal 
 sections) generally reveal on the outer margin corresponding 
 to the external layer of dentine a deep-red coloration, which 
 gradually diminishes toward the inner margin. Large tracts of 
 decayed tissue, especially at the extremities of the specimen, 
 often remain entirely uncolored. This necessitates the conclu- 
 sion that the softening (decalcification) of the dentine extends 
 further than the invasion of the micro-organisms. 
 
 *' Under a somewhat higher power (forty to sixty diameters) 
 we may more easily follow the invasion. Occasionally we find 
 that a majority of the tubules are infiltrated to the same depth;
 
 CARIES OF THE TEETH. 
 
 511 
 
 usually, however, the parasites penetrate the different tubules 
 to very dift'ereiit depths. We also occasionally find that all or 
 nearly all the tubules are filled with bacteria at the surface, 
 while in the deeper parts only a few are infiltrated. 
 
 "A question which has often been mooted now arises : Can 
 the bacteria penetrate into normal dentine ? This question must 
 be answered in the afiirmative. Since the average diameter of 
 the dentinal tubules is greater than that of the bacteria found 
 in the mouth, it is but reasonable to conclude, a priori, that bac- 
 
 FiG. 255. 
 
 Decayed Dentine. 
 Showing total liquefaction of the basis-substance by bacteria. Magnified 400 diameters. 
 
 teria may under certain circumstances make their way into the 
 tubules of apparently intact tissue. Under high power we also 
 often observe that a small number of bacteria, outposts, as it 
 were, have penetrated into the normal dentine, without, how- 
 ever, producing any visible changes. 
 
 " In some specimens all the tubules are enlarged to nearly the 
 same extent, occasionally to three or four times their normal 
 size. This enlargement is caused partly by the disloclgment
 
 512 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 of the neighboring tubules, partly by the loss of the inter- 
 tubular substance. Lastly, the destruction of the intervening 
 substance causes a confluence of two or more adjacent tubules, 
 producing long caverns running parallel to them. By the forma- 
 tion of caverns and by the fusion of adjacent caverns the dentine 
 is broken up, becomes porous, and is gradually destroyed. 
 The tubules are often attacked in groups, while others lying be- 
 tween these groups may be wholly free from infection. In other 
 cases, however, every single canal is stuffed full of bacteria. 
 " In Fig. 255 I have endeavored to reproduce an appearance 
 
 Fig. 256. 
 
 Fig. 257. 
 
 Fig. 268. 
 
 Fig. 259. 
 
 Fig. 260. 
 
 \UmfA 
 
 Single Tubulk. Single Tubule. Single Tubule. Single Tubule. 
 
 Filled with thread Filled with 
 forms. Magnified cocci. Magnified 
 1100 diameters. 1100 diameters. 
 
 Filled with Showing a mix- 
 rods. Magnified infection or infee- 
 1100 diameters, tion with a pleo- 
 morphous b a c - 
 terium. Magnified 
 1100 diameters. 
 
 m,' 
 
 
 very commoiih^ met with in decaying dentine. This 
 specimen clearly shows that the enlargement of the 
 tubules always found in decayed dentine is due to 
 the infection, and that a gradual fusion of the basis- 
 substance may take place, beginning with the sepa- 
 rate tubules, until nothing remains but a ma.=s of 
 bacteria held together liy the remnants of the 
 dentine. 
 
 " In well-stained specimens the individual cells 
 teria are clearly visible under a poAver of 400 to 500 
 although for a thorough study of the specimens oil 
 
 Decayed Den- 
 tine. 
 
 Showing a mix- 
 infection with 
 cocci and ba- 
 cilli. Magnified 
 400 diameters. 
 
 of the bac- 
 diameters; 
 immersion
 
 CARIES OF THE TEETH. 513 
 
 lenses and Al)l)e's condenser are desirable. With tlieir assist- 
 ance we see that the external margin of the specimen consists 
 of l)rokcn-down dental tissue intermixed with enormous masses 
 of micrococci, bacilli, and leptothrix threads. The latter often 
 appear as fringes on the border of the specimen, but are not 
 found along the entire margin, while in some the}' are altogether 
 lacking. In many cases, no doubt, they are torn away in pre- 
 paiing the specimens. It is seldom that they penetrate the den- 
 tinal tubules, unless the dissolution is already far advanced, and 
 even then they are to be found mostly in the external layers. 
 Tulndes containing long, tortuous threads (Fig. 256) are there- 
 fore comparatively rare. 
 
 "If we examine a somewhat deeper zone, we usually iind 
 the tubules filled with micrococci and rods only, the former 
 
 Fig. 261. 
 
 
 Cross-Section of Decayed Dektine. 
 
 Showing tho distention of the tubuli and formation of liquefaction-foci. Magnified 400 
 diameters. 
 
 decidedly preponderating. These two forms of bacteria gen- 
 erally occur in separate tubules; thus we often see a tubule 
 stocked only with micrococci (Fig. 257), the adjacent one only 
 with rods (Fig. 258), while it rarely happens that one extremity 
 of a tubule is filled with rods, the other with cocci. 
 
 " We have consequently in decay of the teeth to do with a 
 so-called mix-infection (Figs. 259 and 260). 
 
 "It is true that we often meet with specimens which appear 
 to contain cocci alone (wlietlier of one or of diflferent varieties 
 the microscopic examination does not tell). On the other band, 
 I have in my possession a few preparations which exhibit a pure 
 bacillus infection, particularly in circumscribed portions. 
 
 "A section cutting the tubules at right angles shows, under a 
 power of 300 diameters, that the tubules filled with micro-organ- 
 
 34
 
 514 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 isms are distended from one to four times their normal diameter, 
 and that often two or more of the enlarged tubules are converted 
 into one by the liquefaction of the membranes and the interven- 
 ing substance (Fig. 261). This melting together of the tubules 
 increases as we near the outer border of the specimen (corre- 
 sponding to the surface of the cavity), until it is no longer pos- 
 sible to distinguish the separate tubules; we then see only 
 irregular masses of bacteria, of different sizes, which are more 
 or less contaminated by the detritus (dibris) of the decomposing 
 dentine. These impure masses are what Abbott calls ' embry- 
 onic elements.' Since they are not homogeneous they take up 
 the coloring-matter unequally at different points, and therefore 
 occasional^ i»resent figures that may bear a certain faint resem- 
 blance to cells. 
 
 "Decay of Cement. — The decalcification and dissolution of the 
 cement proceeds either from the surface inward, in the form of 
 a progressive superficial dissolution of the cement, or the cavi- 
 ties of the cement become infiltrated with bacteria, giving rise 
 to a parenchymatous dissolution, accompanied by phenomena 
 very similar to those of dentine-decay. Its similarity to the 
 latter is especially striking in places where Sharpey's fibers are 
 well developed. Immediately following decalcification these 
 fibers, or rather canals, are infiltrated and enlarged by bacteria 
 which gradually liquefy the intervening tissue. In this way the 
 tissue is rarefied, and finally totally destroyed. I possess several 
 specimens in which this form of cement-caries has been arti- 
 ficially produced. 
 
 " Wlien cement-corpuscles are present, they or their offshoots 
 {as far as I have had opportunity to examine such cases) are 
 infiltrated with bacteria and swollen. I was not able to deter- 
 mine any such inflammatorj' reaction on the part of the cement 
 as occurs, say in bone or cartilage. 
 
 " I affirm that a destruction of the tooth-substance ma}' be 
 brought about artificially, which the most practiced micro- 
 scopist will not be able to distinguish from real decay as it 
 occurs in the human mouth. In fact, not one of the many 
 microscopists who have made the attempt has been able to 
 determine wliicli of a given number of preparations were arti- 
 ficial and which natural. 
 
 " I cut up a number of teeth which were perfectly sound, but 
 of different density, into pieces of dift'erent size, and placed
 
 CARIES OF THE TEETH. 515 
 
 them in a mixture of saliva and l)read. This mixture was for 
 three months at a temperature of 37° C, and during the course 
 of the experiment repeatedly renewed. At the end of this 
 time I showed a number of these pieces to a well-known dentist 
 of thirty-three years' standing, and asked him if these were not 
 peculiar cases of decay. He replied by saying that he saw 
 such cases every day in his practice. In many pieces the den- 
 tine was softened through and through, in all to a considerable 
 depth. When the softening had penetrated through the den- 
 tine to the inner surface of the enamel, the latter was found 
 covered with a layer of white powder exactly as it is found in 
 natural decay. Cracks and fissures in the enamel had an 
 opaque, whitish appearance, and in many cases could be easily 
 penetrated by a sharp instrument. At the neck of the tooth 
 the dentine was likewise much softened, though not to so great 
 a deo;ree as on the crown. The border of the enamel was rousrh, 
 and so brittle that in many places an instrument could be 
 inserted between the enamel and the dentine. On the o-rindino:- 
 surface, in such cases where the structure of the tooth was 
 imperfect and full of fissures or depressions, the whole tissue 
 had been converted into a soft mass, such as is often found on 
 the surface of third molars. 
 
 " j^ll of the phenomena observed in cases of so-called white 
 decay were present in these cases of artificial decay. If the 
 mixture was allowed to stand until the reaction became alkaline, 
 or if the pieces were ex[3osed to the air or to the action of dif- 
 ferent articles of food, such as coflfee, tea, tobacco, fruit, etc., 
 all possible shades of color were produced just as they are found 
 in the mouth. 
 
 " Sections of these pieces showed all the microscopic changes 
 which have been described as characteristic of decay of dentine. 
 
 " Tkc Micro-Organisms of Dental Decag. — Our knowledge of 
 the micro-organisms most dii^ectly concerned in the destruction 
 of the substance of the tooth is as yet very deficient. We have 
 been able to establish the fact that all micro-organisms of the 
 human mouth which possess the power of exciting an acid 
 fermentation of foods may and do take part in producing the 
 first stage of caries ; also, that all possessing a peptonizing or 
 digestive action upon albuminous substances may take part in 
 the second stage ; and, finally, that those possessing both prop- 
 erties at the same time may take part in the production of both
 
 516 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 stages. But whether there is any one bacterium which may 
 alicays be found in decayed dentine, and which might therefore 
 be entitled to the name of the bacterium of tooth-decay, or 
 whether there are various kinds which occur with considerable 
 constancy, we are not able to say." 
 
 From the quotations of Abbott and Miller it follows that the 
 former, although he noticed the micro-organisms in decayed 
 teeth, does not consider them the primary cause thereof. 
 Abbott, however, has accurately observed the tissue-changes in 
 the neighborhood of decay in the enamel, dentine, and cemen- 
 tum. Miller, on the contrary, proved that the invasion of 
 micro-organisms is the only cause of decay; but admits no 
 inflammatory reaction whatsoever in the affected hard tissue of 
 the tooth. In the views of the latter observer, the living tissues 
 are simply destroyed by the micro-organisms without reacting 
 upon the injury. 
 
 From my own researches, I am convinced that the full truth 
 in. regard to the carious process can be established onl}' by a 
 combination of both Abbott's and Miller's assertions. I admit 
 that micro-organisms are the principal cause of the decay of 
 teeth ; but only dead material will be destroyed by them with- 
 out the least reaction. Living tissues — i.e., enamel, dentine, 
 and cementum — ^invariably react upon the invasion of the micro- 
 organisms by an inflammatory process similar to that in otLer 
 living tissues, in the manner described by Abbott. 
 
 The brown discoloration of the dentine in the neighborhood 
 of decay, of which both authors speak, afibrds an excellent op- 
 portunity for 8tud3nng the minute structure, especially in freshly- 
 ground specimens. The reticulum, as I have described it in 
 Chapter VIII, is seen here even with medium powers of the 
 microscope. Pigmentation of enamel in the neighborhood of 
 decay likewise furnishes excellent means for studying its minute 
 structure with high powers of the microscope. 
 
 Another proof of the tissue-changes in the dentine in the 
 vicinity of decay is the healing process occasionally observed. 
 (See Fig. 262.) Here a recalcification of the softened and prob- 
 ably inflamed dentine has taken place, with a new formation 
 of scanty and irregular canaliculi, such as we frecpiently observe 
 in secondary dentine. Since all modern researches in biology 
 prove that no neAV tissue can arise without the previous one be-
 
 CARIES OF THE TEETH. 517 
 
 ing first reduced into an embryonal condition, I do not liesitate 
 to maintain such changes for the living dentine. The difference 
 between the normal and the newly-formed dentine is so con- 
 spicuous, especially in the rearrangement of the dentinal canali- 
 culi, that a mere recalcification could never explain these 
 changes. 
 
 According to the views thus far explained, I will indicate the 
 changes that occur in the process of caries by the following : 
 
 The primary cause of caries is acid fermentation of remnants 
 
 Fig. 262. 
 
 
 
 
 o 
 
 ■^-^ ■ '■■:}%-^f:-^'u-:r^- 
 
 — i _ 
 
 £=» :!■ -iii:-'^-'--.-^^-.''-^''..:^-- 
 
 
 "- R 
 
 
 
 R 
 
 -^X. 
 
 
 Healed Caries of Dkxtine. 
 
 L, colonies of leptothrix ; B, D, decalcified dentine, with enlarged canalieuli ; Ji, R, recalci- 
 fied dentine, with scanty canalieuli ; iV, normal dentine. Magnified 500 diameters. 
 
 of food, induced by micro-organisms. The favorable starting- 
 places of caries in the enamel are grooves, pits, and crevices in 
 the surfaces of the teeth, where particles of food are most 
 readily detained. The further progress of caries is due to an 
 invasion of micro-organisms into the hard tissues of the teeth. 
 The result of this invasion is first decalcification and afterward 
 disintegration. Dead tissues are decomposed without reaction. 
 Living tissues, after decalcification, are reduced to an embry-
 
 518 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 onal or protoplasmic condition (Abbott). According to the 
 amount of lime-salts tlierefor, the constitution of the individual, 
 and according to the number of micro-organisms invading the 
 tissues, the decay is either rapid (acute caries) or slow (chronic 
 caries). In the latter instance a spontaneous healing by a 
 re-formation of the hard tissues is possible. In dentine and 
 cementum acute caries leads to a white discoloration of the 
 tissues involved, while chronic caries frequently causes a 
 brown pigmentation in the neighborhood of decay. 
 
 CHAPTER XLI. 
 
 THE EFFECTS OF ARSENIC DIOXIDE AND METALLIC ARSENIC UPON THE 
 PULPS :0F THE TEETH.-SO-CALLED COAGULATION-NECROSIS. 
 
 In 1884 I published* a brief account of experiments with 
 arsenic dioxide, of which the following is an abstract : 
 
 The action of arsenic dioxide upon the dental tissues has for a 
 long time been a disputed question, and the changes efiected by 
 the poison, when applied to the cavity of a tooth, were thought 
 to be .confined to the pulp-tissue. In 1879, A. Witzel, of Ger- 
 many, published a work on the diseases of the dental pulp. In 
 this he claims that a pulp, if not too much inflamed, can be 
 treated with arsenic dioxide, its coronal portion amputated, and 
 the remaining pulp-stump preserved. This doctrine has 
 created a great deal of controversy in this country, although in 
 Germany it seems to have been almost universally accepted. 
 I have followed this line of treatment in sixteen cases, in an 
 experimental way, selecting teeth which I was able to examine 
 from time to time. The microscopical appearances can best be 
 studied in healthy or superficially decayed teeth of human sub- 
 jects, or in the teeth of such animals as can be easily experi- 
 mented upon. In all cases, therefore, a uniform mode of pro- 
 cedure must be adhered to. The line of study being neces- 
 sarily experimental, has extended over a long period of time, 
 calling for a considerable amount of labor and painstaking care. 
 
 * Dental Cosmos, 1884.
 
 EFFECTS OF ARSENIC UPON TOOTH-PULPS. 519 
 
 The preparation Avhieli I have used exclusively is the well- 
 known one composed of one part of arsenic dioxide and one 
 part of sulphate of morphia, made into a paste with chemically- 
 pure carbolic acid, which was put into a drill-hole in the tooth 
 and covered with a temporary stopping. I will not enter into 
 details, but will only mention that, bearing in mind the results 
 I wished to obtain, I drilled in tlie direction of the pulp- 
 chamber, but did not in any case perforate it. It ap[)eared to 
 be quite immaterial, however, how thick the interposing den- 
 tine was in respect to the changes caused by the poison. 
 
 I used human teeth and those of rabbits. They were 
 extracted in from three to six days after the application of 
 arsenic dioxide. The teeth were opened immediately after 
 extraction, and immersed witliout delay in the proper reagent. 
 It is important to proceed in such manner that the pulp shall 
 not be torn or dislodged, and yet may be acted upon by the 
 fluids while still lodged in its natural position. When the 
 elements of the pulp are once sufliciently fixed, it becomes pos- 
 sible to slice it without causing artificial changes. This is no 
 easy matter, for unluckily the hardening fiuids most generally 
 in use cause some changes. Even water, and, as has been 
 found, the tissue-fluid itself, if allowed to act a sufiicient time 
 after death, gives to the medullated nerve-fibers an appearance 
 which, I have no doubt, has frequently been described as 
 pathological. 
 
 After having used difterent reagents, I have come to the con- 
 clusion that the best results can be obtained by immersing the 
 tooth in the manner described in a one per cent, solution of 
 hyperosmic acid for from ten to twenty hours, according to the 
 density of the tooth. As regards the pulp, this will be found 
 to be sufliciently hardened after a sojourn of two to three hours 
 in the same fluid ; it can then be easily removed from the pulp- 
 chamber wathout fear of serious harm. Both parts are then 
 placed in distilled water and preserved in alcohol. 
 
 The changes due to the poison are quite pronounced. First, 
 if the poison has acted sufliciently long, the whole of the pulp 
 shows to the naked eye, as soon as exposed, all the signs of 
 active inflammation. According to the degree of inflammation 
 resultant from the irritation which the arsenic dioxide undoubt- 
 edly does produce, a greater or less number of nerve-fibers 
 are changed in appearance in such a manner that their myelin
 
 520 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 is separated into larger and smaller masses, between wliicli I 
 have not been able to distingnisli either an axis-cylinder or an 
 intermediate sul)stance. I may, however, mention that I have 
 seen in nerve-fibers, which have remained under the influence 
 of the arsenic dioxide for six days, a granular substance which 
 can be colored b}^ rose anilin, certainly a product of the disin- 
 tegration of the myelin sheath. I have no doubt that this is a 
 stage toward the complete destruction of the nerve-fibers, and I 
 may mention in this connection that, in one instance, I have 
 found similar globules free in the tissue surrounding a number 
 of degenerated nerve-fibers in an incisor of a rabbit after three 
 days' reaction of the arsenic dioxide. 
 
 What will be the result of the arsenic dioxide so applied, not 
 alone to the pulp itself, l)ut in respect to the nutrition and life 
 of the whole tooth, is easily surmised, and can be demonstrated 
 by an examination of the dentine. 
 
 After having treated the newly-extracted tooth witli liyper- 
 osmic acid, and thereby guarded against artificial changes, I 
 prepared ground specimens of the same. These were then 
 stained with picrocarmin, and suitably treated for mounting. 
 Under the microscope the dentinal canaliculi appear enlarged, 
 more so at one place than at another, and filled with a mass 
 deeply stained in Idack. The same can be said of the transverse 
 connections of the canaliculi. When, however, high powers 
 are brought to bear on such places, the black mass is found to 
 be composed of irregularly-shaped bodies, which, I doubt not, 
 are remnants of the dentinal fiber. In tracing such canaliculi, 
 it is seen that the swollen dentine-fibers are broken up more 
 and more as one approaches the seat of the greatest destruction. 
 As a consequence, the basis-substance is narrowed in extent as 
 the canaliculi gain in diameter. 
 
 Since this pnblication I have continued my researches on the 
 action of arsenic dioxide, examining the pulps after exposure to 
 the poison for a time varying from twenty minutes to twenty- 
 four hours. The pulps were obtained either after the extrac- 
 tion of the tooth or extirpation by the broach. 
 
 The effect of twenty minutes' contact of an inflamed pulp with 
 the poison, in a tooth of a patient sixteen years of age, is illus- 
 trated in Fig. 263. 
 
 The inflamed zone is conspicuous by the la'-k of the stain with 
 ammoniacal carmin, which feature we know to be characteristic
 
 EFFECTS OF ARSENIC UPOX TOOTH-PULPS. 
 
 521 
 
 of the death or necrosis of the tissues. Only the walls of the 
 blood-vessels have taken up the stain, which fact proves that 
 the tissues under the influence of circulating blood retain life 
 longer than those away frorci the blood-vessels. The inflamma- 
 
 FiG. 263. 
 
 Pulp affected by Acute Pulpitis treated with Aesexic Dioxide for Twenty Minutes. 
 
 P, portion of pulp'in acute inflammation, showing effect of arsenic dioxide ; M, normal myxo- 
 matous pulp ; C, capillaries engorged with blood ; N, bundle of meduUated nerves. Magnified 
 500 diameters. 
 
 tory corpuscles show a peculiar gloss, at the same time lacking 
 sharply-defined contours. The same happened with the tracts 
 of spindles, obviously the remnants of previous blood-vessels. 
 "The portions nearest to the non-inflamed pulp and the pulp itself,
 
 522 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 being of a distinct myxomatous structure, appear colored with- 
 ammoniacal carmin. The blood-vessels are dilated and en- 
 gorged with blood-corpuscles, showing no reaction upon the 
 arsenic dioxide. The medullated nerves are broken up into 
 inflammatory corpuscles in the region of pulpitis. Farther 
 down the myelin is segmented in a manner known to suc- 
 ceed inflammation. Since it seems impossible that arsenic 
 dioxide should have produced an inflammatory reaction within, 
 twenty minutes, it is reasonable to say that in this case life 
 was destroyed particularly in the inflamed portions of the pulp. 
 At the same time, the elements had been preserved in size 
 and shape, and therefore were mummified. 
 
 C. Weigert* has proposed to term such a condition of tissues 
 and elements " coagulation-necrosis." This term seems to be 
 applicable Avhenever heat or chemical reagents, such as strong 
 solutions of corrosive sublimate, carbolic acid, chloride of zinc, 
 etc., are brought in contact with the tissues, combustion of the 
 skin and mummification of the pulp being good examples. 
 Serious doubts have been raised by good observers against the 
 propriety of the term " coagulation-necrosis" as proposed by 
 "Weigert. 
 
 In a number of pulps treated with arsenic dioxide from one to 
 twelve hours, no evidence of necrosis of the pulp-tissue could 
 be obtained, since the stain with ammoniacal carmin was 
 present and the appearance of mummification absent. An 
 instance of dififtise calcification of the pulp with complete mum- 
 mification from arsenic dioxide after twenty-four hours' contact is 
 illustrated in Fig. 264. This pulp was removed from an upper 
 central incisor of a patient about sixty years of age. The 
 crown was half worn away by mechanical abrasion, nearly 
 approaching the pulp-chamber. The application of arsenic 
 dioxide was made for the purpose of devitalizing the pulp in 
 order to obtain sufficient anchorage for a large contour gold 
 filling. The pulp was extracted by means of a broach. Under 
 the microscope a large portion of the pulp was found diflfusely 
 calcified. The pulp-tissue still showed vestiges of structure, 
 though finely granular throughout. Most of the capillary and 
 venous blood-vessels were found crowded with clusters of 
 irregularly-outlined blood-corpuscles of a dusky red-brown 
 color. The perivascular space around these vessels was widened 
 
 * Deustche Med. Wochenschr., 1883.
 
 EFFECTS OF ARSENIC UPON TOOTH-PULPS. 
 
 523 
 
 and well pronounced. The medullated nerves, some of which 
 entered the calcified region without having caused pain, were 
 broken up into small, glossy, irregularly-shaped lumps, the same 
 
 Pulp affected by Calcification treated with Arsenic Dioxide for Twenty-four 
 
 Hours. 
 
 D, diffuse deposits of lime-salts ; N, bundle of medullated nerves, entering the calcified por- 
 tion of the pulp; M, bundle of medulla*ed nerves, broken up by arsenic dioxide; A, axis-cylin- 
 der, changed by arsenic dioxide ; C, capillary holding changed red blood -corpuscles ; P, P, finely- 
 granular pulp-tissue. Magnified 500 diameters. 
 
 as non-medullated nerves, still traceable here and there. This 
 feature is long since known to me as a result of the action of 
 arsenic dioxide.
 
 524 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 In the highest degrees of mumraiiication, when the reagent 
 has been left in situ for several days, the pulp-tissue is trans- 
 formed into a yellowish-red, glossy, almost waxy-looking mass, 
 in which the tissue-elements are but faintly recognizable. 
 
 My experience with arsenic dioxide has led me to consider it 
 an unreliable agent, often causing the death of the pulp in cir- 
 cumscribed regions, mainly of the coronal portion, leaving the 
 root-portions unaffected. But even in such instances the root- 
 portions are liable to die, and subsequently become a source of 
 suppurative pericementitis. In some cases no reaction whatso- 
 ever follows the application of arsenic dioxide ; in others only 
 pulpitis is brought forth, instead of mummification ; in still other 
 cases the action is too far-reaching, and destroys the whole of 
 the pulp, the crown as well as the root-portions. Exceptionally 
 the inflammatory reaction is so severe that pericementitis sets 
 in, and instances are on record in which extensive gangrene 
 followed the application of arsenic dioxide. 
 
 My advice in regard to the use of arsenic dioxide for the pur- 
 pose of devitalizing the pulps of teeth is to employ it only in 
 exceptional cases, and, if possible, discard it altogether. When, 
 however, it is made use of, this should only be done in normal 
 or in acutehj-inflamed pulps. In all cases of chronic pulpitis, and 
 especially in hyperplasia of the pulp, arsenic dioxide should 
 never be applied. In the latter instances it is liable to produce 
 a very acute attack of pulpitis, accompanied by excruciating 
 pains, and usually without the desired result of devitalizing the 
 pulp. 
 
 In order to obviate the difficulties of filling pulp-canals, Wil- 
 helm Herbst, of Bremen, Germany, recommended a novel 
 procedure.* 
 
 The methods of practice observed by him are as follows : 
 If the pulp of a tooth is in such a condition that it becomes 
 necessary to remove it, an application of cobalt,t to which has 
 been added about eight per cent, of hydrochlorate of cocaine, 
 is made to it, and covered with wax or some other temporary 
 filling-material. After two or three days the temporary filling 
 is removed, the cavity cleansed from all decay, and rinsed out 
 
 * " The Herbst Method of Treating Pulps." Dental Cosmos, 1892. 
 t A sample of cobalt, sent by Dr. Herbst, was examined by Dr. E. C. Kirk, 
 who found it to be metallic arsenic.
 
 EFFECTS OF ARSENIC UPON TOOTH-PULPS. 525 
 
 with water. Then, if practicable, the rubber-dam is adjusted, 
 the cavity thoroughly disinfected, and the coronal portion of 
 the pulp is amputated by means of a large, perfectly clean, 
 sharp, round bur, which is rapidly revolved in the hand-piece 
 of the dental engine. The bur must be nearly as large as the 
 coronal portion of the pulp which is to be amputated. The 
 pulp-chamber is then to be washed out with a solution of corro- 
 sive sublimate of the strength of one-tenth of one percent., and 
 dried. A cylinder, or a loosely-rolled ball of No. 4 tin foil, as 
 large as the cavity will admit, is now placed in the pulp- 
 chamber directly over the amputated pulp-stump, and with a 
 revolving, smooth burnisher, which is smaller than the pulp- 
 
 FxG. 265. 
 
 Diagram of Molar treated by Dr. Herbst. 
 F, filling ; D, dentine ; E, enamel ; T, tin cap over pulp-stumps ; P, pulp ; C, eemontum. 
 
 chamber, the tin is burnished firmly into it. In burnishing, 
 care should be exercised not to press the tin directly upon the 
 pulp-stump, but the force should be exerted more laterally. 
 It is also necessary that the stumps to be capped in this manner 
 be not irritated with small burs, excavators, or nerve-instru- 
 ments, as failure has been observed in those cases in which this 
 was done. Herbst also advises that in case the tooth becomes 
 sensitive to pressure after such an operation, it should be short- 
 ened a little, and the filling in the tooth not left high enough 
 to touch the antagonizing tooth. If amalgam is employed, it 
 is advisable to place a small particle of wax upon the tin cap, 
 and distribute it over the surface of the tin bv means of the rotat-
 
 526 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 ing burnisher. If this precaution is neglected, the mercury of 
 the amalgam will combine with the tin, and the efficiency of 
 the cap be destroyed. 
 
 The theory entertained by Herbst in regard to this treatment 
 of pulps is that by burnishing tin or gold into the pulp-cavity, 
 he creates an absolutely air-tight covering to the root-canal, 
 which is not obtainable with other materials. Herbst claims 
 that good results cannot be expected by the use of amalgam, 
 cement, or gutta-percha, and even tin and gold foils introduced 
 into the pulp-chamber by the mallet system have proved to be 
 failures. In cases of front teeth, he employs gold foil instead 
 of tin, — as he claims, with equally good results. 
 
 One of the teeth, an inferior molar, which Dr. Herbst sent to 
 me for examination, was amputated and capped by him in the 
 manner above described about three years ago, and had been 
 in a normal condition until it was extracted. The tooth was 
 removed on account of an overcrowded condition of the dental 
 arch, as well as to obtain a specimen for examination. Imme- 
 diately after extraction it was immersed in dilute alcohol, in 
 which it was sent to this country. Upon its arrival here it was 
 placed in a solution of chromic acid of the strength of one per 
 cent., which solution was renewed every day until the dentine 
 became sufficiently soft to be sliced by the microtome. For 
 staining, an ammoniacal solution of carmin, and for mounting, 
 glycerin, were employed. 
 
 A longitudinal section through the crown and one of the 
 roots of this tooth yielded an image as depicted in Fig. 266. 
 In the pulp-cavity of the crown we see remnants of a narrow 
 zone of previously-inflamed, necrotic tissue. The outermost 
 border of this layer is conspicuous because of the presence of 
 black metallic particles, probably the tin foil in combination 
 with sulphur. At the point of bifurcation the pulp is pre- 
 served, though changed into a fibrous connective tissue by the 
 process of chronic plastic pulpitis. 
 
 In this fibrous pulp we observe small spiculse of bone-tissue. 
 The boundary zone between the pulp and the dentine shows 
 narrow rows of calcified elongated corpuscles, similar to those 
 which we often observe along the border between the cementum 
 and pericementum of the neck and the roots of normal teeth. 
 The border of the pulp, toward the pulp-cavity, which had been 
 filled with tin, is likewise marked by metallic particles, which
 
 EFFECTS OF ARSENIC UPON TOOTH-PULPS. 
 
 527 
 
 proves that the tin actually has been in contact with the pulp- 
 tissue. 
 
 The border of the dentine, both in the crown and the root, 
 
 /'////;///////7/;/ 
 
 Fig. 266. 
 
 S CM 
 
 /, 
 
 im 
 
 lii'.i, 
 
 Mm: 
 
 
 --^^^■^J^ 
 
 s?.-^ 
 
 (I (/ 
 
 Wwmm 
 
 Section of Lower Molar Border of Pulp-Chamber, xear Bifurcation of Roots. 
 
 D, dentine, canaliculi cut obliquely ; S. secondary changes of dentine; C, colonies of uiicro- 
 cocci in dead pulp ; M, black particles of metal ; P, fibrous pulp, the result of chronic plastic 
 pulpitis; 0. osteoid layer of pulp at the border of dentine ; B, spiculee of newly-formed bone. 
 Magnified 100 diameters. 
 
 is of considerable interest. In the crown the dentine toward 
 the necrotic pulp is thoroughly calcified, without a pronounced 
 structure, evidently in the condition of consolidation and aug-
 
 528 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 mented deposition of lime-salts, such as we often observe in 
 dentine bordering metallic fillings. All along the pulp-canal 
 the dentine is broken up into small globular and oblong cor- 
 puscles, obviously the result of a previous acute eburnitis, with 
 subsequent deposition of lime-salts. This peculiarly altered 
 zone of dentine is broadest along the pulp-chamber of the 
 crown, and gradually tapers along the pulp-canal of the root, 
 while toward the apex it altogether disappears. 
 
 A portion of this wall of the pulp-chamber of the crown is 
 
 Fig. 267. 
 
 
 
 WmrmmMm 
 
 Border of Pulp-Chambek of th« Crown. 
 
 M, black particles of metal at the surface ; N, necrotic vestiges of non-medullated nerves ; 
 P, necrotic remnants of the pulp; T, thickness of specimen, successive layers of dentine; B, 
 border of dentine, with gaping dentinal canaliculi ; 0, region of obliterated dentinal canali- 
 culi ; C, pointed ends of dentinal canaliculi. Magnified 500 diameters. 
 
 illustrated in Fig. 267. Here we observe a layer of necrotic 
 pulp-tissue, with metallic particles at the outermost periphery. 
 The pulp, before it became necrotic by the action of cobalt, 
 must have been in a condition of intense acute pulpitis, which 
 is proved by the presence of numerous vestiges of inflammatory 
 corpuscles. The necrotic pulp shows even remnants of non- 
 medullated nerve-fibers, likewise in a granular disintegrated 
 condition.
 
 EFFECTS OF ARSENIC UPON TOOTII-PULPS. 
 
 529 
 
 In some of my specimens, in the dead pulp I could trace colo- 
 nies of micrococci, developed during the process of pulpitis, 
 and deprived of life and rendered innocuous by the application 
 of cobalt and contact with the tin. 
 
 In that portion of dentine depicted in Fig. 267 a zone is miss- 
 ing. The dentine l)orders the dead pulp in an abrupt line, con- 
 spicuous by regular, though widened and funnel-shaped, den- 
 tinal canaliculi. It seems probable to me that the widening of 
 
 Fig. 268. 
 
 Itilil it 1* lllliliS4i^«^^^^^^ 
 
 
 
 Border of Pulp-Chamber of the Crown. 
 
 /'.protoplasmic layer of inflamed pulp; C, zone of consolidation of dentine; Z), dentine, 
 with L-analiculi without deposits ; /^ dantine in which the canaliculi are loaded with metallic 
 particles. Magnified 500 diameters. 
 
 the canaliculi is the result of an acute pulpitis, which did not 
 last long enough to induce pronounced changes in the tissue of 
 the dentine. The border zone of the dentine is granular, and 
 followed by a zone of consolidation in which the dentinal can- 
 aliculi have completely disappeared. Possibly the whole bor- 
 der of the dentine toward the necrotic pulp is devitalized down 
 to the region in which dentinal canaliculi and unchanged den- 
 tinal fibers are observed. The pulp of the crown, however, is 
 
 35
 
 530 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 not altogether necrotic; there are portions within the crown 
 still supplied with a narrow layer of living pulp, as shown in 
 Fig. 268. 
 
 These vestiges of the pulp are broken up into protoplasmic 
 bodies, which in part have become the seat of calcareous deposits. 
 The only way to explain this remarkable feature is that a thin 
 film of the inflamed pulp has escaped both the process of cauter- 
 ization with cobalt and destruction by the amputation. The 
 
 Fig. 269. 
 
 Border of Root-Canal. 
 
 P, fibrous pulp, tbe result of chronic plastic pulpitis; C, calcified layer of pulp; B, border of 
 ■dentine; (?, granular layer of dentine ; 0, layer with obliterated dentinal canaliculi. Magni- 
 fied 500 diameters. 
 
 zone of dentine nearest to the pulp is consolidated, as shown by 
 its high refraction under the microscope; but even this con- 
 solidated portion is pierced by unchanged dentinal canaliculi 
 holding normal dentinal fibers. The dentine along the pulp- 
 chamber of the crown in many instances exhibits a peculiar 
 black discoloration, which I have often observed in dentine that 
 has been in contact with an amalgam filling. Strange as it may 
 appear, it is nevertheless a fact that the discoloration does not 
 start from the border of the dentine, but a certain distance
 
 EFFECTS OF ARSENIC UPON TOOTH-PULPS. 
 
 531 
 
 away from it. As shown in Fig. 268, the discoloratioa is caused 
 by the presence of metallic particles, lying as if arranged in rows 
 within the dentinal canaliculi, and by the diliused brown pig- 
 mentation of the basis-substance between the canaliculi. The 
 latter color is most intense in an abrupt line, irregular in itself, 
 toward the pulp-chamber. The peculiar discoloration is explic- 
 able only by admitting a transportation of metallic particles by 
 the dentinal libers, a strong proof of the life of both the dentinal 
 fibers and the basis-substance of the dentine. 
 
 Fig. 270. 
 
 Ossification of Fibrous Pulp. 
 
 F, coarse bundles of fibrous pulp, derived from chronic plastic pulpitis; B, spicula of bone, 
 -with bone-corpuscles ; C, calcification of pulp-tissue preceding ossification ; M, medullary tissue. 
 Magnilied 500 diameters. 
 
 I have stated before that the pulp of the root-canals, begin- 
 ning from the point of bifurcation, is transformed into fibrous 
 connective tissue. The nature of this transformation is rendered 
 clear by higher powers of the microscope. (See Fig. 269.) 
 
 The pulp-tissue is really made up of bundles of fibrous con- 
 nective tissue, almost as broad as those of pericementum, peri- 
 osteum, or the derma of the skin. Between the bundles we 
 notice interstices of varying breadth filled with protoplasm, as
 
 532 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 we always observe iu formations of fibrous connective tissue. 
 The bundles toward the dentine terminate in calcified, elongated 
 clusters, corresponding on an average with the breadth of the 
 bundles themselves. The most striking feature is that the 
 interstices between the calcified lumps and the bundles above 
 these lumps contain fibers similar to dentinal fibers. The 
 border of the dentine toward the fibrous pulp is slightly con- 
 solidated, — ^that is, somewhat richer in lime-salts than the rest of 
 the dentine. This consolidated layer is followed by a granular 
 one, which is scantily provided with lime-salts, containing 
 vestiges of dentinal canaliculi. Next follow^s a layer of dentine 
 in which the dentinal canaliculi are obliterated, which a little 
 farther away appear with pointed ends holding normal fibrillfe. 
 In Fig. 266 is illustrated a small spicula of bone in the pulp- 
 tissue, which is of considerable interest W'hen studied with 
 ■higher powers of the microscope. (See Fig. 270.) 
 
 Here we observe normally developed bone-tissue, but lacking 
 Haversian canals and regular lamellae. We also see the manner 
 in which bone-tissue is developed from the fibrous connective 
 tissue of the pulp. This is accomplished by the intervening 
 formation of a medullary or embryonal tissue (see 31), from 
 which the bone-corpuscles, as well as the basis-substance of the 
 bone-tissue, are forming. The formation of bone is not of uni- 
 form progress all around this si>icula, as we observe a bordering 
 of the bone by a fibrous tissue, in some places unchanged, in 
 others slightly reduced to proto[)lasm. The transformation of 
 the medullary into the bone-tissue is not always an immediate 
 one. In some places w^e notice calcified groups of medullary 
 corpuscles (see C) preceding ossification. Unquestionably the 
 lime-salts of such clusters must be dissolved out again before 
 the final appearance of the bone-tis>ue proper. 
 
 The microscopical analysis of this molar is of considerable 
 biological importance. The dentine was found alive, its fibers 
 unchanged throughout the crown and the roots, except a narrow 
 zone which bordered the portion of necrotic pulp. This result 
 is explicable only by the fact that the pulp of the roots, although 
 changed in structure, is still alive. The proof of this assertion 
 is furnished by examining the specimens with high powers of 
 the microscope, as seen in Fig. 271. 
 
 We observe all the bundles of the fibrous connective tissue 
 traversed by a delicate reticulum, without resorting to any
 
 EFFECTS OF ARSENIC UPON TOOTH-PULPS. 
 
 533 
 
 special staining process. Tijis reticulum of living matter inos- 
 culates with the protoplasm between the bundles, and with the 
 fibers which appear like dentinal fibrill^e in the interstices 
 between the bundles. A similar reticulum is noticeable in the 
 consolidated as well as in the granular layers of the dentine. 
 Obviously, the living pulp of the roots, assisted by the nutri- 
 tion derived from the pericementum, kept the dentine of the 
 whole tooth alive. If the dentinal fibers in the canaliculi were 
 the only living formations of the dentine, nothing but the den- 
 
 FiG. 271. 
 
 Border op Dentine of Root toward the Pulp. 
 
 G, granular layer of dentine; C, thoroughly -calcified layer of dentine; F, fibrous pulp 
 made up of coarse bundles. Magnified 1000 diameters. 
 
 tine of the roots could have remained alive after the destruction 
 of the coronal portion of the pulp in the crown of the tooth. 
 Since, however, the whole of the dentine has remained alive, 
 we have another strong proof of interconnections between the 
 dentinal fibers. These interconnections are established by the 
 delicate reticulum of living matter pervading the basis-substance 
 of the dentine. 
 
 Another lower molar was sent to me bv Dr. Herbst, It had
 
 534 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 remained in the mouth about eighteen months after the pulp 
 had been amputated and capped in the manner before described. 
 The tooth had given no trouble since the operation, and was 
 extracted for the same reason as the one described above. 
 
 This tooth was not decalcified in a solution of chromic acid, 
 but split into several pieces by excising forceps, and ground thin 
 upon a corundum-wheel in the lathe, constantly keeping it 
 under an aqueous solution of table-salt. 
 
 The roots of this tooth contained but a narrow mass of pulp- 
 tissue, crowded with globular deposits of lime-salts, and in the 
 process of formation of secondary dentine. The latter was 
 found developed all along the walls of the root-canals in a 
 heavy mass, interposed between the primary dentine and the 
 remnants of pulp-tissue. It consisted of the most common 
 variety, — viz, wavy and irregular canaliculi, traversing the basis- 
 substance. The production of such secondary dentine from the 
 pulp-tissue of the roots is a strong proof of the life of the pulp, 
 which, having been irritated less than the tooth first described, 
 directly led to the formation of secondary dentine. 
 
 In conclusion, I would advise to remove the pulps from those 
 roots which we know can be prepared easily, and treat them in 
 the manner we have been accustomed to, but amputate and cap 
 the others. 
 
 CHAPTEE XLII. 
 
 NECROSIS OF THE JAW-BONES. 
 
 "Whenever purulent pericementitis sets in, there is danger of 
 the inflammation spreading to the adjacent periosteum and 
 causing necrosis or death of the jaw-bone. In previous years 
 the idea prevailed among pathologists that by the intense 
 inflammatory infiltration of the periosteum the blood-vessels 
 were compressed and rendered unfit for carrying nutrient 
 material to the jaw-bones. To-day we know that the discon- 
 tinuance of blood-supply is not due to a compression of the 
 vessels, but to a breaking up of the walls of the blood-vessels 
 first into inflammatory, afterward into pus-corpuscles. As shown 
 in Chapter XXXIX, the capillaries and veins become obliter-
 
 NECROSIS OF THE JAW-BONES. 535 
 
 ated by a proliferation of their endothelial coat ; the same holds 
 good for small arteries, the endothelia here being involved first, 
 and followed by inflammation of the muscle-coat. As soon as 
 a breaking asunder of the inflammatory into pus-corpuscles 
 takes places, all vestiges of such blood-vessels disappear. 
 
 If, in a certain area, the blood-vessels in the periosteum and 
 in the medulla of the, bone arc destroyed, life of the bone ceases ; 
 or in other words, the bone-tissue corresponding to the extent 
 of the bloodless area becomes necrotic. 
 
 In the mildest cases of purulent periostitis, the wall of the 
 alveolus, or portions thereof, may become necrotic. In severe 
 cases the body of the jaw-bone may die; in the worst instances 
 the purulent periostitis suddenly or gradually attacks the 
 whole jaw-bone, especially the lower one. jS'ot infrequently 
 life is endangered by the spreading of the suppuration from the 
 upper jaw-bones to the base of the skull, with subsequent puru- 
 lent meningitis and encephalitis. From the lower jaw the 
 inflammation may extend into the mediastina, causing abscesses, 
 purulent pleuritis, pericarditis, etc. Another source of fatal 
 termination is the formation of pyseraic abscesses in the lungs, 
 tlie liver, etc. All these terminations were far more common 
 in tissues when asepsis was unknown, and eases are on record 
 in which the extraction of a tooth with an unclean pair of 
 forceps had suiRced to produce. purulent or septic periostitis of 
 the jaw-bone, with subsequent pytemia and the death of the 
 patient in a comparatively short space of time. To-day aseptic 
 precautions being used by all intelligent dentists and surgeons, 
 such accidents have become great rarities. 
 
 Staphylococcus (aureus, albus, and citreus) is known to be the 
 cause of suppuration, if invading an already-inflamed tissue. A 
 rapidly-progres>ing suppuration easily terminates in gangrene 
 of the inflamed periosteum, so-called "• gancfrene foudroyante^^ 
 of the French, which probably is caused by a mixed infection 
 with staphylococcus and streptococcus septicus, of which latter 
 as yet little is known. 
 
 Besides purulent pericementitis, the most common cause of 
 necrosis of the jaw-bones in previous years was the inhalation 
 of the vapors of phosphorus in match-factories. It is an estab- 
 lished fact that only the workers with carious teeth were 
 exposed to purulent periostitis. Since the introduction of ven- 
 tilation and other sanitary measures, and since the care of the
 
 536 THE AXATOMY AND PATHOLOGY OF THE TEETH. 
 
 teeth is stringently carried out in match-factories, the so-called 
 phosphorus-necrosis has become of rare occurrence. Purulent 
 pericementitis is, however, of common occurrence, and in every 
 instance a source of possible purulent periostitis and necrosis 
 of the jaw-bones. 
 
 Diagnosis. — Necrosis manifests itself l)y the sensation of 
 roughness, when a probe or another suitable instrument is 
 brought in contact with the hone. The surface of dead bone 
 always is denuded of periosteum, and consequently appears 
 rough, similar to the surface of a piece of wood sawed across 
 its grain, while normal hone to the touch of an instrument is 
 smooth like velvet. A diagnosis of the extent of the necrosis 
 cannot be established either by the probe or by the naked eye. 
 The gum and the periosteum over necrosed bone always 
 appears inilamed, detached from the bone, and upon pressure 
 pus oozes forth. One of the principal characteristics of the 
 presence of necrotic bone from local origin is that pus forms 
 continually, even though the original source of irritation be 
 removed. In such cases, local treatment is sufficient for a cure. 
 When the necrosis is depending upon constitutional derange- 
 ments, such as syphilis or tuberculosis, etc., it will subside only 
 upon a combined constitutional and local treatment. 
 
 Subjective Phenomena. — In mild cases of local necrosis of the 
 jaw-bones the patient suffers no pain, the only annoyance being 
 the constant flow of pus from the fistulous opening. The teeth 
 which produced the trouble may be still involved in the inflam- 
 matory process, but, although loose, they cause no pain. In 
 extensive cases, how^ever, especially those depending upon 
 syphilis, tuberculosis, or the inlialation of the vapors of phos- 
 phorus, the patient may suft'er pain, if the inflammation involves 
 either the superior or the inferior maxillary branches of the 
 fifth pair of nerves. Besides this, the constant discharge of foetid 
 pus often causes a derangement of the digestive organs, and 
 consequently of the general constitution. The necrotic process, 
 if extensive and acute, invariably is accompanied by intense 
 swelling and pain of the aflected region and by high degrees of 
 fever. In a slowly-progressing purulent periostitis only the 
 swelling and dull pains may be conspicuous, without a pro- 
 nounced febrile derangement. 
 
 Diffa^ential Diagnosis. — There is but one disease with which 
 necrosis of the jaw-bone may be confounded, — viz, chronic alve-
 
 NECROSIS OF THE JAW-BOXES. 537 
 
 olar abscess. In most of the cases of local origin, chronic alve- 
 olar abscess is associated with or followed by the necrotic pro- 
 cess. In the beginning of the necrosis an examination by 
 means of the probe will always clear the diagnosis. 
 
 The prognosis of necrosis of the jaw-bones largely depends 
 upon its extent, its acute or chronic course, and the general 
 constitution of the patient. The dental practitioner, if called 
 upon to treat such a case, is in a great measure responsible for 
 the final favorable or unfavorable termination. The pus pours 
 forth from the sockets around the roots of the teeth, and the 
 latter soon become loose. Some practitioners are in the habit 
 of extracting all such loose teeth, with the view of furnishing 
 free exit to the pus and checking the progress of the disease. 
 This practice is not always advisable, since we know that loose 
 teeth after the removal of the sequestrum (necrotic bone) have 
 become firm again by being implanted in the newly-formed 
 bone-tissue produced by the remnants of periosteum, and serve 
 for mastication again, at least for a number of years. 
 
 I have seen many cases of partial necrosis of the jaw-bones 
 from purulent periostitis induced by a root of a tooth. In one 
 instance, that of a lower molar, the two roots were laid bare 
 by necrosis of a portion of the socket, while the lingual portion 
 of the root remained firm and rendered the tooth serviceable for 
 twelve years, when at last it was destroyed by caries. 
 
 Conservative surgery is decidedly in place in every case of 
 necrosis. No surgeon is able to find out the limits of the 
 disease until nature has circumscribed the process. Chiseling, 
 drilling, nor treatment with aromatic sulphuric acid will ever 
 check the process. After a complete sequestration of the cen- 
 tral necrotic bone, the opening of the newly-formed ossified 
 case is an easy matter, and we know that after so-called necrot- 
 omy of the whole lower jaw-bone a fairly well-formed new 
 jaw-bone may be produced, with most of the teeth preserved. 
 (J. R. Wood.) 
 
 A. Lorinser, of Vienna, about fifty years ago, was the first 
 to accurately describe the necrosis of the jaw-bones from phos- 
 phorus-poisoning. From a large experience in these cases, he 
 strictly urged the so-called conservative plan of treatment. 
 Recently he found support by E. Rose, of Berlin,* for all cases 
 
 * " Das Leben der Zahne ohne Wurzeln." Dcnische Zeitsch. fur Chincrgie^ 
 Bd. XXV, 1887.
 
 538 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 of inj3ammations terminating in necroi-is of the jaw-bones. This 
 author claims that the teeth may be saved even when held in 
 place only by the gums, and are wiggling like the stalks of 
 wheat in the wind, the roots being perfectly bare. He asserts 
 that the life of the teeth may remain preserved through the 
 attached gums. In this he unquestionably is mistaken. The 
 serviceability of the teeth, after their impaction in newly-formed 
 bone, does not depend upon their life, but upon their firmness. 
 The final conclusions of his article are as follows: "In all in- 
 flammations of the lower jaw of a dubious nature, we will 
 hereafter preferably make the incision from below, to save the 
 gums at all events ; chisel all bone-cases of the jaw from the 
 lower surface, and extract the dead jaw, as it were, from the 
 teetii. The wiggling of the teeth never ought to induce us to 
 their hasty extraction. We thus will be rewarded by having 
 all teeth fixed in the newly-formed jaw, useful as ever." 
 
 The histology of necrotic bone I have published many years 
 ago.* As to the microscopical differences between normal and 
 necrotic bone, the successful study of the elements of bone- 
 tissue mucb depends upon the method employed. I have fol- 
 lowed the methods of examination of bone-tissue after decalci- 
 fication in solution of chromic acid. This enabled me, by the 
 use of the razor, to obtain sections fit to be examined by an 
 immersion-lens magnifying 800 to 1000 diameters. I noticed 
 that the canaliculi could be plainly seen in sections, the basis- 
 substance of which had retained a small quantity of lime- 
 salts ; in completely-decalcified specimens they are but faintly 
 discernible. According to my experience, it is better to stain 
 the sections with a solution of chloride of gold of the half of 
 one per cent,, whereby a better view of both protoplasm and 
 basis-substance is obtained. Another good way is to stain the 
 sections with carmin and h^ematoxylin. 
 
 The results of my observations with high magnifying powers 
 are that the bone-tissue presents faint parallel lines, dividing it 
 into the so-called lamellae, within which we find the bone-cor- 
 puscles of varying shapes. As bone-corpuscles are flattened 
 lenticular bodies, we will recognize them in this shape in the 
 front view only. Longitudinal sections through these bodies 
 give a spindle-shaped outline, small when cut near the boun- 
 dary^ broad when cut through the middle line of the lentiL 
 
 *" Necrosis." Denial Cosmos^ 1877.
 
 NECROSIS OF THE JAW-BONES. 539 
 
 A cross-section through a bone-corpuscle shows a somewhat 
 irregular body. A cross-section from the compact bone of a 
 lower jaw presents invariably bone-corpuscles in all three 
 varieties. 
 
 Fig. 272 shows three bone-corpuscles, from the lower jaw 
 of a man about thirty years of age, who died of an aneurism. 
 All three bone-corpuscles are drawn in the front view. 
 
 We see three large spaces, showing a number of ray-shaped 
 offshoots. Besides these coarse oifshoots, innumerable extremely 
 fine light ones are present. The larger as well as the smaller 
 ones interconnect by this delicate net-work throughout the 
 basis-substance. Within the three lacunae are present proto- 
 
 FiG. 272. 
 
 
 
 
 Normal Bone-Tissue of the Lower Javt of a Man aged Thirty Years. CHROiiicr 
 Acid Specimen, Stained with Chlobideop Gold. 
 
 Three bone-corpuscles : F^, with an oblong nucleus ; P"^, with a globular nucleus, both ex- 
 hibiting indistinct nucleoli ; I", with a finajl compact nucleus. Magnified 1000 diameters. 
 
 plasmic bodies. We observe in the center of the protoplasmic 
 bodies P^ and F"^ a shining oblong nucleus in P^, and a round 
 one in P-, in which the nucleoli are not distinctly visible. 
 Around the nuclei we see a narrow seam, traversed by numer- 
 ous fine conical threads. Their bases are directed toward the 
 nucleus, from the periphery of which they arise, while their 
 points are in connection with the nearest granules of the proto- 
 plasm. Within the protoplasmic substance there are liner and 
 coarser granules, all being interconnected byline threads. The 
 seam around the nucleus, as well as the spaces between the 
 meshes of the threads, are observable, being much lighter thfin 
 the latter.
 
 540 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 From the periphery of the protoplasmic body numerous thick 
 otitshoots enter the hirger canaliculi, which sometimes can be 
 followed up until they communicate with the other large neigh- 
 boring canaliculi. Besides these, many delicate offshoots run 
 from the periphery of the protoplasm contained in the larger 
 canaliculi toward the basis-substance. Some of them can be 
 seen to enter the fine canaliculi, but their course cannot be dis- 
 tinctly followed. P^ shows a protoplasmic body without nucleus ; 
 probably this has been cut near to its periphery without touch- 
 ing the nucleus. Though I am not able to demonstrate the 
 presence of living matter in the finest canaliculi, yet, as we find 
 it in all other kinds of connective tissue, I am justified in assum- 
 ing it. In normal bone the lacunae and canaliculi are not 
 entirely filled bv the living protoplasm. At the periphery of 
 each protoplasmic body we see a distinct light seam, traversed 
 by the offshoots, which in a cross-section only show the living 
 part of the protoplasm in the center of the canaliculus, hence 
 leaving sufficient space for the nutrient circulation. 
 
 The minute changes of necrotic bone are highly interesting, 
 but it is impossible to study the dift'erence between it and normal 
 bone in specimens prepared from dry osseous tissue. 
 
 The methods employed were exactly the same as before 
 described from normal bone. The necrotic sequestra, as soon 
 as they had been taken from the mouth, were put into the solu- 
 tion of chromic acid, and cut in due time. Some I stained with 
 chloride of gold, some with hsematoxylin, and some I mounted 
 unstained. 
 
 The results of these examinations were as follows : 
 
 The outer surface of the necrotic bone, which, to the naked 
 eye, looked rough and eaten out, when brought under the micro- 
 scope showed bay-like excavations, known formerly as " How- 
 ship's lacunae," in which there was visible a granular mass 
 mixed with pus-corpuscles. In the middle of the bone I found 
 all the Haversian canals more or less enlarged, some showing the 
 bay-like excavations. The contents of the Haversian canals 
 were everywhere the same, — a conglomerate mass of darkly- 
 shaded granules, which I was unable to stain with carmin ; 
 therefore micro-organisms, such as we see in decomposition of 
 organic matter, — " micrococci." Here and there some medullary 
 corpuscles and multinuclear protoplasmic bodies (myeloplaxes 
 of Robin, giant-cells of Virchow) were recognizable. I did not
 
 NECROSIS OF THE JAAV-BONES. 541 
 
 see blood-vessels in any of the Haversian canals. In the necrotic 
 bone I found the traces of former osteitis. The enlargement of 
 the Haversian canals and lacunre is direct proof of this ; the 
 dissolving out of the basis-substance on the periphery ma}-, on 
 the contrary, have been due to chemical changes, produced by 
 infiltrations from the neighboring inflamed tissues. Billroth 
 has shown that if pieces of bone or ivory are driven into living 
 bone, in which they excite inflammation, they will afterward 
 exhibit a pecnliar dissolution of basis-substance analogous to 
 that which we see in the primary stage of inflammation. The 
 Haversian systems and concentric lamellae were unchanged. 
 The lacunae and canaliculi were yet preserved. In preparations 
 
 Xecrotic Boxe-Tissce of the Lower Jaw op a Womax aged Thirty-eight 
 Years. Chromic-Acid Specimen, Stained- with Chloride op Gold. 
 
 Three lacunae: V-, with two clusters of a granular mass; X-, with scanty granules ; X^, with 
 a nearly homogeneous mass. Magnified 1000 diameters. 
 
 from the necrotic lower jaw I observed many lacunae, in which 
 the protoplasmic body, with its living net-work, was yet distin- 
 guishable, especially where the sequestrum had been attached to 
 the periosteum. I found also, in specimens from the necrotic 
 upper jaw, some comparatively unchanged bone-corpuscles. 
 But the majority of the bone-corpuscles, and especially in the 
 neighborhood of the Haversian canals, were either empty, or 
 their protoplasmic bodies were shriveled up (probably the 
 remains of the living matter), only showing a few coarse 
 granules, illustrated in Fig, 273; but no signs of fatty degen- 
 eration could be seen, for the granules were stained violet by 
 chloride of gold. Many lacunae showed no structure at all, the
 
 542 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 contents looking rather like a mass of coagulated albumin. In 
 none of tliese lacunae was the characteristic structure of proto- 
 plasm recognizable. 
 
 To sum up mj observations, I found, — 
 
 First. The lacunar of normal bone contain a protoplasmic 
 body, with a net-like arrangement, to be regarded as the living 
 matter of the protoplasm. 
 
 Second. The basis-substance is pierced by numerous coarse 
 and line canaliculi, communicating with one another, as well as 
 with the lacunae. 
 
 Third. The protoplasmic bodies, which do not quite fill the 
 lacunae, send ofi'shoots of the living substance into the canali- 
 culi, but can only be seen in the coarser ones. 
 
 Fourth. In necrotic bone, traces of former osteitis are visible, 
 but no blood-vessels in the Haversian canals, which are filled 
 with micrococci. 
 
 Fifth. In necrotic bone, most of the lacunae contain no proto- 
 plasm, but either a coarsely-granular or a structureless mass, — 
 remnants of the living matter and coagulated albumin. 
 
 CHAPTER XLIIL 
 
 EMPYEIVTA OP THE ANTRUM. 
 
 This term implies a chronic inflammatory condition of the 
 mucous membrane lining the antrum, and an accumulation of 
 serum and mucus mixed with more or less pus in the cavity. 
 The disease may originate from a catarrhal condition of the 
 lining membrane of the nasal cavities ; chronic alveolar abscess ; 
 chronic hyperplastic difl:use pericementitis; or cystic formations. 
 The teeth most liable to cause empyema antri are the second 
 upper bicuspids and the first molars ; although any tooth of the 
 upper jaw, by protracted purulent inflammation, may induce 
 the disease. While an alveolar abscess or hyperplastic perice- 
 mentitis may be present for a long period without causing 
 empyema of the antrum, sometimes the antrum becomes 
 affected in a comparatively short space of time, due to consti- 
 tutional disturbances, such as scrofula, anaemia, chronic dis-
 
 EMPYEiMA OF THE ANTRUM. 543 
 
 eases of tlie kidneys or the liver, tuberculosis, etc. In many 
 instances, empyema of the antrum has been confounded with 
 ■cystic formations or myxomata, so-called " poh^pi," developed 
 in the antrum, or its immediate vicinity. Sometimes, as Zuck- 
 ■ erkandl mentions, cysts fill the entire cavity of the antrum, 
 and simulate the symptoms of empyema antri. Such cysts have 
 probably been the cause of terming the disease under considera- 
 tion " hydrops antri." The ailment, therefore, can only be 
 called " empyema antri" when the accumulated secretion is 
 derived from the lining membrane. In this condition we find 
 the mucous membrane of the antrum considerably swollen and 
 spongy. The communication between the antrum and the nasal 
 •cavity (" ostium maxillare") in light attacks usually is pre- 
 served, while in severe cases it often is found to be temporarily 
 closed. In quite chronic cases, however, the ostium maxillare 
 may be found completely obliterated ; although this may also 
 occur in consequence of the formation of polypi in the hiatus 
 semilunaris (Zuekerkandl). When the ostium maxillare is 
 closed, the facial plate of the antrum becomes more or less ex- 
 tended, often causing considerable disfigurement of the patient's 
 fdce. 
 
 Diagnosis. — The principal characteristic of empyema antri is a 
 <3atarrh of the mucous membrane of the affected side of the nose, 
 accompanied by a peculiar disagreeable odor. The nasal 
 catarrh is quite pronounced if the ostium maxillare is open, 
 and in these instances the accumulated secretions of the antrum 
 flow out freely when the patient occupies the recumbent posi- 
 tion resting upon the unafi'ected side of the face. When the 
 ostium maxillare is closed the face shows more or less swellino-, 
 and the facial plate of the afiected antrum easily gives way upon 
 pressure, producing the peculiar crepitation similar to that of 
 parchment. In severe cases the eye protrudes from its socket, 
 and the nasal cavity becomes obstructed in consequence of the 
 bulging of the nasal wall of the antrum, A characteristic 
 feature of this swelling is the absence of fluctuation. By plac- 
 ing the index finger of one hand on the palatine surface under 
 the antrum, and the index finger of tlie other hand upon the 
 facial portion over it, by alternating pressure we are sometimes 
 enabled to produce a movement of the contents of the antrum. 
 In these instances the bony palatine wall of the antrum has like- 
 wise been absorbed, and crei»itation upon pressure is present.
 
 544 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 Since the majority of antrum troubles are caused by diseased 
 teeth, the principal attention should be directed to the examina- 
 tion of every tooth in the upper jaw of the affected side. As a 
 rule, the offending tooth is easily detected by its color, as Avell 
 as its sound upon percussion, because such teeth invariably are 
 devitalized. AVhen the ostium maxillare is closed, we some- 
 times notice a slight protrusion of the second bicuspid and first 
 and second molars, usually outward, although the teeth may 
 appear comparatively firm in their sockets. If the offending 
 tooth is situated under the antrum, we are frequently enabled to 
 obtain entrance to the antrum through the pulp-canal by means 
 of a fine long nerve-broach. The result of this procedure is the 
 evacuation of a large quantity of a badly-smelling fluid. The 
 o-ums, thouo;h more or less inflamed, seldom show fistulous 
 openings, unless extensive necrosis be associated ^^dth the dis- 
 ease under consideration. Transillumination by means of a 
 small electric mouth-lamp usually yields the most satisfactory 
 results in the diagnosis of empyema of the antrum. This 
 method enables us to notice the slightest hypertrophic as well as 
 catarrhal condition of the mucous lining of the antrum. 
 
 Subjective Phenomena. — In the incipient stage empyema antri 
 mav present the symptoms of acute purulent diffuse pericemen- 
 titis, and cause considerable pain, swelling of the face, and fever, 
 which, however, seldom lasts longer than from two to three 
 days. This is followed by a period of an uneasy sensation, 
 though the tooth has remained quite sensitive to the touch ; the 
 pain and swelling of the face, as well as the general symptoms 
 of fever, mostly having abated. The patient usually becomes 
 affected with more or less headache and earache, and sometimes 
 with more or less neuralgia of the affected side of the head. 
 By the constant discharge of foetid pus, either through the nasal 
 cavity or directly into the mouth, the patient's general health 
 becomes noticeably affected. Sometimes the mucous membrane 
 of the nose is infected, and ulceration, so-called ozsena, is the 
 result. In one instance the author has observed an extensive 
 eczema of the affected side of the face in consequence of a 
 severe empyema antri. In exceptional cases the patient notices 
 a clicking sound in the affected antrum, upon turning the head 
 from one side to the other. This sound is said to be similar to 
 that produced by a closed bottle half filled with water, when 
 the bottle is suddenly inverted.
 
 EMPYEMA OF THE ANTRUM. 545 
 
 Dif ere iitial Ding liosis. — Empyema of the antrum may easily be 
 confounded with ozsena of the nose, cysts, or polypoid growths. 
 
 Empyema of the antrum is easily differentiated from ozeena; 
 as in the latter disease the catarrh and ulceration are present in 
 both nasal cavities, while in empyema antri the catarrh only 
 involves one side of the nose. Uni- or multilocular cysts, when 
 located in the alveolar process at the base of the antrum, are 
 not easily diagnosed, especially when they are large. A charac- 
 teristic feature, however, of a large cyst developed into the 
 antrum is that the inner (nasal) wall of the antrum seldom 
 bulges into the cavity of the nose, and as long as the cyst is 
 intact no secretion or odor can be noticed in the corresponding 
 nostril. Furthermore, the walls of a cyst of the alveolar pro- 
 cess usually are hard and unyielding, while those of the antrum 
 affected with empyema sometimes are yielding to pressure. 
 
 When a cyst occupies the cavity of the antrum, the ostium 
 maxillare appears closed, unless the wall of the cyst becomes 
 ruptured. The formation of a cyst in the antrum always is 
 slow, extending over a period of many months, and its develop- 
 ment never is accompanied by fever or other systemic derange- 
 ments. 
 
 Myxomatous tumors, so-called l>olypi of the antrum, accord- 
 ing to Zuckerkandl* are found in two forms, — viz, those contain- 
 ing glands, and others without them, corresponding to the irreg- 
 ular distribution of glands in the mucous membrane of the 
 antrum. This author is of opinion that some of the polypi 
 containing glands degenerate into cysts (Cysten-Polyj^en). Such 
 polypi are richly supplied with blood-vessels, and upon the 
 slightest injury by an instrument introduced into the antrum 
 bleed profusely, w^hich fact is characteristic of their presence. 
 
 The protinosis of empyema antri largely depends upon the 
 general constitution of the patient, which when good w411 
 greatly enhance the cure of the disease. Should the trouble be 
 caused by purulent pericementitis, the tooth must be sacrificed 
 at once. In most of these instances, however, there is present, 
 besides the empyema of the antrum, more or less necrosis of the 
 alveolar process or jaw-bones, which must be removed before 
 the mucous membrane of the antrum can be successfully treated. 
 This having been accomplished, the communication between 
 the mouth and the antrum in a healthy person usually obliter- 
 
 * "Die Noniialo and Pathologische Anatomic der Nasenhohle." Wien, 1892. 
 
 36
 
 546 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 ates within one to four weeks, providing that the mucous mem- 
 brane of the antrum has reached a normal condition. Empyema 
 antri in consequence of an infection from the nasal cavities, in 
 most instances abates by the treatment of the nasal cavity, and 
 does not strictly belong to the sphere of dentistry. 
 
 CHAPTER XLIV. 
 
 THE CLINICAL AND ANATOMICAL FEATURES OF TUMORS IN (3ENERAL. 
 
 Definition. — Whenever new" tissue is formed at the surface of 
 the body, in the walls of its cavity, or in internal organs, we 
 designate it as a tumor, provided the augmented bulk of tissue 
 is not caused by inflammation. The best detinition of a tumor 
 ever made is that of A. Liicke,* who claims that an inflam- 
 matory new formation is of a limited course, and even suppura- 
 tion terminates with cicatrization ; whereas the augmentation 
 of a tissue caused by a tumor has no physiological termination, 
 therefore grows indefinitely. 
 
 Mtiology. — The cause of the growth of a tumor, as a rule, is a 
 local slight irritation, often repeated or continuous. In previous 
 years the term " disposition" was resorted to, to explain the 
 appearance of tumors. Obviously, this term did not explain 
 anything. J. Cohnheimf established the theory that malignant 
 tumors ahvays originate from germs misplaced at the earliest 
 period of development, which theory has proven fallacious. 
 The celebrated surgeon Langenbeck,;}; of Berlin, has demon- 
 strated that so-called gummy tumors of the tongue often become 
 cancerous, Tliis observation alone is suflicient to overthrow 
 Oohnheim's theory. In many instances w^e are at a loss to 
 explain the origin of tumors. It is always the safest way 1o 
 confess ignorance instead of promulgating wrong theories. 
 
 Growth, Benif/nit)/, cmd Maligmty. — Although the properties of 
 the tumors concerning their innocuity or malignity are strictly 
 of a clinical value, they are of the utmost importance to the 
 oral surgeon, in order to advise his patient whether a tumor is 
 
 * Chirurgie von Pitha und Billroth. Art. Geschwiilst. 
 
 t Allg. Pathologie. 
 
 X Archil-, f. Klin. Chirurfiie. 1875.
 
 CLINICAL AND ANATOMICAL FEATURES OF TUMORS. 547 
 
 harmless, not endangering life, or whether the removal of the 
 tumor is an absolute necessity to preserve life. The points of 
 diiferentiation are as follows : 
 
 Pain. — Benign tumors, as a rule, are not painful, unless ex- 
 posed to mechanical injuries. Cavernous angioma and neuroma 
 are an exception to this rule, since, although of a benign type, 
 they are painful often in a high degree. 
 
 Deiiiarkatlon. — Benign tumors appear, in the majority of cases, 
 sharply circumscribed to the eye, as well as to the touch with 
 the point of a linger. Their borders are easily defined, the 
 tumors often being inclosed in a capsule, which renders them 
 movable. Malignant tumors, on the contrary, are always infil- 
 trated, designating that they lack a distinct border, but diftusely 
 blend with the adjacent tissues. It is exceptional that a malig- 
 nant tumor is ensheathed by a capsule and circumscribed to the 
 touch. 
 
 The growth is not always decisive. Some benign tumors, 
 especially if inflamed, may grow rapidly; whereas malignant 
 tumors may exceptionally make slow progress. On an average, 
 however, it is true that benign tumors grow slowly ; the malig- 
 nant ones, on the contrary, rapidly. A benign fibroma requires 
 years before it attains a conspicuous size, say that of a hazel- 
 nut; while a sarcomatous or cancerous tumor may reach such a 
 size within one year, eventually within a few months. 
 
 The covering skin or mucosa will remain movable, even pliable, 
 over a benign tumor, unless inflammation should lead to its 
 fi.xation. Malignant tumors almost invariably soon become 
 infiltrated into the tissues of the skin or mucous membrane, 
 which renders them immovable. This symptom may be missing 
 if a heavy aponeurotic layer be interposed between the tumor 
 and the surface. 
 
 Reaction upon. Adjacent Tissues. — Benign tumors, growing 
 slowly, cause no irritation or inflammation of tlie neighboring 
 tissues, especially no increase in the size of the adjacent lymph- 
 ganglia. Malignant tumors always cause irritation in their 
 environments, and especially cancerous tumors will, sooner or 
 later, cause a swelling of the lymph-ganglia in the vicinity, due 
 to an invasion of the lymphatics with cancer-epithelia and a 
 transformation of the lymph- into cancer-tissue. Sarcomatous 
 tumors do not always attack the lymph-ganglia, though they 
 are tumors of a malignant type.
 
 548 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 Ulceration of the Surface. — Benign tumors will ulcerate only 
 if subjected to an improper treatment with caustics. Other- 
 wise it is a rare occurrence for benign tumors to ulcerate in 
 consequence of their weight and pressure exerted upon the 
 covering skin or mucous membrane. Cancerous tumors invari- 
 ably will ulcerate sooner or later, owing to a local sloughing 
 from obliteration of blood-vessels. Such ulcers are crateriform, 
 with sharply-raised borders, of an uneven, as if corroded, base, 
 lacking granulations, and never discharging pus copiously. 
 The dried pus frequently produces a crust over the ulcer. In 
 such cases the practitioner should beware of forcibly removing 
 the crust or pressing hard upon the tumor. A. G. Gerster ha& 
 shown that by such rough treatment cancer elements are driven 
 into the lymphatics, thereby causing a rapid infiltration of the 
 neighboring lymph-ganglia, as well as a rapid spreading of 
 the disease. Sarcomatous tumors likewise may ulcerate on the 
 surface, producing smooth, raw surfaces, discharging but little 
 pus. For sarcoma, however, an ulceration is not the rule, as 
 is the case in cancer. 
 
 Infection of Remote Tissues and Organs. — Benign tumors may 
 be present in large numbers over the surface of the body, or 
 scattered in internal organs. They will never cause an impair- 
 ment of the general constitution, and never be multiplied by 
 being disseminated through the blood or lymph-vessels. Malig- 
 nant tumors will, sooner or later, debilitate the organism and 
 produce secondary tumors of their own kind in internal organs, 
 mainly the lungs, the liver, and the kidneys ; though there is 
 no organ of the body exempt from the appearance of secondary 
 deposits. The name given to such a dissemination of malig- 
 nant tumors (sarcoma and cancer) is "metastasis." To-day we 
 know that it is a carrying away of particles of. the primary 
 tumor to distant organs, especially those provided with a narrow 
 capillary net-work. Here the dragged-otf particles lodge by a 
 process called embolism and thrombosis. Wherever particles 
 of a malignant tumor are wedged into a normal tissue or organ, 
 a new tumor will be produced at the expense of the surround- 
 ing tissue, which is directly transformed into the type of the 
 tissue of the tumor. Sarcomatous tumors are disseminated 
 mainl}^ by the system of blood-vessels ; cancer tumors mainly 
 through the lymphatics. Sometimes the last-named tumors are 
 disseminated through the lymphatics in a retrograde manner, —
 
 CLINICAL AND ANATOMICAL FEATURES OF TUMORS. 549 
 
 /,('., opposite to the current of the lymph. The secondary 
 tumors, in the majority of cases, possess the properties of the 
 original one. Exceptions to this rule are cases in which a 
 rapidly-growing cancer causes the appearance of secondary 
 nodules in the lungs, the liver, etc., with all characteristics of 
 sarcoma; lacking, tlierefore, the epithelial structure of carci- 
 noma altogether. About iifty years ago, R. Virchow* already 
 estahlished the fact that intensely malignant and rapidly-grow- 
 ing cancers change into sarcoma. Later researches have fully 
 corroborated this statement of the great German pathologist. 
 
 Diagnosis. — In many cases of tumors the recognition of their 
 nature is not difficult. In others the clinical features may not 
 be so pronounced as to warrant a diagnosis. In such cases the 
 microscope is called upon to decide dubious questions, provided 
 that the microscopist himself is an experienced and conscientious 
 observer. A wedge-shaped piece, the size of a pea, is cut out 
 of the tumor, the hemorrhage being checked by the liquor 
 eesquichloride of iron. The excised piece is placed into a fifty 
 per cent, alcohol, or, preferably, into a fifth of one per cent, 
 solution of chromic acid. After two days' hardening the tumor 
 is ready for examination with the microscope, first being sliced 
 into thin slabs by means of a razor. 
 
 The main question to be decided by the microscope is. Is the 
 tumor of a benign, suspicious, or malignant type? Again, in 
 the majority of instances, the microscope is able to give a 
 definite answer to the above questions. The features upon 
 which decision is possible are simple enough. The more basis- 
 substance is present between the protoplasmic bodies, the so- 
 called cells, the more certain it is that the tumor is benign. 
 The more crowded, on the contrary, the protoplasmic bodies, 
 the less, therefore, the basis-substance, the more certain it is that 
 we have to deal with a malignant tumor. In the worst types of 
 malignant tumors the basis-substance is completely absent. A 
 mixture of these two features will render the tumor suspicious, 
 necessitating an early extirpation. 
 
 Even a well-versed microscopist may meet, exceptionally, 
 with difficulties in determining the nature of a given tumor. 
 For instance, it is difficult to difterentiate between a subacute 
 inflammatory process of the fibrous connective tissue and a fibro- 
 sarcoma; the latter being usually diffuse, the former scattered 
 
 * Archio.f. Path. Anat., 1843.
 
 550 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 in the shape of inflammatory nests. It is impossible to dif- 
 ferentiate between the tissue of a syphilitic gumma and a highly 
 malignant lympbo-sarcoma, because both are made up of similar 
 elements. jSTeither the clinician nor the microscopist alone 
 should rely with absolute certainty upon their findings. Co- 
 operation of both is, as a rule, necessary to reach a correct final 
 diagnosis. 
 
 Frognosis. — A tumor of the benign type will grow slowly and 
 cause disfigurement of or discomfort to tbe patient, but will not 
 endanger his life, unless vital functions, such as mastication, 
 deglutition, etc., be interfered with. Repeated hemorrhages may 
 considerably debilitate the constitution. The removal of such 
 tumors is left to the judgment of the surgeon. Quite different 
 is it with suspicious or malignant tumors, the removal of which 
 is an urgent necessity on account of tbe dangers involved by a 
 rapid local growth, by ulceration, by repeated hemorrhages, 
 by the infiltration of neighboring lymph-ganglia, and the pro- 
 duction of secondary tumors in distant parts. The sooner such 
 tumors be removed, the better are the chances of a permanent 
 cure. Again, the question, whether or not a tumor is operable, 
 sometimes is left altogether to the judgment of the surgeon. 
 
 Classification. — G. Heitzmann in 1879* issued a system of 
 classification of the tumors, entirely based upon histological 
 principles. This system is simple and comprehensible. Accord- 
 ing to tlie four main varieties of basis-substance of connective 
 tissue, the myxomatous, the fibrous, the cartilaginous or chon- 
 drogenous, and the osseous, he arranges the benign connective- 
 tissue tumors proper as follows : 
 
 1. 31)/xoma or mucoid iimior (so-called polypoid tumors of 
 mucous membranes). 
 
 2. Fibroma or fibroid tumor (hard, painless tumors to be found 
 anywhere in the connective tissue). 
 
 3. Chondroma or eartdaginous tumor (hard, smooth, or lobulated 
 tumors met with in the bony system, the lungs, etc., of rare 
 occurrence). 
 
 4. Osteoma or i)ong tumor (hard, globular, or pointed growths 
 found upon the skeleton ; rare). 
 
 The embryonal or medullary condition of the connective 
 tissue furnishes a malignant type : 
 
 5. Myeloma or sarcoma. The term " sarcoma" j^roposed by Vir- 
 
 * "Microscopical ilorphology." New York, 1883.
 
 CLINICAL AND ANATOxMICAL FEATURES OF TUMORS. 551 
 
 chow is objecti enable, since it im[)]ies a flesliy tumor {<Jo.oy, 
 flesh), whereas iuyeloma means what these tumors in reality 
 are, — i.e., medullary tumors. The main types are : the globo- 
 min'loma (round-celled sarcoma of Virchow), and spindle nv/eloma 
 (spindle-celled sarcoma of Virchow). Such tumors are of a 
 white color, the so-called encephaloid of old authors, or more or 
 less piirmented melnnotir iiiydoiiKi. 
 
 The combination of connective tissue with fat, with a large 
 amount of blood-vessels, with smooth muscles, and with nerves, 
 provides four other benign varieties of tumors : 
 
 6. Lipoma ov faW/ tumor (common in the subcutaneous, rarer 
 in the submucous tissue). 
 
 7. Am/ioma or vascular tumor. 
 
 Such tumors consist either mainly of newly-formed blood- 
 vessels, being common in the mucous membrane of the oral 
 cavity, or of newly-formed lymphatics, rarities in the tissue of 
 the skin. 
 
 8. Mt/oma or muscular tumor (most common in the walls of 
 the uterus, rarer in the skin). 
 
 9. Ncnroina or nerve tumor (rare, exceedingly painful tumors, 
 met with in the skin and the central nervous organs). 
 
 Any one of these eight benign tumors may combine with the 
 type of myeloma furnishing the so-called dubious, or suspicious 
 tumors, which according to the admixture of the varieties of 
 connective tissue are termed myxo-myeloma, fibro-myeloma, 
 chondro-niyeloma, and osteo-myeloma ; according to the amount 
 of fat, blood-vessels, smooth muscles, or nerve-fibers, lipo-mye- 
 loma, angio-myelonia, myo-myeloma, neuro-niyeloma. Such 
 combinations invarial)ly show a tendency toAvard malignancy, 
 and tumors of this type are rather prone to recur after extirpa- 
 tion. 
 
 The combination of connective with epithelial tissue results 
 in the production of two varieties of benign tumors : 
 
 10. Papilloma, or warty tumor, in which the epithelium fur- 
 nishes the outer investment of the tumor (common on the skin, 
 comparatively rare on mucous membrane). 
 
 11. Adenoma, or glandular tumor, in which the epithelia pro- 
 duce regular glandular formations of the acinous or tubular 
 variety, often combined with cysts. 
 
 The great majority of cysts, being lined at the inner surface 
 with epithelia, are secondary formations of adenoma. Glandular
 
 552 THE AXATOMY AND PATHOLOCxY OF THE TEETH. 
 
 tumors may be built up, aside from the epithelial formations, 
 of myxomatous or fibrous connective tissue. If the connective 
 tissue be in an embryonal or medullary condition, we speak of 
 an adeno-mveloma. This combination is rare in comparison with 
 the transformation of adenoma into carcinoma. Cvstic cavities 
 may occur in any of the Ijenign tumors, but not being lined 
 with epithelia, should not be termed cysts proper, but serous 
 accumulations, indicated by the addition of the word hydro; 
 such as hydro-myxoma, hydro-fibroma, etc. (W. Freudenthal.)* 
 
 The combination of connective tissue with epithelium inter- 
 mixed in the shape of solid nests, plexuses, pegs, or imperfect 
 tubular, gland-like formations, establishes the malignant type 
 of— 
 
 12. Carcinoma or cancer. If small groups of epithelia are sur- 
 rounded by, and intersected with, a large amount of dense, 
 fibrous connective tissue, this form is termed "■ sciirhus." If 
 epithelial pegs, holding concentrically arranged nests, in the 
 centers of which we find glossy colloid lumps (so-called " cancer 
 pearls"), penetrate into the connective tissue, we speak of 
 " dermoid cancer' or " epithelioma.^' The presence of tubular 
 glands means the adenomatous preliminary stage of carcinoma, 
 which form is dubbed " adenoid cancer.''' If epithelial nests are 
 abundant, lacking regularity, we have before us the worst type, 
 — i.e., " medullar^/ cancer." The connective tissue around the 
 epithelia often exhibits glossy corpuscles of the size and aspect 
 of lymph-corpuscles. The more numerous such corpuscles the 
 more malignant is the cancer, and the more rapidly it grows. 
 Virchow termed this feature " small cellular infiltration ;" Wal- 
 deyer, " inflammatory infiltration.'" Heitzmann has proven that 
 the corpuscles under consideration present the earliest stage in 
 the development of cancer-epithelia. If, after extirpation of a 
 cancer, the cut surface exhibits such corpuscles, ever so few in 
 number, we can with certainty expect a recurrence of the cancer. 
 
 * "Two Nasal Polvpi." Arr/nns <.f Ophilialm. ami Otology, 1893.
 
 TUMORS OF THE TEKTll. 
 
 553 
 
 CHAPTER XLV. 
 
 TUMORS OF THE TEETH. 
 
 The majority of tumors of the hard tissues of the teeth are 
 congenital. All of them are of a benign type, and either sta- 
 tionary or of an extremely slow growth. The only known 
 tumor of the pulp is malignant myeloma. 
 
 I. Odontoma, Tumor of the Dentine. — Up to Virchow's time 
 every tumor of the teeth was dubbed odontoma. Virchow 
 
 Odontoma ov x Lower Molak. (From Wedl. 
 Fig. 275. 
 
 Odontoma. Section through thk Thorny Portion of Fig.- 274. (From Wedl.) 
 
 a, o, folds of enamel ; b, b, layers of enamel ; c, central space, around which the dentinal 
 •canaliculi. are arranged in a radiating manner. Magnified 10 diameters. 
 
 confined this term to tumors of the dentine only, and we ought 
 to adhere to this nomenclature. Dentine tumors may arise 
 from either the crown or the root in the shape of sessile or 
 pedieulated, smooth or lobate, even thorny outgrowths. (See 
 Fig. 274.) If sprung from the dentine of the crown, they are
 
 554 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 covered, as a rule, with an imperfect enamel, or with vestigeB 
 of formations arising from the root portion; such appear 
 coated with a more or less perfect layer of cement. Their 
 structure is sometimes similar to that of primary, sometimes to 
 that of secondary, dentine, with irregularly-distributed groups 
 of dentinal canaliculi. In rare cases the dentinal canaliculi are 
 arranged radiatingly around spaces carrying blood-vessels, so- 
 called vaso-dentine. (See Fig. 275.) 
 
 Fio. 276. 
 
 Teeth with Amelomata or Enamel-Drops. (From Wedl.) 
 
 ^, ameloma on posterior surface of a left upper molar; JS,a, right upper molar with four 
 roots, holding an ameloma between the internal roots ; C, a left upper molar with four roots, 
 holding an ameloma between the two posterior roots. 
 
 Fig. 277. 
 
 Ameloma or Enamel-Drop. (From Wedl.) 
 
 Z7, stratified enamel, deeply pigmented, especially toward the outer surface ; iV, dentinal 
 cone, with irregularly-distributed dentinal canaliculi and interglobular spaces. Magnified 50 
 diameters. 
 
 II. Ameloma, Tumor of Enamel. — Formations of this descrip- 
 tion are found in rare instances in the shape of white, smooth 
 nodules, either globular or oblong, varying from the size of a
 
 TUMORS OF THE TEETH. 
 
 555 
 
 pin's head to that of a small pea. They are invariably found 
 at the beginning of the bifurcation of the roots near the neck, 
 and are often connected with the enamel of the neck by means 
 of a narrow ridge. (See Fig. 276.) In malformed or dwarfed 
 teeth they are often found in numbers protruding from the 
 ill-developed crowns. Their structure is that of normal enamel. 
 At their base, which, as a i'ule, is broad, is seen a peg of normal 
 dentine penetrating the center of the enamel-drop to a varying 
 distance. (See Fig. 277.) 
 
 Fig. 279. 
 
 Pig. 278. 
 
 Osteoma or Neck and Root 
 OF A Molar. (From Salter.) 
 
 Osteoma of Neck axd Root of a Molar. 
 Vertical Section. ( from Salter.) 
 
 C, layer of cementum ; D, layer of dentine ; B, bone-tissue, 
 the main mass of the tumor; /, islands of dentine. Magnified 
 3 diameters. 
 
 III. Osteoma, Bony Tumor of the Roots. — A tumor arising 
 from the cementum of the roots is termed exostosis if circum- 
 scribed, and hyperostosis if diffuse. Such formations are prob- 
 ably the outcome of a long-continued irritation of the cementum. 
 (See Chapter XXX.) In rare instances tumors of considerable
 
 556 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 size are found upon the roots, composed either of cancellous or 
 compact bone-tissue with islands of dentinal tissue interspersed. 
 For such tumors Salter proposed the rather awkward term 
 " hernia." (See Fig. 278.) Sometimes, instead of regular bone- 
 tissue, we meet with globular masses, the so-called osteoid tis- 
 sue. Cancellous bone is traversed by numerous blood-vessels; 
 compact or osteoid tissue is scantily supplied with them. In 
 Salter's case small islands of dentine were found in the middle 
 of the newly-formed bone-tissue. (See Fig. 279.) 
 
 IV. Gigantic Growth, or Teratoma of Teeth. — This term 
 may be applied to extremely rare specimens of an enormous 
 
 Fio. -^80. 
 
 B. 
 
 Gigantic Growth of a Right Upper 
 Molar. Natural Sizk. (From Wedl.) 
 
 Gigantic Growth op a Right Upper 
 Molar. Section through the Inner 
 and between the two outer roots. 
 Natural Size. (From Wedl-) 
 
 outgrowth of the teeth, especially of their crowns, in wdiich all 
 three hard tissues of the tooth are involved. They may also be 
 termed " teratoid," on account of their complicated structure. 
 The best- studied example of such an enormous growth is 
 that of C. Wedl, of the illustrations of which a copy is herewith 
 shown. (See Fig. 280, A and B.) 
 
 V. Myeloma of the Pulp. — This form of malignant tumor 
 was first described by C. Wedl. Another example is included 
 in my own collection. Unfortunately, in neither of these 
 instances is anything known concerning the history of the pulps 
 affected.
 
 TUMORS OF THE TEETH. 
 
 557 
 
 In both cases the tumor proved under the microscope to be a 
 so-called " round-celled sarcoma," or as I would prefer to term 
 them, "lympho-myeloma." In both instances the tumors had 
 grown in largely-decayed cavities of molars, much resembling 
 the appearance of a granuloma or proud flesh of the pulp. 
 
 Fig. 281. 
 
 .S', surface made up of I)lunt papillary elevations, covered with a single laj'er of epithelia ; L, 
 tissue of lympho-myeloma ; il/, multinuclear protoplasmic body; (,', capillary ; T, vein. Mag- 
 nified 50 diameters. 
 
 With low powers of the microscope the surface appears slightly 
 lobated, in contradistinction to granuloma, which is distinctly 
 papillary at its surface. (See Fig. 281.) In granuloma the 
 blood-vessels are abundant; in myeloma scanty. The surface
 
 658 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 in the case examined was found to be covered with partly 
 stratified epithelium, the same as in the case of granuloma 
 described in the chapter on " Morbid Anatomy of Pulpitis," 
 page 403. 
 
 Fig. 282. 
 
 Lympho-Mteloma of Pulp. 
 
 E, columnar epithelia at the surface ; M, M, tissue of lympho-myeloma, with scanty spindles ; 
 C, C, capillary blood-vessels. Magnified 500 diameters. 
 
 With higher powers of the microscope there is a pronounced 
 difference between granuloma and myeloma. (See Fig. 282.) 
 In the former we see myxomatous tissue with a distinct quantity 
 of basis-substance, especially in the deeper portions of the
 
 CYSTS IN THE ORAL CAVITY. 559 
 
 growth. In myeloma only vestiges of fibrous connective tissue 
 can be seen, but no myxomatous basis-substance. The proto- 
 plasmic bodies are, in some places, crowded together to such a 
 degree that they flatten one another. The proportion of living 
 matter is much greater in the tissue of myeloma than in that of 
 granuloma. 
 
 As to the origin of the covering epithelia, the chapter above 
 referred to considers the two possibilities at some length. 
 
 CHAPTER XLVI. 
 
 CYSTS IN THE ORAL CAVITY. 
 
 From a histological point of view, only those tumors with 
 liquid or semi-solid contents in which the connective-tissue sac 
 is lined on its inner surfjice by epithelia can properly be called 
 cysts. The best opportunity for studying genuine cysts is 
 afforded by the skin, where the so-called sebaceous " wens" are 
 of frequent occurrence. We know that every one of these cysts 
 has an adenomatous preliminary stage. 
 
 In a certain portion of the acinous sebaceous glands new 
 formations occur, with an augmentation of the epithehal 
 structures, after which the gland becomes dilated, and fills with 
 either a fatty, cream-like sebaceous mass, or a jelly-like liquid 
 resembling honey, or with a serous liquid rich in albumin. 
 The sebaceous mass which primarily filled the cyst becomes 
 transformed by secondary changes into the semi-liquid or liquid 
 material. 
 
 About the jaws we occasionally meet with epithelial growths 
 originating from the remnants of the external epithelium, and 
 the epithelial cord of the former enamel-organ, to which Magitot 
 was the first to draw attention. These remnants consist of flat 
 epithelia, arranged in concentric, onion-like nests, which may 
 give rise to epithelial tumors even after the eruption of the per- 
 manent teeth. Cases have been observed in which such tumors 
 formed on the internal surface of the cheek, of hard consistence, 
 ulcerating on their surface, but entirely painless. Upon removal,
 
 560 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 a number of epithelial pearls were found imbedded in newly- 
 formed connective tissue. (See Fig. 283.) Under the micro- 
 scope these pearls can only be interpreted as remnants of the 
 external epithelium or of the epithelial cord of the enamel- 
 organ, which have been carried away from their original site 
 into the mucous membrane of the cheek. 
 
 Such epithelial formations unquestionably may give rise to 
 cysts, which, obviously, will be lined by epithelia and develop 
 without symptoms of inflammation, though a cyst of this type 
 may become inflamed and may even suppurate. 
 
 Quite difiierent is the source of cystic tumors around the 
 apices of the teeth, which, clinically as well as microscopically, 
 demonstrate their origin from an inflammatory process; prim- 
 arily, an accumulation of pus in a so-called alveolar abscess. 
 The cavity is filled with a serous liquid, occasionally slightly 
 turbid from remnants of pus. From what I have stated, the 
 term cyst is not properly applied to instances where we find no 
 epithelial lining, but we may resort to this term if we call them 
 inflammatory cysts. 
 
 For convenience' sake I will divide the cysts occurring in the 
 oral cavity into two classes, — viz: 
 
 I. Cysts arising from epithelial tissue ; and 
 
 II. Inflammatory cysts. The latter develop from a so-called 
 pyogenic membrane. 
 
 I. Epithelial Cysts. — The tumors of this class embrace all 
 growths which develop either from glands or the remnants of a 
 former enamel-organ, which are enumerated as follows : 
 
 1, Ranula; 2, Mucoid Cysts; 3, Dental or Dentigerous Cysts; 
 and 4, Alveolar Cysts. 
 
 1. Ranula. — This term has been applied to cystic formations 
 occurring in the salivary glands on the floor of the oral cavity. 
 Their size varies considerably; usually it is that of a hazel-nut, 
 but sometimes they attain the bulk of a man's flst. Ranula 
 always grows slowly, and when large it may become an impedi- 
 ment to speech, mastication, and respiration. It is sometimes 
 translucent, in which case it exhibits a thin sac fllled with 
 liquid or semi-liquid contents. In other instances it is opaque 
 and almost solid, which is due to a thick inclosing wall and 
 semi-solid contents, consisting mainly of epidermal scales in 
 fatty degeneration, and cholesterin crystals. The origin of ran- 
 ula is as yet unsettled ; tlie most commonly accepted theory
 
 CYSTS IN THE ORAL CAVITY. 
 
 561 
 
 being that the cyst originates by a dilatation of the salivary 
 gland. This theory, however, will not explain the appearance 
 of ranulse tilled with epidermal scales. The latter variety prob- 
 ably originates from the so-called gill-ducts, which are present 
 in the earliest stages of embryonal life. 
 
 2. iMucoid Cysts. — These tumors are of rare occurrence. They 
 appear at almost any part of the oral mucous membrane where 
 there are mucous glands, but usually on the inner surface of the 
 cheeks and on the gums. They are translucent, bag-like forma- 
 
 FiG. 283. 
 
 Epithelial Globules from Scrapings op the Inner Cyst-Wall op the 
 Right Cheek. 
 
 G, G, globules made -up of concentrically-arranged epithelia; F, shreds of fibrous connective 
 tissue. Magnified 500 diameters. 
 
 tions, never larger than a pea in size, are superficially imbedded 
 in the mucous membrane, and easily movable in all directions. 
 They probably originate from adenomata of the mucous glands 
 of the oral cavity. Their contents are usually of a liquid or a 
 mucoid consistence. 
 
 3. Dental or Dentigeroas Cysts. — According to John Tomes,* 
 the term " dentigerous cyst" is limited to cysts which arise in 
 connection with developing teeth, or teeth which, though their 
 development has been completed, are retained within the sub- 
 
 * "A System of Dental Surgery," 1873. 
 37
 
 562 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 stance of the jaw. In the majority of cases they are connected 
 with permanent teeth, and in some instances with snpernumer- 
 ary teeth. This author describes a remarkable cyst which con- 
 tained twenty-eight supernumerary teeth. The patient stated 
 that on the right side of the upper jaw the cuspid, bicuspids, 
 and first molar had failed to make their appearance. At the 
 age of twelve a hard, painless swelling appeared on that side of 
 the jaw, which subsequently became inflamed and painful ; at the 
 same time pus oozed out in large quantities around the root of 
 a temporary molar which had been retained. The twenty-eight 
 teeth were dwarfed, and of very irregular form, one having no 
 less than nine cusps. (See Fig. 284.) 
 
 Fig. 284. 
 
 -? ^ 
 
 ^ 
 
 t) a M 
 
 Dwarfed and Malformed Teeth out of a Dextigerous Cyst of the Right Side of 
 THE Upper Jaw. (From John and Charles S. Tomes.) 
 
 Another instance of a dentigerous cyst is described b}' John 
 Tomes in a patient aged twenty-iive, who presented with a 
 large tumor in the front of the upper jaw, the surface of which 
 was eroded by ulcers and profusely discharging offensive pus. 
 Fifteen ill-developed, partly hyperplastic, and gigantic teeth 
 were extracted, and probably a few more had been lost in the 
 operation. The teeth absent from the mouth were the central 
 and lateral incisors, the cuspids occupying their usual position. 
 
 J. Tomes states that cysts arising in connection with teeth 
 retained in the jaw do not always contain a number of super- 
 numerary teeth ; often onl}^ a single tooth, commonly belong- 
 ing to- the permanent set, is found, though cases are recorded 
 of cysts arising in connection with temporary teeth. In some 
 cases bony walls develop around the cyst. Tumors of this type
 
 CYSTS IN THE ORAL CAVITY. 
 
 563 
 
 may attain to an enormous size, but they are very rare. Fig. 
 285 represents the bony wall of a dentigerous cyst, from a ease 
 in which Lisfranc had extirpated the affected half of the jaw. 
 
 Fig. 285. 
 
 Dentigerous Cyst involving the Body and the Ramus of the Right Half of the 
 Inferior Maxilla. (From Forget.) 
 
 M, inverted third molar ; /, inferior dental canal ; C, internal wall of the cyst. 
 
 John and Charles S. Tomes remark that, had a correct diagnosis 
 been made, a much milder procedure would have led to a cure. 
 Fig. 286 represents three teeth of the upper jaw found in a 
 cyst by Dr. M. H. Cryer, of Philadelphia, and kindly offered to 
 me for illustration. 
 
 Fig. 286. 
 
 Right Upper Incisors and Cuspid pound in a Cystic Cavity. 
 
 4. Aloeolar Cysts. — In this group I propose to locate all 
 cysts of undoubted epithelial origin, but not depending upon 
 retained teeth. The case of which illustrations are attached 
 was that of a man, about fifty years of age. The cyst, of the size
 
 564 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 of a hazel-nut, was situated at the site of the left lower first 
 molar, which was extracted some fifteen years ago. The wall 
 of the cyst presented the appearance illustrated in Fig. 287. 
 The inner surface was studded with papillse covered by epithe- 
 lia, the whole appearing lobulated. The lobules, two of which 
 are seen in the figure, consist of bundles of fibrous connective 
 tissue, freely supplied with capillary and venous blood-vessels, 
 the connective tissue being, in many places, crowded with in- 
 flammatory corpuscles. 
 
 Fig. 287. 
 
 Papill.\ry Vegetations at the Inner Surface of Cyst-Wall. 
 
 A , B, vegetations crowded with papillae ; E, E, stratified epithelium covering the papillae. 
 Magnified 50 diameters. 
 
 With higher power of the microscope, the epithelium cover- 
 ing the pajnllfe proved to be indistinctly stratified. (See Fig. 288.) 
 
 II. Inflammatory Cysts.— The origin of inflammatory cysts 
 is, in the majority of cases, as follows : 
 
 The pulp of a tooth becomes devitalized, causing an alveolar 
 abscess, whereby a portion of the adjacent cancellous bone- 
 tissue of the socket is destroyed. The pus makes its way to
 
 CYSTS IN THE ORAL CAVITY. 
 
 565 
 
 the surface of the alveohir process, which is covered with rem- 
 nants of the periosteum or only with mucous membrane. The 
 suppuration comes to a standstill, and the abscess is what the 
 surgeons usually call encysted. In turn, the pus-corpuscles 
 
 Fig. 288. 
 
 Papillary Vegetations at the Inner Sureace op Cyst-Wall. 
 
 /', /', papillaB made up of fibrous connective tissue, with numerous capillary blood-vessels ; 
 /, inflammatory infiltration of fibrous connective tissue ; E, E, stratified epithelium covering 
 the papillfc. Magnified 500 diameters. 
 
 either creep back into the lymphatics and are carried away, or 
 they become hydropic and are destroyed. If mucous membrane 
 is the only outer covering of the sac, it usuiilly bulges into the 
 oral cavity in the shape of a tense, elastic tumor, exhibiting
 
 566 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 fluctuation, but lacking symptoms of inflammation. Should 
 the wall of the sac hold remnants of periosteal tissue that have 
 escaped destruction, it will give rise to a new formation of bone, 
 which, in turn, may envelop the sac with an osseous wall. Since 
 such a newly-formed bonj- wall is, as a rule, thin and imperfect, 
 the tumor will remain elastic and compressible. 
 
 A noteworthy fact about these inflammatory cysts is that 
 tliey occur only in persons of a poor constitution, in whom the 
 inflammatory process advances but slowly. The pus in these 
 instances is rather serous, containing but a limited number of 
 pus-corpuscles that are easily liquefled. 
 
 The diagnosis of alveolar cysts is usually not difficult. Such 
 cysts are met with more frequently in the upper than in the 
 lower jaw, and they are mostly situated in the outer wall of the 
 alveolar process. They are fonnd more frequently upon the in- 
 cisors and bicuspids than the molar teeth, and very seldom near 
 the roots of the cuspids. AYhen a cyst develops in the neigh- 
 borhood of the antrum, it may lead to an incorrect diagnosis. 
 In these instances the cyst may bulge into the antrum, pressing 
 its floor upward, thus occupying almost the entire cavity. In 
 such a case the cyst may be mistaken for empyema of the antrum, 
 especially if the offending tooth or root has been removed some 
 time previous. The wall separating the cyst from the antrum 
 is usjially left intact, and the communication between the antrum 
 and the nasal cavity is cut off". Another important fact in the 
 diagnosis of alveolar cysts is the absence of catarrhal inflamma- 
 tion in the nasal passage on the affected side, which, in an empy- 
 emic condition of the antrum, always is or has been present. 
 We also have to take into consideration the size of the cyst. If 
 this be large and occupying almost the whole of the antrum, the 
 wall common to both the antrum and the cyst may become 
 perforated, and a discharge of the contents of the cyst into the 
 nasal cavity be the result. When the outer bony wall of a cyst 
 is thin, the tumor will be compressible, with the sensation of 
 crepitation. The growth of a cyst usually is slow. In the first 
 stages, and so long as no acute inflammation occurs, the patient 
 experiences no pain, nor inconvenience. When, however, the 
 sac begins to assume greater dimensions, the patient may be 
 troubled b}' headaches as well as a disturbance of the eyesight, 
 more Or less "confined to the aftected side. Pressure with the 
 finger produces no pain, unless the tumor has become large and
 
 CYSTS IN THE ORAL CAVITY. 567 
 
 tense. In the advanced stages slight percussion upon the 
 tooth from wliich the cyst originated is painless, and the tooth 
 itself is usually firm in its socket. 
 
 The prognosis of cystic tumors is generally favorahle, except 
 in those rare instances when a perforation of the wall of the 
 antrum has taken place. The complete removal of the sac or a 
 portion of it will usually prevent recurrence. 
 
 When a cvt-t develops around the root of an incisor tooth 
 without the root being absorbed by the inflammatory process, 
 the removal of the tooth is not absolutely necessary. If the 
 root-canal of an otherwise normal tooth with but one root be 
 thoroughly disinfected and filled, it may be left in the mouth 
 without fear of recurrence of the cyst. 
 
 The microscopical study of specimens from the wall of the 
 cyst is of considerable interest, since it offers an opportunity to 
 trace both the destructive and formative actions of the inflam- 
 matory process. 
 
 Transverse sections through the wall of the cyst exhibit the 
 following. (See Fig. 289.) 
 
 The outermost layer is established by the unbroken gum, 
 partly normal and partly changed by chronic ulitis. The papillae 
 in the latter places are irregular in size and shape, the border 
 toward the epithelial covering being rather indistinct. The 
 connective-tissue layer of the gum exhibits dilated blood-ves- 
 sels. ]^ext follows the periosteum of the socket, composed of 
 coarse interlacing bundles of fibrous connective tissue, with 
 numerous inflammatory nests. The most pronounced inflam- 
 matory changes are observed along the border of the cancellous 
 bone-tissue. The bony wall of the alveolus is considerably re- 
 duced in bulk, being pierced by numerous bay-like excavations 
 filled with medullary or myxomatous tissue. Where the outer 
 lamellated layer of the socket is still preserved, the cancellous 
 bone-tissue has been reduced by the inflammatory process to 
 scanty and irregular spicul?e of bone-tissue. These are in con- 
 nection with the outer wall of the socket, or apparently isolated 
 by a newly-formed myxo-fibrous connective tissue Avhich forms 
 the wall of the cyst. This tissue again holds spicula3 of newly- 
 formed bone. The specimens in man}- places are crowded with 
 red blood-corpuscles, so-called ha^morrhagic inforctions, Avhich, 
 judging from the fresh appearance of the red blood-corpuscles, 
 must have been produced by extravasation during the removal
 
 568 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH, 
 
 of the wall of the cjst. The contents of the cyst are made up 
 of coagulated albumin and red blood-corpuscles. No vestige of 
 previous pus-corpuscles can be detected. 
 
 Fig. 289. 
 
 Walt, of an Inflammatory Cy.st ix Transverse Section. 
 
 G, G, stratified epithelium of gum ; jV, partly normal, partly inflamed papilla' of gum ; P, 
 periosteum with inflammatory nests; A. A, wall of alveolus, much reduced by osteitis; W, W, 
 myxo-fibrous tissue-wall of cyst, partly in hoemorrhagic infarctus ; B, newly-formed spicula of 
 bone-tissue ; C, contents of cyst. Magnified 2-5 diameters. 
 
 The layers adjacent to the tissue of the gum are the periosteum 
 and the bone, both considerably altered by the inflammation, 
 as represented in Fig. 290. 
 
 The fibrous tissue of the periosteum holds numerous inflam- 
 matory nests. They consist of granular protoplasmic bodies
 
 CYSTS IN THE ORAL CAVITY. 
 
 •569 
 
 which had not developed into new fibrous connective tissue. 
 At its surface the bone-tissue is marked by numerous excava- 
 tions varying in depth, and tilled with multi unclear protoplasmic 
 
 Fio. 290. 
 
 Periostitis axd Ostkitis. 
 
 //, longitudinal bundles of periosteum; 2", transverse bundles of periosteum ; JV, N, inflam- 
 matory nests ; M, luyxo-fibrous connective tissue ; /', inultinuclear protoplasmic bodies filling 
 the bays of bone-tissue : 0, 0. osteitis, enlarged and confluent bone-corpuscles ; S, S, medullary 
 spaces of inflamed bone-tissue, filled with myxo-fibrous tissue ; (' calcified rim around medul- 
 lary space. Magnified 200 diameters. 
 
 bodies, or myeloplaxes. The bone is honeycombed with 
 medullary spaces that are filled partly with myxo-fibrous tissue, 
 resembling that of the cyst- wall' proper.
 
 570- 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 The changes in the inflamed boue-tissue are still more con- 
 spicuous if examined with higher powers. (See Fig, 291.) 
 
 Here we observe bone-corpuscles of greatly varying sizes. 
 The smallest are scarcely as large as normal ones, so that we 
 
 Fig. 291. 
 
 OstEITIS AND MyXO-FiBROUS TiSSUE OF CyST-WaLL. 
 
 T. 2', trabecula; of bone, much reduced by osteitis ; C^, bone-corpuscles, slightly enlarged ; C*, 
 bone-corpuscles, much enlarged ; C'\ bone-corpufcles, transformed into a medullary space; M, 
 myxo-fjbrous connective tissue ; 2'(right upper), capillary blood-vessel in transverse section; 
 X, capillary blood-vessel in longitudinal section. Magnified 500 diameters. 
 
 may consider them as former offshoots, so-called canaliculi, 
 which have been enlarged by the liquefaction of the decalcified 
 glue-yielding basis-substance. Other bone-corpuscles are not 
 materially altered in size, but dift'erent from normal ones by a
 
 CYSTS IN THE ORAL CAVITY. 571 
 
 coarse granulation of their protoplasm. Many, however, 
 have become augmented in size to such a degree that they have 
 reached the diameter of Haversian canals. All these enlarged 
 bone-corpuscles hold, besides coarse granules, a varying number 
 of homogeneous lumps, some reaching the size of nuclei. By 
 a contiuence of such enlarged bone-corpuscles we observe the 
 origin of medullary spaces in the bone, independent of pre- 
 vious medullary spaces or Haversian canals. 
 
 The cyst-wall proper is altogether made up of a myxomatous 
 and myxo-fil)rous connective tissue, only scantily supplied with 
 capillary blood-vessels. Thirty years ago this tissue was not 
 recognized by R. Virchow, who claimed that the layer bordering 
 upon a pus-cavity was unfinished pus, which he termed "pus 
 crudum." That this view is not correct is proved not only by 
 my specimens, but also by the study of L. Heitzmann on 
 " Abscesses in the Skin" [Arch. f. Dermatol.^ 1892). 
 
 The myxomatous tissue is composed of branching tracts of a 
 delicate fibrous reticulum, at the points of intersection of which 
 we see so-called branching stellate protoplasmic bodies. The 
 fields of basis-substance are likewise of a delicate reticular 
 structure, and contain small homogeneous or coarsely-granular 
 bodies, about the size of lymph-corpuscles. It can scarcely be 
 doubted that this newly-formed tissue, the like of which is never 
 observed in normal bone or periosteum, is the outcome of an 
 inflammatory or medullary tissue, into which both the bone and 
 the periosteum have been transformed by the process of inflam- 
 mation. 
 
 In the myxo-fibrous cyst-wall we frequently meet with depo- 
 sitions of lime-salts, as well as newly-formed spicul?e of bone- 
 tissue. (See Fig. 292.) 
 
 The trabecule of this newly-formed bone in the wall of the 
 cyst are but few and small in size. We notice in their vicinity 
 deposits of lime-salts without any indication of bony new for- 
 mation. The only feature indicative of future bone is the 
 presence of calcified medullary corpuscles, arisen from the 
 myxomatous tissue. The next step toward the formation of bone 
 is the appearance of territories. By the coalescence of a number 
 of territories a spicula of bone-tissue will be formed, which 
 invariably shows at its periphery more or less perfect rows of 
 medullary corpuscles, the so-called " osteoblasts." A second 
 ■characteristic feature of the newly-formed bone-tissue is the
 
 572 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 large size and great irregularity in the shape of the bone-cor- 
 puscles, the offshoots of which are unusually well pronounced. 
 The third feature is the absence of lamellae. Such bony spicule 
 
 Fig. 292. 
 
 Newly-Fohmed SncuLA of Bone-Tissue in Cyst-Wali-. 
 
 B. spicula of bone, traversed by medullary spaces ; 0, row of osteoblasts : T, territory of 
 bone-tissue; M, myxo-fibrous tissue of cyst-wall ; L. capillary blood-vessel in longitudinal 
 section; C capillary blood-vessel in transverse section ; //, hemorrhagic infarctus. Magnified 
 500 diameters. 
 
 are found imbedded in fibrous or myxo-fibrous connective tissue, 
 but never in a purely myxomatous one.
 
 TUMORS OF THE JAWS. 573 
 
 CHAPTER XLYII. 
 
 TUMORS OF THE JAWS.* 
 
 I. Myxoma. — This variety of tumor is not rare on the gums 
 around the teeth. The specimen under observation is the size 
 of a robin's egg, with a nodulated surface, originally of a blood- 
 red color, of rather soft consistence, and grown upon the gum 
 of the lower jaw, left side between the second bicuspid and lirst 
 molar. It had recurred at every pregnancy, this being the third, 
 in the mouth of a lady aged about twenty-six years. Tumors 
 had been removed from the same locality four ditferent times, 
 when the patient was a girl from twelve to fourteen years of age. 
 
 With low powers of the microscope the raspberry or papillary 
 appearance was well marked upon the surface, as represented 
 in Fi«:. 293. The surface is coated with a sins-le row of colum- 
 nar epithelium, without distinct boundary toward the subjacent 
 connective tissue, the lowest portions of columnar epithelia and 
 the bodies wedged in between them blending with the adjacent 
 layers of medullary tissue. The so-called structureless layer 
 can be made out in but few places. The main mass of the 
 growth consists of an extremely delicate net-work of fibrous 
 connective tissue with interspersed nuclei mainly at the points 
 of intersection. The meshes of this net-work contain as a rule 
 only one medullary corpuscle ; but near the surface the cor- 
 puscles are present in large numbers, to such an extent that the 
 reticulum is rendered invisible. The corpuscles are compara- 
 tively small and nearly compact near the periphery, while they 
 are granular and markedly larger in the deeper portions. The 
 outermost portions of the tumor, ow'ing to the abundance of 
 medullary corpuscles, have the character of a myeloma; but 
 the gradual appearance of a myxomatous basis-substance in the 
 deeper portions proves that the tissue is myxomatous, and the 
 clusters of the medullary corpuscles merely signify a rapid 
 growth at the surface. 
 
 A striking feature of this growth is the large number of wide 
 capillary blood-vessels, which run mainly in a vertical direction 
 to the surface, and therefore appear in transverse sections where 
 
 *The greater portion of this chapter has been taken from an article. " Contri- 
 butions to the Knowledge of Tumors of the Juws,'' l>y Carl Ilcitzinann and 
 Frank Abbott. De?ital Cosmoa. 1888.
 
 574 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 Fig. 293. 
 
 Myxoma or Graxuloma of the Gum of the Loweh Jaw. 
 
 L, longitudinal ; T, transverse section of the papilla on the surface ; M. myxomatous tissue ; 
 F, blood-vessels traversing the myxomatous tissue. Magnified 200 diameters.
 
 TUMORS OF THE JAWS. 575 
 
 the papillne are cut transversely. The arrangement of the capil- 
 laries in a tassel-like manner seems to account for the papillary 
 or nodular architecture of the surface. The so-called proud- 
 flesh or granulation-tissue of suppurating wounds has the same 
 structure as the tumor under consideration, and some authors 
 speak of a granuloma corresponding to the structure of a myx- 
 oma, but being a product of an inflammator}'^ process. In the 
 deeper portions of the tumor delicate bundles of fibrous connec- 
 tiA^e tissue are visible, and most of the vessels are accompanied 
 by tracts of such tissue, by which an adventitial coat is produced, 
 even around the capillaries, which is not visible in normal tissue. 
 In the deepest portions the fibrous connective tissue is rather 
 abundant, the medullary corpuscles being at the same time 
 scanty, and the blood-vessels bearing the character of veins, 
 
 II. Myxo-Fibroma. — This variety of benign tumors is likewise 
 known as occurring frequently, taking issue both from the gums 
 and the periosteum. Its consistence is harder than that of a pure 
 myxoma, and softer than that of a pure fibroma. (See Fig. 294.) 
 
 The illustration is taken from the deepest portions of the 
 myxoma above described. It consists of interlacing bundles ot 
 a delicate fibrous connective tissue, exhibiting therefore an in- 
 distinct reticular arrangement. The meshes between the bun- 
 dles are filled with a finely-granular basis-substance, in which 
 medullary corpuscles are stored up in varying numbers. The 
 blood-vessels are comparatively scanty, consisting of capillaries 
 and veins, all of which are surrounded by a distinct layer of 
 fibrous connective tissue. The endothelia of the capillaries are 
 unusually large and bulging toward the channel. In some places 
 the capillary appears to be surrounded by two or more endo- 
 thelial layers, which add considerably to the thickness of the 
 vascular wall. The specimen affords a good opportunity for the 
 study of the manner in which, first, myxomatous arises from 
 medullary, and fibrous from myxomatous tissue, a process which, 
 as is well known, is of frequent occurrence in the history of de- 
 velopment of normal fibrous connective tissue. At first the 
 tissue is apparently nothing but an aggregation of indifterent or 
 medullary corpuscles, the tissue nature of whicii is determined 
 only by the fact that all the corpuscles are united with one an- 
 other by means of delicate threads. The corpuscles themselves 
 are originally small homogeneous lumps, of a high degree of 
 refraction. Soon afterward a number of such indifferent cor-
 
 576 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH, 
 
 puscles assume a granular appearance, and between them an 
 extremely delicate reticulum appears as the first trace of a reticu- 
 lar structure. At this stage of development, which we often see 
 
 Fig. 294. 
 
 Myxo-Fibro.ma of the Gum of the Lower Javt. 
 
 Jkf. myxomatous tissue, composed of delicate fibrous bundles ; M^, the bundles coarser still, 
 exhibiting the reticular arrangement ; M-, the fibrous bundles, broad, inclosing fields of a 
 myxomatous basis-substance ; V, V, large capillary blood-vessels. Magnified 500 jjiameters.
 
 TUMORS OF THE JAWS. 577 
 
 in inflamed tissue, some authors have spoken of an adenoid or 
 lymph-tissue, by which designation is meant the appearance of 
 a dehcate myxomatous reticulum. In the next stage many of 
 the medullary corpuscles are transformed into a mj'xomatous 
 basis-substance, which with lower powers of the microscope 
 looks either homogeneous or finely granular. Fields of such 
 transformed medullary corpuscles have either one or several 
 corpuscles unchanged, and are bordered by a delicate fibrous 
 reticulum at the points of intersection, at which small oblong 
 or globular corpuscles are seen. In this stage of development 
 the tissue is called purely myxomatous. 
 
 If, by a further splitting up of the medullary corpuscles into 
 delicate spindles, the fibrous reticulum is augmented, and the 
 fields of myxomatous basis-substance narrowed, we have a tran- 
 sition from myxoma into myxo-fibroma, and this transition is 
 the more marked the broader the bundles of fibrous connective 
 tissue. All these stages, to be sure, cannot be traced in direct 
 transition from one into another, but we conclude, from observ- 
 ing the successive portions of the same tumor, being medullary 
 at the periphery and fibrous at its base, that the former are the 
 youngest and least developed, and the latter the oldest and 
 most advanced. 
 
 III. Fibroma. — Solid and dense tumors of a very slow growth, 
 starting from the periosteum of the jaw-bones, are of rather 
 frequent occurrence and well known to surgeons. The name 
 given to them was " epulis," which means a tumor growing 
 upon the gum. Obviously this is a misnomer, since we know 
 that tumors of this description take issue as a rule from the 
 periosteum, and invade the gum in a rather secondary way. 
 •One of the striking features of such benign tumors is the pres- 
 ence of protoplasmic masses with a varying number of nuclei, 
 the so-called giant-cells of previous pathologists. They are 
 present in greatly varying numbers, mainly in that portion of 
 the tumor nearest the periosteum, often being arranged in 
 groups, and lacking altogether in the peripheral portions of the 
 growth. (See Fig. 295.) When such liodies are visible they 
 are, as a rule, surrounded by embryonal tissue, and it is easy to 
 observe their origin from a varying numl)er of medullary cor- 
 puscles. The latter coalesce, thereby losing their individual 
 boundary lines, and produce a uniformly granular mass of pro- 
 toplasm, in which we recognize either scattered nuclei or 
 
 38
 
 678 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 coarser granules, so-called nucleoli. Around the corpuscle, 
 which is often of irregular shape, sending offshoots into the 
 neighboring medullary tissue, the adjacent medullary corpus- 
 cles produce a kind of capsule, between which and the multi- 
 
 FiG. 295. 
 
 Base of Fibroma with Multimclear Bodies, so-called Giant-Cells. 
 
 5. spindle-shaped medullary corpuscles ; F. fibrous basis-Fubftance having originated from 
 spindle-shaped medullary corpuscles ; M. multinuclear body retracted from the surrounding 
 medullary tissue ; 3/^, multinudtar b( dy in coi iieciion with large medullary or endothelial 
 elements. Magnified 1200 diameters. 
 
 nuclear bodies a gap is not infrequently seen, — caused, as it 
 were,, by the shrinkage of the "giant-cell."" It is known that 
 bodies of this description are often met with in the normal 
 medullary tissue of forming and growing bone. AVe often find
 
 TUMORS OF THE JAWS. 579 
 
 them in those bay-like excavations that appear in the cementum 
 and dentine of temporary teeth during the process of their 
 absorption. The prevaiUng idea as to their. significance is that 
 they grow by coalescence of leucocytes or medullary corpuscles, 
 from without into the cement or dentinal tissue, liquefying on 
 their way these tissues, and breaking them up. Hence their 
 name, "osteoclasts," or "bone-breakers." 
 
 We must decidedly disagree with such views, since we have 
 seen multinuelear protoplasmic bodies arising from the living 
 matter of cementum and dentine itself, after the dissolution of 
 the lime-salts and the liquefaction of the basis-substance." Fur- 
 thermore, we have often seen such bodies in the medulla, pre- 
 ceding the formation of bone-tissue. Since the territori6s of 
 formed bone-tissue often are transformed into such multinuelear 
 bodies, the idea becomes admissible that they can appear prev- 
 ious to development of the osseous territory; and to this \iew 
 corresponds their presence in the periosteal portion of fibrous 
 tumors. We admit, however, that this view does not account 
 for the presence of so-called giant-cells in every instance, since, 
 as we will show later on, they accompany blood-vessels, and are 
 known to exist in inflammatory products, — for instance, in 
 tubercles. 
 
 The tumor before us appeared on the alveolar process of the 
 upper jaw in the shape of a sessile nodule, the size of half a 
 hickory-nut, in a youth about twenty years of age. (See Fig. 
 296.) "'•■"' 
 
 The surface of the tumor looked comparatively smooth to the 
 naked eye, but microscopical specimens show remnants of the 
 papillse of the gum, rather shallow and blunt, and some distance 
 apart. The outer coiJting is made up of stratified epithelium, 
 whose layers are noticeably diminished, probably owing to the 
 pressure of the growth from within. Tlie first row of columnar 
 epithelia is well marked only in the valleys between the remnants 
 of the papillPB, while on their summits the first row is com- 
 posed of short columnar, or rather cuboidal epithelia. In these 
 places botli the epithelia of the first and the neighboring epi- 
 thelia of the adjacent layers exhibit central vacuoles, or plas- 
 matic spaces, from which the nuclei have dropped out. 
 
 The bundles of the fibrous connective tissue are of consider- 
 able breadth throughout the mass of the tumor, but their 
 breadth increases from the outer to the deeper portion. The
 
 580 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 protoplasmic tracts are well marked between the bundles both 
 in longitudinal and transverse sections. The bundles are freely 
 decussating or interlacing, by which an extremely dense trestle- 
 
 Fig. 296. 
 
 FiiU!O.M.\ oi- THE Alvkulak I'rocks.s of the Upper Ja\\-. 
 
 E stratifiea epithelium of the gum ; P, blunt papilla, of the gum: X, L longitudinal, T 2. 
 
 fnVvc se sections of bundles of fibrous connective tissue ; C, C. capillary blood-vossels. Mag- 
 
 transverse sections 
 nified 500 diameters
 
 TUMORS OF THE JAWS. 
 
 581 
 
 work, similar to that of the derma of the skin, is produced. 
 The vessels are scanty throughout the tissue, consistino; mainly 
 of capillaries. 
 
 At the outer portion of the tumor, between the bundles, 
 small nests of medullary tissue are discernible. The deepest 
 portions, on the contrary, are made up largely of medullary tis- 
 sue, composed of globular and spindle-shaped corpuscles, with 
 a goodly number of interspersed multinuclear bodies. The 
 latter feature docs not mean a transformation from the benign 
 ■fibroma into a malignant myeloma, but the juvenile condition 
 of the connective tissue, and a somewhat accelerated growth 
 from beneath. This is proved from the fact that the tumor did 
 not return after removal. 
 
 IV. Osteoma. — The great majority of bony tumors of the jaws 
 are of the cancellous or spongy variety. Compact or cortical 
 osteoma is a great rarity. The specimen illustrated in Fig. 297 
 
 YiQ. 297. 
 
 Cancellous Osteoma or Hard Palate. 
 
 P, periosteum; 0, thin cortical layer ; T, trabecule of cancellous bone ; J/, medullary space. 
 Magnified 100 diameters. 
 
 was taken from a tumor the size of a small hazel-nut, which 
 grew in the median line of the hard palate near the soft palate. 
 A similar though much smaller tumor had been reniov'd two
 
 582 THE AXATOMY AIsD PATHOLOGY OF THE TEETH. 
 
 years previously from the hard palate of the same patient, a 
 man about forty years of age. The structure is strictly that of 
 epiphyseal bone, composed of osseous trabeculse inclosing medul- 
 lary spaces and surrounded by a thin cortex. ' 
 
 V. Chondroma. — A numl)er of tumors of cartilaginous nature 
 have been ol:)served upon the jaws (Rokitansky, Pitha, Wedl, 
 etc.), all with a hyaline basis-substance in which protoplasmic 
 bodies, so-called cartilage-corpuscles, were imbedded. Ko speci- 
 men of this type of tumor being at our disposal, its illustration 
 is omitted. 
 
 VI. Lipo-Fibroma. — In our collection there is no tumor from 
 the jaws made up of fat to such an extent as to warrant a diag- 
 nosis of lipoma. One specimen, hoAvever, removed from the 
 lower jaw, the size of a cherry, shows a combination of fibrous 
 connective with fat-tissue, and thus gives the variety expressed 
 in the title. The fat-globnles are greatly varying in size, and 
 either arranged in groups or scattered singly in the connective 
 tissue ; arteries are accompanied by rows of such globules. 
 Most of the latter contain vacuoles and peculiar star-shaped 
 formations in their centers, which very probably are not crystals 
 of margaric acid, as some previous observers have believed, but 
 remnants of protoplasm which are known to exist in each fat- 
 globule. (See Fig. 298.) 
 
 The connective tissue is of two kinds, — viz, parth' broad and 
 heavy bundles, and partly narrow spindles, not arranged in 
 distinct bundles. These two varieties are intermixed without 
 any regularity throughout the entire tumor, the latter being 
 especially conspicuous in the neighborhood of the fat-tissue, 
 where it produces a thin layer, carrying blood-vessels between 
 the fat-globules, or surrounds groups of them. The connec- 
 tive tissue contains a number of clusters of medullary cor- 
 puscles, which, if tlattened out and 'rendered polyhedral by 
 mutual pressure, present the aspect of endothelia, and if coal- 
 esced into one mass represent multinuclear bodies or giant- 
 cells. The history of development of fat-tissue demonstrates 
 that each globule of a larger size arises from a number of medul- 
 lary corpuscles, which are transformed chemically into fat, 
 whereas the central portions remain unchanged protoplasm, 
 with branching ott'shoots ; much on the plan of territories with 
 central cartilage or bone-corpuscles. Small fat-globules maybe 
 the products of transformation of single medullary corpuscles,
 
 TUMORS OF THE JAAVS. 
 
 583 
 
 or a limited number thereof. It has long been known that, in 
 animals in which emaciation is induced rapidly by starvation, 
 each fat- globule breaks up into a number of medullary corpus- 
 
 Fi;. 298. 
 
 LiPu-Fiiutu.M.v ()i- LuwEU Jaw. i 
 
 /s/', fat-globules; M. clusters of medullary corpuscles; G, multiimclear body or giant- 
 cell; .4, artery. Magnified 4U0 diameters.
 
 584 THE ANATOMY AND PATHOLOGY OF THE TEETH, 
 
 cles, — viz, into the embryonal material which originally gave 
 rise to the formation of a globule. If we recall the fact that 
 each fat-globule is surrounded by a thin connective-tissue cap- 
 sule, invariably supplied with a nucleus, fat at once appears as 
 a variety of myxomatous tissue, the difference being only a 
 chemical alteration of the protoplasm into carbohydrates or fat, 
 instead of a mucoid basis-substance. 
 
 From this point of view, the clusters of medullary or endo- 
 thelial corpuscles would simply represent a pre-stage of future 
 fat-globules or remnants of previous ones. Since multinuclear 
 bodies or giant-cells are known to result from a coalescence of 
 medullary or endothelial corpuscles, there is good reason to 
 assume that these bodies likewise would represent, eventually, 
 either a previous or a past stage of fat-globules. A fat-globule, 
 according to our view, is a globular territory with a central pro- 
 toplasmic body, growing in exactly the same manner as a terri- 
 tory of myxomatous, cartilaginous, or osseous tissue ; the 
 nucleus always belonging to the capsule around the globule, 
 and not to the globule itself. A territory of any of the tissues 
 named will break up, in the process of physiological or reduc- 
 tion in pathological conditions, into clusters of medullary cor- 
 puscles, or into multinuclear protoplasmic bodies. 
 
 VII. Angioma. — A boy, eleven years of age, presented him- 
 self with a tumor the size of a small hickory-nut on the gum of 
 the lower jaw, occupying the region of the right lateral incisor 
 and cuspid, having its rise in a somewhat narrow pedicle between 
 the teeth. The surface was nearly smooth, slightly lobulated ; 
 its consistence rather soft, and easily compressible; its color 
 dark red. Pressure with the linger rendered the tumor pale, 
 considerably diminishing its bulk at the same time, but as soon 
 as the pressure ceased the previous size and color returned. 
 Three months previously a similar tumor had been removed 
 from the same place, but it almost immediately commenced to 
 grow again with alarming rapidity, causing a slightly uneasy 
 feeling, but no pain. 
 
 Vertical sections through the body of the tumor revealed the 
 fact that its interior was composed mainly of blood-vessels, but 
 that the outer and inner portions differed in structure. The 
 former exhibited the features of a lobular, the latter of a cavern- 
 ous, angioma. 
 
 a. Lobular Anr/ioma. — The surface of the vascular or erectile
 
 TUMORS OF THE JAWS. 
 
 585 
 
 tumor is covered with a stratified epithelium, beiiiii; normal in 
 its breadth at the borders, and much thinned in the middle por- 
 tions of the tumor. In the former places there are visible 
 
 Fig. 299. 
 
 Lor.LLAK ANtnoMA OF TlIK Gu.M OP THE LoWKR JaW. 
 
 EI\ stratified epithelium whose columnar epithelia toward the right side are breaking up 
 into medullary corpuscles; EN, endothelial layer traversed by radiating tracts of a delicate 
 fibrous connective tissue; C, capillary blood-vessels in the endothelial layer; L, L, lobules com- 
 posed mainly of capillary blood-vessels. Magnified 500 diameters.
 
 586 . THE ANATOMY AXD PATHOLOGY OF THE TEETH. 
 
 numerous rather shallow papillae, a certain number of which are 
 united into a group by deep epithelial valleys. In the central 
 portions only a limited number of layers of cuboidal epithelia 
 are discernible, the deepest layer being absent, and replaced by 
 medullary corpuscles to such an extent that no boundary line 
 could be made out between the epithelium and the subjacent 
 connective tissue. (See Fig. 299.) 
 
 The connective-tissue layer beneath the epithelium is made 
 up of nucleated granular corpuscles, closely packed together, — 
 so much so that they flatten each other into broad spindles. 
 Bodies of this description are termed endothelia. A limited 
 number of tumors of this variety have been described since Biz- 
 zozero, of Italy, drew attention to their occurrence, and dubbed 
 them endothelioma. They are found mainly in connection with 
 lipoma and angioma. 
 
 The endothelia appear to be arranged in clusters, between 
 which delicate tracts of a fibrous connective tissue run in a some- 
 what radiating order, which tracts,if viewed with higher powers 
 of the microscope, appear to be made up of narrow, partly- 
 nucleated spindles. The tracts spread toward the periphery in 
 a fan shape, and no clear distinction is possible here between the 
 broad spindles of the endothelia and the narrow spindles of the 
 tracts. 
 
 Some distance below the epithelia, or close beneath them, a 
 large number of capillaries are seen cut in longitudinal, oblique, 
 and transverse sections, which means that these blood-vessels 
 are coiled up into a lobular shape. Between the lobules there 
 are either tracts of endothelia mixed with fibrous connective 
 tissue, or bundles of the latter alone, and these interstitial tracts 
 bear capillaries of their own, independently of those within the 
 lobules. 
 
 The most striking feature in the endothelial layers is the 
 formation of red blood-corpuscles and blood-vessels. At first 
 isolated lumps appear in the endothelia, characterized by a high 
 degree of refraction, and yellow in color. They are smaller 
 than red blood-corpuscles, and are known by the name of 
 '' hsematoblasts," Increasing in size, they assume the appear- 
 ance and structure of red blood-corpuscles. Clusters of 
 hsematoblasts, or fully-formed red blood-corpuscles, are sur- 
 rounded by circular tracts of endothelia which, being hollowed 
 ijut in part, load to the formation of channels alreadv filled with
 
 TUMORS OF THE JAWS. 587 
 
 blood, whereas a number of enclothelia of rather large size fur- 
 nish the walls of the capillaries. Thus the formation of red 
 blood-corpuscles precedes that of blood-vessels, as stated some 
 forty-iive years ago by the late Rokitansky, of Vienna. Thus 
 it also becomes plain that the tissue termed endothelioma is, 
 at least in many instances, a pre-stage of angioma. Obviously 
 the newly-formed blood-vessels, though containing blood-cor- 
 puscles from the very issue, are closed tubes or saccules, which 
 later, through a continued vacuolation of the endothelia, inoscu- 
 late with already-formed blood-vessels ; their tenants, the blood- 
 corpuscles, entering into circulation. 
 
 b. Cavernous Angioma. — The lower portions of the tumor 
 under consideration have a different structure, gradually blend- 
 ing with that of lobular angioma. Here we notice large cavities, 
 at tirst lined by several layers of endothelia, and containing a 
 varying number of red blood-corpuscles, until at last very large 
 spaces make their appearance, filled with red blood-corpuscles; 
 and thus the character of a cavernous angioma is established. 
 (See Fig. 300.) ' 
 
 We observe, at first, tracts of endothelia accompanied by a 
 delicate fibrous connective tissue, with irregular calibers, in 
 which a liquefaction of a certain number has taken place, as 
 indicated b}^ their hydropic condition, to such an extent that 
 only a delicate frame-work of previous endothelia is discernible. 
 A certain number of endothelia have been transformed into red 
 blood-corpuscles; another set furnishes colorless blood-corpuscles, 
 or possibly these arise from the nuclei of previous endothelia. 
 The process is known to histologists by the term of " vacuolation 
 of the endothelia." The calibers at first are very irregular, 
 being bounded by several layers of endothelia, and it sometimes 
 occurs that tolerably well-formed calibers of the same vessel are 
 connected with one another by narrow canals, owing to the 
 presence of little changed endothelia. Blood-corpuscles may be 
 seen in one part of the caliber, and are absent in another, so 
 long as the vessels are not complete. The remaining endothelia 
 are large, and supplied with oblong nuclei of considerable size. 
 
 Fully-formed cavities in connection with the physiological 
 vessels are characterized by smaller endothelia, not surpassing 
 in size those of normal veins. The trabecules inclosing the 
 venous cavities are made up of fibrous connective tissue, carry- 
 ing their own capillary blood-vessels. In many places, how-
 
 588 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 ever, even the trabeculae are made up of endothelia, and it is 
 easy of demonstration that the endothelia are merely the medul- 
 lary or embryonal stage of connective tissue, since we can trace 
 
 Fig. 300. 
 
 Caverxods Angioma from the Base ov a Vascular TusrfjR op thk Gum. 
 
 (', f, cavernous spaces filled with venous blood ; V, F, capillary blood-vessels of the trabeculte 
 bounding the cavities; E, E, endothelia in transition, partly into myxomatous and partly into 
 fibrous connective tissue. MaKnified 500 diameters.
 
 TUMORS OF THE JAWS. 589 
 
 Its transformation both into myxomatous and fibrous connective 
 tissue. This portion of the tumor contains solid masses of a 
 dense fibrous connective tissue, wliich in all probability are 
 not newly formed, but represent residues of the former tissue 
 of the gam or the periosteum. 
 
 VIII. Myeloma. — These tumors are by no means of rare 
 occurrence, as shown by our comparatively small collection, 
 which embraces five specimens of myeloma and its combina- 
 tions out of seventeen representatives of tumors in genend. 
 All these tumors are considered malignant with but one excep- 
 tion, which concerns the variety termed " epulis sarcomatosa," 
 or, as we propose to call it, fibro-myeloma. This variety is 
 well known to surgeons as admitting of a radical cure if thor- 
 oughly extirpated. Multinuclear bodies are of such frequent 
 occurrence that an authority like Virchow speaks of a variety 
 which he calls "giant-cell sarcoma," growing in the majority 
 of cases from the periosteum. We have described, under a 
 previous heading, benign tumors, especially fibroma, contain- 
 ing a varying number of so-called giant-cells in their juvenile 
 portions, where medullary tissue prevails, and we have empha- 
 sized that no stress is to be laid upon the presence of " giant- 
 cells." If the tumor is intermixed with medullary tissue 
 throughout, the diagnosis will be fibro-myeloma, which is still 
 of a low degree of malignity, as shown by clinical experience. 
 "We can state positively that the number of multinuclear bodies 
 is of great value for determining the degree of malignity in any 
 iCiven case. The o-reater their number the surer it is that the 
 tumor is not very malignant, and will not recur if radically 
 removed. On the contrary, the smaller their number the 
 greater is the malignity and the danger of recurrence ; whereas, 
 in the Avorst cases of pure globo- or s})indlo-myeloma, multi- 
 nuclear bodies are lacking altogether. In such cases the danger 
 to the life of the patient is imminent, in spite of all attempts 
 at thorough eradication. 
 
 According to our nomenclature, we will dwell upon combina- 
 tions such as myxOr,fibro-,and osteo-myeloma, and at last consider 
 the two purely malignant forms, — viz, globo- and spindle-mye- 
 loma. Either of these forms may arise primarily from the peri- 
 osteum or medulla of the jaw-bones, or start in the nasal cavity, 
 the antrum of Highmore, or the soft palate, and invade tlic 
 upper jaw in a secondary manner. In several instances of
 
 590 
 
 THE ANATOMY AXD PATHOLOGY OF THE TEETH. 
 
 primary myeloma we found, in the tissue of the tumor, ckisters 
 of pigment indicative of a previous hemorrhage, possibly in 
 connection with a traumatism (blow, kick, fall, etc.), which, as 
 is admitted, often causes — for reasons unknown — the growth of 
 malisnant tumors. 
 
 Myxo-Myei-oma of Upper Jaw filling the Antrum of Highmore. 
 
 F, tract of fibrous connective tissue ; V, capillary blood-vessel ; S, S, nucleated protoplasmic 
 tracts branching and finely interconnecting : B, B, myxomatous basis-substance with a delicate 
 reticulum in connection with the protoplasmic bodies. Magnified 1200 diameters. 
 
 o. Miixo-31i/eloma. — This specimen originally started on the 
 soft pahite of a young lady near twenty years of age, and after 
 extirpation recurred on the base of the upper jaw-bone, invading 
 in turn both the antrum and the nasal cavities. With low powers 
 of the microscope the tumor shows a thin investment of fibrous
 
 TUMORS OF THE JAWS, 591 
 
 connective tissue, libers from which penetrate the morbid growth, 
 scantily supplied with blood-vessels, and producing imperfect 
 septa, by which an indistinct alveolar structure results. The 
 alveoli are filled with protoplasmic bodies, either globular or 
 spindle-shaped, or provided with numerous ofishoots, by means 
 of which a net-like structure is established. (See Fig. 301.) 
 
 Globular corpuscles are arranged in clusters, with a scanty 
 intervening basis-substance. Spindle-shaped corpuscles are 
 arranged in tracts, freely connecting at acute angles, and sepa- 
 rated from one another by a slight amount of a finely-granular 
 basis-substance. This latter form would correspond to that 
 variety of myeloma termed by Virchow " net-celled sarcoma."" 
 The prevailing formation within the alveoli, however, corre- 
 sponds to the illustration, being composed of very large poly- 
 morphous protoplasmic masses, some containing a number of 
 nuclei, and interconnected by comparatively narrow ofishoots 
 in all directions. The basis-substance betw^een these forma- 
 tions is conspicuous, and traversed by an extremely delicate 
 reticulum, which arises from the finest ofishoots in a brush- 
 like manner. This tissue is myxomatous in structure, the pre- 
 dominance of which over the structures before mentioned 
 entitles the tumor to the name of myxo-myeloma. The myxo- 
 matous tissue contains no blood-vessels, which invariably run in 
 tracts of fibrous connective tissue, at rather distant intervals. 
 As the consistence of the tumor was soft, almost jelly-like, the 
 basis-substance must be of the mucoid or myxomatous variety. 
 In cases where the basis-substance is more firm the tumor has 
 been termed chondro-myeloma, or malignant chondroma, 
 although we would consider the latter term as illogical. 
 
 I). Fibro-Miidnma. — Among several tumors of this variety, 
 we have selected the present specimen for description, its clini- 
 cal history being better known. It was located upon the right 
 side of the lower jaw of a man about thirty-five years of age. 
 the size of half a hen's Qgg, occupying the space between the 
 first bicuspid and the ramus; the teeth in this locality having 
 previously been removed. Its consistence was firm, its surface 
 slightly nodular, its color purple, and there were nowliere signs 
 of ulceration. For a while previous to its removal it caused 
 considerable pain of a shooting character. It had grown within 
 about two years. 
 
 Under the microscope the tumor appears to be composed of
 
 592 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 Fig. 302. 
 
 FtBUO-MvBI.OMA WITH MlLTIXrCLKAR BoDIES FROM THE LoWKR J.'IW. 
 
 L, L. loriKitudinal, T. transverse sections of bundles of fibrous connective tissue; M, M, clus- 
 ters of medullary corpuscles ; G, 0, multinuclear bodies or so-called giant-cells, retracted from 
 the adjacent connective tissue ; V, blood-vessel in transverse section surrounded by a cluster of 
 medullary corpuscles. Magnified 1200 diameters.
 
 TUMORS OF THE JAWS. 593 
 
 interlacing tracts of fibrous connective tissue, with interstices 
 filled either with medullary corpuscles or with multinuclear 
 protoplasmic bodies ; the fibrous portion everywhere being in 
 excess over the medullary tissue. (Fig. 302.) The clusters of 
 medullary corpuscles are rather numerous, exhibiting an endo- 
 thelial appearance. In some places blood-vessels are seen to be 
 surrounded with or accompanied by such medullary corpuscles, 
 and in a few places multinuclear bodies are visible in small num- 
 bers, but in a remarkably regular arrangement. The fact that 
 blood-vessels traverse the clusters excludes their being of an epi- 
 thelial nature, and therefore the diagnosis of cancer, which could 
 be made upon a superficial glance at the tumor, is untenable. 
 This tumor we would not consider a very malignant one, and 
 the diagnosis of a fibroma would be admissible if the medullary 
 nests were not so profusely scattered throughout the tissue. 
 
 A far more malignant case of fibro-myeloma is the following: 
 A man about twenty-five years of age showed a hard swelling 
 upon the right upper maxilla, which had developed within three 
 years. The tumor occupied not only the region of the alveolar 
 process, but also the antrum of Highmore. Most of the teeth 
 had become loose and been removed, the two last molars being 
 left, but very loose, and nearly imbedded in the dark-red mass 
 of the tumor. The diagnosis was malignant tumor, either can- 
 cer or myeloma. The entire right maxilla was extirpated, and 
 a portion of the alveolar process with a tooth in it came into 
 our possession. 
 
 At the microscopical examination no trace of a bony struc- 
 ture could be found; the mass of the tumor consisting mainly 
 of clusters of small globular shining corpuscles, between which 
 an indistinct fibrous reticulum was discernible. The clusters 
 were separated from one another by bundles of fibrous connec- 
 tive tissue, greatly varying in amount; the surface of the tumor 
 was bordered by an indistinct capsule of the same tissue, which 
 itself contained smaller clusters of myeloma corpuscles, and 
 showed irregular, blunt elevations belonging to the gum, and 
 covered witli a thin layer of stratified epithelium. 
 
 In the neighborhood of the tooth the pericementum was still 
 recognizable, in the shape of straight bundles of fibrous con- 
 nective tissue, still in connection with the cementum, but 
 crowded with myeloma corpuscles. (See Fig. 303.) 
 
 In this situation it is evident that the tissue of the myeloma 
 
 39
 
 594 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 grew at the expense of the fibrous connective tissue of the peri- 
 cementum. In some places the bundles of the latter tissue are 
 still broad, containing in their middle slit-like groups of medul- 
 
 Fibko-Myeloma ok the Vpper Jaw ikvaping the Pericementum. 
 C cementum ; li, B. bundles of fibrous connective tis.ue : S, S, dusters of myeloma corpuscles 
 between the bundi;s ^ S\ transformation of the bundles into the t.s.ue of myeloma. wUh .cant> 
 traces of the bundles. Magnified 500 diameters.
 
 TUMORS OF THE JAWS. 595 
 
 lary corpuscles. In other places these corpuscles have replaced 
 the bundles to a great extent; in still other places, only scanty 
 and thin bundles are seen traversing the tissue of the myeloma. 
 At the last elements of myeloma occupy large fields, with scanty 
 or no fibrous tissue between them. Obviously the process of 
 transformation is explicable only if we admit that the whole of 
 the fibrous connective tissue, the protoplasmic bodies as well as 
 the basis-substance, is supplied with living matter, from which 
 the new formation of the medullary corpuscles takes its origin. 
 
 If we confine ourselves to the examination of a limited portion 
 of this tumor, no differentiation between myeloma and an acute 
 inflammatory process can be made out, since the medullary cor- 
 puscles constituting myeloma are identical with inflammatory 
 corpuscles about ready to break up into pus. It should also be 
 borne in mind that a rapidly-growing cancer may change its 
 character into that of a myeloma, or fibro-rayeloma, as first 
 stated by Virchow. In specimens of such rapidly-growing 
 tumors we have always to keep a sharp lookout for epithelial 
 nests, the presence of which would be evidence of cancer. 
 Should such nests be absent, we diagnosticate myeloma. We 
 are, however, aware that either of these tumors involves con- 
 siderable danger to the life of the patient. 
 
 c. Osteo-Myeloma. — This tumor was found in the mouth of a 
 lady aged about thirty, in the region of the bicuspids upon the 
 left upper jaw, and had reached the size of half a robin's i^gg 
 in a year and a half, the teeth having previously been removed. 
 The tumor exhibited the structure of a fibro-myeloma, invad- 
 ing mainly the alveolar process, which was reduced to minute 
 remnants of bone scattered throughout the tissue. (See Fig. 
 304.) 
 
 The term osteo-myeloma is confined to growths primarily 
 arising in the medulla of bone, or to growths holding newly- 
 formed bone-tissue. As the tumor in this instance started in 
 the medulla of the alveolar process, and is largely intermixed 
 with fibrous connective tissue, its proper title would be osteo- 
 fibro-myeloma. The remnants of bone-tissue give evidence of 
 its transformation into the mass of the tumor through the inter- 
 vening stage of medullary tissue. In a few places we find near 
 the border of trabecuhe enlarged lacunoe containing several 
 medullary corpuscles, obviously sprung from previous bone- 
 corpuscles, and still surrounded by a calcified basis-substance.
 
 596 
 
 THE A>'ATOMY AND PATHOLOGY OF THE TEETH. 
 
 In other places a number of bone-corpuscles are seen connected 
 by means of broad oiFshoots into chains. In still others, the 
 first step toward the dissolution of the bone-tissue is the appear- 
 
 FiG. 304. 
 
 Osteo-Fibro-Myeloma of thk Alvkolar Process of the Upper Jaw. 
 
 F, F, fibrous connective tissue with numerous clusters of medullary corpuscles; P, P, clusters 
 of pigment-granules ; B, trabeculi« of bone indistinctly lamellated, with normal bone-corpuscles ; 
 H, medullary space with central blood-vessels ; 1>, bay-like excavation of the bone. Magnified 
 500 diameters.
 
 TUMORS OF THE JAWS. 
 
 597 
 
 auce of bay-like excavations corresponding to a previous terri- 
 tory, in which protoplasm makes its appearance ; or the border 
 of the bone is split up into a number of medullary corpuscles, 
 which are not yet entirely freed from basis-substance. All 
 this is strong proof that the bone actively participates in the 
 new formation of the morbid tissue, the same as it participates 
 in the process of inflammation. To say, as some authors do, 
 that the bone is simply eaten up from without by the newly- 
 formed tissue, does not prove much acuteness of observation, 
 since it is by no means difficult to satisfy one's self as to the 
 active proliferation of the bone-corpuscles within the lacunae. 
 It is invariably the medullary corpuscles that lirst appear from 
 bone-tissue, and by subsequent splitting into spindles and rein- 
 filtration with basis-substance give rise to the fibrous portion 
 of the morbid e:rowth. 
 
 Globo-Myeloma up the Pkkiostku.m of the Alveolar Process of the Upper Jaw. 
 
 B, delicate bundles of fibrous connective tissue ; G, globular corpuscles of myeloma in dif- 
 ferent stages of development. Magnified 1200 diameters. 
 
 d. Gloho- Myeloma. — This specimen was obtained from a 
 tumor taken from the mouth of a young lady about twenty 
 years of age. It was located on the right upper jaw, in the 
 region of the bicuspids, and had grown to the size of half an 
 English walnut in about two years. The teeth had previously 
 been removed. It was diffusely infiltrated toward the neigh- 
 boring tissue, and evidently started from the periosteum. (See 
 Fig. 305.)
 
 598 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 The most striking feature was the scarcity of fibrous connec- 
 tive tissue, which in delicate Imndles traverses the growth with- 
 out any reguhirity. The main mass is composed of medullary 
 corpuscles, either globular or polygonal, the latter produced by 
 mutual pressure. Between small groups of such corpuscles 
 extremely delicate septa of fibrous tissue are visible, in which 
 the blood-vessels are located, though present only in small 
 numbers. 
 
 Higher powers reveal two facts, — viz, first, that the corpuscles 
 are interconnected by delicate radiating offshoots, traversing the 
 narrow spaces between them; second, that in a limited field 
 of the tissue all stages of development of myeloma can be made 
 out. 
 
 We see small granules of a high refraction, structureless, not 
 even reaching the size of red blood-corpuscles. We see larger 
 granules and lumps with a varying number of vacuoles in 
 their interior. We furthermore see lumps with large, com- 
 pact nuclei, and at last corpuscles with reticulated nuclei, with 
 granules in their interior, and of the ordinary reticulated struc- 
 ture of protoplasm. Any granule within the protoplasm may 
 grow to the size of a nucleus, or a nucleated corpuscle ; the 
 nuclei themselves are in an active process of division, as shown 
 by numerous dumb-bell forms, and figures of double or treble 
 nuclei within a single corf)UScle. All this is proof of a very 
 rapid multiplication of the corpuscles, causing an extremely 
 rapid growth of the tumor, and indicative of a high degree of 
 malignancy. In accord with the latter features, not a single 
 multinuclear body or "giant-cell'" can be seen, not even where 
 somewhat broader bundles of fibrous tissue, probably belonging 
 to the periosteum, are present. 
 
 e. Spindle- Myeloma. — This tumor, corresponding to what Vir- 
 chow has termed " spindle-celled sarcoma," is represented in our 
 collection by a specimen, the history of which is unknown to us. 
 All we can say is that it had grown in the upper jaw. (See 
 Fig. 306.) 
 
 The tumor is largely composed of spindles, but in some places 
 globular corpuscles are seen, which feature would entitle the 
 tumor to the name of a combined globo- and spindle-myeloma. 
 The tumor has comparatively little of fibrous connective tissue, 
 in which scanty blood-vessels are coursing. The spindles are 
 arranged in interlacing groups, — in almost every field we meet
 
 TUMORS OF THE JAWS. 
 
 599 
 
 with longitudinal and transverse sections of spindles, all of 
 which are interconnected by delicate oiFslioots. The rapid 
 growth of the tumor is indicated mainly by coarsely-granular 
 nuclei, or chains of coarse granules, replacing the nuclei. In 
 some places clusters of red-brown pigment-granules are seen, 
 but in such small numbers that the tumor cannot be properly 
 called pigmented or melanotic myeloma. The pigment appears 
 either in spindle-shaped or irregular clusters, partly within and 
 partly between the spindle-shaped corpuscles. These pigment- 
 clusters are unquestionably the result of a previous hemorrhage, 
 
 Fig. 306. 
 
 « Spindle-Myeloma of Upper Jaw. 
 
 L, L, longitudinal sections of spindles; T, T, transverse sections of spiudles; F, P, clusters 
 of pigment from previous hemorrhage. Magnified 1200 diameters. 
 
 possibly caused by a mechanical injury, giving issue to the mye- 
 lomatous new growth. 
 
 IX. Papilloma or Warty Tumor is rare upon the mucous 
 membrane of the oral cavity. By direct venereal infection 
 the tonsils and the soft palate of women may become covered 
 with so-called venereal warts, which in fact are papillary out- 
 growths of the oral mucosa, sometimes attaining the size of a 
 pea, and being present in large numbers. In men, upon the 
 mucosa covering the hard palate, warty tumors not of venereal 
 origin have been observed, varying from the size of a pin-head
 
 600 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 to that of a split pea. The specimen from which the illustra- 
 tion is taken was of the latter size, and had grown upon the 
 hard palate of a middle-aged married man. (See Fig. 307.) 
 
 Fig. 307. 
 
 UoRXY Papilloma ok Hard Palate of a Man. 
 
 E, epidermal layer; R, rete mueosum ; L, papilla in longitudinal section; 0, papilla in 
 oblique section ; T, papilla in transverse section ; (', fibrous connective tissue. Magnified 50 
 diameters. 
 
 The characteristic feature of such tumors is their warty sur- 
 face, owing to the presence of papillse covered with a heavy 
 layer of stratified epithelia. The papillse are outgrowths of the 
 connective tissue of the mucous membrane, and are often richly 
 supplied with blood-vessels. (See Fig. 308.) 
 
 Tumors of papillary structure are known to be difficult of 
 eradication. Unless thoroughly extirpated they are prone to 
 recur, and repeated attempts at eradication may cause a change 
 of the tumor into a malignant cancer, generally of the type of 
 epithelioma.
 
 TUMORS OF THE JAWS. 
 
 601 
 
 X. Cysto- Adenoma. — Glandular tumors of the jaws, the 
 mucous membrane of which abounds in mucous glands, are 
 nevertheless of rare occurrence. A combination of adenoma 
 with cystig cavities is extremely rare. The case to be consid- 
 ered came under the observation of Dr. Wm. Carr, who kindly 
 
 Fig. 308. 
 
 HoKNY Papilloma of Hakd Palatk. 
 
 T, papilla in transverse section ; bundles of fibrous tissue in longitudinal and tran-sverse sec- 
 tion, with protoplasmic tracts between the bundles : F, capillary blood-vessel ; 6', row of col- 
 umnar opithelia ; it", rete mucosum composed of cuboidal epithelia ; /', horny layer, composed 
 of fiat epithelia. Magnified 500 diameters. 
 
 furnished the details of the history, and supplied me with a 
 freshly-excised piece of the tumor for study. The tumor had 
 begun to grow upon the left side of the lower jaw, behind the 
 second molar, w^hen the patient was seventeen years of age; and
 
 602 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 when he had reached the age of nineteen, it had grown to the 
 size of a goose's egg. It was soft and fluctuating to the touch, 
 and bled profusely upon the slightest mechanical injury. 
 
 The basis of the cyst, from which the specimen was taken, 
 
 Fig. 309. 
 
 Cysto-Adenoma ur Lower Jaw. 
 
 .5', surface toward cystic cavity, with numerous epithelial prolongations; F, myxo-fibrous 
 connective tissue ; N, nodule of myxomatous tissue, freely vascularized ; 6', fibrous connective 
 tissue; /, /, enlarged glandular cavities filled with indifferent elements ; M, myxomatous tissue, 
 sprung from epithelia ; G, unchanged glandular formations. Magnified 50 diameters. 
 
 proved to be made up largely of acinous glands of great irregu- 
 larity, lined partly by cuboidal and partly by short columnar 
 epithelia. (See Fig. 309.) With higher powers of the micro-
 
 TUMORS OF THE JAWS. 
 
 603 
 
 scope a peculiar change of the epithelia became noticeable, 
 much resembling that of the epithelia of the enamel-cord pre- 
 ceding the production of the enamel-organ in the normal 
 development of the teeth. In the tumor a great many epithe- 
 
 FiG. 310. 
 
 Cysto-Adenuma of Luwee Jaw. 
 
 E, row of columnar epithelia lining the gland ; T. top view of columnar epithelia ; M, inodul- 
 lary tissue, sprung from epithelia : S, basement-membrane around the glands ; F, F, fibrous 
 connective tissue between the glands; 6', capillary blood-vessel in transverse section. Magni- 
 fied 500 diameters. 
 
 lia were transformed into solid indifferent or medullary cor- 
 puscles, from which, in turn, myxomatous tissue developed. 
 Close to the lining epithelia we frequently meet with a layer 
 bearing resemblance to the intermediate layer of the enamel-
 
 604 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 organ. By a gradual liquefaction of the myxomatous tissue 
 cystic cavities of varying sizes arise, and, no doubt, the main 
 cystic cavity in this case owed its origin to such a change in 
 the intra-glandular myxomatous tissue. (See Fig. 310.) 
 
 XI. Carcinoma. — This type of tumors is characterized l>y the 
 presence of epithelial nests, scattered without regularity in the 
 connective tissue, which may be either myxomatous or fibrous. 
 Most pathologists claim that cancer may originate only in such 
 tissues as are covered with or contain normal epithelia. The 
 mucosa of both the oral and nasal cavities is the starting-point 
 of cancerous growths, and in the upper jaw there is an additional 
 source in the mucosa of the antrum. Again, the cancer may be 
 primary in the tissue just named, or secondary by invasion from 
 the skin or any glandular formation, — for instance, from the 
 salivary glands. 
 
 There are three varieties of cancer recognized by modern 
 pathologists, — viz, first, scirrhus, with comparatively small nests 
 of epithelia, and a large amount of fibrous connective tissue 
 around the nests; second, epithelioma or dermoid cancer, with 
 concentrically-arranged fllat epithelia filling the nests, and a 
 varying amount of fibrous tissue between them ; and, third, 
 medullary cancer, with small and irregular epithelia in the 
 nests, and a scanty fibrous tissue between them. Of these three 
 varieties our collection has two, — viz, epithelioma and medullary 
 cancer, both having reached the upper jaw from adjacent epithe- 
 lial structures, skin and mucous membrane. 
 
 a. Epithelioma, or Dermoid Cancer. — AVe have two examples 
 of this type of cancer, both from men over forty years of age. 
 In one the tumor arose in the mucosa of the antrum, and in the 
 other in that of the floor of the nasal cavity, both being similar 
 in structure. (See Fig. 311.) 
 
 In viewing a specimen of epithelioma from the mucosa of the 
 antrum, we observe marked dififerences in the structure of the 
 epithelia. jSTear the boundary toward the connective tissue they 
 are smaller and narrower than in the middle portions of the 
 nests. They are often replaced by a row of medullary corpuscles, 
 to such an extent that no sharp boundary line exists between 
 the connective tissue and the epithelial nest. This obviously 
 means a gradual transformation of the medullar}' into epithelial 
 tissue, a process which leads to increase of the bulk of the nests 
 and a decrease of that of the connective tissue. At last, the
 
 TUMORS OF THE JAM'S. 
 
 605 
 
 blood-vessels being finally obliterated, the nests are deprived of 
 nourishing material, and a local necrosis — viz, ulceration — 
 takes place, which is a common feature in all cancers. 
 
 The second prominent feature is an active new formation of 
 
 Fig. 311. 
 
 Epithelioma of the Mdcos.\ op the Antrum. 
 C delicate fibrou3 connective tissue crowded with medullary corpuscles; I .capillary blood- 
 vessel in uJ: connective tissue. E, E, epithelial nests madeup of eonc.ntncal ™n.ed flat 
 epithelia; P, /', cancer-pearls composed of changed epitheha. Magmhod ,00 diameters.
 
 606 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 living matter in the epithelia. This causes the nuclei to become 
 homogeneous; then to assume an hour-glass shape, and lastly a 
 division into several nuclei. Not infrequently we see several 
 nuclei or several medullary corpuscles within a considerably 
 enlarged epithelium. Such formations have been termed 
 " mother-cells" by previous pathologists, whereas to-day we 
 know that they are the outcome of an active endogenous new 
 formation. Around the nucleus often are seen vacuoles, or 
 plasmatic spaces, which evidently contain nourishing liquid, 
 enabling the nucleus to rapidly increase its amount of living 
 matter, with the result of fission and division, with a rapid new 
 formation of epithelia. Except where the nucleus is surrounded 
 by a vacuole, it is in connection with the adjacent protoplasm of 
 the epithelium, by means of delicate conical offshoots. Similar 
 offshoots also traverse the cement-substance between the epithe- 
 lia, thus uniting all into a continuous mass of protoplasm. The 
 central portions of the nests often contain groups of epithelia, 
 which have assumed a high degree of refraction, a yellowish 
 color, and a homogeneous appearance. At first the nuclei re- 
 main, though faintly discernible; but in the more advanced 
 degrees of this metamorphosis even the traces of nuclei are lost, 
 and a certain number of epithelia are transformed into structure- 
 less glistening plugs, representing the well-known cancer-pearls. 
 The nature of this process is not yet known. 
 
 The connective tissue is either of the myxomatous or fibrous 
 variety, never very rich in blood-vessels; mainly capillaries 
 and veins. In many places the connective tissue is crowded 
 with medullary or lymph-corpuscles, between which a delicate 
 reticulum is seen. Some authors claim that this is the result 
 of an inflammatory reaction of the epithelial upon the connec- 
 tive tissue; whereas we claim that it is the medullary condition 
 of the connective tissue from which new epithelia arise. We 
 base our views upon direct observation, since we know that if, 
 after removal of a cancer, lymph-corpuscles be left behind, even 
 though at a great distance from the cancer itself, the disease 
 will invariably recur. This fact urges the necessity for removal 
 of large portions of tissue in the neighborhood of cancer. Mod- 
 ern surgeons, by clinical experience, have reached the same 
 conclusion, which they consider the only safeguard against re- 
 lapses, so very common in this disease. Unfortunately, we are 
 not able to say why the lymph-corpuscles or the medullar_y tissue.
 
 TUMORS OF THE JAWS. 607 
 
 into which the connective tissue is transformed in an almost 
 identical way with inflammatory infiltration, should have such 
 a marked capacity for changing into epithelia; in other words, 
 wherein the contagion of the tissue lies. 
 
 b. Medullary Cancer. — Our specimen is taken from the enor- 
 mously enlarged alveolar process of the upper jaw of a man 
 over sixty years of age. Twelve years pre\dous to his death he 
 was first operated upon for a so-called rodent ulcer, upon the 
 left wing of the nose, which about fifteen years previously had 
 originated from a slight injury, causing a shallow ulcer, which 
 could never be induced to heal. The scooped-out particles of 
 tissue from the first operation were examined under the micro- 
 scope, and showed the structure of a shallow oi* flat epithelioma, 
 which previous authors termed "rodent ulcer." 
 
 Repeated recurrences and operations took place afterward, 
 until the left upper jaw began to swell, the left eye was pushed 
 up and forward, and the teeth became so loose and troublesome 
 that they had to be removed. The swelling of the face proved 
 to be greatly augmented by an apparently long-standing abscess 
 in the antrum, the result of the death of a second molar many 
 years before, the roots of which penetrated its floor. Upon the 
 removal of this tooth a large quantity of foetid pus escaped, and 
 a temporary improvement was the result. Later the swelling 
 invaded the front of the mouth and passed to the right side to 
 such a degree that several operations were required to remove 
 the fungoid, easily-bleeding masses of the alveolar process, 
 gum, and hard palate, which were almost choking the patient. 
 The purpose of these operations was not to remove the cancer, 
 but to prevent death from suifocation or starvation. This 
 tumor is a type of medullary cancer. (See Fig. 312.) 
 
 The specimen exhibited in some places an almost unchanged 
 stratified epithelium covering the papillae of the gum. In other 
 places the papillae were much enlarged and flattened. Still 
 further, the papillae have entirely disappeared and the epithelial 
 layer is considerably thinned, until at last the epithelium has 
 disappeared, and an ulcerating cancer-tissue appeared upon the 
 surface. In those places where the epithelial stratum of the 
 gum appears thinned, the deepest or columnar row of epithelia 
 as well as the lower layers of cuboidal epithelia are absent, and 
 are replaced by a medullary tissue of a myxomatous tharacter, 
 which has incidentally sprung from the previous epithelia.
 
 608 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 We feel the more confident of such change having taken place 
 from the fact that at the border between the epithelial and 
 medullary tissues the epithelial bodies themselves show a 
 marked increase of living matter, and a gradual transforma- 
 tion into medullary corpuscles. 
 
 Fig. 312. 
 
 --^^~^^f2sis 
 
 
 Medullary Cancek of the Left Upper Jaw, invading the Alveolar Process and 
 
 Gum. 
 
 jY, N, nests of irregular polyhedral epithelia; C, C, delicate fibrous connective tissue between 
 the nests ; V, vein. Magnified 1200 diameters. 
 
 Close lieneath the medullary layer nests of epithelia make 
 their appearance, separated from one another by, first, medul- 
 lary, and deeper down by a delicate fil>rous connective tissue, 
 which latter has evidently originated from the former. We
 
 MALFORMATIONS AND MALPOSITIONS OF THE TEETH. 609 
 
 therefore maintain that a medullary tissue which arose from 
 previous normal epithelia may change into tibrous connective 
 tissue, and vice versa, that medullary tissue which arose from 
 connective tissue may eventually be converted into epithelia of 
 cancer. 
 
 The medullary nests are made up of very irregular bodies, 
 which by pressure have assumed a polygonal form. In man}' 
 instances a whole nest or a portion of it is made up of granular 
 protoplasm, with nuclei scattered at regular intervals, without 
 any intervening cement-substance. Where the latter is present 
 in the shape of a narrow ledge, it is invariably pierced by deli- 
 cate offshoots or thorns, interconnecting the single epithelial 
 elements. The changes of the epithelia toward proliferation 
 are much the same as in the epithelioma before described. 
 The connective tissue shows a transformation into lymph-tissue 
 to a great extent. Where it has retained its fibrous character 
 it is scanty, separating the epithelial nests and carrying a large 
 number of protoplasmic bodies. The blood-vessels running 
 therein are scanty, and prevailingly capillaries and veins. The 
 latter often show sinuous contours, and are replete with blood- 
 corpuscles. As stated under the heading of epithelioma, the 
 secret of the o;eneral and local contagiousness of cancer has 
 never been unveiled, but is left for future discovery. 
 
 CHAPTER XLYIIL 
 
 MALFORMATIONS AND MALPOSITIONS OF THE TEETH. 
 
 I. Dwarf Teeth. — In Chapter XVIII, on the development of 
 teeth in embryos affected with rhachitis, dwarf teeth from the 
 lower jaws of a foetus affected with congenital rhachitis are 
 illustrated and described. In rare instances we find the dentures 
 of adults made up of normal teeth with dwarfed third molars 
 in the upper jaw.* 
 
 II. Hyperplasia of Roots. — In Chapter XXX I have copied 
 from" Frank Abbott's paper a number of teeth, the roots of 
 which were affected with hyperostosis of the cementum, caus- 
 ing pronounced malformations. 
 
 * In Chapter XLVI, Fig. 284, dwarfed and malformed teeth are depicted as 
 found in a dentigerous cyst of the upper jaw. 
 
 40
 
 610 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH. 
 
 Fig. 313. 
 
 III. Supernumerary Teeth. — Xot infrequently we see super- 
 numeraiy teeth in temporary dentures, usually behind the upper 
 lateral incisors. Such teeth are smaller than normal ones, and 
 of a more or less conical shape, hence German authors have 
 dubbed them "• peg teeth."' (See Fig. 313.) In rare cases there 
 are present three bicuspids on one side of 
 the upper jaw, and only one on 
 the other side. Two or even 
 three third molars, or wisdom- 
 teeth, may be found on one side 
 of the upper jaw, while the op- 
 posite side has only one. E. 
 Zuckerkandl has seen epithelial 
 germs — i.e., enamel pegs not de- 
 veloped into teeth — behind the 
 
 Fig. 814. 
 
 IV. Lobulation of Crowns. — 
 
 Supernumerary Teeth. 
 
 (From Wedl.) 
 A, superntimerary tooth 
 of the right side of the up- 
 per jaw, between the first third Uiolars. 
 and second bicuspids towai d 
 the palate ; B, supernum- 
 erary tooth of the upper Occasionally the crowns of teeth 
 
 jaw, implanted in the pal- -,..,,. 
 
 ate behind the incisors, are divided luto iinger-like lob- 
 ules. The illustration (Fig. 314) 
 represents a tooth, probably a bicuspid of the lower jaw, with 
 this anomaly. 
 
 V. Devious Course of Roots. — This anomaly is not very rare, 
 and is a great obstacle to the extraction of the tooth. The 
 
 Lobulated 
 
 Crowx, 
 
 probably of 
 
 A Lower 
 
 Bicuspid. 
 
 (From AVedl ) 
 
 Fig, 316. 
 
 Left Upper First Molar (Carious), with 
 Devious Roots. 
 
 Two Lower Molars with Devious Roots. 
 ( From Wedl.) 
 A, lower third molar with fused roots, hooked 
 and thickened by hyperplastic cementum ; B. 
 lower third molar, the anterior root pushed 
 through an opening of the posterior, likewise 
 hooked on. 
 
 deviations are so manifold that a description is scarcely possible. 
 I attach three illustrations, one from a left upper molar of my 
 own collection, and two from Wedl's Atlas. (See Figs. 315 
 and 316.)
 
 MALFORMATIONS AND MALPOSITIONS OF THE TEETH. 611 
 
 Fig. 317. 
 
 Fig. 318. 
 
 VI. Multiplication of Roots.—This anomaly is by no means 
 rare. I liave seen lower lateral incisors with two roots, of which 
 I give an illustration; a lower cuspid with three distinct small 
 
 roots; a first upper 
 bicuspid with three 
 distinctly separated 
 roots ; first lower 
 molar with three pro- 
 nounced roots, two 
 in the mesial and 
 one in the distal por- 
 tion of the crown. 
 Wisdom-teeth with 
 
 Teeth with Double and 
 Multiple Roots. 
 
 Fusion of Two Lower In- 
 cisors. (From Abbott.) 
 A, left lower lateral incisor, 
 
 with double root, symmetrical as many as five roots are not uncommon. 
 
 with the root of the opposite /Qqp Trirr ^17 ^ 
 side: B, molar of the lower V^^^ -"^^i-* ^^'•) 
 
 jaw. with five well-developed VII. FusloH of Orowns of Teeth. — Frank 
 
 roots. (From Wedl.) ., , ,, . ,, -r\ , i ^ -^^^ t 
 
 Abbott, m the Dental Cosmos, 1891, de- 
 scribes two lower incisors fused together at their 
 crowns and necks. (See Fig. 318, «, b.) ^^^- ^^^■ 
 
 VIII. Fusion of Roots is likewise of not in- 
 frequent occurrence, especially in the wisdom- 
 teeth. Fig. 319, taken from "Wedl's Atlas, repre- 
 sents an upper molar with a regularly-developed 
 crown and completely-fused roots. 
 
 IX. Fusion of Two Teeth. — This anomaly is of 
 rare occurrence. Abbott (loc. cit.) illustrates a 
 fusion of the second lower molar with the third 
 molar by hyperplastic cementum. (See Fig. 320, 
 
 a, b.) C. Wedl met with a permanent upper central fused with 
 the lateral incisor, (See Fig. 321.) 
 
 Fig. 320. Fig. 321. 
 
 I 
 
 Upper Molar 
 
 with 
 Fused Roots. 
 (From Wedl.) 
 
 Fusion op Two Molars. 
 (From Abbott.) 
 
 Fusion of Left Per.manext Upper Cf.xtral 
 
 and Lateral Incisor. (From Wedl.) 
 
 A, labial surface, showing faint line of union 
 
 of the two teeth; B, lingual surface, line of 
 
 union marked both on roots and crown.
 
 612 
 
 THE ANATOMY AND PATHOLOGY OF THE TEETH, 
 
 Fig. 322. 
 
 • X. Breach in the Continuity of the Crown. 
 
 {lac. cit.) illustrates this rare occurrence on 
 incisor, which probably 
 finds its explanation in 
 a fracture or breach of 
 the crown, shortly after 
 its formation, while still 
 covered with soft tissue. 
 (See Fig. 322, «, h.) 
 
 XI. Healed Frac- 
 tures of Teeth. — A 
 small number of w^ell- 
 observed instances of healed fractures are re- 
 corded in the literature. I have chosen for 
 illustration the case of H. Hertz.* The tooth, 
 
 — Frank Abbott 
 an upper lateral 
 
 Breach .\t the Neck of In- 
 cisors. (From Abbott.) 
 
 Fig. 323. 
 
 Healed Fracture of 
 Left Upper Lat- 
 eral Incisor. (From 
 H. Hertz.) The 
 
 Tooth a^ewed from 
 Behind and Above. 
 C. crown ; R, root 
 with two exostoses; E, 
 newly-formed enamel- 
 ridge. 
 
 Fig. 324. 
 
 Healed Fracture of the Left Uppei: Lateral Incisor. Transverse Section. 
 
 (From H. Hertz.) 
 jE^. enamel: £'7^, enamel-ridge ; i), broken-off enamel; F, F, vascular canals, around which 
 thedentin;il canaliculi radiate ; P, pulp-chamber ; 7^, root- canal ; C, C, layer of cementum, 
 between which an island of dentine {D, upper) has formed. Magnified 8 diameters. 
 
 * " Ein Fall Geheilter Zahnfractur." Virchow's Archiv, 1867.
 
 MALFORMATIONS AND MALPOSITIONS OF THE TEETH. 
 
 613 
 
 a left upper central, was extracted from a girl eighteen years of 
 age, who about eight years previously had a fall, after which the 
 tooth changed its position and became painful. Microscopical 
 examination revealed the peculiar fact that, in consequence of 
 the injury, — the direction of the fracture being probably the 
 fissure seen in Fig. 324 on the left upper periphery of the crown, 
 — a marked new formation of enamel (-E'i?) took place. A 
 second remarkable feature is the formation of several vascular 
 canals ( V, V) in the dentine, around which the canaliculi take a 
 fan-like course. Inexplicable is the fact that at the apex of the 
 root, between two layers of cementum, a layer of dentine had 
 formed. (See Fig. 324.) 
 
 Fig. 325. 
 
 Right Upper Lateral Incisor ix a Horizontal Position. Natural Size. (From WedL) 
 j4, edge of the tooth protruding on the surface; (?, imperfect lateral temporary incisor; C, 
 empty alveoli. 
 
 XII. Malpositions of the Teeth are quite frequent, and too 
 variable to be enumerated in any particular way. As many 
 excellent works have been written on this subject, I refer those 
 who take special interest in this topic to .the books of John 
 and Charles S. Tomes, Baume, Farrar, Kingsley, and Talbot. 
 
 In rare cases teeth, usually fully developed, are found in the 
 antrum, in the nasal cavities, and under the skin on almost any 
 part of the face. 
 
 In conclusion, I wish to mention that several cases of absolute 
 absence of both temporary and permanent teeth are on record 
 in the literature, so-called " edentuli."
 
 LITERATURE. 
 
 The author is sensible that the references to the literature of the subjects 
 treated in this book are incomplete, but he nevertheless cherishes the hope that 
 his earnest eflbrts hare added real value to the catalogue of authors who have 
 contributed to the general stock of knowledge in this direction, and that the 
 labors of those who delve in the same field after him will thus be lightened. 
 
 To avoid frequent repetitions the standard works are given first, as bearing 
 more or less on every chapter of this work. The remainder of the literature has 
 been arranged as nearly as possible in the order of the chapters, having been 
 collected from the principal American, English, and German journals, as well 
 as from the works of Miller, Arkdvy, and Schetl'. 
 
 J. HrxTER. The Xat. History of the Human Teeth. London, 1778. 
 
 M. Desirabode. Science and Art of the Dentist. Baltimore, 1847. 
 
 E. Saunders. Diseases and Operations on the Teeth. [Atn. Jour, of Dent. 
 Sci. 1846.) 
 
 J. ToME.s. A Course of Lectures on Dental Physiology and Surgery. Lon- 
 don, 1848. 
 
 J. Tomes and C. S. Tomes. A System of Dental Surgery. Philadelphia, 
 1873. 
 
 P. B. GoDDARD. The Anatomy and Physiology of the Human Teeth. 
 Philadelphia, 1844. 
 
 J. v. Metkitz und C. Wedl. Atlas zur Pathologic der Zahne. Wien, 
 1889. 
 
 C. Gegexbauer. Lehrbuch der Anat. des 3Ienschen. Leipzig, 1889. 
 
 J. Hyrtl. Lehrbuch der Anat. des Menschen. Wien, 1881. 
 
 S. T. SOmmekixg. Der Bau des 3Ienschl. Korpers. Frankfurt, 1800. 
 
 A. Colemax. Dental Surgery. 
 
 S. J. A. Salter. Dental Pathology and Surgery. London, 1874. 
 
 J. Linderer. Die Zahnheilkunde nach ihrem neuesten Standpunkt. Erlan- 
 gen, 1851. 
 
 — Meckel. Tab. anat. path Ease. III. Lipsiae. 1812. 
 
 E. Jessex. Lehrbuch der Praktischen Zahnheilkunde. Wien, 1890. 
 
 C. Demoxtporcelet et E. Decaudix. Manuel d'Anatomie Dentaire Hu- 
 maine et Comparee. Avec introduction par M. le Professeur P. Brouardel, 
 doyen de la Faculte de Medecine de Paris. 1891. 
 
 A. BuzER. Handb. der Zahnheilk. Berlin, 1887. 
 
 S. Stricker. Manual of Histology. New York, 1872. 
 
 C. Wedl. The Pathology of the Teeth. Philadelphia, 1872. 
 
 K. Owen. Odontography. London, 1840-1844. 
 
 L. S. Beale. On the Structure and Growth of the Tissues and on Life. 
 London, 1865. 
 
 614
 
 LITERATURE. 615 
 
 A. KOTHMAN. Patho-Histologie der Zahiipulpii und Wurzelhuut. Stuttgart, 
 1889. 
 
 J. ArkOvy. Diagnostik der Zahnkrankheiten. Stuttgart, 1885. 
 
 H. Helmkampf. Diagnose and Therapie der Erkrankungen des Mundes und 
 Kachens. Stuttgart, 1886. 
 
 H. Gray. Anatomy 
 
 C. Heitzmaxx. Die Descriptive und Topographische Anatomie. Wien, 1875. 
 E. Zl'CKERKAXDL. Normale und Pathologische Anatomie der Nasenhohle. 
 
 Bd. I and II. Wien und Leipzig, 1882 und 1892. 
 
 J. ScHEFF, Jr. Handbueh der Zahnheilkunde. Wien, 1891. 
 
 J. E. Garretson. a System of Oral Surgery. Philadelphia. 
 
 R. Baume. Odontol. Porschungen. Leipzig, 1882. 
 
 L. Brandt. Lehrbuch d. Zahnheilk. Berlin, 1890. 
 
 J F. Plagg. Dental Pathology and Therapeutics. Philadelphia, 1872, 
 
 E. Parmly. An Essay on the Disorders and Treatment of the Teeth. New 
 York, 1822. 
 
 L. S. Parmly. Lectures on the Natural Historj^ of the Teeth. Xew York, 
 1 8'2(). 
 
 T. Bell. The Anatomy, Physiology, and Diseases of the Teeth. Phila- 
 delphia, 1837. 
 
 S. S. Fitch. System of Dental Surgery. New York, 1829. 
 
 J. Fox. The Natural History and Diseases of the Teeth. London, 1814. 
 
 D. W. Jacobsox. Outlines of the Anatomy and Physiology of the Teeth. 
 Edinburgh, 1834. 
 
 L. KoECKER Principles of Dental Surgery. Baltimore, 1842. 
 
 C. A. Harrls. Dissertation on the Diseases of the Maxillary Sinus. Phila- 
 delphia, 1843. 
 
 A. Nasmyth. Eesearches on the Development, Structure, and Diseases of 
 the Teeth. 1849. 
 
 P. F. Blaxdin. Anatomy of the Dental System. Baltimore, 1845. 
 
 G. Carabelli. Systemisches Handbueh der Zahnheilkunde. Wien, 1844. 
 
 J. Fox and C. A Harris. The Natural History and Diseases of the Human 
 Teeth. Philadelphia, 1846. 
 
 C. O. Cone. An Essay ou the Structure and Formation of Teeth in Man and 
 Various Animals. Baltimore, 1848. 
 
 T. Berdmore. a Treatise on the Disorders and Deformities of the Teeth and 
 Gums. Baltimore, 1844 
 
 D. W. JoBSOX'. A Treatise on the Anatomy and Physiology of the Teeth. 
 Baltimore, 1844 
 
 C. A. Harris. The Principles and Practice of Dental Surgery. Phila- 
 delphia, 1866. 
 
 R. Baume Lehr])uch der Zahnheilkunde. Leipzig, 1885. 
 
 J. ScHEFF. Lehrbuch der Zahnheilkunde. Wien, 1884. 
 
 J. R. Metnitz Lehrbuch der Zahnheilkunde Wien, 1891. 
 
 N. W. Kixgsley. a Treatise on Oral Deformities. New York, 1880. 
 
 M. H. Crykr. (American System of Dentistry ) Philadelphia, 1886. 
 
 A. P. Brubaker. (American System of Dentistry.) Philadelphia, 1886. 
 
 J. L WoRTMAN. (American System of Dentistry.) Philadelphia, 1886. 
 
 W. X. SuDDUTH. Embryology, etc. (American System of Dentistry.) Phila- 
 delphia, 1886. 
 
 C. S. Tomes. A Manual of Dental Anatomy. Philadelphia, 1876.
 
 616 LITERATURE, 
 
 H. Ji'DD. An Anatomical Description of the Permanent Teeth. St. Louisa 
 1877. 
 
 P. Pfeffermann. Passliche Darstellung d<.r Gesamten Zahnheilkunde. 
 Stuttgart, 1864. 
 
 M. Heider und C. Wedl. Atlas zur Pathologic der Zahuo Zeichnungen 
 von C. Heitzmann. Leipzig, 1869. 
 
 E. MfJHLREiTER. Anatomic dcs Mcnsclilichen Gebisscs. Leipzig, 189 i. 
 P. ScHECH. Die Krankheiten der Mundhohle, etc. Wien, 1892. 
 
 A. S. Underwood. Aids to Dental Histology. London, 1892. 
 
 C. Keschreiter. Zur Morphologic des Sinus Maxillaris. Stuttgart, 1878. 
 
 J. Parreidt. Zahnheilkunde. Leipzig, .1891. 
 
 K. Spieltogel. Die Ursachen der Zahnkrankheiten ; ihre Polgen, Verhii- 
 tung, und Behandlung, etc. Landsberg a. d. W., 1891. 
 
 M. Small and J. F. Colter. Diseases and Injuries of the Teeth. London, 
 1893. 
 
 L. Hollaexder. Das Piillen der Ziiline. Leipzig, 1885. 
 
 J. Taft. Operative Dentistry. Philadelphia, 1869. 
 
 A. "Witzel. Deutsche Zahnheilkunde in Yortragen Hagen, 1886. 
 
 A. Witzel. Die Antiseptische Behandlung der Pulpakrankheiten. Berlin, 
 1879. 
 
 A. Witzel. Compendium der Pathologic und Therapie der Pulpakrank- 
 heiten des Zahns. Hagen in W., 1886. 
 
 H. Prey. Compendium of Histology. New York, 1876. 
 
 L. Ranvier. Technisches Lehrhuch der Histologic. Leipzig, 1877. 
 
 C. H. Stockwell. The Microscopic Structure of a Human Tooth. Ann 
 Arbor, 1887. 
 
 CHAPTERS I, II. 
 
 J. B. Sutton. Development of the Lower Jaw. [Denial Cosmos. Vol. 
 XXY.) 
 
 C. Heitzmann and F. Abbott. Senile Atrophy of the Upper Jaw. [Dental 
 Cosmos. Vol. XXXIY.) 
 
 J.Wolff. Uber das Wachsthum des Unterkiefers. [Virchmv's Arch. 1888.) 
 
 H. Welker. Untersuchungcn iiber Bau und Wachsthum des Menschlichen 
 Schadels. Leipzig, 1862. 
 
 G. RuGE. Beitrjige zum Wachsthum des Menschlichen Unterkiefers. Berlin, 
 1876. 
 
 F. Strassmann. Xonnull. observ. de ossium. increment, pertinentes. Diss 
 inaug. Berolini, 1862. 
 
 G. M. Humphry. On the Growth of the Jaws. (Trans of the Cambridge 
 Philos. Soc. Vol. XI.) 
 
 O. Zsigmondy. Uber die Yeraenderungen des Zahnbogens bei der Zweiten 
 Dentition. [A)r/<./. Anai. >n«/ r/>>/sio/ 1890.) 
 
 CHAPTERS III, I Y. 
 
 E. MuiiLREiTEK. Uber Maximal- und Minimalgrossen der Ziihue. [Dent 
 Vier. Jahrsch.f. ZahnheUk. 1874.) 
 
 J. S. Latimer. Anatomy and Physiology <if the Teeth. [Denial Cosmos. 
 Vol. YIII.) 
 
 W. H'. Flower. On the Size of the Teeth as a Character of Race. [Denial 
 Cos7nos. Vol. XXVII.)
 
 LITERATURE. 617 
 
 J. PoHLMAN. Hamuu Teeth and Evolution. (Dcitfal Chstnos. Vol. XXIX.) 
 
 E. T. Stark and F. L. Hisk, Typical Tooth Forms. {Denial Cosmos. Vol. 
 XXXI ) 
 
 M. A. BuRCH. The Growth and De\'elopment of the Jaw. California State 
 Odont. Soc, 1886 
 
 Fr Blandin. Historische Skizzeiiberdie Anatomieder Zahne. {Dcr Za/inarzi. 
 1848.) 
 
 Fr. Blandin. Uher den Ban und die Organisation der Men.schl. Zahne. {Der 
 Zahnarzt 1848 ) 
 
 H Allen. The Facial Region. {Denial Cosmos Vol. XIV.) 
 
 A H. Thompson. The Homology of the Dental Tissues, etc. {Denial Cosmos. 
 Vol. XIX.) 
 
 C. N. Peirce. The Development of the Teeth, etc. {Denial Cosmo.^. Vol. 
 XIX.) 
 
 J. W. Wick. A Reunited Tooth. {Archh-es of Di'iiil^iri/. 1887.) 
 
 M. Heider Anatomische Beobachtungen iiber die Z;iline und Zahnreihen. 
 {Deid. Vier. Jahrsch.f. Zahnheilk. 1868.) 
 
 E. ScHWARTZKOPF. Die Zahne bei Zwergen. {Deui. Monai.'i.sch.f. Zahnheilk, 
 1884.) 
 
 J. Parreidt. Uber die Bezahnung bei Menschen mit abnormer Beharung. 
 {Deut.Monaisschr.f. Zuluiheilk. 1886) 
 
 J. Parreidt. Sind die mittleren oberen Schneideziihne bei der Frau absolut 
 oder verhiiltnissmassig breiter als beim Manne, etc. {Deui. Monaisschr. f. Zahn^ 
 hellk. 1886 ) 
 
 F. BtrscH. Die tjberzahl und ITnterzahl in den Zahnen des Menschlichen 
 Grebisses, etc. {Dent Monaisschr. f. Zahnheilk. 1887.) 
 
 H. JxJDD. The Deciduous Teeth. {Missou7-i Denial Junrnal. 1874.) 
 
 J. Parreidt. Die Ursachen der Missverhaltnisse zwischen den Grossen der 
 Kiefer und denjenigen der Z:ihne. {Deat. Monaisschr. f Zah>iheilk. 1884) 
 
 E. Muhlreiter. Anat. des Menschl. Gebisses. Leipzig, 1870. 
 
 E. ZucKERKANDL. Uber rudimentiire Zahne. {Medici n. Jahrb. 1885) 
 
 H. Hertz. Ein Fall von geheilter Zahnfractur mit nachfolgender abnormer 
 Schmelzbildung. {Virchoiv's Arch. 1867.) 
 
 E. ZucKERKANDL. Macroscopischc Anatomic in Handb. der Zahnheilk . von 
 J. Scheff, Jr. Wien, 1891. 
 
 J. F. Rymer. Notes on Dental Anatomy. London, 1892. 
 
 A. B. Salzer. Die Milchzahne in der Praxis. {Odonioskop. 1893.) 
 
 M. Schlosser. iiber die Deutung des Milchgebisses. {Bioloy. Centralbl. 
 1890.) 
 
 M. Schlosser. Die Ditfcrcnzirung des Siiugethiergebisses {Biolog. Ceniralbl. 
 1890.) 
 
 W. KtJHNTHAL. Einige Bcmericungen iiber die Saugethierbezahnung. {Avat. 
 Anzeiger. 1891 ) 
 
 C. Rose, iiber Entstehung und Formabanderung der Menschlichen Molaren. 
 {Anat. Anzeiger. 1892 ) 
 
 E. Mahieu. Contribution a 1 'etude de la premiere dentition. (These.) Paris, 
 1894. 
 
 CHAPTERS V, V I. 
 
 T.L.James. ■ Pulp-Canals of Human Teeth. {Denial Review. 1890.) 
 C. E. Latimer. Pulp-Cavities, {Denial Cosmos. Vol. VI.)
 
 618 LITERATURE. 
 
 "W. G. A. BoxAviLL. Articulation and Articulators. (Trans. Am. Dent. Ass. 
 18G5.) 
 
 W. G. A. BoNWiLL. What has Dentistry to Demonstrate against the Hypoth- 
 esis of Organic Evolution? [Dental Cosmos. Vol. XXXV.) 
 
 I. B. Davenport. Articulation of the Teeth. [Intern. Dent. Jour. 1892.) 
 
 I. B. Davenport. The Significance of the Natural Form and Arrangement 
 of the Dental Arch, etc. [Dental Cosmos. Vol. XXIX ) 
 
 L W ARNEKRos. Die Fixirung der Bewegungen des Unterkiefeis beim Kauakt. 
 Berlin, 1892. 
 
 CHAPTERS VIII, IX. 
 
 C. Havers. Osteologia Nova London, 1691. 
 R. Nesbitt. Human Osteogeny. London, 1731. 
 
 — Duhamel. Memoires de I'Acad. Paris, 1742. 
 
 J. Hunter. Experiments and Observations on the Growth of Bone. London, 
 1798. 
 
 J. Howship. Microscopic Observations on the Structure of Bone. [Med. 
 
 Chirnr. Trans. London, 1816.) 
 
 J. MuLLER. [Muller'.s Arch. 1836.) 
 
 — Lessing. tJber ein plasmatisches Gefass-System in alien Geweben, insbe- 
 sondere in Knochen und Zahuen. Hamburg, 1846. 
 
 R. ViRCHOW, Wiirzburger Verhandlungen. 1850. 
 
 E. Neuman. Beitrage zur Kenntniss des normalen Zahnbeins und der 
 Knochengewebe. KOnigsberg, 1863. 
 A. KOlliker. Mikroskopische Anatomic. 1850. 
 
 — De Morgan. Observations on the Structure and Development of Bone. 
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 H. MuLLER [Zeitschr.f.Wiss. Zool. Bd. IX. 1858.) 
 
 E. Lang. Untersuchungen iiber die ersten Stadien der Knochenentziindung. 
 {Wiener Med. Jahrb. 1871.) 
 
 — RuGE. [Virchow's Arch. Bd. XLIX.) 
 J. Wolff. [Virchow's Arch. Bd L.) 
 
 N. LiEBERKUHN. [Sltzungsher. der Marhur(jer Grsells. 1872.) 
 
 — Strelzoff. Untersuchungen aus dem Pathol. Instit zu Zurich 1878. 
 
 — Stel'dener. Beitrage zu der Lehre von der Knochenentwicklung (Abh. 
 der Naturf. Ges. zu Halle. 1875.) 
 
 L. Beale. The Structure of the Simple Tissues of the Human Bodv. London, 
 1860. 
 
 M. ScHULTZE. Reichert und Du Bois Reymond's Arch. 1861. 
 
 Tii. Schwann. Microskopische Untersuchungen. Berlin, 1839. 
 
 J. Henle. . Allgemeine Anat. 1845. 
 
 31. ScHULtZE. [Centralbl.f. d. Med. Wi.ss. 1864.) 
 
 A. Spina. Tiber die Saftbahnen des hyalinen Knorpels. [Sitzxnq.sb. der Wiener 
 Akad. d. Wiss. 1879.) 
 
 S. Stkickkr. Mittheiluiigeii liber Zcllcn luid (4ruiidsub.stanzen. [Wiener Med. 
 Jahrb. 1880.) 
 
 A RoLLET. S. Strickcrs Maiuial of Hi.-^tology. 1872. 
 
 F. V. Recklinghausen. Wanderzellen. [Virchow's Arch. Bd. XXVIII.) 
 C. ToLirr. Lehrbuch der Gewebclehre. 1877. 
 
 . L. R.\NviKR. Des Lesions du Tissu Ccllulaire lache dans I'Oedeme. [Comptes 
 r.cndf's. 1871.)
 
 LITERATURE. 619 
 
 W. Hassloch. Cornea. {Arch, of OiMhal. Otnl. Vol, VII. 1878.) 
 W. Waldeyer. Cornea. (In Graefe Saemisch's Handb. 1874.) 
 
 — DoNDERS, {Zeitschr. f. Wiss. Zool. Bd. III.) 
 
 — FuRSTEXBERG. [Midler^ s Arch. 1857.) 
 K. ViRCHOW. Cellularpathologie. 1858. 
 
 R. Heidexhaix. Studien des Physiol. Instit. zu Breslau. 1863. 
 
 L. Elsberg. Contributions to the Normal and Pathological Hi.stology of the 
 Cartilage.? of the Larj-nx. [Arcli. of Laryngology .^ Vol. II , 1881, where a good 
 collection of the literature on cartilage-tissue will be found.) 
 
 P. T. Smith Cell-Metamorphosis. {Lifern. Dent. Jour. 1893.) 
 
 E. R. Warxer Products of the Epiblast [Denial Cosmos. Vol. XXX.) 
 
 W. H. Atkinsox. Epithelium. [Trans. N. Y. Odoniol. Soc. 1877.) 
 
 Th. Schwaxx. tJntei-suchungen iiber die Ubereinstimmung in der Structur 
 und dem Wachsthum der Thiere und Pflanzen. Berlin, 1839. 
 
 M. ScHULTZE. tlber Muskelkorperchen und das was man eine Zelle zu nennen 
 habe. [MuUer's Arch. 1861.) 
 
 E. Brucke. Die Elementarorganismen. [Sit^ungsher. (/>'/■ Wiener Akadeni. der 
 W!ss. 1861.) 
 
 S. Stricker. Handbuch der Lehre von den Geweben. 1868. 
 
 Jul. Cohxheim. tJber die Endigungen der sensiblen Nerven in der Horn- 
 liaut. [Virchoio's Arch. 1867.) 
 
 — • Gegexbauer. [Jenaische Zeitschr. f. Med. imd Naturwi.ss. 1864.) 
 
 R. ViRCHOW. Die Cellularpathologie. 1871. 
 
 K. KOsTER. tJber die feine Structur der Menschlichen Nabelschnur. Wiirzburg, 
 1868. 
 
 E. V. Recklinghaxtsex^. Die Lymphgefiisse und ihre Beziehung zum Binde- 
 gewebe. Berlin, 1862. 
 
 Th. Billroth. (Arch.f Klinische Chirurgle. Bd. XI.) 
 
 W. Krause. tlber den Bau der quergestreiften Muskelfaser. [Zeitschr. f. rat. 
 Med. 1868.) 
 
 V. Hexsex. ttber ein neues Structurverhaltniss der quergestreiften Muskel- 
 faser. (Arbeiten des Kieler Physiol. Instit. 1868.) 
 
 T. W. Exgelmaxx. Microsk Untersuchungen iiber die quergestreiften Muskel- 
 ■substance. [Pfluge>''s Arch. 1873.) 
 
 E. Brucke. Unters. iiber den Bau der Muskelfasern, etc. [Denkschr.d. Wiener 
 Akad. der Wiss. Bd. XV.) 
 
 L. Elsberg. [Virchoio's Arch. Bd XXXVIII.) 
 
 L, UxGER. Untersuchungen iiber die Entwicklung der centralen Nerven- 
 gewebe. [Sitznngsber. der Wiener Akad. der Wiss. 1879.) 
 
 C. Heitzmaxn. Untersuch. iiber das Protoplasma. [Sitzungsher. der Akad. 
 der Wiss. in Wien. 1873.) 
 
 C. Heitzmaxx. Studien am Knochen und Knorpel. [Med. Jahrh. 1872.) 
 
 V. V. Ebxer. tlber den feinen Bau der Knochensubstanz. [SitzKngsher. der 
 Wiener. Aka/l. der Wiss. 1875.) 
 
 C. Laxger. tJber das Gefass-System der Rohrenknochen. [Denk.'ichr. der 
 Wiener. Akacl. der Wiss 1875.) 
 
 C. Langer. Uber die Blutgefasse der Knociien des Schiideldaches. [Denk- 
 schr. der Wiener Akad. d. ir/.s.s-. 1879.) 
 
 M. Kassowitz. Die Normale Ossitication. [Wiener Med. Jahrh. 1879.) 
 
 C. Heitzmaxx. Microsc. ^Morphology. New York, 1883. 
 
 — Drysdale. The Protoplasmic Theory of Life. London, 1874.
 
 620 LITERATURE. 
 
 J. Fletcher. Eudiments of Physiology. Edinburgh, 1835. 
 
 Ferd. Cohn. Nachtrage zur Naturgeschichte des Protococcus pluvialis. 
 (Nova acta Acad. Leop. Carol. Vol. XXII ) 
 
 T. H. Huxley. Review of the Cell-Theory. {Brit, and Foreign Medico-Chirurg. 
 Review. 1853.) 
 
 L. Ukger. Anat. und Physiol, der Pflanzen. 1855. 
 
 M. Schtjltze. tJber innere Bewegungs-Erscheinungen hei Diatomeen. 
 {Muller's Arch. 1858.) 
 
 M. Schtjltze. tlber Cornuspira. {Arch. f. Naturriesch. IS^iO.) 
 
 M. Schtjltze. Das Protoplasma der Rhizopoden und der Pflanzenzellen. 
 Leipzig, 1863. 
 
 Haeckel. Monographie der Radiolarien. 1862. 
 
 Haeckel. Uber den Sarcodekorper der Rhizopoden. {Zeitschr. f. Wiss. 
 Zool. 1866.) 
 
 Haeckel. Generelle Morphologie. Yol. I. Pp. 269 and 289. 
 
 Haeceel. Monographie der Moneren. {Jenaische Zeitschr. f. Med. wnd Natur- 
 wiss. 1868.) 
 
 — Ba.stian. The Beginnings of Life. London, 1872. 
 
 C. Heitzmann. Epithelium and Its Performances. {Aeiv York Med. Jour.. 
 1878.) 
 C. RoKiTAiv-SKY. Handb. d. Allg. Pathol. Anat. 1846. 
 L. Ranvier. Traite Technique d'Histologie. Paris, 1889. 
 A. KOlliker. Handbuch der Gewebelehre. Leipzig, 1889. 
 C. Told. Lehrbuch der Gewebelehre. Stuttgart, 1888. 
 0. Hartavig. Lehrbuch der Entwicklungsgeschichte. Jena, 1893. 
 
 CHAPTERS X-XY. 
 
 — EusTACH, 1574. (M. Pfliiger, Dent. Vier. Jahrschr.f. Zahnheilk. 1867.) 
 
 — Herissant, 1745. (M. Pfliiger, Deid. Vier. Jahrschr. f. Zahnheilk. 18i7.y 
 Yon Swinton und Brunner, 1771. (M. Pfliiger, Dent. Vier. Jahrschr. f. 
 
 Zahnheilk. 1867.) 
 
 R. Blake, 1780. (M. Pfliiger, Dent. Vier. Jahrschr.f. Zahnheilk. 1867.) 
 
 — Delabarre, 1805. (In Syst. Handb. d. Zahnheilk. von G. v. Carabelli. Wien, 
 1844.) 
 
 H. M. Hayden, 1813. {Am. Jour, of Dent. Science. Yol. I.) 
 
 J. Fox. The Natural History and Diseases of the Teeth. London, 1814. 
 
 — Leszai, in 1830. (In Deut. Vier. Jahrschr. f. Zahnheilk. 1867. By M. 
 Pfliiger. ) 
 
 F, Arnold. {Medic. Chirurg. Zeitung. Insbrack. 1831.) 
 
 PuRKiNJE and Raschkow, 1835. In Nasmyth Researches, etc. (1. c.) 
 
 — Fraenkel. De penitiori dentium hum. Struct. Diss. Yratislav. 1835. 
 J. MtJLLER. {Arch. f. Anat. und Physiol. 1836.) 
 
 A. Retzius. {Arch.f. Anat.., Physiol., und Wiss. Med., Miiller'^. 1837.) 
 
 T Bell. The Anatomy, Physiology, and Diseases of the Teeth. Philadelphia, 
 1837. 
 
 J. LiXDERER. Handbuch der Zahnheilk. Berlin, 1837. 
 
 A. Nasmyth. ResearcliPS on the Development, Structure, and Diseases of the 
 Teeth. London, 1839. 
 
 J. GoODSIR. {Edinburgh Med. and Surg. Jour. 1839.) 
 
 R. Owen. Odontography. London, 1840-1845.
 
 LITERATURE. 621 
 
 C. A. Harris. On the Vascularity of Dental Bnne. [Am. Jour, of Dent. 
 Science. 1841.) 
 
 J. B. Gariot. Treatise on the Diseases of the Mouth. Baltimore, 1843. 
 
 P. F. Blandine. Anat. of the Dental System. Baltimore, 1835. 
 
 C. O. Cone. Origin, Development, and Eruption of the Teeth. {Am Jour, of 
 Dent: Sci. 1845.) 
 
 J. GiBSOX. (In Ber Zuhnarzi. 1846. P. 89.) 
 
 J. LiNDERER. Physiologist-he unci Pathologische Untersuchungen der Zahne. 
 {Der Zahnarzi. 1847.) 
 
 M. Desirabode. Science and Art of the Dentist. Baltimore, 1847. 
 
 J. Tomes. A Course of Lectures on Dental Physiology, etc. London, 1848. 
 
 J. Tomes. Philosoph. Transactions! 1849, 1850, and 1856. 
 
 E. Blake. An Essay on the Structure and Formation of the Teeth of Man 
 and Various Animals. Baltimore, 1848. 
 
 M. Joi:rdaix. A Treatise on the Diseases of the Mouth. Baltimore, 1849. 
 
 K. B. Todd and W. Bowman. Anat. and Physiol, of Man. Philadelphia, 
 1850. 
 
 A. Krukenberg. (In Der Zuhnarzt. 1850. P. 118.) 
 
 J. N. CzERMAK. {Zeitsehr.f.Wis.s. Zool. 1850.) 
 
 John Tomes. The Structure and Development of Bone. {Am. Jour, of Dent. ■ 
 Sd. 1852.) 
 
 J. D. White. Anatomy and Physiology of Dentine. {Dental Neivs Letter. 
 1852.) 
 
 H. White. Anatomy and Physiology of Dentine. {A)n. Jour, of Dent. Sci. 
 1852.) 
 
 W. BoGERS. tjber die Entwicklung der Kinnlade und der Zahne. [De/' Zahn- 
 arzi. 1852 and 1853.) 
 
 A. KoLLiKER. (Microsk. Anat., Bd. II. Leipzig, 1852.) 
 
 A. KoLLiKER. {Zeitsch. Wiss. Zool. 1862.) 
 
 A. KoLLiKER. Gewebelehre. 1867. 
 
 A. KoLLiKER. Entwicklungsgeschichte des Menschen und der Hoheren Thiere. 
 Leipzig, 1879. 
 
 W. T. KussEL. An Essay on the Structure and Development of the Dental 
 Tissues. {Am. Jmir. of Dent. Science. 1853.) 
 
 J. E. OuDET. Microskopi.-^che Studien liber die Ziihne. {Am. Jour, of Dental 
 Science. 1854.) 
 
 J. LEForLON. Pathologische Betrachtungen iiber die Zilhne. {Am. Jour, of 
 Dental Science. 1856 and 1857.) 
 
 E.Lent. {Zeitschr. /. Wi.<<s. Zool. 1855.) 
 ■ T. H. Huxley. {Quart. Jour, of Micro. Science. London, 1853, 1854, and 
 1855.) 
 
 — Hannover. Die Entwicklung und der Bau des Sjiugethierzahns. {Verhandl. 
 d. Kaiserl. Akad. d Nciturfo7:sch. 1856.) 
 
 J. Tomes. On Certain Conditions of the Dental Ti.ssues. {Am. Jour, of Dent. 
 Science. 1856.) 
 
 C. Johnston. Contributions to the Minute Anatomy of the Teeth. {Am. 
 Jour, of Dent. Science. 1857.) 
 
 S. J. A. Salter. Papers on Dental Pathology. {Am. Jour, of Dent. Science. 
 1857.) 
 
 A. F. Talma. (In Der Zahnarzt. 1853. P. 193.) 
 
 J. E. Oudet. (In Der Zahnarzt. 1853. P. 256.)
 
 622 LITERATURE. 
 
 M. Franko. {In Der Zahnarzt. 1856. P. 1.) 
 
 N. GuiLLOT. {1\\ Der ZaJmarzt. 1858. P. 177.) 
 
 Ch. Kobin and E. Magitot. {Jour, de Physiol, de Brou-n-Seqtcard. 1860 and 
 1861.) {'EnsMsh., Dental Cosmos. 1861.) 
 
 A. HOPPE. {Virchoto' s Arch. 1862.) 
 
 L. S Beale. On the Structure and Growth of the Tissues, and on Life. London, 
 1865. 
 
 G. Hertz. {Virchow's Arch. 1866.) 
 
 G. Hertz. {Virchoiv-s Arch. Bd. XXXVIII.) 
 
 J. H. McQuiLLEX. 3Iicroscopy of the Dental Tissues. {Dental Cosmos. Vol. 
 VII.) 
 
 J. H. McQuiLLEN. The Interglobular Spaces in Dentine. {Dental Cosmos. 
 Vol. VIII.) 
 
 S. P. Cutler. Microscopy of the Teeth. {Dental Cosmos. Vols. VIII, 
 IX, and X.) 
 
 J. H. McQriLLEX. The Interglobular Spaces. (Trans. Am. Dent. Ass. 
 1866.) 
 
 S. P. Cutler. Microscopy of the Teeth. (Trans. Am. Dent. Ass. 1868 ) 
 
 W. Waldeyer. Uber die Entwickelung der Ziihne. {Kbnigsherger Med. 
 Jahrhucher. 1864.) 
 
 W. Waldeter. (In S. Strieker's Manual of Histology. New York, 1872.) 
 
 M. Pfluger. {Deut. Vier. Jahrsc.hr. f. Zahnheilk. 1867. P. 167.) 
 
 E. F. Wexzel. {Arch, der Heilk. 1868. P. 97.) 
 
 G. G. Ziegler. Dental Tissues. {Dental Cosmos. Vol. XL) 
 
 J. KoLLMAXX. {Sitzum/sberichte der K. B. Akademie dei' Wiss. zii Munchen. 
 1869. P. 162.) 
 
 J. KoLLMANX. {Sitzungsbei-ichte der K. B. Akademie der Wiss. zu Munchen. 
 1871. P. 243.) 
 
 E, MuHLREUiER. {Detit. Vicr. Jahrsch. f. Zahnheilk. 1868. P. 168.) 
 
 E. DuRSY. Zur Entwicklungsgeschichte des Kopfes des Menschen und der 
 hoheren Wirbelthiere. Tubingen, 1869. P. 211. 
 
 C. Tomes. {Quart. Jour, of Micro. Science. Vol. XII. P. 321.) 
 
 F. Leydig. {Arch. f. Micro. Anat. Bd. IX. P. 1.) 
 
 C. Wedl. The Pathology of the Teeth. Philadelphia, 1872. 
 
 G. RoLLESTOXE. {Quar. Jour, of Micro. Science. London, 1872. P. 109.) 
 J. F. Flagg. {Dental Cosmos. Vol. XIV. Pp. 680 and 633.) 
 
 J. KoLLMANX. {Zeitschr.f. Wiss. Zool. 1873. P. 354.) 
 
 H. Sewill. {Dental Cosmos. Vol. XVII. P. 658. ) 
 
 — Heixcke. {Zeitschr.f. Wiss. Zool. 1873. P. 495.) 
 
 U. Hertwig. {Jennische Zeitschr. 1874. P. 381.) 
 
 H. Frey. Grundziige der Histologic. Leipzig, 1885. 
 
 H. Beales. A Study of Tooth-Development, etc. {Indep. Fract. 1885.) 
 
 R. R. Andrews. The Development of the Teeth. {Arch, of Dentistry. 1885.) 
 
 C. Tomes. {Monthly Micro. Jour. 1874. P. 85.) 
 
 C. Tomes. {Quar. Jour, of Micro. 1874. P. 44.) 
 
 C. Leqros and E. Magitot. The Origin and Formation of the Dental Follicle. 
 (Engli.?h by M. S. Dean. Chicago, 1880.) 
 
 A. V. Brunn. {Gbitinger Nachr. 1875. P. 626.) 
 
 R. Baume. {Deut Vier. Jahrsch. f. Zahnheilk. 1875. Pp. 125 and 265.) 
 
 T. C. "White. On Some Points in the Minute Anatomy of the Pulps of the 
 Teeth. (Trans. Odont. Soc Gr Britain. 1870.)
 
 LITERATURE. 623 
 
 T. C. Stellwagen. Dovelopmejit of Cells of the Dental l*ul]) intu Tulmli. 
 {^Dental Cosmos. Vol. XII.) 
 
 G. B. Harriman The Discoveiy of Nwve-Fibers in the Soft Solids of the 
 Dentine. [Doifal Cosmos. Vol. XIII.) 
 
 F. Eberman. Zahnheinnerven. {Dent. Vier. Jahrsch. f. ZahnheAlk. 1872.) 
 R Baume. AllgeineiiU'r.sclu'iliunt;*')! iiii Zahnbein. [Dent. Virr. Jahrschr. f. 
 
 ZahnheUk. 1873, 1874, 1875.) 
 
 R. Baxtme. Bemerkuiigen iiber die Entwickehing und den Ban des Saugethier- 
 zahns. {Dent. Vier. Jahrsch. f. Zahtihcilk. 1875.) 
 
 W. C. Barrett. The Anatomical and Histological Structure of the Deciduous 
 Teeth (Trans. Dent. Soc. of the State of New York. 1874.) 
 
 C. S. Tomes. Studies u})on the Attachment of Teeth. (Trans. Odont. Soc. 
 Gr. Britain. 1874.) 
 
 — HuTCHixsox. The Dental Xerve-Pulp in Life and in Death. (Trans. Od^nt. 
 Soc. Gr Britain. 1875.) 
 
 H. S. Chase. Histology of Dentine. {Missouri Dent. Jour. 1875.) 
 
 J. E. Cravexs. Pathology and Therapeutics. {Missouri Dent. Jour. 187G.) 
 
 H. JvDD. Contribution to the Study of the Dental Fissures. (Missouri Dent. 
 
 Jour. 1877.) 
 
 C. F. W. BOdeckek. The Distribution of Living Matter in Human Dentine, 
 
 Cement, and Enamel. {Dental Cosinos. 1878-1879.) 
 
 C. F. W. BOdecker. Pericementum and Pericementitis. {Dental Cosmos. 
 
 1878-1879.) 
 
 C. F. AV. BOdeckek. On Secondary Dentine. {Dental Cosmos. Vol. XXI.) 
 
 D. C. Hawxhurst. Interglohular Spaces. {Dental and Oral Science Magazine. 
 1878.) 
 
 G. V. Black. Microscopy and Histnlogy. {Mi.wouri Dent. Jour. 1878 ) 
 W. A. Pease The Dental Pulp. {Missouri Dent. Jonr. 1878.) 
 
 G. V. Black. The Odontoblasts. (Trans. Am. Dent. Ass. 1878.) 
 
 W. Hailes. Sections and Section-Cutting. {Am. Jour, of Insanity. 1879.) 
 
 F. Abbott. The Minute Anatomy of Dentine and Enamel. {Dental Co.<»no.-<. 
 Vol. XXI.) 
 
 C. S. Tomes. On the Development of the Teeth. (Philns. Trans, Vol. 
 CLXV., Proceedings of the Royal Society, Vol XXIII. , and Monthly Micro Jour . 
 V..1. XIV.) 
 
 T. H. 3IcGiLLAVRY. Uber die Schiicidezabne von Mus decunianus. (Veriiandl. 
 Med. d. K. Akd. at Amsterdam. 2 K . IX.) 
 
 C. S. Tomes. On the Development <if Teeth, {(.^uar. Jour, of Micro. Sci. 
 1876.) 
 
 J. ArkOvy. On the Development of Dentine. (Trans. Odont. Soc. Gr. 
 Britain. 1876.) 
 
 — Tauber Existance dc lemail .-ur les dents de laits du Tatusia peba. {Jour, 
 de Zool. 1877.) 
 
 C. S. To.MEs. On Some Forms of Dentine Calcilication, with Notes on their 
 Bearing on Dental Pathology. (Trans. Odont. Soc. Gr. Britain. 1877.) 
 
 C. S. Tomes. On the Structui f Vaso-Dmtinr. (Philns. Trans., Proc of 
 
 the Royal Society. 1878.) 
 
 C. Aeby. Architektur uiiviiDkoiiimen getheilter Zahmvur/.eln. {Arch f. Mn^ru. 
 Anat. 1878.) 
 
 Ch. Legros et E. ^IaciITot. .Mnrpbnlogic <lu follieule dentaire chez les vei- 
 tebres. {Jour, de VAnnt. ct d, hi I'hysiol. 1879.)
 
 624 LITERATURE. 
 
 — Boas. Die Ziihne der Scaroiden. [Zeitschr. f. Wiss. Zool. 1879.) 
 
 E. Kleix and E. Xoele. Atlas of Histology. London, 1880. 
 
 A. DE Sareax. Vaisseaux sanguines des racines dentaires. [Gaz. Med. de 
 Paris. 1880.) 
 
 C. W. DuNX. Abstract of "A Study on Diseases of the Teeth." (Trans. 
 Odont. Soc. Gr. Britain. 1881.) 
 
 J. ArkOvy. Formation of Dentine. (Trans. Odont. Soc Gr. Britain. 1880.) 
 
 T. Gadde.s. Dental Anatomy and Physiologj*. (Trans. Odont. Soc. Gr. 
 Britain. 1881.) 
 
 A. J. DouDS. Pathology of the Osseous Structure of the Teeth. (Missouri 
 Bent. Jour. 1881.) 
 
 R. R. Axdreats. Formation of Mati-ix of Dentine. (New England Journal of 
 Dentistry. 1883.) 
 
 C. Matr. TVhat is the Vitality of a Tooth ? [Xew England Journal of De7i- 
 iistry. 1883.) 
 
 F. Abbott. Minute Anatomy of the Human Tooth. (Trans, of the Dent. 
 Soc. of the State of Xew York. 1882.) 
 
 C. F. W. BOdecker The Minute Anatomy, Physiology, Pathology, and 
 Therapeutics of the Dental Pulp. (Dental Cosmos. Vol. XXIY.) 
 
 J. B. St'TTOX. Development of the Inferior Maxilla. (Trans. Odont. Soc. 
 Gr. Britain. 1882.) 
 
 J. ArkOvy. Investigations into the Mode of Development of Odontoma In- 
 ternum Liberum. (MontJdy Beview of Dental Surgery. 1883.) 
 
 C. S. Tomes. On Some Scientific Problems of Dental Surgery. (Monthly 
 Review of Dental Surgei-y. 1883.) 
 
 F. Harrisox. Notes on the Alveolo-Dental Membrane. (British Journal of 
 Dental Science. 1 884 ) 
 
 C. S. Tomes. Note upon the Eeformation of Bone. (Monthly Review of 
 Dental Surgery. 1885.) 
 
 F. Harrison. Preparing Tissues for Microscopical Examination. (Monthly 
 Review of Dental Surgery. 1885.) 
 
 W. X SuDDUTH On Some of the Pathological Conditions Found in Dentine 
 and Ivory. (Dental Cosmos. Vol. XXIX.) 
 
 F. Abbott. Teeth of Pvabbits. (Dental Cosmos. Vol. XXIX.) 
 
 T. L. BrcKiNGHAM. (Trans New York Odont. Society, April 20, 1880.) 
 
 L. Loewe. Beitrage zur Kenntniss des Zahns, etc. (Arch. f. Micro. Ana.t. 
 1881.) 
 
 A. Sternfki.d ijber die Structur des Hechtzahnes, etc. (Arch. f. Micro. 
 Anat. 1881.) 
 
 C. Benda Die Dentinbildung in den Hautzahnen der Sclachier. (Arch, 
 f. Micro Ana.t. 1881.) 
 
 R Mathes. (Deut Vier. Juhr.sch f. Zahnhcilk. 1881. P. 262.) 
 
 C. Legros et E. Magitot. Contribution a I'etude des dents. III. Developm. 
 de I'organe dentaire chez les-mammiferes. (Jour de I' Anat. et de la Phys. 17 
 annee l^^Sl.) 
 
 C. SiHi.KK Notes on the Formation of Dentine and of Osseous Tissue. (Stud. 
 Biol. Laborat Johns Hopkins Univ 1881.) 
 
 6. Annell. Beitrage zur Kenntni.ss der Zahnbildenden Gewebe, etc. Biol. 
 Unters von. G. Retzius. Stockholm, 1882. 
 
 R Baume. Odontologische Forschungen. Leipzig, 1882. 
 
 J. E. Garret.><on. (New England Journal of Dentistry. 1883. P. 369.)
 
 LITERATURE. 625 
 
 — AVallauer Eia Zahnschliff. [Deut. Monntstickr f Zahnheilkunde. 1884) 
 P. Nepper. Eecherches sur la structure at la genese de I'ivoire {Annalea de la 
 
 Sci. (I p. Med. de Grand. 1884.) 
 
 — PoucHET et Chabry. Contributions a I'odontologie de mammiferes. {Jour, 
 de I'Anat. et de la Phijsiol. 1884.) 
 
 O. Walkhoff. Microskopische Untersuchungen iiber Pathologische Veriin- 
 derungen des Dentins. {Dent. Mo/iatsschr. f. ZahnheUk 1885) 
 
 M. Morgensterx. Meine Methode Zahnschliffe herzustellen {Deui. Monats- 
 schr.f. ZahnheUk. 1885.) 
 
 M. Morgensterx. Untersuchungen iiber den Ursprung der bleibenden Zahno. 
 [Deut. Monatssch. f. ZahnheUk. 1885.) 
 
 W. X. SuDDUTH. Dento-Eml)rynnal Histology and Technology. {Dental 
 Cosmos. Vol. XXVI.) 
 
 W. X. SuDDUTH. The Embryonic Malpighian Layer. {Dental Cosmos. Vol. 
 XXVI.) 
 
 0. 'Walkhoff. Beitrag zur Lehre von den Contourlinien und zur Physiologic 
 dee Zahnbeins. {Dcut. Monatssch f. ZahnheUk. 1885.) 
 
 — Malassez. Laboratoire d'histologie de France Traveaux de I'annee 1885. 
 J. L. "Williams. On Certain Disputed Points in the Development and His- 
 tology of the Teeth. {Dental Cosmos. Vol XXVI.) 
 
 J. L Williams. Embiyology : W^ith Special Reference to the Development 
 of the Teeth and Contiguous Parts {Dental Cosmos. Vol. XXVI.) 
 
 J. L Williams. A Ciitical Essay on the Development and Minute Anatomy 
 of the Teeth, etc. {Dental Cosmos. Vol XXVIII.) 
 
 R. R. Andrews. The Development of Enamel. {Dental Cosmos. Vol. 
 XXXIII.) 
 
 R.R.Andrews Growth of the Cementum. {Dental Cosmos. Vol. XXXIII.) 
 
 R. R. Andrews. A Contribution to the Study of the Development of the 
 Enamel. (Dental Cosmos. Vol. XXXV.) 
 
 G. S. Allan. Enamel and Dentine, etc. {Dental Cosmos. Vol. XXIX.) 
 
 — Williamson. United Fracture of Tooth-Roots. {Dental Cosmos. Vol. 
 XXX.) 
 
 F.Abbott. Annual Address. (Tran.s. Am Dent Ass. 1888.) 
 F J Bexnet. Certain Points Connected with the Structure of Dentine. 
 (Trans Odont. Soc. Gr. Britain. 1888.) 
 
 J. H. MtTMMERY. Notes on the Preparation of Microscopical Sections of 
 Teeth and Bone. (Trans. Odont. Soc. Gr. Britain. 1889.) 
 
 T. C. AVhite and J. B Sutton. Observations on the Structure and Develop- 
 ment of Ovarian Teeth. (Trans. Odont. Soc. Gr. Biitain. 1S89.) 
 E. D. SwAix. Embryology. {Dental Review. 1888 ) 
 G. S All AX. The Ameloblasts. {Internat. Dent. Jour. 1889.) 
 R. R. Axdrews. The Borderland of Calcification. {Internat. Dent. Jour. 
 1889.) 
 
 G. H. :McCal-sey. The Relation of the Tooth-Pulji, etc. {biternat Dent. 
 .Jour. 1890.) 
 
 P. Caxalis. Sullo sviluppo dei denti nei mammiferi. {Anatom. Anzeiger. 
 1886. P. 187.) 
 
 — Debierre et Pravaz. Contribution a rodontologie. {ArcJi. de Phijsio. 
 1886.) 
 
 A. Bruxn. Ubcr die Ausdehnung des Schmclzorgans, etc. {Arr/i./. Micro. 
 Anat. 1886 ) 
 
 41
 
 626 LITERATURE. 
 
 K. R. Andrews. The Origin of the Dental Fibers. [Arch, of Dentistry. 1887) 
 
 L. A. Weil. Zur Histologie der Zahnpulpa. {Dad. Monaissch. f. Zahnheilk. 
 1887.) 
 
 0. Walkhoff. Die Normale Entwieklung und die Physiologie des Zahnbeins, 
 in den verschiedenen Altei-sperioden des Menschen. [Deut. Monaissch. f. Zahnheilk. 
 1887.) 
 
 Gr. Spee. Uber die ersten Yorgiinge der Ablagerung des Zahnsohmelzes. [Anat. 
 Anzeiger. 1887.) 
 
 — Malassez. Sur lu structure du gubernacuhim dentis et la theorie paraden- 
 taire. {Compt. rend, de la Societe de Biologic 1887 and 1888 ) 
 
 A. Eterxod. Des lois mathematiques et mecaniques dans la distribution des 
 prismes de I'email. {Bcv. et Arch. Suisses d' Odontologie, I annee, No. 9. Geneve, 
 1887.) 
 
 F. Abbott. Odontoblasts in their Eelation to Developing Dentine. [Dental 
 Cosmos. Yol. XXX.) 
 
 F. J. Bennett. The Structure of Dentine. [The Lancet. 1888.) 
 
 A. .V. Brxtnn. ttber die Membrana Praeformativa, etc [.biat. Anz. 1888.) 
 
 li. E. Andrew.s. The Pits and Fissures of the Enamel. [Dental Cosmos. 
 Yol. XXX.) 
 
 E. E. Andrew.^. The Development of the Teeth. (Trans N. Y. Odont Soc 
 1888 ) 
 
 J. Schaffer. Die ^'erknochcrung des Unterkiefei-s und die iletaplasiefrage. 
 [Arch./. Micro. Aunt. 1888.) 
 
 L. Schmidt. Structurverhaltnisse eines Zahnrudimentes. [Dent Monfit.'^.sch f. 
 Zahnheilk. 1889.) 
 
 F. Abbott. Growth of Enamel [Dental Cosino.s Yol XXI.) 
 
 F. Eotter. ITber Entwieklung und Waehsthum der Schneidezahne bei Mus 
 musculus. [Morpti. Jahrh. 1889) 
 
 F. J. Bennett. Certain Points Connected with the Structure of Dentine 
 [.\m. Journal of Dental Science l^i89 ) 
 
 A. KOlliker. Handbuch der Gewebelehre Leipzig, 1889. 
 
 C. S. Tomes. A Manual of Dental Anatomy London, 1889. 
 
 L. Schmidt. Beitrag "zur Histologie der Kiiochen und Ziihne in den Der- 
 moidcysten der Ovarien [Di'iit Monats.sc]i. f ZahnJieilk. 1890.) 
 
 F. KOtter. ilber die vergleichende Entwicklungs- und Wachsthums-Ge- 
 schichte der Zahne. [Dent. Monaissch f. ZahnJieilk 1890 ) 
 
 Y. V. Ebner. Streitige Fragen iiberden Bau des Zahnschmelzes [Sitzungsber. 
 der K. Akad. der Wiss. Wien, 1890.) 
 
 Hertwig. Entwickelungsgeschichte ."^d edition 
 
 J Schaffer. Yerhalten fossiler Zahne in polarisirtem Licht. [Sitznngshcr. 
 der K Akad. der Wi.^s Wien, 189'1 ) 
 
 A. CoLLAUD. Etude sur le ligament alveolo-dentaire [Internal Monaissch. 
 f Anat. und Physio 1890 ) 
 
 M. Morgenstern. Entwicklungsgeschichte der Zahne. in Handbucli der 
 Zahnheilk. von J. Scheff, Jr AVien, 1891. 
 
 Y. V. Ebner Histologie der Zahne. Handbuch der Zahnheilk von J. Schetf, 
 Jr AYien, 1891. 
 
 K EOsE tJber die Zahnentwicklung der Eeptilien [Dent Monaissch. f 
 Zahnheilk. 189-2) 
 
 K. EOsK. Uber die Entwieklung der Zahne des Menschen. [Arch. f. Micro. 
 Anat. 1891.)
 
 LITERATURE. 627 
 
 K. KOsE. Uberdie Entwicklung des Mensclilichen Gehissos. {Vcrh. d. Dent. 
 Od'ont. Gesell. Bd. III.) 
 
 K. KOSE. Modellft zur Di'moiistnitiiHi der Entwickluii^- dcr Ziihne des Meii- 
 schen {Vf-rh. d Dnif Odoni. Geftell. Bd, IV.) 
 
 K. KosE. Uber die Schmelzlosen Zalinnidiment(> dos Men.scheii. ( Verh. d. 
 Deut. Odont. Gesell Bd. IV.) 
 
 K. RO.iE. Contributions to the Hi.<togeiiy and Histology of the Bony and 
 Dental Tissues. {Denial Cosmos. A"ol. XXXV.) 
 
 M. MoRGENSTERX. Vorlaufigc Mittheilung liber das Vorkommen von Nerven 
 in den harten Zahnsubstanzen. [Driif MoiHitsscJi. f. ZdhnlieUh 1892.) 
 
 O Walkhoff. Neue Untersucliungen iiber die Pathohistologie des Zahnbeins. 
 {Deut Monaissch. f ZahnheUk. 1892.) 
 
 F. Abbott. Congenital Defects in Enamel {Dental Cosmos. 1891.) 
 
 J. W. DuNKERLEY. The Development, Forms, Structure, and Modes of At- 
 tachment of Teeth, Human and Comparative {British Journal of Dental Science. 
 1890 ) 
 
 C. S. Tomes Studies on the Growth of the Jaws. (Trans. Odont. Soc. Gr. 
 Britain. 1891 ) 
 
 A. Hopewell. On a Xew Method of Preparing Sections of Teeth and Bone, 
 to Demonstrate the Hard and Soft Tissues in Combination. (Trans. Odont. Soc. 
 Gr. Britain. 1891 ) 
 
 W. R. Garrould. Some Observations on the Development, Diseases, and 
 Deformities of the Upper Jaw. {British Journal of Dental Science. 1891.) 
 
 J. I. Hart. Minute Structure of Dentine. {Dental Cosmos. Vol. XXXIII ) 
 
 "VV. C. Barrett The Condition of the Dentine in Pulpless Teeth. {Dental 
 Cosmos. Vol. XXXIV ) 
 
 G. H. McCaxt.sey. Enamel, Dentine, and Xerve. {Dental Review. 1892.) 
 G H. McCausey. Development of the Teeth. {Dental lieriew. 1891.) 
 
 J HirMPHREYS. The Development of Human Teeth. {Mimthhj Reriew of 
 Dental Surgery. 1892) 
 
 A H. Smith. Some Points on the Patho-Hi.stology of the Dental Pulp. 
 {Monthly Review of Deyital Surgery. 1892.) 
 
 C. Heitzmann and F. A. Roy. Contributions to the Minute Anatomy of 
 the Cementum {Intern. Dent. Jour. 1892.) 
 
 R R Andrews. A Contribution to the Study of the Development of the 
 Enamel. {Intern. Dent. Jour. 1893.) 
 
 A. H. Smith Some Observations on the Cellular Elements of the Dental 
 Pulp. {British Journal of Dental Science 1893.) 
 
 A. V. Brunx. Beitrage zur Kenntniss der Zahnentwicklung. {ArcJi.f. Micro. 
 Anat 1891.) 
 
 — Ballowitz. Das Schmelzorgan der Edentaten, etc. {Arch. f. Micro. Anat. 
 1892.) 
 
 C. R5.se Beitrage zur Entwicklung der Edentaten. {Anat. Anzeiger. 1892.) 
 
 P. Frei-xd Beitrage zur Entwicklungsgechichte der Zahnanlagen bei Nage- 
 thieren. {Arch f. Micro. Anat 1892 ) 
 
 R. Mahx. Bau und Entwicklung der Molaren by Miis und Arvicola. Er- 
 langen, 1891.) 
 
 E. Zuckerkaxdl Uber das epitheliale Rudiment eines 4"" Malilzahns beim 
 Menschen. {Akad d. Wissensch. Wien, 1892.) 
 
 G. RUDAS. Uber mangelhafte Entwicklung dor Ziihne und der Zalingewebe. 
 {Odontoskop. 1893.)
 
 628 LITERATURE, 
 
 G. RuDAS. tJber eine auf der Zalmwurzel seltener Leobat'hteten Veranderung 
 {Odontoskop. 1893.) 
 
 G. RuDAS. Von den Interglnbular-rviiumen. [fldoidoskop. 1893.) 
 
 G. Eetzius. {Deid. MonaUschr.f. Zahnhfilk. 1893. P. 59.) 
 
 H. BuRCHARD. Amelitication and Epithelial Development. {Dental Cos- 
 mos. Vol. XXXVI.) 
 
 W. E. Christexsex. Dr. WeiVs Method of Preparing Teeth for Microscopical 
 Study. [Dental Cosmos. Vol. XXXVI.) 
 
 J. ScHAFFER. tJber Roux'scheKanaleinmen«'hlichen Zjihnen Leipzig, 1890 
 
 C Rose. Uber die Nervenendigungen in den Zahiien. [Deut. Mo7iatssehr.f. 
 Zahnhe'dk. 1893.) 
 
 W. Lepkowski. Beitrag zur Histologie de.- Dentins niit Angabc einer neuen 
 Methode [Anat. AnzeAger. 1892 ) 
 
 J. H. Mummery Einige Punkte uber Structur und Entwicklung des Dentins. 
 (Philos. Trans of the Royal Society of London. 1893.) 
 
 E. Magitot. Contribution a Ihistoire des mutilations dentaires. {Revue et 
 Arch. Suisses d'Odontologic. Dec, 1890.) 
 
 O. Walkhoff. tJber die Bedeutung des Vitalen Princips im Zahnbein 
 {Deut. Monatsschr.f. Zahnheilk. 1893.) 
 
 G. Carpenter and R. D. Pedley. Primary Dentine in its Relation to Rickets 
 {Lancet. 1892.) 
 
 CHAPTER XVI. 
 
 J. HuTCHiNsox. On the Influence of Hereditary Syphilis on the Teeth 
 (Trans. Odont. Soc. Gr. Britain. 1850 and I8«0.) 
 
 E. W. Richardson. Medical History and Treatment of Diseases t)f the Teeth, 
 etc London, 1860. 
 
 L. Down. (Trans. Odont. Soc. Gr. Britain. 1871 ) 
 
 E. Magitot. Traite de la Carie Dentaire Paris, 1867. 
 
 H.W.Williams. Recent Advances in Ophthalmic Science. Boston, 1881. 
 
 B. Hell, Eftects of Syphilis on the Teeth and Mouth. {Monthly Reriew of 
 Dental Surgery. London, 1872.) 
 
 T. B. Hitchcock. Syphilitic Teeth. {Johnston s Dental Miscellany 1874.) 
 
 C. T. Cvjhman. a Curious Case of Anomalous and !N"on-development of 
 Teeth. {Am Jonr. of Dent. Sci 1855.) 
 
 C. T. Cu-shman. Entire Absence of all the Teeth. {Am. Jour, of Dent. Sci. 
 1855 ) 
 
 J. L. Levison. On Dental Deformities. {Atn Jour, of Dent. Sci. 1856.) 
 Dr. CoLBURX. Anomalous Development, etc. {A7n. Jour, of Dent. Sci. 1856.) 
 S. WiLK.s. Hereditary Syphilis {Dental Cosmos. Vol. VIII.) 
 S. WiLKs. Malformed Tooth from Hereditary Syphilis. {Dental Cosmos. 
 
 Vol. VIII. P. 280.) 
 
 G. H. Perixe. Congenital Atrophy of Temporary Teeth. {Missouri De^it. 
 
 Jour. 1876.) 
 
 J. W. White. Syphilitic Teeth. {British Journal of Dental Science. 1884.) 
 J. Hutch ix'.sox. A Surgeon on Certain Diseases and Malformations of the 
 
 Teeth. (Trans Odont Soc Gr. Britain. 1888.) 
 
 H. Moox. On Irregular and Defective Tooth Development. {Johnston's 
 
 Dental Miscellany 1877.) 
 
 D. B.. Freeman. The Effect <.f Eruptive Diseases on the Teeth. {Dental 
 Review. 1890.)
 
 LITERATURE. 629 
 
 J. S. Dodge, Jr. Anomalous Affections of the Toetli. (.-Iw* Jonr. of Dent. 
 Sci. 1859) 
 
 O. Y. ZsiQMONDY. On Congfnital Defects of the Enamel. [Intern. Dent. 
 Jour. 1893.) 
 
 M. Napikk. ^Manifestations of Syphilis in the Teeth. [Denial Cosmos. Vols 
 XVIII. and XIX.) 
 
 — Cartwright. Syphilitic Teeth. [Denfnl Cosmofi. Vol X;VIII.) 
 
 — QuiNET. On Syphilitic Teeth. [Dental Coamos. Vol. XXII.) 
 
 F. Abbott. Studies of the Pathology of Enamel of Human Teeth, etc 
 [Dental Cosmos. Vol. XXVII ) 
 
 E. L. Keyes. The Hutchinson Teeth. [Dental Cosmos. Vol. XXVII.) 
 
 A. H. Thompson. Pathological Heredity and Gouty Teeth. [Denttd Cosmos. 
 Vol. XXVIIT.) 
 
 J. Hutchinson. Syphilitic Teeth. [Dental Cosmos, Vol. XXXI.) 
 
 0. ZsiGMONDY'. Congenital Defects of the Enamel. [Dental Cosmos. Vol. 
 XXXV.) 
 
 A. G. Friedrichs. Syphilitic Teeth. (Trans. Am Dent Ass. 1883.) 
 
 H. Moon On Irregular and Defective Tooth Development. (Trans. Odont. 
 Soc. Gr. Britain. 1876 ) 
 
 O. Walkhoff. Die Defecte der harten Zahnsulistanzen ohne Erweichung. 
 [Deut. Monatsschr.f. Zahnheilk. 1886.) 
 
 J. ScHEFF, Jr. tJber Rudimentiire (Schmelzlose) Zilhne [Deut. MonatsscJtr . 
 /. Zahnheilk. 1888.) 
 
 Ed. AlbWEcht. Hei-editiire Syiihilis und Ahnorme Zahnliildung. [Dent. 
 Vier. Jahrsch.f Zahnheilk. 1862.) 
 
 M. Parrot. La Rhachitis et la Syphilis hcreditairc (Trans. Intern. Med 
 Congress 1881.) 
 
 CHAPTEPt XVTTT. 
 
 E. Magit(jt Concerning the Syphilitic Origin of llhachiti.s. [Archives of 
 Dentistry. 1885.) 
 
 — BoHN. Rhachitis and Dentition. [Dental Cos)nos. Vol. XI ) 
 
 C. C. RiTCHfE Rickets a Cause of Late Dentition. [Dental Cosmos. Vol. 
 XIII.) 
 
 — Edes. Rhachitic Cat. [Dental Cosmos. Vol. XVII.) 
 
 — Seemann. Pathogenesis and Etiology of Rhachitis. [Dental Cosmos. Vol. 
 XXIL) 
 
 M. Parrot. Hereditary Syphilis as the Constant Cause of Rickets. [Dental 
 Cosmos. Vols. XXIII and XXV.) 
 E. H. Bradford. Causation of Rhachitis. [Dental Cosmos. Vol. XXIII.) 
 J. M. Keating. The Rhachitic Diathesis. [Dental Cosmos. Vol. XXV.) 
 M, Kassowitz. Pathogenesis of Rhachitis [Dental Cosmos. Vol. XXVII.) 
 
 — . Hereditary Syphilis. [Dental Cosmos. Vol. XXVII.) 
 
 — . Rickets and Syphilis [Dental Cosmos. Vol XXX.) 
 
 — BoucHUT. De la Syphilis comme cause de Rhachitisme et de Malformation 
 dentaire. (Trans Intern. Med Congress. London, 1881.) 
 
 CHAPTER XIX. 
 
 W. II. Atkinson. Dental Pulps. [Denial Cosmos. \o\. .\.) 
 J. Brockway. Dental Pulp, etc. [Dental Cosmos. Vol. X.)
 
 630 LITERATURE. 
 
 L. C. Ingersoll. The Relations of the Tooth-Pulp to the other Tooth-Tissues. 
 {Dndal Cosmos. Vol. XXXI.) 
 
 W. X. SuDDUTH. The Dental Pulp. {Denial Cosmos. Vol. XXXIII.) 
 
 C. P. W BOdecker. The Minute Anatomy, Physiology, Pathology, and 
 Therapeutics of the Dental Pulp (Trans. N. Y. Odont. Soc. 1881.) 
 
 J H. McGatsey. The Pvelations of the Tooth-Pulp to the other Tooth-Struc- 
 tures. (Trans X. Y. Odont. Soc. 1890.) 
 
 P. Y. Cl.\rk. Diseases of the Dental Pulp. (Trans. Am. Dent. Ass. 1868.) 
 
 CHAPTER XX. 
 
 C. Wedl. ijher Gefassknauel im Zahnperiost. [VlrcJioir's Archli). 1881.) 
 
 L. C. Ingersoll. The Alveolar Dental Membrane, etc [Dental Cosmos. 
 Vol. XXVII.) 
 
 I. P. "SViLSOK. The Apical Portion of the Ct'mentum, Physiologically and 
 Pathdlogically Considered. {Dental Cosmos. Vol. XXX ) 
 
 — HoHL Die Befestigung des Zahns in der Alveole {Dcut.Vier. Ja/u-sc/i f. 
 ZahnhcUk. 1867) 
 
 S Bennett. The Adaptation of the Teeth to the Alveolar Process. {Monthly 
 Revieiv of Dental Surgery. 1884.) 
 
 F Harri.son. Notes on the Alveolar Dental Membrane {Monthly Review 
 of Dental Surgery. 1884.) 
 
 CHAPTER XXI. 
 
 G. W. Ellis. Dcntitinn, etc. {Dental Cosmos. Vols. VIII, IX, X ) 
 
 J. D White. First Dentition. {Dental Cosmos. Vol. XXVII.) 
 
 C. N Peirce. The Deciduous Teeth : Their Eruption and Removal. (Trans. 
 Am. Dent. Ass. 18«7.) 
 
 R Baxjme. Der Durchbruch der Zahne {Dent. Vicr. Jahrsch. f. Zahnhcilk. 
 1873.) 
 
 31. EicHLER. Dentition. (In llandb. der Zahnheilk., von J. Schetl', Jr. 
 Wien, 1891.) 
 
 O.Fiedler. Uber die Erste Zahnung. Halle, 1891. 
 
 R HoERNES. Zur Kenntniss der Milchbezahnung. Wien, 1892. 
 
 AV. H. Flower Notes on the First or Milk Dentition of the ^Mammalia. 
 (Trans. Odont Soc Gr. Britain 1870.) 
 
 CHAPTER XXII. 
 
 W. H Elliot. Absorption of Dental Bone. {Am. Jour, of Detit. Sci. 1847.) 
 J. H. McQuillen Absorption of the Roots of Deciduous Teeth. {Penn. 
 Jour, of Dent. Sci. 1874.) 
 
 J. H. McQuillen. Absorption of the Fangs of Decidu<nis Teeth. {Dental 
 Cosmos. 1860.) 
 
 C. N. Peirce. Calciticatinn and Decalcitication of the Teeth. {Dental Cosmos. 
 Vol. XXVI.) 
 
 W. X. SuDDtrni. Res!)rpti<m of Tissue. {Dental Cosmos. Vol XXVIII.) 
 F. Abbott. Microscopical Studies upon the Absorption of the Roots of Tempo- 
 rary Teeth. {Dental Cosmos.) 
 
 F. Akbott. Report on Physiology. (Trans. Am. Dent. Ass. 1867.) 
 J. H. McQuillen. Absorption of tlic Roots of the Deciduous Teeth. (Trans. 
 Am. Dent. Ass. 187o.)
 
 LITERATURE. G31 
 
 E. SciiWAKTZKOPF. Kesorption der Zabnwurzdn ]m rifguliningeu. [Jhni. 
 Monatsschr. f. Zahnheilk. 1887.) 
 
 J. Pakreidt. Vollstandige Resorption dcs Zalmbein.s eincs ^Milchzahiis 
 {Deut. Motiatsschr. f. Zahnheilk. 1890.) 
 
 J. V. Mettkitz. Das Sohwinden der Mik-hzitlinwurzeln. "Wien, 1889. 
 
 H. J. L. Struiken. Die Kesorption der Milchzahne und die Odontoklasten. 
 {Ceniralhl. f. d. Med. Whs. 1890.) 
 
 G. H. Hardikg. On the Proce-ss of Absorption in Bone and Tooth-Structun- 
 (Trans. Odont. Soc. Gr. Britain. 1877.) 
 
 W. K. Bridgeman. On the Ab-sorption of Bone and Dentine. (Trans. Odont 
 Soc. Gr. Britain 1861.) 
 
 C H A P T E Pv X X I Y. 
 
 J. M. Keevil. The Physiology and Treatment of Sensitive Dentine. (Brit- 
 ish Journal of Dental Science. 1890.) 
 
 T. Gadde8. Notes on the Anatomy, etc , in Pelation to Dental Diseases. 
 
 {Dental Review. 1891 ) 
 
 A. Harris. Characteristics of the Teeth, etc. [Am. Joitr. of Dent. Sci. 
 
 1841.) 
 
 C. N. Peirce. Dental Diagnosis. [Intern Dent. Jour. 1893.) 
 
 H. S. Chase History of Dental Calculi. {Missouri Dent Jnu-. 1869.) 
 
 E. C. Chase The Causes of the Deposition of Salivary Calculus. {Missouri 
 
 Dent. Jour. 187-2.) 
 
 H. JuDD. Of Dental Tartar, etc [Missouri Dent. Jour. 1874.) 
 
 L. C. Ingersoll. Diagnosis. {Missouj'i Dent. Jour. 1878) 
 
 G. B. Clement. Dental Pathology. [Archives of Dentistry. 188G.) 
 
 A. Forget. Dental Anomalies, etc [Dental Cosmos Vol. I.) 
 
 A. Robertsox. Effects of Disease on Teeth' [Dental Cosmos. Vol. 1 ) 
 
 T. Laycook. On Physiognomical Diagnosis of Disease. [Dental Cosmos. 
 
 Vol. III.) 
 
 W. H. Atkinson. Teiapei'ament [Dental Cosmos Vol VI.) 
 
 — Hodges. Salivary Calculi. [Dental Cosmos Vol. VII ) 
 
 H. S. Chase Tartar: Its Conservative Effects {Dental Cosmos Vol. VII.) 
 
 J. McManus Diagnosis [Dental Cosmos. Vol VII ) 
 
 G. J. Ziegler. Temperaments, etc [Dental Cosmos. Vol. VIII.)* 
 
 G. J. Ziegler. Influence of Extreme Cold, etc [Detital Cosmos. Vol. IX.) 
 
 . Illuminating the Interior of the Living Body. [Denial Cos)nos. 
 
 Vol. IX.) 
 
 G. J. Ziegler. On Heat in its Vital Relations. {Dental Cosmos. Vol. IX.) 
 M. Bazin. Differential Diagnosis between Syphilis and Scrofula. {Dental 
 
 Cosmos. Vol XII.) 
 J. L. "Williams. Tlie Influence of the Nervous System on the Health of tlie 
 
 Teeth and Mouth. [Dental C.snws Vol XIV.) 
 
 J. E. Garretson. Diagnosis in X'euralgia [Dental Cosuujs. Vol. XV.) 
 
 A D. Williams. Care in Diagnosis. [Dental Cosuujs. Vol. X\'I.) 
 
 J. C. Scott. Diagnosis. [Dental Cosmos. Vol. XVI. ) 
 
 A. Miller. Neuralgia Caused by Granules of O.steo-Den tine. [Dental Cosmos. 
 
 Vol XVI.) 
 
 L. G. Noel. Rheumatic ^Farkings upon the Teeth. [Dental Cosmos. Vol 
 
 XVII.) 
 
 E. D. S. NiLEs. Odontolithus, etc. [Dental C»s)nos. Vol. XXI II.)
 
 632 LITERATURE. 
 
 L. Elsbero. Electric Illumination and Cautery of the Mouth. [Dental Cos- 
 mos, Vol. XXIV.) 
 
 E. Magitot. Ditterontial Diagnosis of Tic Douloureux and Dental Neuralgia. 
 (^Dental Cosmon. Vol. XXVI ) 
 
 C. J. EssiG. Differential Diagnosis, [Denial Cosmos. Vol. XXVI ) 
 
 W. C. Phillips. Transilluminiition of the Antrum, etc. [Dental Cosmos. 
 Vol. XXXIII.) 
 
 W. H. METCALr. Dental Diagnosis [Denial Cosmos. Vol. XXXV.) 
 
 O. WiTZEL. Die Affectionen des Mundes bei Diabetes mellitus. [Dent. Vier. 
 Jahrsch.f. Zahnheilk. 1879 ) 
 
 G. NiEMEYER. UnsicliereDiagnosen. [Deni. Vier. JahrseJt.f. ZaJinhellk. 1882.) 
 
 J. Parreidt. Zur Diagnose der Pulpareizung und des emptindlichen Zahn- 
 beins [Dcut.'Monai.^schr f. Zahnheilk. Ib83 ) 
 
 R. F. H. KiKG. Some Points in Dental Diagnosis. [British Journal of Dental 
 Science. 1885.) 
 
 L. Elsberg. (Trans New York Odont. Soc. 1881.) 
 
 W. Freudenthal. Die Durchleuchtung in der Laryngologie. [Med, Wo- 
 chcnschr. 1889.) 
 
 T. Heryng. Die Electrische Durchleuchtung der Highmorshohle bei Empvem. 
 [Berliner Klin. Wochensch?'. 1887.) 
 
 — ZiE.M. Durchleuchtung der Oberkieferhohle. [BerHner Klin. Wochenschr. 
 1890.) 
 
 — VoHSEN. Zur Electrisclien Beleuchtung und Durchleuchtung der Korper- 
 liohlen. . [Berliner Klin. Wochrnsciir. 1890.) 
 
 — Srebrny. Zur Erage der Durchleuchtung der Oberkieferhohle bei Enipyem 
 derselben. [Berlhier Klin Wochenschr. 1890.) 
 
 W. D. Miller. The Deposits upon the Teeth, with Special Pveference to Green 
 and Metallic Deposits [Denial Cosmos 1894.) 
 
 M. Bastyr. Die Zahnbeljige. (In Handb. der Zahnheilk., von J. Scheff, Jr. 
 Wien, 1892.) 
 
 K. OTTOLENGiri. [Denial Cosmos Vol. XXXIV. P. 707.) (Trans. Dent. 
 Soc. State of New York 1898 and 1894 ) 
 
 T. Heryng. The Electric Light in Empyema of the Antrum. [British Journal 
 of Dental Science. 1 889. ) 
 
 J. Maitghan, Remote Pain in Dental Disease. (Trans. Odont. Soc. Gr. 
 Britain. 1893.) 
 
 CHAPTERS XXV-XXVII. 
 
 J.M.Howe. Secondary Dentine (Trans. N. Y. Odont. Soc. 1877.) 
 
 G. Blume. tjber die fortwahrende Verknocherung ini Zahnkanale. [Der 
 
 Zahnarzt. 1851 ) 
 
 W. DiECK. Dentin Neubildungen von Seiten derdurch eine ZahnfVactur 
 
 freigelegten Pulpa, etc. [Verh. d Deal Odoni Gcsell. Bd. II.) 
 
 R. Hohl. tJber die Entwicklung der inneren Odoutome. [Deid Vier. Jahrsch. 
 
 f. Zahnheilk. 1872.) 
 
 R. Baume. Bemerkungcn iiber interstitiolle Dentikel. [Dcut. Vier. Jahrschr. 
 
 /. Zahnheilk. 1874.) 
 
 G Henry. Remarks on " Inostosis." (Trans Odont. Soc. Gr. Britain. 1871 ) 
 
 J. F. Flagg. Tubular Condensation. [Denial Neivs Letter. 1857.) 
 
 J. H. MoQuillen. Caries Arrested by Consolidation of the Dentinal Tubules 
 
 [Dental News Letter. 1859.)
 
 LITERATURE. 633 
 
 A. F. TowNSEND. Abrasion of the Teeth. {Dental Cosmos. Vol. XXXII.) 
 
 J. Taft. Abrasion of the Teeth. {Am. Joxr. of Dent. Sid. 1847.) 
 
 R. E. AxDREW.s. {Intn-ii. Dnd. ,Ji,nr. 1889. F. 109. (Reaction of Fillings.) 
 
 CHAPTER XXYIII. 
 
 C. H. KoBixsoif. Abrasion and Erosion. {Dental Review. 1889.) 
 
 E. Brooks. Erosion of the Enamel. {Dental News Letter. 1852.) 
 J. D. W. Tooth Edge. {Dental News Letter. 1857.) 
 
 J. 31. Howe. A Contribution to the Study of Erosion. {Intern. Dent. Jour. 
 1893.) 
 
 L. A. Obrian. ■ Erosion. . {Dental Cosmos. Vol. XXX.) 
 
 I. B. Davenport. Etiology of Chemical Abrasion, etc. (Trans. Am. Dent. 
 Ass. 1881.) 
 
 J. C. TiLGE. Uber die Atrophic und Erosion der Zahne. {Der Zahnnrzt. 
 1846.) 
 
 — Reid. iJber die Er'isicm der Ziihne. {Der Zahnarzf. 1848.) 
 
 — Albrecht. Atroi)hie und Erosion der Zahne und Folgen von Ernahrun^s 
 storungen zur Zeit der Zahnbildung. {Der ZaJinarrJ, 1861.) 
 
 L. H. Hollander. ttlH-r Erosion der Zahne. ( Verh. d. Dent. Odmit. Gesell. 
 Bd. I.) 
 
 O. ZsiGMONDY. tlber die Enstehung der Keilformigen Einschnitte an der 
 Facialseite der Zahnhillse, etc. {Dent. Vier. Jahrseh. f. ZahnheUk. 1873.) 
 
 R. Baume. Die KeilfLirniigen Defects an den Zahnhiilsen, Zei-storung der Zahii- 
 substanzen durch Alivalien. {Dent. V'ler. Jahrseh. f. ZahnheUk. 1876.) 
 
 — Herrmax. Alirasioii derZiilme. {Deut. Vier. Jahrseh. f. ZahnheUk. 1879.) 
 
 — Niemeyer. Die Keilformigen Defccte. {Den't.Vier. Jahrseh. f. ZahnheUk. 
 1879.) 
 
 Gr. V. Black. Abrasion and Erosion of the Teeth. (American System of 
 Dentistry. Philadelphia, 1886.) 
 
 F. BusCH. Uber die Entstehung der Erosionen an den Kronen der Zahne. 
 {Deut. Med. Wochenschr. 1886.) 
 
 W. K. Bridge.man. On the Electro-Chemical Action of Metallic Substances 
 
 upon the Teeth. (Trans. Odont. Soc. Gr. Britain. 1869.) 
 E. C. Kirk. Erosion. {Intern. Dent. Jonr. 1886.) 
 C. R. E. Koch. Abrasion and Erosion. {Dental Cosmos. Vol. XV.) 
 C. A. Kingsbury. Abrasion of the Teeth. {Dental Cosmos. Vol. XX.) 
 C. E. Kells. Erosion. {Dental Cosmos. Vol. XXXIII.) 
 E. T. Darby. Dental Erosion and the Gouty Diathesis. {Dental Cosmos. 
 
 Vol. XXXIV.) 
 
 H. JuDD. Spontaneous or Chemical Abrasion. {Missouz-i Dent. Jour. 1873.) 
 M. Bastyr. Die Erworbenen Defecte der harten Zahnsubstanz. (In Handb. 
 
 der Zahnheilk., von J. Scheff, Jr. Wien, 1891.) 
 
 A. S. Underwoob. On Erosion in Connection with Some Points in thr .Minute 
 
 Anatomy of Enamel. (Trans. Odont. Soc. Gr. Britain. 1888.) 
 
 S. J. Hutchinson. A Note on Erosion. (Trans. Odont. Soc. Gv. Britain. 
 
 1888.) 
 
 A. Coleman. Erosion "f the Tectii. {Monthli/ Review of Dmtal Snriimi. 
 
 1881.) 
 
 S. G. Perry. Erosion of the Teetii. {Intern. Dent. Jonr. 1893. ) 
 
 42
 
 634 LITERATURE. 
 
 C. H. Robinson. Abrasion and Erosion. {Denfnl Reviem. Yo). III.) 
 G. J. Friebriohs. Erosion of the Teeth. {Do/fal ('osj)ws. Vol. XXI.) 
 L. A. Obrian. Erosion. [Denial Cos^ios. Vol. XXX,) 
 
 W. H. Trueman. Erosion. {Intc>-Ji. Dtnt. Jour. 1891.) 
 
 CHAPTER XXX. 
 
 Dr. Perry. Exostosis. [Denial News Leiter. 1853.) 
 S. M. Shepherd. Alveolar Exostosis. {Am. Jo?ir. of Deut. Sci. 1841.) 
 J. Robinson. Dental Exostosis. [Am. Jour, of Dent. Sci. 1846 ) 
 M. Roux. On Exostosis. [Am. Jour, of Dent. Set. 1848.) 
 
 D. Vandenburgh. Observations on Exostosis. [Am. Jour, of Dent. Sci. 
 1850.) 
 
 W. C. Barrett. Exostosis or Dental Osteoma. [Indep. Pract. 1886.) 
 H. S. Chase. Exostosis. [Missouri Dent. Jour. 1875.) 
 
 E. L. WiLLARD. Exostosis of the Fang of a Tooth, with Osteo-Sarcoma of the 
 Maxilhirv Bone. [Denial Cosmos. Vol. VIII.) 
 
 J. H. McQuillen. Case of Cemental Hypertrophy. [Denial Costnos. Vol. 
 XIII.) 
 
 F.Abbott. Hyperostosis of Roots of Teeth. [Dental Co.^mos. Vol. XXVIII.) 
 J. E. Cravens. Dental E.vostosis, (Trans. N. Y. Odont. Soc. 1881.) 
 G. Welland. Einige Worte iiber die Exostosen der Ziihne. [Drr Za/marzi. 
 1846.) 
 
 G. A. Oenicke. Uber Hypertrophia dentium. [Der Znhnarzt. 1848.) 
 W. Reichel. tlber Gesichts- und Kopfschmerzen als Folge von krankhaft 
 verjinderten Zahnwurzeln, hauptziichlich von Exostosen derselben. [Der Znhn- 
 arzt. 1852.) 
 E. Kroenele. tjber eine Exosto.se, etc. [Der Zahnarzt. 1854.) 
 L. A. AVeil. Uber Cementhyperplasie. [Oest. Ung. Vler. JahrscJir. f. 
 Zahnheilk. 1891.) 
 
 D. Headridge. a Case of Ditfuse Osteoma of the Lower Jaw. [Brifls/i 
 Jinirnal of Dental Science. 1893.) 
 
 D. E. Caush. Exostosis. (Trans. Odont. Soc. Gr. Britain. 1890.) 
 
 CHAPTER XXXI. 
 
 C. RoKiTANSKY. Handb. d. Allg. Patliol. Anat. 1846. 
 
 C. RoKiTANSKY. Uber das Auswaohsen der Bindegewebssubstanzen und die 
 Beziehung dersellien zur Entziindung. [Sitzioifisher. der Wiener Akad. dcrWiss. 
 1854.) 
 
 R. ViRt'How. U])er Parenehyniatose Entziindung. [Vij-choiv's Arch. Bd. 
 IV. 1852.) 
 
 R. ViRonow. U])er die Theilung der Zi'llenkerne. [Vi7-chou''s Arch. Bd. 
 
 J. Cotinheim. Uber das "S'orhalten der tixen Bindegeweliskorperclicn l>ei der 
 Entziindung. [Virchon;'s Arch. Bd. XIV.) 
 
 — Waller. [PhUo.'^oph. Magazine. 1846.) 
 
 S. Strk'KER. Studien viber den Ban und das Le])en der Capill. Blutgefasso- 
 [Sitzmuishcr. d. Wiener Akcid. der Wins. 1865.) 
 
 J. Cghnhkim. Uber dii' Kntziindimg und Kiterung. [Virc)ioie's Arch. 
 Bd. XI.)
 
 LITERATURE, 635 
 
 S. Stricker. Studien aus dcm lustitutt- f. ExpL-rimontoUi- I'utlioloi^ML- in 
 Wien, 1870. 
 
 Also a series of articles by Stricker and some of his pupils in the Wiener Med. 
 Jahrb., 1871-1881. 
 
 C. Heitzmaxx. Studien am Knoclicn und Kuorpel. {Wiener Med. Jahrb. 
 1872.) 
 
 C. Heitzmann. ilber die Ifiick- und Neuhildung von Blutgef:i.ssen in Knoi-hcn 
 und Knorpel. ( Wiener Med. Jnhrb. 1873.) 
 
 C. Heitzmann. Die Entziindung der Beinhaut des Knuchens und dos Kiior- 
 pels. [Sitzungsber. d. Wiener Akad. drr Wifis. 1873.) 
 
 — Eedfern. Abnormal Xutrition in the Articular Cartihiges. London, 1850. 
 
 — KusTiZKY. Untersuchungen iiber Knochenciterung. ( Wiener Med. Jahrb. 
 1871.) 
 
 K. YoLKMAXK. (Langenbeck's yl/rA./. A7i?i. Chirnrgie. 1863.) 
 H LossEX. ( Virchouj's Ar^chiv. Bd. IV.) 
 
 J. HoFMOKL. itber Callusbildung. [Wiener Med. Jahrb. 1874.) 
 P. Gkawitz und W. de Bary. (In Virchow's Arch. 1887.) 
 P. Grawitz. {Virchoii/s Arch. 1887.) 
 
 C. Weigert. {Deid. Med. Wuchcnschr. 1892.) 
 
 G. Klempekek. tjbcr die Beziehungen der Micro-Organismcn zur Eiterung. 
 {Zeitschr.f. Klin. Med. 1885.) 
 
 A. ZuCKERMANX. Ubcr die Ursaclie der Eiterung. [Cenira/b. f. Bacteriologie 
 und ParasM. 1887.) 
 
 R. Koch Aetiologie der Wundinfection<krankh. Leipzig, 1878. 
 
 P. Grawitz. Beitrag zur Therapie der Eiterung. [Virchoic's Arch. Bd. 
 CXYI.) 
 
 Kreibohm und Kosexhach. Experimentelle Bcitriige zur Frage : Kann 
 Eiterung ohne Mitbetheiligung, etc. [Arch. f. Kli)t. Chirnrgie. 1888.) 
 
 — Brieger. Uber Ptomaine. 1885 und 1886. 
 
 — Scheurlex. Weitere Untei-suchungen iiber die Enstehung der Eiterung, ihr 
 "N'erhaltniss zu den Ptomainen und zur Blutgerinnung. [Fortschritte der Med. 
 1887.) 
 
 D. BioxDi. Contributione alletiologia della suppurazione. [Im liifvrma 
 Med. 1886.) 
 
 — Nathax. [Ixv Arch. f. Klin. Chirnrgie. Bd. XXXVII.) 
 
 L. Heitzmaxn. Uber Eiterbildung in der Lederhaut. [Arch. /. Derma- 
 
 tologie. 1892.) 
 
 P. J. Kester. Pus. [Dental licriew. 1890.) 
 
 G. H. McCausey. Inflammation. [Dental Rcvieir. 1888.) 
 
 G. V. Black. Are Micro-Urganisms necessary to Pus-Eormation ? [Dmfa/ 
 
 Revieio. 1887.) 
 
 G. V. Black. Recent Tlieories of the Formation of Pus. [Indep. Pract. 
 
 1887.) 
 
 W. H. Atkixson. Inflammation. [Missouri Dent. Jour. 1878.) 
 
 — UsoKOFF. Suppuration without Micro-Organisms. [Missouri Dent. Jour. 
 1882.) 
 
 G F. Eames. Intimate Nature of Inflammation. [Arch. >>/ Dent. 1885.) 
 J. L. Sl'ESSEROTT. Inflammation. [Denf(d Conmo.i. Xo\. I.) 
 W. II. Atkix.sox. Inflammation [Dental Cosmos, ^'ols. \' and X.) 
 G. J. ZiEGLER. Periscope of Medical and General Science in their Relations 
 to Dt'ntistry. [Dental Cosmos. Vol. VII.)
 
 636 LITERATURE. 
 
 J. F. HiBBERT. Pus-Formation. [Dental Cosmos. Vol. X.) 
 W. H. Atkinson. The Origin of Pus. {Denial Cosmos. Vol. XXXI.) 
 G. S. Dean. Concerning Suppurative Inflammation. [Dental Cosmos. Vol. 
 XXXII.) 
 
 D. E. Stubblefieli). Pus-Formation Ecvived. [Dental Cosmos. Vol. 
 XXXIV.) 
 
 K. B. Winder. The Etiology of Pus-Formation. [Dental Cosmos. Vol. 
 
 XXXV.) 
 
 L. F. Harvey. Inflammation. (Trans. Dent. Soc State of N. Y. 1876.) 
 W. H. Atkinson. Pus. (Trans. Dent. Soc. State of N. Y. 1876.) 
 W.H.Atkinson. Inflammation. (Trans. Dent Soc. State of X. Y. 1878.) 
 G. S. WooDHEAD. On Inflammation in Bone. (Trans. Odont. Soc. Gr. 
 
 Britain. 1893.) 
 
 CHAPTEE XXXII. 
 
 L. Ottofy. Hypertrophy of the Oral Mucous Memhranc. [Dental Review. 
 
 1892.) 
 
 A. C. Hugensc'hmidt. Lingual Ulceration of an Epitheliomatous Appearaiu-o 
 
 due to an Upper Full Artificial. Denture. [Dental Review. 1892.) 
 
 C. A. Harris. Diseases of the Gums. [Am. Jour, of Dent. Sci. 1841.) 
 
 H. H. Hayden. The Diseases of the Gums. [Am. Jour, of Dent. ScL 
 
 1841.) 
 
 G. Waite. The Gums, etc. [Am. Jour, of Dent. Sci. 1841.) 
 
 L. KoECKER. Extraordinary Fungous Disease of the Gums, etc. [Am. Jour. 
 
 of Dent. Sci. 1843.) 
 
 A. A. B. Diseases of the Mucous Memhrane, etc. [Am. Jour, of Dent. Sci. 
 1866.) 
 
 Dr. Goddard. Hypertrophy of the Gums. [Dental Register. 1856.) 
 
 E. B. Eey'Nolds. Mercurial Stomatitis, etc. [Am. Jotir. of Dent. Sci. 1856.) 
 H. S. Chase. Inflammation of the Gums and Lips. [Missouri Dent. Jour. 
 
 1870.) 
 
 Dr. Williamson. Aphthous Disease of Dentition. [Missouri Dent. Jour. 
 1874.) 
 
 H. JuDD. Gingivitis in Pregnant Women. [Missouri Dent. Jour. 1877.) 
 
 — ■ . Acute Ulitis. [Archires of Dentistry. P. 95. 1885.) 
 
 J. G. Templeton. Calcic Inflammation. [Archives of Dentistry. 1889.) 
 J. P. H. Brown. Morhid Growth of the Gums. [Dental Cosmos. Vol. I.) 
 
 — GooDE. Cancrum Oris. [Dental Cosmos. Vol VI.) 
 
 — CociiRAN. Cancrum Oris. [Dental Cosmos. Vol. IX.) 
 
 T. AVaterman. Hypertrophy of Gums. [Dental Cosmos. A'ol. XL) 
 T. E. Gly'NN. Cancrum Oris. (De7ital Cosmos. Vol XII.) 
 
 — Cripps. Cancrum Oiis. [Dental Cosmos Vol. XXII.) 
 
 — Cleveland. Cancrum Oris. [Dental Cosmos. Vol. XXIII.) 
 
 J. S. Cohen. Syphilitic Inflammation of Gums. [Dental Co.^mos. Vol. 
 XXV.) 
 
 W. Bryden. Case of Cancrum Oris in the Adult. [Dental Cosmos. Vol. 
 XXV.) 
 
 Prof. Monti. Aplithous Stomatitis. [Dental Cosmos. Vol. XXVI.) 
 
 Prof.- Monti. Cancrum Oris. [Dental Cosmos. Vol. XXVI.) 
 
 B. ^I. Ekkktts. Oidium Alhicans. [Dental Cosmos. Vol. XXIX.)
 
 LITERATURE. 637 
 
 J. D. Patterson. Diseases of the Oral Mucous ;Membrane. {Dental Cosmos. 
 Vol. XXXIII.) 
 
 E. C. KiNQSFORD. Caucruiu Oris. [Dental Co.Hmos. Vol. XXXIV.) 
 
 J. W. HisEY. A Case of Extensive Hypertrophy of the Gums. {Denial Cos- 
 mos. Vol. XXXV.) 
 
 J. Lefoitlox. tjber die Krankhoiten des Zahntteisches. {Dei- Zahnarzt. 1855.) 
 
 C. Krakait. Stomatitis Gangnenosa. {Deid. Monaf.ischr.f. Zohnhellk. 1885.) 
 W. D Miller. Ein Beitrag zur Aetiologie der Leucoplakia oris. {Deui. 
 
 Monntsschr. f. Zahnhnlk. 1892.) 
 
 — BoHN. Die Mundkrankheiten. (Gerhard's Haiidb. der Kiiidorkranklieiten. 
 Tiibingeii, 1880.) 
 
 G. ScHEFF. Erkraiik. d. Mundsfhleiiiihaut. (Haudb. der Zahnheilk. Wien, 
 1892.) 
 
 H. Paschkis. Syphilis des Muiides. (Handb. der Zahnheilk., von J. Seheff, 
 Jr. Wien, 1892.) 
 
 D. M. Sabater. Some Diseases of the Gums, etc. {Intern. Dent. Jour. 1894.) 
 J. ArkOvy. Gingivitis nudata. {Ocst. Ung. Vier. Jahrschr. f. ZaJinheilk. 
 
 1893.) 
 
 — V. KACZOROW.SKI. Dor aetiologischo Zusammenhang zwischen Entziindung 
 des Zahnfleisehes und aiiderweitigeii P]rkrankuiigen. {Dcid. Med. Woch. 1885.) 
 
 — Galippe. Die infectiose arthro-dentiire Gingiviti.s. 1888. 
 
 CHAPTEK XXXIII. 
 
 E. Towx,sENi>. Speeulations upon Inflammation of Dentine, etc. {Dental 
 Neivs Letter. 1853.) 
 
 W. D. Miller. Studies on the Anatomy and Pathology of the Tusks of the 
 Elephant. [Dental Cosmos. 1890-1891.) 
 
 F. BuscH. Zur vergleichenden Pathologic der Zahne, mit besonderer Beriick- 
 sichtigung des Stosszahnes des Elephanten. (Trans. Xinth International Med. 
 Congress.) 
 
 C. Heitzmaxx and C. F. W. BOdecker. Inflammation of Dentine 
 (Eburnitis). {Indep. Prdct. 1886.) 
 
 C. S. Bate. Abscess in the Dentine. (Trans. Odont. Soc. Gr. Britain. 1864.) 
 
 CHAPTEPv XXXIV. 
 
 .1. ArkOvy. On tln' lielations of Pathological Concretions of the Tooth-Pulj> 
 to Prosopalgia (Tic Douloureux). {Monthly Reciew of Dental Surgery. 1882.) 
 
 H. Sewill. The Etiology and Pathology of Dental Disea.ses, etc. {Monthly 
 Review of Dental Surgery. 1882.) 
 
 — Galen, who was born A. D. 131. Systemischcs Handb. der Zahnheilk., von 
 Georg von Carabelli. Wien, 1844. 
 
 Georcui Prochaska. Operum Minorum Anat. Physiol, et Path. Argunienti. 
 Pai-s II. Viennic, 1800. 
 
 — Rousseau. Anat. Comp. du Syst. Dent. Chez JTIoinmect Cliez les Princij*. 
 Anim. Paris, 1827. 
 
 — Easciikow. Mtlftciiiata Circa Manunalium Dentiimm Evolutioncm. 
 Wai-schau, 1836. 
 
 A. Hartung. Vcrlarvte Zahnkrankli. Leij)zig, 1824. 
 J. Bauer. De Odontalgia Mon. 1830.
 
 638 LITERATURE. 
 
 J. G. G. Werth. Die Odontalgie. Berlin, 1836. 
 
 M. MoKGEX.STERN. Einwiinderung von Pilzen in die harten Zuhnsubstanzen. 
 {Deut. Monatssc.hr. f. Zahnheilk. 1882.) 
 
 J. ArkOvy. tJberdie Beziehungen der Pathologischen Concretionen der Zahn- 
 pulpa zur Prosopalgie. {Jou7\ 1883.) 
 
 L. M. Dennis. Beobachtungen iiber Neuralgien, welche von Ziihnen her- 
 ruhren, ihre Diagnose, etc. [Ceiitralbl. f. Zahnheilk. 1884.) 
 
 J. ScHEFF, Jr. Zur Differentialdiagno.se der Pulpiti.s gangraen. total humi., 
 etc. [Oest. Ung. Vier. Jahrschr. f. Zahnheilk. 1887.) 
 
 A. RoTHMAX. Pathologic und Therapie der Pulpakranklieiten. (In Handb. 
 der Zahnheilk., von >J Scheff, Jr. Wien, 1891.) 
 
 M. ScHLENKER. Pulpen Odontinoide. (Handb. der Zahnheilk., von J. SchetF, 
 Jr. Wien, 1891.) 
 
 G. KiRCHNER. Aetiologie, Diagnose und Therapie der Pulpakranklieiten in 
 nichtcariosen Zahnen. {Deut. Monatsschr. f. Zahnheilk. 1892.) 
 
 0. Walkhoff. Eine Conservative Behandlung der erkrankten Zahnpulpa. 
 Leipzig, 1888. 
 
 C. P. W. BOdecker. The Minute Anat., Physiol., and Therap. of the Dental 
 Pulp. [Devtal Cosmos. Vol. XXIV.) 
 
 M. LiPsCHNiTZ. Uber die Atrophien der Pulpa als Folge der Bildung von 
 Ersatzdentin. {Deut. Monatsschr. f. Zahnheilk 1892.) 
 
 R. HoHL. Uber Neubildungen der Zahnpulpa Halle, 1868. 
 
 E. Albrecht. Die Krankheiten der Zahnpulpa. Berlin, 1858. 
 
 H. Friedberg. ilber einige Falle von Heilung der Prnsopalgie, etc. [Vir- 
 chow's Arch. 1860. Bd. 18.) 
 
 — Underwood and Mill.s. An Investigation into the Eft'ects of Organisms 
 upon the Teeth and Alveolar Portions of the Jaws. (Trans Intern. Med. Con- 
 gress. London, 1881.) 
 
 1. A. Freeman. Pulpitis {Dental Review. 1892.) 
 
 H. H. Fitch. Ossification of the Pulp. {Dental Review. 1889.) 
 
 F. H. Badger. Ossification of the Pulp {Am. Jour, of Dent. Sci. 1853.) 
 S. J. A. Salter. Intrinsic Calcification of the Permanent Tooth-Pulp, etc. 
 
 {Am. Jour, of Dent. Sci. 1856.) 
 
 E.D.Swain. Calcific Deposits in Tooth-Pulps. {Indcp. Pract. 1886.) 
 W. P. Cooke. Formations in the Pulp-Cavity. {Intern. Dent. Jour. 1890.) 
 R. Ottolengui. Pulp-Stones : Their Significance, etc. {Intern. Dent. Jour. 
 1892.) 
 
 A. C. Huoenschmidt. Partial Suppurating Puljjitis, etc. {Intern. Dent. 
 Jour. 1892.) 
 
 E. C. Kirk Lime-Formations in the Pulp-Chamber. {Intern. Dent. Jour. 
 18'.l3.) 
 
 H. Judd. Cssification of the Dental Pulp. {Missouri Dent. Jour. 1869.) 
 H.S.Chase. A Calcified Pulp. {Mis.souri Dent. Jour. 1870.) 
 H. S. Chase. Calcification of the Pulp. {Missouri Dent Jour. 1875.) 
 I. Campbell. Loss of Sight by Pulpitis. {Missouri Dent. Jour. 1876.) 
 W. R. Hayes. Calcified Pulp {Missouri Dent. Jour. 1876.) 
 T. O. Oliver. Calcification of Pulp. {Missouri Dent. Jour. 1876) 
 A. H. Thompson. Calcification Nodule. {Missouri Dent. Jour. 1876.) 
 H. S. Chase. Pulp Nodules. {Missouri Dent. Jour. 1876.) 
 W. H. Atkinson. Explosion of Teeth with Audible Report. {Dental Cos- 
 mos. \t>\. II.)
 
 LITEKATURE. 639 
 
 . Explosion of a Tooth. {Denial Cosmos. Vol. VII]. P. 588.) 
 
 J. H. IMcQuii.LKN. Ciilcitication of the Dental Pulp. [Denial Cosmos. Vol. 
 \.) 
 
 S. P. Cutler Ossified Pulps. [Denial Cosmos. Vol. XV.) 
 
 A. Coleman. Spontaneous Fracture of Teeth. [Denial Cosmos. Vol. XXV.) 
 
 W. D. Miller. Gangrenous Tooth-Pulps as Centers of Infection. [Dental 
 Cosmos. Vol XXX.) 
 
 S RoBicsEK. Uber die wichtigsten Consequenzen der in Folge von Caries 
 t'litblossten Zahnpulpa, etc [Dent. Vier. JahrscJi f. Zahnheilk. 1877.) 
 
 L. Hollander Die Odontalgie, etc. [Dent. Vier. Jahrsch. f. ZaJinhcilk. 
 1876.) 
 
 P. Macarovici. Pulpitis Chronica Idiopathica. [Denial Cosmos. Vol. 
 XXXV.) 
 
 D. E. Caijsh. Some Changes that Take Place in and around the Pulp-Canal. 
 [Dental Cosmos. Vol. XXXV.) 
 
 L. C. Ingersoll. Eelations of the Dental Pulp to the Other Tooth-Tissues- 
 (Trans. N. Y. Odont. Soc. 1878.) 
 
 W. DiECK. Einige Seltene Beobaehtungen, Verkalkung der Pulpa, welche 
 durch eine Zahnfraktur freigelegt war, etc. (Verh. d. Deut Odont. Gesell., 
 Bd. IV.) 
 
 — Blume. Beitrag zur Pathologie der Dentinneubildungen in der Pulpa. 
 {Deut. Vier. Jahrsch. f. Zahnheilk. 1874.) 
 
 — Detzner. Pulpa Neubildung, Pulpapolyp, Hypertrophie der Pulpa. 
 [Deut. Vier. Jahrsch./. Zahnheilk. 1876.) 
 
 A. Scheller. Beitrag zur Symptomatologie der Pulpaerkrankungon. [Deut. 
 Vier. Jahrsch./. Zahnheilk. 1888.) 
 
 J. Parreidt. Pulpitis in einem nichtcariosen Zahn. [Deut. Vier. Jahrsch. /. 
 Zahnheilk. 1880.) 
 
 A. WiTZEL. Die Antiseptisehe Behandlung der Pulpakrankheiteii des Zahns. 
 Berlin, 1879. 
 
 A. WiTZEL. Compendium der Pathologie und Therapie der Pulpakrank- 
 heiten des Zahns. Hagen i. W., 1886. 
 
 A. WiTZEL. Deutsche Zahnheilkd. in Vortriigen. Hagen i. W., 1886. 
 
 G. V. Black. Pathology of the Dental Pulp. Am System of Dentistry. 
 Philadelphia, 1886. 
 
 J. Troman. Diseases of the Dental Pulp. Am. System of Dentistry. 1886. 
 
 M. ScHLENKER. ITntcrsuchungen iiber die Verknocherung der Zahnnerven, 
 etc. [Deut. Monatssehr. /. Zahnheilk. 1883.) 
 
 J. E. Garretson. Diagnosis in Neuralgia [Dental Cosmos. Vol. XXV.) 
 
 J. A. Klump. The Effects of Malarial Poisoning on the Dental'Pulp. [Dental 
 Cosmos. Vol. XXV.) 
 
 A. KozMA. Investigation into Statistics of Diseases of the Tooth-Pulp, Perios- 
 teum, and Alveolus. [Monthly Review n/ Denial Surgery. 1886.) 
 
 K. T. Hulme. On Calcifications of the DentalPulp. (Trans, of the College 
 of Dentists of England 1861.) 
 
 F. Boll. [In Arch. /. Micr Anat. Vol. IV. Bonn, 1868.) 
 
 F. ITlrich. (In Zelisch. K. K. Ge.fell. zu Wien. 1852.) 
 
 J. Brl'ck, Jr. Bcitrilge zur Histologlr und Pathohigio der Zalinpulpa. Bre.s- 
 lau, 1871. 
 
 L. A. Weil. Zur Histologic! der Z:iliii]Mil])a. Leipzig, 1887. 
 
 L. A. Wkil. l)ir Odonthele del- Zahnpulpa. I?remcn, 1890.
 
 640 LITERATURE. 
 
 C. Kn.SE. Ziir Histol(><;ie dor Zahnpulpa. {Deut. Motwissclir. f. ZahvheWk. 
 1892.) 
 
 L. A. Weil. Erwiderung of Dr. C. Kose's Aufeatz, '-Zur Lfhre der Hist, 
 der Zahnpulpa." {Dcut. Momdsschr. f. Zahnheilk. 1892.) 
 
 — Pautsch. Die von Weil bescliriehene Schicht unter den Odontoblasten. 
 {Deui. Mo7iatsschr. f. Zahnheilk. 1892.) 
 
 H. BuRCHARD. Ulceration and Ab.sco.s.'? of the Dental Pulp. {Dental Cosmos. 
 Vol. XXXVI.) 
 
 W. D. Miller. An Introduction to the Study of the Bacterio-Pathology of 
 the Dental Pulp. {Dental Cosmos. Vol. XXXVI.) 
 
 L. Hattgasy. Ein Fall von Pulpitis chronica idiopathica. {Ocst. Uiig. Vie?: 
 Jahrschr.f. Zahnheilk. 1892.) 
 
 S. Cartwright. On Disease.s and Treatment of the Pulp. (Trans. Odont. 
 Soc. Gr. Britain. 1861.) 
 
 C. S. Tomes. On a Case of Abscess of the Pulp in a Grampus. (Trans. Odont. 
 Soc. Gr. Britain. 1872.) 
 
 G. W. Watson. Pathological Conditions of the Dental Pulp. (Trans. Odont. 
 Soc. Gr. Britain. 1892.) 
 
 M. Small. Ossification of Pulp in Healthy Tooth. {Monthly Review of Dental 
 Surgery. 1880.) 
 
 CHAPTEE XXXVIII. 
 
 G. D. Pollock. Alveolar Abscess. {Johnston^ s Dental Miscelbnuj. 1876.) 
 J. M. KiGQS. Suppurative Inflammation of the Gums and Absorption of the 
 Gums, etc. {Johnston's Dental Miscellany. 1878. ) 
 
 0. Coles. Discu.ssion on Kiggs's Disease. (Trans. Odont. Soc. Gr. Britain. 
 1878.) 
 
 M. W^. Swartz. Pyorrhrea Alveolaris or Riggs'.^ Disease of the Gums. 
 {Dental Eeview. 1892.) 
 
 W. P. Dickinson. The Peridental Membrane and Apical Pericementitis. 
 {Dental Review. 1891.) 
 
 G. Newkirk. Some of the ,Surgical Asj)ects of Eiggs's Disease, etc. {Dental 
 Review. 1890.) 
 
 A. C. HuGENScnMiDT. The Occasional Origin of True Alveolar Absce.*s from 
 Teeth with Living Pulps. {Dental Review. 1890.) 
 
 E. J. Perry. Diseases of the Peridental Membrane, etc. {Dental Review. 
 1889.) 
 
 W. H. WiiiTSLAR. Tumors of the Peridental ilembrane. {Dental Review. 
 1889.) 
 
 C. T. CusiiMAN. Dental Periostitis and Necrosis, etc. {Dental Neivs Letter. 
 1861.) 
 
 D. B. Whipple. Perio.stitis. {Dental News Letter. 1853.) 
 
 .J. D. White. Absorption of Dentine. {Dental News Jjctter. 1853.) 
 
 1. I. Greenwood Alveolar Akscess. {Am. Jour, of Dent. Sci. 1842.) 
 
 S. P. HuLLiiiEN. Ab.'icess of the .law, etc. {Am. Jour, of Dent. Sci. 1846.) 
 S. M. Sheppard. Spontane<ms Destruction of the Alveoli. (.4m. Jour, of 
 Drni. Sri. 1847.) 
 
 .1. C. House. Chronic Abscess, etc. {A)n. Jour, of Dent. Sci. 1859.) 
 H. N. Wadsworth. Alveolar Abscess.^ {Am. Jour, of Dent. Sci. 1859.) 
 
 — . Alveolar Ab-scess. {Missiuiri Deut. Jour. 1869.)
 
 LITERATURE. 6-tl 
 
 H. JuDD. Alveolar Abscess. {Missouri Dent. Jour. 1869.) 
 C.S.Smith. Alveolo-Dental Periostitis. {Missouri Dent. Jour. 1869. j 
 H. JuuD. Alveolar Abscess. {Missouri Dent. .Jour. 1870.) 
 W.S.Elliott. Alveolar Abscess. {Missouri Dent. Jour. 1870.) 
 O. Coles. Dental Periostitis. {Missouri Dent. .Jour. 1872.) 
 T. F. KuMBOLi). Destruction of the Gums and Alveolar Process, etc. {Mis- 
 souri Dent. Jour. 1873.) 
 
 H. S. Chase. Alveolar Periostitis. {Missouri Dent. Jour. 1873.) 
 
 X. K. HiTRD. Alveolar Abscess. {Missoitri Dent. Jour. 1874.) 
 
 A. "W. Harlan. Alveolar Ab.-cess {Missouri Dent. Jour. 1875.) 
 
 H. S. Chase. Kesoi-ption of Dental Tissue. {Missouri Dent. Jour. 1875.) 
 
 P. Masox. Periostitis. {Missouri Dent. Jour. 1875.) 
 
 V. PiETKiEwicz. Alveolar Dental Periostitis. {Missouri Dent. Jour. 1877.) 
 
 W. H. Eames. Pyorrhoea Alveolaris. {Missouri Dent. Jour. 1878.) 
 
 E. T. Darby. Acute and Chronic Alveolar Abscess. {Missouri Dent. Jour. 
 
 1869.) 
 
 M. P. FiXLEY. Alveolar Abscess. {Missouri Dent. Jour. 1880.) 
 
 J. S. Smith. Alveolar Periodontitis. {Missouri Dent. Jour. 1880.) 
 
 C. R. E. Koch. Alveolar Abscess. {Missouri Dent. Jour. 1880.) 
 
 L. C. Ingersoll. Alveolar Abscess. {Missotcri Dent. Jour. 1880.) 
 
 L. C. IxGERSOLL. Alveolar Ulceration Distinguished from Alveolar Abscess. 
 
 {Missouri Dent. Jour. 1881.) 
 
 G. H. Harding. On the Process of Absorption in liouc and Tooth-Structure. 
 
 {Missouri Dent. Jour. 1882.) 
 
 G. A. Mills. Pericementitis. {Missouri Dent. .lour. 1882.) 
 
 A. H. Thompsox. Cases of Absorption of the Roots of Permanent Teeth. 
 
 {Archives of Dentistry. 1884.) 
 
 W. S. Elliott. Periodontitis, etc. {Dental Cosmos. Vol. X.) 
 
 H. S. Chase. Periostitis. {Dental Cosmos. Vol. X.) 
 
 M. DoLBEAU. Absorption of Jaw. {Dental Cosmos. Vol. XI.) 
 
 W. H. HowLAXD. Maxillary Al)sorption. {Dental Cosmos^ Vol. XI.) 
 
 M A. Spexcer. Periostitis. {Denial Cosmos. Vol. XII.) 
 
 W. A. Broxsox. Peridentitis. {Dental Cosmos. Vol. XII.) 
 
 V. A. Latham. Diseases of the Maxillary Bones and their Pei-iosteum- 
 
 {Dental Cosmos. Yol. XXXV.) 
 
 L. Requa. Destroying Pulps with Ar.<^eiiic. {Dent<U Cosmos. Vol. XXXV.) 
 M. Stavely. Case of Acute Periostitis of the Jaw from Mercui-ial Poisoning 
 
 {Dental Cosmos. Vol. XXXV.) 
 
 Q. Mayr. The Chemistry of Disinfectants and .Vntiseptics. (Trans. X. Y. 
 
 Odont Soc. 1884.) 
 
 G. A. Maxfield. Alveolar Absce.-s. (Trans N. Y. Odont. Soc. 1888 ) 
 A. C. Hawes. Exposed Pulps and Alveolar Abscess. (Trans. .\m. Dent. 
 
 A.SS. 1863.) 
 
 S. E. KxoWLES. Alveolar Abscess. (Trans. California State Dent. Ass. 1886.) 
 J. M. SuLLiVAX. Alveolar Abscess. (Trans. California State Dent. Ass. 
 
 1885.) 
 
 C. S( HMEDicKE. tJber die Ver/.ehrung der Zahnfacher. [Dcr Zulmarzt. 
 
 1851.) 
 
 E. Foucher. tJber einige Varietaten der am Obcrkiefcr vorkommonden 
 
 Abscesse. {Der Zahnarzt. 1857.) • 
 
 J. P. II. Browx. Alveolar Abscess, etc. {Dmtul Cosmv.'<. Vol.1.) 
 
 43
 
 642 LITERATURE, 
 
 F. Si'HNEiDER. rvui'ihoc dev Alvcolen. {Deiii. Vler. Jahrsclt. f. ZalmheUk. 
 1875.) 
 
 M. ScHLEXKKR. Alveolar Pyorrhoc. {Dent. Vler. Jahrseh. f. Zahnheilk. 
 1877.) 
 
 — Detznek. Tod durch Pyaemie in Polge von Parulis. [Dad. Vier. .Jahrscli. 
 J. ZaInihcUk. 1877.) 
 
 J. Jaegle. Haemorrhagie, Pyaemie, und Tod in Folge eines fungosen Aus- 
 wuchses der Pulpa, etc. [Dent. Vier. Jahrsch. f. Zahnheilk. 1878.) 
 C. G. JiTXKERMAX. Pyon-hoea Alveolaris. {^Arch. of Dentistry. 1887.) 
 C. "W. Merry. PyoiThcea Alveolaris. [Arch, of Dentistry. 1887.) 
 Dr. EiGGS. Pyorrhoea Alveolaris. [Arch, of Dentistry. 1885.) 
 J.D.Patterson. Pyon-hoea Alveolaris. [Arch, of Dentistry. 1885.) 
 South. Dental Ass. Pyorrhoea Alveolaris. [Arch, of Dentistry. 1885. 
 Pp. 352 and 361.) 
 
 R. Ottolexgiti. Pyorrhcea Alveolaris. [Arch, of Dentistry. 1889.) 
 J. "W. Miller. Pyorrhoea Alveolaris. [Arch, of Dentistry. 1889.) 
 31. L. Rhein. Pyorrhoea Alveolaris. [Arch, of Dentistry. 1889.) 
 A\'. Conrad. Pyorrhcea Alveolaris. [Airh. of Dentistry. 1889.) 
 H. Breslatjer. On Causes of Inflammation of the Periosteum of the Teeth. 
 [Dental Cosmos. Vol. II.) 
 W. H. Atkinson. Alveolar Abscess. [Dental Cosmos. Vols. Ill and YIII.) 
 
 G. W. Ellis. Periodontitis. [Dental Cosmos. Vol. III.) 
 
 W. H. Atkinson. Alveolar Abscess. [Dental Cosmos. Vol. IV.) 
 
 C. P. Pitch. Alveolar Abscess. [Dental Cosmos. Vol. V. ) 
 
 J. W. Clowes. Alveolar Abscess. [Dental Cosmos. Vol. VI.) 
 
 W. H. Atkinson. Absorption of the Alveoli. [Dental Cosmos. Vol. VII.) 
 
 H. S. Chase. Absorption of Dentine, etc. [Dental Cosmos. Vol. VIII.) 
 
 E. Williams. Abscess from a Carious Tooth. [Dental Co.wios. Vol. VIII.) 
 
 E.Abbott. Alveolar Abscess. [Dental Cosmos. Vol XIV.) 
 
 — Maunder. Acute Abscess. [Dental Cosmos. Vol. XIV.) 
 
 — Bremer. Alveolar Absorption. [Dental Cosmos. Vol. XIV.) 
 
 H. Sewfll. Eistulous Opening on the Face. [Dental Cosmos. Vol. XV.) 
 W. C. Wardl.vw. Pericementitis. [Dental Cosmos. Vol. XVI.) 
 A. W. Barrett. Decomposition of the Dental Pulp, etc. [Dental Casinos. 
 Vol. XVII I.) 
 
 C G. Davis. Gum and Alveolar Diseases. [Dental Cosmos. Vol. XXI.) 
 I). H. (Joodwillie. Maxillary Abscess, etc [Dental Cosmos Vol XXIII.) 
 
 C. J. KssiG. Some of the Causes of the Loss of the Teeth in the Adult. 
 [Dental Cosmos. Vols. XXII and XXIII.) 
 
 G. A. Mills. Some of the Causes of Loss of the Teeth in the Adult, etc. 
 [Dental Cosmos. Vol. XXIII.) 
 
 II. C.vrtwright. Riggs's Disease. [Dental Co.smos. Vol XXIII.) 
 
 D. Hepburn. Chronic Suppuration Connected with the Teeth. [Dental Cos- 
 mo.''. Vol. XXIII.) 
 
 H. Seavill. Alveolar Periostitis in Diabetes Mellitus. [Dental Cosmos. Vol. 
 XXR'.) 
 
 W. H. Atkinson. Alveolar Ab.scess [Dental Cosmos. Vol. XXV.) 
 
 G. H. Mu^iMERY. Alveolar Abscess of Obscure Origin. [Dental Cosmos. 
 Vol. XXVI.) 
 
 J. D. PvVTTERSON. The Catarrhal Xature of Pyorrhoea Alveolaris [Dental 
 Cosmos. Vol. XXVII.)
 
 LITERATURE. 643 
 
 A 0. Kawls. Pyorrhoea Alveolaris. {Dental Cosmos. Vol. XXVII.) 
 
 — SAUJfDBY. Gouty Teetli. {Dental Cosmos. Vol. XXVII.) 
 
 E S Talbot. Pyorrhoea Alveolaris. {Denial Cosmos. Vol XXVIII.) 
 N. Padley. Pyorrhoea Alveolaris. {Dental Cosmos. Vol. XXIX.) 
 
 — Edmunds. Pyorrhoea Alveolaris in the Elephant. {Dental Cosmos. Vol. 
 XXX ) 
 
 M L Rhein Pyorrhoea Alveolaris. {Dental Cosmos. Vol. XXX.) 
 
 J. D Patterson Points in the Etiologj^ of Pyorrhoea Alveolaris. {Dental 
 
 Cosmos. Vol. XXX ) 
 C B. Atkinson Pj^orrhoea Alveolaris. {Dental Cosmos. Vol. XXXII.) 
 J. S Marshall. The Rheumatic and Gouty Diathesis, etc. {Dental Cosmos. 
 
 Vol XXXIII.) 
 
 W D Miller. Asepsis and Antisepsis in Practice. {Dental Cosmos. Vol. 
 
 XXXV ) 
 
 W. C. Barrett. Some Thoughts upon Pyorrhoea Alveolaris. {Dental Cosmos. 
 
 Vol. XXXV. ) 
 
 E. L Clifford. Infection from the Mouth. {Dental Cosmos. Vol. XXXV.) 
 
 G NewivIkk. , Antiseptic Dentistry. {Dental Review. 1892.) 
 
 W. L. Jerman. Reports on Pyorrhoea Alveolaris, etc. {Dental Review. 
 
 1891.) 
 
 Mr. Stanley. Periostitis of Upper Jaw, etc. {Am. Jour, of Dent. Scl. 1850.) 
 
 C. Bew. Alveolar Ahscess. (Am. Joitr. of Dent. Sei. 1851.) 
 
 J. M. Riggs. Suppurative Inflammation of the Gums, etc. {Penn. Jour, of 
 
 Dent. Scl. 1876.) 
 
 J. Requa. Dental Periostitis. {Inde.p. Fract. 1883.) 
 
 W. D. Miller. Proliferation of Epitlielium in an Alveolar Ab.^cess. {Indep. 
 
 Pract. 1885.) 
 
 A. R. Starr. Pyorrhoea Alveolaris. {Indep. Pract. 1886.) 
 
 J. N. Farrar. Loculosis Alveolaris. {Indep. Pract. 1886.) 
 
 G. A. Maxfield. Alveolar Abscess. {Indep. Pract. 1887.) 
 
 R. B. Adair. Alveolar Abscess. {Indep. Pract. 1889.) 
 
 J. Head. Alveolar Abscess. {Indep. Pract. 1889.) 
 
 W. H. Trueman. Intentional Devitalization of the Dental Pulp. {Intern. 
 
 Dent. Jour. 1889.) 
 
 E. C. Kirk. Alveolar Abscess. {Intern. Dent. Jour. 1889.) 
 
 G. S. Allan. Pyorrhoea Alveolaris. {Inte7-n. Dent. Jour. 1889.) 
 
 E. F. Stevens. Pyorrhoea Alveolaris. {Intern. Dent. Jour. 1892.) 
 
 C. N. Peirce. Pyorrhoea Alveolaris. {Intern. Dent. Jour. 1892.) 
 
 J. M. Potter. Pulpless Teeth : Abscess. {Intern. Dent. Jour. 1892.) 
 
 E. C. Kirk. Alveolar Abscess. {Intern. Dent. Jour. 1892.) 
 
 H. A. Kelley. a Study of the Diseases of the Peridental ^Membrane. 
 
 {Intern. Dent. .Jour. 1893.) 
 G. A. Mills. Riggs's Disease. {Interii. Dent. Jour. 1893.) 
 
 . Alveolar xVbsorption. {Missouri Dnd. Jour. 1869.) 
 
 T. Rou.x:. Observations de listules dentaires remarquabies par I'obscurite du 
 
 diagnostic et la gravite des lesions consecutivcs. {Bull. gen. d. Chirug., Aoui. 15.) 
 E. Magitot. Odontalgic. Diet, encycl. d. Sc. Medic. Tome XIV. 
 
 PiETKiEWitv,. Des fistules dentaires. {Gaz. dcs Hop. 1874.) 
 
 RioHAUD. Essai sur Ics iistules in Jahrb. Virch-Hirsch. 1877. 
 
 E. De.mange. Chute spontanee des dents et crises gastriqucs, etc. {Rev. de 
 
 Med. 1882.)
 
 644 LITERATURE. 
 
 — DoLBEAi'. Affection singuliere du maxill. sup. caracterisee surtout par la 
 disparition du bord alveulaire. {Gaz. des Hop. 1869 ) 
 
 E. Magitot. Rapport sur la pathogenic et traitem. de la ging-ivite expulsive. 
 {Bnll. Soc. dc Chlriirq. 1880.) 
 
 A. DE Sadran. Pathogenie et traitem. de la gingivite expulsive. [BuU. d. I. 
 Soc. de Chir. 1880.) 
 
 J. Israel. Xeue Beobachtungen auf dem Gebiete der Mvkosen des Menschen. 
 {Virch.Arch. BdLXXIY. 1880.) 
 
 C. S. Tomes. In Trans. Odont. Soc. ,Gr. Britain. 1883. Pp. 4 and 5. 
 
 J. Eichardsox. Eefles Lesions of the Ural Cavity a.ssociated with Pregnancy. 
 [British Journal of Dental Science. 1882.) 
 
 C. S. To.MES. On Premature Lo.ss of the Teeth. [Monthly Review of Dental 
 Surgery. 1874.) 
 
 A. ScHELLER. Uber Alveolarabsorption und Behandlung der.selben. [Deut. 
 Vier. .Tahrschr. f. ZahnJheilk. 1871.) 
 
 — Yallix and Luts. The Loosening of the Teeth in Ataxy. [Dental 
 Cosmos. Vol. XXIII.) 
 
 T. Davis. Lesions of the Teeth in Locomotor Ataxy. [Dental Cosmos. Vol. 
 XXIV.) 
 
 J. Parreidt. Periostitis Alveolo-Dentalis Idiopathica. [Deut. Vier. Jahrsch. 
 /". Zahnheilk. 1880.) 
 
 G. V. Black. Disea.<es of the Peridental Membrane. (American System of 
 Dentistry. Philadelphia, 1886.) 
 
 P. Bros. Ein Fall von Periostitis alveolaris Maxillae inferioris mit todtlicheiii 
 em Ausgange. [Dent. Monatsseli. f. ZahnJieilk. 1883.) 
 
 J. Parreidt. Zahniistel in Polge eines iiberstandenen Typhus. [Deut. 
 jl Tonatssch. f. Zah n heilk. 1 883 . ) 
 
 — Wallauer. Uber vereinzelt auftretende Verkiimmerungen der Prae- 
 molaren beim Menschen als Folge acuter und chronischer Eiterung der !Milch- 
 molaren. [Deut. Monotssch. f. Zahnheilk. 1885.) 
 
 — IvOBiscEK. TVe.senund Behandlung der Alveolarpyorrhoe. [Deut. Monatssch. 
 f. Zahnheilk. 1885.) 
 
 J. ScHEFF, Jr. Zur Differentialdiagno.<e der Zahnfleisch-AYangenfistel, etc. 
 
 [Deut. 2Ionats.srh. f. Zahnheilk. 1887..) 
 
 G. P. Geist. Pyorrhoea Alveolaris. [Deut. Monatssch. f. Zahnheilk. 1891.) 
 A. Pilliet. Double suppuration des glandes sous-maxillares. [Bullet, de la 
 
 Soc. anat. de Paris, 7. 1891.) 
 
 — Hatty ASI. Oest. Ung. Vier. Jahrsch. f. Za/inheilk. 1890. Xo. 3. 
 Ed. Xessel. Oest. Ung. Vier. Jahrsch./. Zahnheilk. 1888. Xo. 4. 
 
 — Schnitzler. Beitr. zur Casuistik der branchiogenen Eisteln. AVien, 1890. 
 L. Hollaender. Drei Fiille aus der Praxis. [Oest. Ung. Vier. Jahrsch. f. 
 
 Zahnheilk. 1886.) 
 
 A. WlTZEL. Pyon-hoea Alveolaris. [Oest. Ung. Vier. Jahrsch. f. Zahnheilk. 
 1881.) 
 
 — RoBiscEK. Pvorrhoea Alveolaris. [Juhrb. der Ver. Oest. Zahnarzte 1883- 
 84.) 
 
 J. "Walker. On the Premature Loss by Destruction of the Alveoli. (Trans. 
 Intern. Med. Congress. London, 1881.) 
 
 — Ballerio. Resorption d. Zahnfaches. [Correspond, f. Zahnarzte.. 1883.) 
 I). DrcKwoRTii. The Characters of the Teeth in Persons of the Arthritic 
 
 Diathesis. (Trans. Odont. Soc. Gr. Britain. 1883.)
 
 LITERATURE. 645 
 
 — FlClNUS. tjber das Austalleu der Ziihne. ( Walter's uml Ammon^s Jour. f. 
 Chlrurgie. 1847.) 
 
 — V. Bergmann. Erkrankungen der Lymphdriiseii. (Gerhard's Handb. d. 
 Kiiiderkrankh. Bd. VI.) \ 
 
 — V. Tadex. Tiefe Abscesse am Kieferwinkel. (Mittli. f. d. Vereiii Scblesw. 
 Hoist. Artze. in Jahrb. 1872 ) 
 
 — AuBURTix. Essai sur les kystes dentaires. Paris, 1874. 
 
 — KosEXBACH. Zur keniitniss der Strahlenpilzerkrankungen beim ^leuschen. 
 {Centralhl. f. Chirurcjle. 1880.) 
 
 P. Kraske. tJber eine wahrscheinlich mykotische Affection der Kiefer- 
 knoclieu. [Arch.f. Klin. Chirurgie. 1880.) 
 
 E. Albert. Diagnostik der chirurgischen Krankheiteu. Wien, 1885. 
 
 J. R. Bate. Alveolar Abscess. {Monthly Review of Dental Surgery. 1883.) 
 
 D. Hepbttrx^. On Chronic Suppuration Connected with the Teeth. (Trans. 
 Odont. See. Gr. Britain. 1880.) 
 
 E. Magitot. Recent Researches on Symptomatic Alveolar Arthritis. (Trans. 
 Odont. Soc. Gi-. Britain. 1887.) 
 
 F. N. Pedley; On the Pathology of Riggs's Disease or PyoiThfpa Alven- 
 laris. (Trans. Odont. Soc. Gr. Britain. 1887.) 
 
 E. L. Williams. The Pathology of Alveolar Abscess. (Trans. Odont. Soc. 
 Gr. Britain. 1888.) 
 
 O. Coles. On the So-called Riggs's Disease. (Trans. Odont. Soc. Gr. Britain. 
 1877.) 
 
 W. J. EiSK. Pyorrhoea Alveolaris. [BrlflsJi .fnurnal of Dental Science. 1892.) 
 C. N. Peirce. Etiology of Pyorrhoea Alveohiris. {Intern. Dent. Jour. 1894.) 
 
 F. T. Vax Woert. Pyorrho-a Alveolai-is. [Intern. Dent. Jour. 1894.) 
 
 G. S. Allan. Pyorrhoea Alveolaris. [Intern. Dent. Jour. 1894.) 
 J. Trumax. Pyorrhoea Alveolaris. {fntern. Dejit. Jour. 1894.) 
 
 R R. AxDREW.s. Pyorrhoea Alveolaris. {Intern. Dent. Jour. 1894.) 
 S. H. Guilford. Pyorrhoea Alveolaris. {Intern. Dent. Jour. 1894.) 
 M. L. Rheix". Pyorrhoea Alveolaris. {Intern. Dent. Jour. 1894.) 
 A. P. Brvbaker. Pj'orrhoea Alveolaris. {Intern. Dent. Jour. 1894.) 
 E. T. Darby. Pyorrhoea Alveolaris. {Intern. Dent. Jour. 1894.) 
 R. Ottolex'giti. PA'orrhoea Alveolaris. {Intern. Dent. .Tour. 1894.) 
 
 — TixKER.' Pyorrhea Alveolaris in Domesticated Animals (Panther, Kan- 
 garoo, Dog, Ape). {Odoniogr. Jour. 1894.) . 
 
 W. X. Sudduth. Pj-orrhoea Alveolaris. {Dental C<)s>nos. Vol. XXXVI.) 
 C. Jung. Die Erkrankungen der Wurzelhaut des Zalins, etc. ( Drut. Monatsschr. 
 f. Zahnheilk. 1894.) 
 
 — Pedley. On the Pathology of Riggs's Disease. {Denial Record. 1887.) 
 V. Mettnitz. Ein Fall von acuter Osteomyelitis des Unterkiefers mit todtlich- 
 
 cm Ausgange. {Oestr. Ung. Vier. Jahrsehr. f. ZaJniheilk. 1887.) 
 
 G. D. Pollock. Alveolar Abscess Di'pondont on Diseased Teeth. (Trans. 
 Odont. Soc. Gr. Britain. 1876.) 
 
 H. Moser. Two Cases of Periostitis of the Upper Jaw in Close Relationship 
 to Influenza. {British .lournal of Dental Science. 1890.) 
 
 J. Maughax. a Case of Extended Alveolar Ab.scess. {British Journal of 
 Dental Science. 1893.) 
 
 M. Heide. a Cutaneous Fistula of Dental Origin. {British .Journal of 
 Dental Science. 1893.)
 
 646 LITERATURE. 
 
 CHAPTEE XL. 
 
 W. D. Miller. The Micro-Orgaaisms of the Human Mouth. Philadelphia, 
 
 1890. 
 
 J. C. Strahl. Uber den Influss der Siiuren aut' die Zahne. {Der Zalmarzi. 
 
 1846.) 
 E. FiciNUS. tJber das Ausfallen der Zahne, und das Wesen der Zahnkaries. 
 
 (Der Zahnarzt. 1847.) 
 J. Brxjck. Die Ursacheu der Zahnverderbniss, etc. {Der Zahnarzt. 1852 ) 
 — Bauer. Betrachtungen iiber die Karies der Ziihne. {Der Zahnarzt. 185..) 
 
 Eossi. tJber die Verderbniss der Zahne. {Der Za.hnarzt. 18 )2 and 1853.) 
 
 V. PiAULT. tJber die Karies der Zahne.. {Der Zahnarzt. 1861.) 
 
 SCHROTT. Die Bewohner des Mundes und der Ziihne. {Deut. Vier. Jahrschr. 
 
 f. Zahnheilk. 1868.) 
 
 J. LiNDEREB. Die innere Caries. {Deut. Vlcr. Jahrschr. f. Zahnheilk. 1873.) 
 E. MiJHLREiTER. Die Natur der anomalen Hohlenbildung im Oberen Seiten- 
 
 schneidezahn. {Deut. Vier. Jahrschr./. Zahnheilk. 1873.) 
 
 Gr. V. Black. Dental Caries. (American System of Dentistry. Philadelphia, 
 
 1886.) 
 
 . Brunsman. tJber Progres.sive Zahnverderbniss. {Deut. Monatssch. f. Zahn- 
 heilk. 1885.) 
 E. Hesse. Zahnkaries bei Backei-n. [Deut Monatssch. f. Zahnheilk. 1886.) 
 W. K. Bridqemax. On Caries and its Treatment. (Trans. Odont. Soc. Gr. 
 
 Britain. 1861.) 
 
 W. K. Bbidgeman. On the Pathology of Dental Caries. (Trans. Odont. Soc. 
 
 Gr. Britain. 1861.) 
 
 C. S. Batk. Pathology of Dental Caries. (Trans. Odont. Soc. Gr. Britain. 
 
 1864.) 
 
 E. W. EotJGHTON. The Micro-Organisms of the Mouth. {British Journal of 
 
 Dental Science. 1893.) 
 
 H. Sewill. The x\_rtiticial Production of Dental Caries. (Trans. Odont. Soc. 
 
 Gr. Britain. 1890.) 
 
 C. S. BoYNTON. Eole of Bacteria Eermentation, etc. {New Emjlund Journal 
 
 of Dentistry. 1883.) 
 
 C. Mayr. Chemical Composition of Decayed Dentine. {New England Journal 
 
 of Dentistry. 1883.) 
 
 C. S. BoYNTON. Germ Theory Mortally Wounded. {Neiv Enyland Journal 
 
 of Dentistry. 1883.) 
 
 A. S. Underwood. On the Influence of Micro-Organisms in the Production 
 
 of Caries. {Neio Enyland Dental Journal. 1884.) 
 
 C. S. BoYNTOisr. Bacteria. {New England Dental Journal. 1884.) 
 
 Y. Searle. The Septic Theory of Dental Caries. {New Enfihmd Dental 
 
 Journal. 1884.) 
 . E. T. Clark. Which was Eirst — the Hen or the Egg, the Bug or the Acid ? 
 
 {Neio England Journal of Dentistry. 1884.) 
 
 G. V. Black. Dental Caries, etc. {Archives of Dentistry. 1885.) 
 
 A. L. LooMis. Bacteriology. {Archives of Dentistry. 1885.) 
 
 J. M. EiGUS. On Dental Caries. {Archives of Dentistry. 1885.) 
 
 H. Sewill. Dental Caries, etc. {Archives of Dentistry. 1885.) 
 
 E. E. Smilie. Dental Caries. {Dental Cosmos. Vol. YIII.) 
 
 J. PiDDUCK. Dental Caries. [Dental Cosmos. Vol. VIII.) 
 
 M. BisCHOEF. Dental Caries in the Ape. {Dental Cosmos. \()\. ^MI1.)
 
 LITERATURE. 647 
 
 J. P. II. Brown. Cause of Caries in Teelli. {Dental Comnos. \\A. \.) 
 
 C. S. Weeks. Causes of the Decay of Teeth. {Dental Cosmos. Vol. X.) 
 
 (t. J. ZiEQLER. Dental Caries, etc. {Dental Cosmos. Vol. XIT.) 
 
 J. Beddoe. Dental Caries. {Dental Cosmos. Vol. XIII.) 
 
 S. E. Knowles. Pathology of Caries. {Dental Cosmos. Vol. XV.) 
 
 C. ]!^. Peirce. An Essay on the Lower Forms of Life, etv. {Dental Cosmos 
 
 Vol. XVII.) 
 
 T. C. Stellwagex. Dental Caries. {Dental Cosmos. Vol. X\'II.) 
 
 F.Abbott. Caries of Human Teeth. {Dental Cosmb.'<. Vol. XXI.) 
 
 J. D. Clark. Caries of the Teeth. {Dental Cosmos. Vol. XXIII.) 
 
 H. Gerhart. Primal Cause of Dental Caries. {Dental Cosmos. A'ul. 
 
 XXIII.) 
 
 B. W. EiCHARDSox. On the Origin of Dental Caries. {Dental Cosmos. \o\. 
 XXIV.) 
 
 G. P. RiSHKL. Dental Caries. {Dental Cosmos. Vol. XXIV.) 
 
 — SiTHERWooB and HAjfLAX. Cerebral Origin of Dental Deeav. {Dcnfal 
 Cosmos. Vol. XXV.) 
 
 H. Sewill. Dental Caries. {Dental Co.rmos. Vol. XXV.) 
 
 — Carpenter. Causes of Dental Decay. {Dental Cosmos. Vol. XXV. ) 
 W. D. Miller. Agency of Micro-Organisms in Decay of the Human Teeth. 
 
 {Dental Co.?mos. Vol. XXV.) 
 
 W. D. Miller. The Agency of Acids in the Production of Caries of the 
 Human Teeth, with Comparative Analysis of Carious Dentine and Dentine Soft- 
 ened by Acids. {Dental Cosmos. Vol. XXV.) 
 
 C. N. Peirce. Calcification, Decalcification, Absorption, HvjxTti'ophv. 
 {Dental Cosmos. Vol. XXV.) 
 
 A. Morsmax. Dental Caries. {Dental Cosmos. Vols. XXVII and XXVIII, ) 
 V. Galippe. The Influence of Sex on the Frequency of Dental Cari(>s. 
 
 {Dental Cosmos. Vol. XXVII.) 
 
 W. X. SuDDtJTH. Is Decay of the Teeth an Inflammatory oi- a Chemical 
 
 Action? {Dental Cosmos. Vol. XXVIII.) 
 
 A. Gysi. Dental Caries under the ]\[icroscope. {Dental Cosmos. Vol. XXIX.) 
 G. V. Black. An Examination of the Phj'sical Forces with Reference to the 
 
 Germ Theory, etc. {Dental Cosmos. Vol. XXX. ) 
 
 L. Ottofy. The Incipiency of Dental Caries. {Dental Cosnms. Vol. XXXI ) 
 
 E. P. Beadles. The Bacteria of the Human Mouth. {Dental Cosmos. Vol. 
 XXXIV.) 
 
 H. Block. The Causes of Dental Caries. {Dental Cosmos. Vol. XXXV.) 
 S. B. Palmer. Dental Decay, etc. {Dental and Oral Science Mac/azine. ISTS.") 
 
 F. Y. Clark. Bacteria. (Trans. N. Y. Odont. Soc. 1881.) 
 
 G. S Allan. Caries of the Teeth. (Trans. N. Y. Odont. Soc. 1886.) 
 
 J. Cheesebroi:gh. Sympathetic Relations of the Teeth with the Viscera. 
 
 (Trans. Am. Dent. Ass. 1866.) 
 
 C. Tomes. A Cause for Dental Caries. {Johnston' s Dental Miscellany. 1878.) 
 E JSToyes. The Etiology of Dental Caries. {Dental Remew. 1890.) 
 G V l^LACK. Fermentation and Putrefaction. {Dental Review. 1890.) 
 F H. Rehwinkel. Caries of the Teeth, etc. {Am. Jour, of Dent. Sci. 
 
 1855.) 
 
 J. Taft. Caries of the Teeth. {Am. Jour, of Dent. Sci. 1856.) 
 
 A. F. McLain. Causes of Decay in Human Teeth. {Fenn. Jour, of Dent. 
 
 Sci. 1874.)
 
 648 LITERATURE. 
 
 C. N. Peirce. Lower Forms of Life, etc. [Penn. Jour, of Dent. Scl. 1876.) 
 C. N. Peirce. Dental Caries. [Penn. Jour, of Dent. ScL 1876.) 
 
 F. Y. Clark. Bacteria the Cause of Caries. (Indcp. Prac.t. 1882.) 
 J. S. Dodge. Senile Decay. {Indep. Praet. 1884.) 
 
 W. D. Miller. Absorption of Dentine, etc. (Indep. Pract. 1887.) 
 
 G. P. KiSHEL. Causes and Treatment of Dental Caries. {Indep. Pract. 1887.) 
 
 F. Abbott. On Caries. {Indep. Pract. 1889.) 
 
 E. Laplace. Fermentation, etc. {Indep. Pract. 1890.) 
 
 J. N. Crotjse. Dental Caries. {Missouri Dent. Jour. 1869.) 
 
 E. C. Edsill. Why do the Teeth Decay ? {Missouri Dent. Jour. 1869.) 
 
 J. M. "Whitney. Is Dental Caries the Kesult of Civilization? {Missouri 
 
 Dent. Jour. 1872.) 
 
 K. Cutter. Does the Use ot Flour Promote Decay of the Teeth ? {Missouri 
 
 Dent. Jour. 1874.) 
 
 W. K. Bridgeman. Dental Caries. {Missouri Dent. Jour. 1878.) 
 S. M. Prothro. Caries. {Missouri Dent. Jour. 1879.) 
 
 G. Y. Black. Caries of Teeth. {Missouri Dent. Jour. 1880.) 
 
 C. T.'Stockwell. Etiology of Dental Caries. {Missouri Dent. Jour. 1882.) 
 
 C. W. Spatjldixg. Suggestion Kelative to the Cause of Eapid Dental Decay. 
 {Missouri Dent. Jour. 1882.) 
 
 C. T. Stock well. Etiology of Dental Caries. {Xea: Emjlaiul .lour, of Dent. 
 1882.) 
 
 C. T. Stockwell. Micro-Organisms, the Essential Factor in Dental Canes. 
 {New Englaml Jour, of Dent. 1883.) 
 
 E. "W. Eoughton. The Micro-Organisms of the ilouth. (Trans. Odont. Soc. 
 Or. Britain. 1893.) 
 
 C. A. Hayman. The Physiology and Pathology of Dental Caries. {Monthly 
 Review of Dental Surgery. 1881.) 
 
 P. Dietrich. Bacteriologie in Handb. der Zahnheilk. von .J. Schetf, jr. Wien, 
 1891. 
 
 ^l. Bastyk. Zicbni lekarstoi, I. S. 249. 
 
 M. Bastyr. Casopis ceskych Ickaru. XXII. 1883. S. 318. 
 
 F. Wallauer. Caries der Zahne in Hanub. der Zahnheilk. von J. Scheif, jr. 
 Wien, 1891. 
 
 E. Magitot. Treatise on Dental Caries. Boston, 1878. 
 
 W. D. Miller. Die Mundhohle als Infectionsherd. {Deut. Monutssch. f. 
 Zuhnhcilk. 1892.) 
 
 K. Telschow. Die wahren Ulirsacheu der Zahncaries, etc. Berlin, 1892. 
 
 R. HoppE. Mundbakterien. {Deut. Monatsschr. f. Zahnheilk. 1893.) 
 
 C. .IrxG. Untersuchungen iiber die Bakterien der Zahncaries. Berlin, 1892. 
 
 E. Nei'max. tlber das Wesen der Zahnverderbniss. 
 
 A. Carpenter. A Consideration of Some of the Causes which Give Rise to 
 Dental Decay. {Br. Jour, of Dent. Sci. 1883.) 
 
 R. H. Moore. Dental Caries as a Result of Inflammation of the Dentine. 
 {Brit. Jour, of Dent. Sci. 1889.) 
 
 G. W. Watson. The ^Micro-Organisms of the ^Moutb and their. Association 
 with Disease. {Brit. Jour, of Dent. Sci. 1889.) 
 
 J. H. Mummery. On the Action of Micro-Orgainsm> in Caries of the Teeth. 
 {Brit. Jour of Dent. Sci. 1890.) 
 
 A. Carpenter. A Consideration of Some; of the Causes wliich Give Rise to 
 Dental Caries. (Trans. Odont. Soc. Gr. Britain. 1882.)
 
 LITERATURE. 649 
 
 — De Bary. Vergl. Morphologie und Bioli.jjic dm- Pilze. S. 490. 
 
 — Fluoge. Die Mikroorganisineii. Leip/.ig, 1886. S. 76. 
 
 — Fkank. Leunis' 8vii()})sis dor drci NaturreielK'. I'.d. 111. Specielle 
 Botanik, Kryptogamcn. S. 842. 
 
 — ZoPF. Die Spill tpilze. S. 1. 
 
 CoRXiL et Babes. Les Bacteries. P. 173. 
 
 — EiiRENBERG. Organisation, Systematik und geograpliisches Verhaltniss der 
 Tnfusionsthierchen. Berliji, 1830. Die Infusioni^thierchon ali? vollkoinmene 
 Organismen. Leipzig, 1838. 
 
 — Letjwenhoek. Opera omnia sive arcana naturie ope microscopitn-um 
 exactissimorum detecta. 1722. 
 
 — Nencki. Beitriige zur Biologie der Spaltpilze. 1880. 
 CoHN und Mendelsohn. Cohn's Beitrage. Bd. Til, Heft 1. 
 
 — Miller. Ueber Gahrungsvorgange im Yerdauungstractus und die dabei 
 bctheiligten Spaltpilze. {Deutsche Med. Wochenschr: 1886. No. 49.) 
 
 — Flugge. Die Mikroorganisuien. Leipzig, 1886. 
 
 — Pasteur. Annales de Chiniie et Physiologie. 1867. 
 
 — HuEPPE. Ueber die Zer.?etzung der Milch. [MiHh. a. d. Reichsfjesundheitscwif. 
 Bd. II, S. 807.) 
 
 — Black. Gelatine-Forming Micro-Organisms, [Independent Practitionn^, 
 1886. P. 546 ) 
 
 — Prazmowski. ITntcrsuchungen iiber die Entwickelung und Fermentwir- 
 kung einiger Bacterienarten. Leipzig, 1880. 
 
 — Brieqer. XJel)er S})altungsproduete der Bacterien. [Zeifsckr. f. phyxial. 
 Chemie. Bd. VIII, Heft 4 und Bd. IX, Heft 1.) 
 
 — FiTZ. Berlchte der Chem. GrseU. 1873, Bd. VI, S. 48; 1876, Bd IX, 2, 
 S 1848; 1878, Bd. XI, S. 42; 1879, Bd. XIT, 1, S. 374; 1880, Bd. XIII, 1, s'. 
 1309; 1882, Bd. XV, 1, S. 867; 1883, Bd. XVI, S. 844; 1884, Bd. XVII. S 
 1189. 
 
 — BouTROUX. Sur la fermentation lactique. {Comptcs rendus. Bd. LXXXVI, 
 P. 605. 1878.) 
 
 — Flugge. Die Mikroorganismen. S. 486. 
 
 — Nkncki. Ueber die Zersetzung der Gelatine und des J]iweisses bei der Ftiul- 
 ni.<.s u. s. w. Bern, 1876. 
 
 — Hansen. Contributions a la connaissance des organismes qui peuvent se 
 trouver dans la biere et la mout de biere et y vi\re. [Meddclser fra Carlsherq- 
 lahoratoriet. 1879. Heft 2.) 
 
 SchlOsing und Muntz. Comptcs rendus. Bd. LXXXIX. Pp. 891 et 1074 ; 
 Bd. LXXXIV, P. 301 ; Bd LXXVII, Pp. 203, 353. 
 
 Gayon et DuPETiT. Comptes rendus. 1882. Bd. XCV, Pp. 664, 1365. 
 
 Dehkkain et Maquenne. Sur la reduction des nitrates, etc. {Comptcs rendus. 
 1882. II. Bd. XCV, Pp. 691, 732, 854 ) 
 
 — Heraeus. LTeber das Verbalten der Bacterien im Brunnenwasser. {Zeitschr. 
 f. Hygiene. Bd. I.) 
 
 — Warrington. Journal of the C/imi. Society. Augu.st, 1888. P. 727. 
 
 — BiNZ. Arznoimittellelire. S. 197, 198. 
 LiBORius, Flijooe. Die Mikroorganismen. S. 455. 
 
 Ellenberger und Hofmeister. Der Speichel dor Wiederkiiuei-. {lierir/it 
 uber das Veterinaruiesen bn Kmiigrelch SacJisen. 1885. S. 119.) 
 
 Ellenukkgku und Hofmeister. Die Function der Speicheldrasen der 
 Haussiiugethiere. {Ai-chivf. wLssench. u. prakt. Thierhe'dk. 11, 1885.) 
 
 44
 
 650 LITERATURE. 
 
 — Hkkmann. Physiologie. S. 94. 
 
 — Leuwenhoek. Operii omnia, etc. Bd. II, S. 40, 1722. 
 
 — Mandl. Coinpte.s reudus hebd. des Seances de 1' Academic des Sciences. 
 Bd. XYII, P. 213. 
 
 — BtJHLMANN. Miiller's Archiv f. Anatomie. 1840. 
 
 — Henle. Pathologische Untersuchungen. 1840. 
 
 Erdl. Allgemeiiie Zeitiuni f. Cliirurgie von Rohatzsch. 1843. No. 19, 
 
 S. 159. 
 
 — Robin. Histoire naturelle des vegetaux parasites. 1853. 
 
 Robin. Des vegetaux qui croissent sur les animaux vivants. Paris, 1847. 
 
 P. 42. 
 
 — Klkncke. Die Verderbni.s.s der ZJihne. Leipzig, 1850. 
 
 Hallier. Die pflanzlichen Parasiten, etc. Leipzig, 1866. 
 
 Leber und RoTTENSTEiN. XJeber d Caries der Zahne. Berlin, 1867. 
 
 ViGNAL. Reclierches sur les Microorganismes de la bouche. {Archives de 
 
 pliysiol. norm, et paihol. 1886. No. 8 ) 
 
 Miller. Zur Kenntniss der Bakterien der Mundhohle {Deidsche Med. 
 
 Wochenkchr. 1884. No. 47.) 
 
 — Le^vIs. Lancet. September, 1884. 
 
 Miller. Ueber einen Zahn-Spaltpilz, Leptotbrix gigantea. {Berichte der 
 
 Bothnischen Gesellschaft. 1883. S. 224.) 
 
 — Miller. Biological Studies on the Fungi of the Human Mouth. [Indep. 
 Practitioner. 1885. Pp. 227, 283.) 
 
 — Black. Trans, of 111. State Dental Society. 1886. 
 
 — Watt. Chemical Essays. 
 
 — ViGNAL La France inedicale. Aoiit 25, 1887. 
 
 — HuEPPE. Deutsche Med. Wochenschr. 1884. Nos. 48, 49. 
 
 — EscHERiCH. Die Darmbacterien des Siiuglings. 1886. 
 
 — Baginsky. Deutsche Med. Wochenschr. 1888. No. 20. 
 
 — Krautermann. Sicherer Augen- und Zahnarzt. 1732. 
 
 — BouRDET. Recherches et observations sur toutes les parties de I'art du den- 
 tiste. 1757. P. 95. 
 
 — ScHLENKER. Die Yerdcrbniss der Ziihne. 
 
 — V. Carabelli. Handbuch der Zahnheilkunde. 
 
 -— EusTACHtxJS. Opviscula anatomica et de dentibus. 1574. 
 Frank Abbott. Caries of the Human Teeth. [Dental Cosmos. 1879. 
 February, March, April.) 
 
 C. Heitzmann. Neio England. Journal of Dentistry. Vol. I, P. 193. 
 
 — Fauchard. Le chirurgien-dentiste. Paris, 1728, 1746, 1786. 
 
 — Pfaff. Abhandlung von den Zahnen. 1756. 
 
 W Robertson. A Practical Treatise on the Human Teeth, etc. 1835. 
 
 — RoGNARD. Gaz. des Hopit. 1838. 
 
 — Magitot. La salive. Paris, 1867. 
 
 — Magitot. Etudes et experiences sur la salive. Paris, 1867. 
 MiLLES and Underwood. Trans. Intern. Med Congr. 1881. 
 
 Ad. Weil. Vortrage, gehalten zu Miinchen in der Sitzung des arztlichen 
 Vereins. 1880. S. 187. 
 
 — Bastyr. Oesterreichiseh-Un.g. Vierteljahrsschr. f. ZiJmhcilk. 1885-86. 
 S 355. 
 
 — Miller. Dental Cosmos. 1881. P. 91. 
 
 — Magitot. Itcchon'bcs sur la carie des dents. 1871.
 
 LITERATURE. 651 
 
 — Miller. Eintluss dor Mikroorganismen auf die Caries der mcn>ciiliclien 
 Ziiliiie. [Archir fur experhiii'idcUr Puiholoifie. Hd. XVI. 1882.) 
 
 MiLLKs and Uxderwood. 'PnniA.uf thr. Odont. Soc. of Great Hr'ihiin. 1884 
 P. TI2. 
 
 Ellenherokr und Hofmkister. Arc.hiv. f. lolssensch. u. prakf. Tkiifrlndk. 
 Bd. XI, S. 162. 
 
 — Hesse. Deutsche Med. Wochensrhr. 1885. No. 24. 
 
 (tALIPI'e et ViuNAL. Note sur Ics niicroorganisni.>; de la carie dentaiiv. 
 [1/ Odovtologie. ]N[ars, 1889.) 
 
 — Magitot. Traite de la carie dentaire. 1867. P. 60. 
 
 — Mummery. Trans, of the (Mont. Soc. of Gr. Britain. New Series. 1870. 
 Vol. II. P. 7. 
 
 W. C. Barrett. An Examination of the Condition of the Teeth of Certain 
 Prehistoric Kaces. [Indep. Pract October, 188:^.) 
 
 — Miller. Prehistoric Teeth. {Ibid. 1884. P. 40.) . 
 
 R. Koch. Ueher Desinfection. [Mittheilungen ans dem Kaiserl. Gr.sandheit.s- 
 <nnt. Bd. I, S. 234 ) 
 
 — Black. Antiseptics. [Dental Bavew 1889. Nos. 2 and 3.) 
 
 — Miller. Indep Pract. June, 1884. 
 
 — Tassinari. Centralblattfur Baetcriologie und. Parasitenknnde. 1888. Bd. 
 IV, S. 449. 
 
 — Hunter. A Treatise on the Venereal Disease. 1786. P. 391. 
 
 — Lettsom. Transactions of the Medical St)ciety of London. Aut;-. 2, 1786. 
 
 — Stricker. Die Bedeutung des Mundspeichels. 1889. S. 138. 
 
 — Eberle. Die Verdauung. 1834. S. 34. 
 
 — Senator. Untersuchungen iiber d. fieberhaften Process. 1873. S. 6. 
 
 — Raynaud et Lannelongue. BuUctinde V Acadhnie de med. 18 Janvier, 
 1881. 
 
 L.Pasteur. Ibid. 18 et 26 Janvier, 1881. 
 
 — VULPIAN. Ibid. 29 Mars, 1881. 
 
 — Sternberg. Bulletin of the National Board of Health. April 30, 1881. 
 
 — Griffin. Archlvio per le scienze mediche. Vol. V. Fasc. 3. 
 
 ( Jaglio et Di Mattel Sulla non essistenza di una proprieta tossica della saliva 
 uinana. {Arch, per le scirnze med. 1882. Vol. VI, Fa.sc. 1. Referat ini 6V'»./ra//;/. 
 f. kirn. Med. 1883. S. 261.) 
 
 A. Frankel. Verhandl. d. 3. Congr. f. innere Mod. 1884 
 
 — Miller. Deutsche Med. Wochenschr. 1884. No. 25. 
 
 — Klein. Ein Beitrag zur Kenntniss der Pneutnokokkon. [Ccntralbl f 
 mcd. Wissensch. 1884. No. 30. S 529. ) 
 
 — Kreihohm. Fliigge, Mikroorgani.smen. S. 257. 
 
 A. Frankkl. Zeitschr.f. klin. Med. 1880. Bd. X. S. 401. 
 
 — Baumgarten. Lohrbuch d. pathol. Mykologie, 1888. S. 245 
 
 — Koch. Mitth. a. d.. Kais. Gesnndhcitsamt. Bd. II. S. 42. 
 
 — Gaffky. r. Lancjenbeck's Archip. Bd XXVIII, Heft 3. S. 500. 
 
 — Biondi. Breslauer arztlicho Zeitsehr. September, 1887. No. 18. 
 
 — Zakharevitsch. Vrach No. 34. S. 623. 
 
 — V. MosETlG-MoORlloF. Ocstcrr .-Ung. Viertrljahr.'ischr. /. Zahnheilknudc 
 1885. Heft 2. 
 
 — Zawadzki. Gaz. lekarska. 1886. No. 8. Fri>m tlic Deutsche Mcd 
 Wochenschr.
 
 652 LITERATURE. 
 
 — Parreidt, Zur Antiseptik beim Zahiiausziehen. [Dcufsc/ir Moixifsf^c/ir. f. 
 Zahnlu'llk. 1888. Heft 7. S. 254.) 
 
 — BuscH. Deutsche, Med. Wochcnschr. 1885. No. 24. 
 
 — PoRRE. Dental Record. October, 1887. 
 
 — Baker. Ibid. July, 1888. 
 
 — PoxcET. Gaz. des Hopit. No. 19. 
 
 — Fripp. Dental Record. August. 1887. 
 
 — CooPMAX. CorrespondenzM. f. Zahnarzte. Januar, 1888. S. 56. 
 
 — PiETRZiKOWSKl. Oester.-Ung Vierteljahrssckr. fur Zahnheilk. 188G. S 
 363 
 
 — ScHMiD. Oesterr.-Uiig. Vierteljahrssckr. f. Zahnheilk. 1885. Heft I. 
 
 — RiTTER. Correspondenzbl. f. Zahnarzte. October, 1888. 
 
 — Odexthal. CariOse Zahiie als Eingangspforte infectiosen Materials unci 
 Ureache chroniscber Lymphdrusenscbwellungen am Halse. (Inaugural Di.sserta- 
 tion. Bonn, 1887 ) 
 
 — Ungar. Sitzung der Niederrbein. Gesollscbaft fiir Xatur- und Heilkunde 
 y.w Bonn, 1884. Mai 17. 
 
 — .Jaffe. Lungengrangriin, durcb einen verscliluekten Kirscbkern erzeugt. 
 (Allgem 7ne<l. Zeitimg. 1886. S. 233.) 
 
 Leyden und Jaffe. Ueber putride (fo?tide) Sputa. [Deatsches Archiv. f. 
 klin. Med 1867. Bd II. S. 488.) 
 
 — B.vuMGARTEN. Jabresbericbt. 1 .Jabrgang. S. 142. 
 
 — Baginsky. Deutsche Med. Woehenschr. 1888. No. 20. 
 
 — Bedxar. Krankbeiten der Neugeborenen und Siiuglinge. 18o4. S. 54. 
 
 — Hexoch. Klinik der ITnterleib.skrankbeiten, S. 589 und Beitrage zur 
 Kinderbeilkunde. Bd. I, S. Ill, und Bd. II, S. 809. 
 
 — Nauxyn. Ueber da.s Verbaltniss der Magengahrungen zur mecbaniseben 
 Magen-Insufficienz. [Archie f. klin. Med. Bd. XXXI, S. 225.) 
 
 — Leube. Archiv f. klin. Med. Bd. XXXIII, S. 4. 
 
 — De Bary. Zur Kenntnis.s der niederen Organismen im Mageniiilialte 
 {Archiv f. e.rper. Pathol, v. Pharmakol. 1886. Bd. XX, S. 243.) 
 
 — Frerich.s. AVagner's Handworterbucb der Pby^iol. Bd. III. 1 Abtb 
 S. 869. 
 
 — EwALD. Die Lebre von der Yerdauung. 1886. S. 104. 
 
 — Escherich. Beitrage zur antiseptiseben Bebandlungsmetbode der Magen- 
 Darmerkrankungen des Siiuglings. [TJicrap. Monatshrftr 1887. S 890) und 
 Die desinlieirende Behandlungsmetbode der Magen-Dannkrankbeiten des Siiug- 
 lingsaltci-s [Centralhl. f . Bactcriol. u. Parasitenkunde. 1887. Bd. II, No. 21). 
 
 — ^IixKowsKi. Ueber die GJihrungen im Magen. 1838. 
 
 — Miller. Deutsche Med Wochenschrift. 1885. No. 49. 
 
 — MaoFady'ax. Fliigge. Mikroorganismen. 1885. S. 590. 
 
 — Sucksdorf. Das quantitative Yorkommen von Spaltpilzon im inenseli- 
 liclien Darmcanal. [Archiv./.' H)/(/iene. 1886. Bd. lY.) 
 
 — BArMGARTEX\ Centrulbl. f. klin. Med. 1884, No. 2. 
 
 — Miller. Deutsche Med. Wochcnschr. 1885, No. 49. 1886, No. 6. 
 
 — Kofii. Zweite Serie zur zur Erorterung der Cbolerafrage. [Deutsche Med. 
 Woehenschr. 1885. No. 19, etc.) 
 
 Bland Sutton. Deutsche Med. Woehenschr. May, 1887. 
 
 — Reeve. Indep. Pract. Yol. YI, P. 367 
 
 — Bexxett. Dental Record. May, 1887. Pp. 229, 233. 
 
 — ScHECH. Krankbeiten der Mundboble. des Racbeiis und der Nase.
 
 LITERATURE, 653 
 
 — LOkfi.kk. Mitth. a. d Kills. Gcsundhe'dsunU. VA. li, S. 480. 
 
 — DtnxES. Medical and Surgical Reporter. Januiuy, 1878. 
 
 — Otis. Lectures on Syphilis. New York, 1887. P. 102. 
 
 — Lax(JEraux. Proceedings Academic de .Medicine de Paris. {L' Union 
 Medlcale. 1889. P. 655.) 
 
 — GiovAXNi. Lo S|K'riinentale. 1889. P. 262. 
 
 — Lenoir. Le9ons sur la Syphilis. 1886. P. 62. 
 
 — Lyuston. Jour, of the Am. Med. Ans. 1886. P. 664. 
 
 — PtODDicK. Montreal Med. Jonr. August, 1888. P. 93. 
 
 — Pakkkk. Western Dent. Jour. Fel)ruary, 1890. 
 
 — BoLMXGKR. Centralbl f. d. Mel. Wissench. 1877. No. 27. 
 
 — Bo8Tr5m. Verh. d. Congr. f inuerc Med. Wiesbaden, 1885. S. 94. 
 
 — PoxFicK. Ueber eiue wahrscheinlich mykotische Form von Wirbelcaries. 
 {Berliner klin. Wochenschr. 1879. S. 345.) 
 
 James Israel. Klinische Beitrage zur Aktinomykosc di-s Mcn.sclien. 1885. 
 
 — HocHEXEGG. Zur Casuistik der Aktinoniyko.s() des Menscheii. [Wiener 
 Med. Presse. 1887. No. 16-18.) 
 
 — KoTTER. Demonstration von Inipfaktinomykose. {Tagebl. der Natnrfor- 
 scher-Versumrnlmig. Wiesbaden, 1887. S. 272.) 
 
 — Partsch. Einige ueue Falle von Aktinomykosc des Menschon. [Dcufsche 
 Zeitschr.f. Chirurgie. 1886, Bd. XXIII, S. 498.) 
 
 — Moosbrugger. Ueber die Aktinomj^kose des Mcnsclien, (Sue Baunigar- 
 tcn' s Jahre.sbericht, \886. S. 317.) 
 
 — KosER. Deutsche Med. Wochensckr. 1886. No. 22. S. 369. 
 
 — Braux. Ueber Aktinoniykose des Menschen. 
 
 — Laurent. Handbuch der ges. Medicin. S. 263. 
 
 — Plaut. Neue Beitrage zur systematischen Stellung des Soorpilzes in der 
 Botanik. Leipzig, 1887. 
 
 — Klemperer Ueber die Natur des Soorpilzes. {Centralhlatt fiir klin. Med. 
 1885. No. 50. S. 849.) 
 
 — Baojnsky. Ueber Soorcultunai. [Deutsche Med. Wochenschr. 1885. No. 
 50. S 866.) 
 
 P. Grawitz. Ueber die Parasiten des Soors, etc. {Virchoiu^s Archie. 1886. 
 Bd CIII, S. 393.) 
 
 — Fraxkel. Grundriss der Bacterienkuude. 
 
 — ZoPF. Pilzthiere oder Schleimpilzc. 1885, 
 
 — De Bary. Morphologic und Biologic der Pilze. 1884, S. 453. 
 
 — WoRoxix. Pringsheim's Jahrbiiclier fiir Wissensch. Botanik. 1878. Bd. 
 XI. 
 
 K. Kocii. Mitth. aus d. Kais. Gesundlieitsant, 1881. Bd. I. 
 
 — EiDAM. Allg. landwirtltschojrt. Zeitung. 1880. No. 97. 
 
 CHAP TEH XLI. 
 
 0. Weigert. Deutsche Med. Wochenschr. 1893. 
 
 A. W. IIari.ax. The Dittusibility of ^[edicaments in Living und Dead Den- 
 tine. [Denial Review. 1891.) 
 
 W, E, Ii)E. The Use of Arsenious Acid, etc. {A}n. Jour, of Dent. Set. 
 1842.) 
 
 . Arsenic as a Dental Therapeutic Agent. {A»i. Jour.of Dent, Sri. 
 
 1845.) 
 
 45
 
 g54 LITERATURE. 
 
 A. Westcott. Arsenic as a Remedy, etc. (^1//^. Jour, of Dent. Sci. 1845.) 
 A*. C. Castle. The Use and Abuse i.f Arsenious Acid, etc. {Arn. Jour, of 
 
 Bent. Sci. 1850.) 
 
 Application of Arsenic to Teeth. {Am. Jour, of Dent. Sci. 1869.) 
 
 L. A. Faught. a Study of Arsenious Acid. {Indep. Pract. 1889.) 
 
 J. Truman. The Pulp and Treatment of Pulp-Canals. {Intern. Dent. Jour. 
 
 1889.) 
 
 C. BiNZ and H. ScHULZ. The Action of Arsenic. {Missouri Dent. Jour. 
 
 1879.) 
 
 GiKS. Plivsiological Eflect of Arsenic. {Missouri Dent. Jour. 1879.) 
 
 C. BiNZ and H. Schulz. Chemical Cause of the Poisonousness of Arsenic. 
 {Missouri Dent. Jour. 1881.) 
 
 F. Wakdroi'Es. Arsenical Poisoning. {Misstmri Dent. Jour. 1882.) 
 
 . Arsenical Application. {New Eng. Jour, of Dent. 1882.) 
 
 Arsenic, etc. {Archives of Dent. 1886. P. 331.) 
 
 J. G. Hari'ER. Dental Medicine and Therapeutics. {Archives of Dent. 
 
 1889.) 
 
 H. (i. Crowell. Arsenic. {Archives of Dent. 1891.) 
 
 H. H. SiLLiMAN. Pain Following Arsenic Application. {Archives of Dent. 
 
 1891.) 
 
 J. W. Ellis. Arsenic. {Dental Cosmos. Vol. III.) 
 
 H. Meredith. Arsenic. {Dental Cosmos. Vol. III.) 
 
 C. B. Foster. Arsenic. {Dental Cosmos. Vol. III.) 
 
 H. Vi. White. Arsenic. {Dental Cosmos. Vol. III.) 
 
 W. H. Atkinson. Arsenical Treatment, etc. {Dental Cosmos. Vol. III.) 
 
 J. H. McQtjillen. Experimental Observations on the Action of Arsenic, etc. 
 
 {Dental Cosmos. Vol. III.) 
 A. C. HaweS. Use of Arsenic, etc. {Dental Cosmos. Vol. V.) 
 Editorial. Sensitive Dentine — Arsenic, etc. {Dental Cosmos. Vol. V.) 
 W. H. Atkinson. Treatment of Sensitive Dentine. {Dental Cosmos. 
 
 Vol. V.) 
 W. Dickinson. Cobalt, etc. {Dental Cosmos. Vol. VII.) 
 J. F. Flagg. Arsenious Acid, etc. {Dental Cosmos. Vol. X.) 
 J. H. McQuiLLEN. Ai-senical Applications. {Dental Cosmos. Vol. XIII.) 
 C. F. AV. BOdecker. On the Action of Arsenious Acid upon Dentinal and 
 
 Pulp-Tissue. {Denial Cosmos. Vol. XXV.) 
 
 L. A. Faught. Ai-senious Acid. {Dental Cosmos. Vol. XXXI.) 
 
 C. F. W. BOdecker. The Herbst Method of Treating Pulps, {Dental Cos)nos. 
 
 Vol. XXXIV.) 
 
 A. W. Harlan. The Herbst Method of Treating Pulps. {Dental Cosmos. 
 
 Vol. XXXV.) 
 
 W. E. Christensen. Some Comments upon the Herbst Method of Treating 
 Pulps. {^Dental Cosmos. Vol. XXXV.) 
 
 J. F. Flagg. Arsenious Acid as a Devitalizer of the Dental Pulp. (Trans. 
 Amer. Dent. Association. 1862.) 
 
 F. A. Brewer. The Tendency of Arsenic as Applied to Dental Tissue to 
 Develop Pericementitis, and Its Sequence — Alveolar Abscess. (Trans. California 
 State Dental Association. 1882.) 
 
 — Hohl. Beitrag zur Arsenik Frage. {Deut. Vier. Jahrsch. f. Zahnheilk. 
 
 1868.) 
 FLtJQQE. Die Mikroorganismen. S. 110.
 
 LITERATURE, 655 
 
 H. HuMM. Tiber Arsonpasta. {De.ut. Vier. .Tahrsch. f. Zahnheilk. 1876.) 
 C. KtTHNS. Arsenicum nativura. [Dent. Vier. Jahrsch.f. Zahnheilk. 1876.) 
 A. F. Schmidt. Nochmals Arseu, {Dent. Monatsschr. f. Zahnheilk. 1884.) 
 
 — Schneider. Die Auwciidung des Ai-sens in der Zahniirztlichen Praxis. 
 {Dent. Viert.J. Zahnheilk. 1880.) 
 
 J. Arkovy. Berichte iiber einige Experiiuente beziiglich dm- Devitalisation 
 der Pulpa. {Deut. Monaf,is<-h/: f. Zahnheilk. 1882.) 
 
 J. E. Dexter. Arsenic. (Trans. First Dist. Dent Soc. X. Y. 1883.) 
 
 S. Bauer. Kalium ursenieosuni ein neues Dentine Anaestheticum. {Odonto- 
 skop. 1893.) 
 
 T. Stevenson. On the Behavior of Arsenic in Contact witli Putrefvino- Or- 
 ganic Substances. {Brit. Jour, of Dent. Sci. 1883.) 
 
 W. R. Tuck. Ai-senical Poisoning. {Brit. Jou?: of Dent. Sci. 1891.) 
 
 CHAPTER XLII. 
 
 T. L. Gilmer. Necrosis of Maxillary Bones. {Denial Rnnrm. 1891.) 
 
 G. H. McC.vusEY. Necrosis. {Dental Review. 1890.) 
 
 T. W. Bropiiy. Caries and Necrosis of the Maxillary Bones. {Dental 
 Review. 1888.) 
 
 J. D. White. Caries and Necrosis of Bone. {Dental News Letter. 1850 and 
 1867.) 
 
 M. Dei'AUL. Necro.sis of the Lower Jaw. (.4/^. Jour, of Dent. Sei. 1845.) 
 
 M. MoNOD. Necrosis from Pres.sure of the Dens Sapientise. {Am. Jour, of 
 Dent. Sci. 1845.) 
 
 Dr. Heifelder. Necrosis of the Jaw-Boaes. {Am. Juar. of Dent. Sci. 1845.) 
 
 A. A. Blandy. Inflaniiuation of the Gums and Exfoliation of the Alveolar 
 Proce.ss. {Am. Jour, of Dent. Sci. 1849.) 
 
 W. .Jones. A Case of Reproduction of the Inferior Maxillary Bone. (.1/;;,. 
 Jour, of Dent. Sci. 1852 and 1853.) 
 
 — . Necrosis of the Superior and Inferior Maxillio. {Ant. Junr. of 
 
 Dent. Sci. 1862.) 
 
 W. A. Shelby. Caries and Exfoliation of the Jaw. {Am. Jonr. <f Dent. Sci. 
 1853.) 
 
 W. G. Smull. Necrosis of the Lower Jaw. {Am. Jonr. <f Dent. Sci. 1854 ) 
 J. R. Wood. Necrosis of the Inferior Maxillary from the Vapor of Phos- 
 phorus. Removal of the Entire Lower .law, etc. {Am. Jour, of Dent. Sci. 1856.) 
 J. Richardson. Gangrenous Degeneration of the Cheek and Gums, with 
 Necrosis, etc. {Am. Jour, of Dent. Sci. 1857.) 
 
 J. H. Martindale. Caries and Necrosis of the .laws. {Indc/). Practitioner. 
 1886.) 
 
 H.S.Chase. Necrosis. {Mintiourl Dent. Jonr. 1875.) 
 J. D. Pearson. Necrosis. {Missouri Dent. Jour. 1876.) 
 R. G. Pearson. Necrosis. {Min.'iouri Dent. , /our. 1877.) 
 G. A. Christman. Necrosis. {Missouri Dent. Jour. 1879.) 
 W. H. Atkinson. Necrosis. {Missouri Dent. Jour. 1881.) 
 H. 0. Cameron. Phosphorus Necrosis. {Missouri Dent. Jour. 1882.) 
 Dr. Cripps. Cancrum Oris leading to Necrosis of Lower Jaw. {Archives of 
 Dent. 1884.) 
 
 J. F. McCarthy. Necrosis of the Maxillary Bones after Measles. {Archives 
 of Deut. 1891.)
 
 656 LITERATURE. 
 
 J. McCalla. Spontaneous Necrosis of the Alveolar Process. {Dental Cosino.s. 
 Vol, I.) 
 
 . On the Osteogenic Properties of the Periosteum. {Dn/fal Cosmos. 
 
 Vol. I.) 
 
 M. Grandidier. Necrosis of the Upper Jaw, etc. {Denial Oismos. Vol. 
 III.) 
 
 Prof. Billroth. Pho.sph or Necrosis. {Denial Cosmos. \ ol. III.) 
 
 — Lawson. Necrosis of Lower Jaw. {Denial Cosmos. Vol. IV.) 
 
 H. Jackson. Exfoliation of One f>f the Pre-Maxillary Bones after Measles 
 {Denial Cosmos. Vol. IV.) 
 
 W. S. Savory. Caries and its Kelation to Necrosis. {Denfal Cn.sinos. Vol. 
 
 V.) 
 
 T. Bryant. Exfoliation of the Intermaxillary Bones of an Adult. {Dental 
 
 Cosmos. Vol. VI.) 
 
 C. P. Fitch. Necrosis of the Teeth. {Dental Cosmos. Vol. VI.) 
 N. E. Smith. Necrosis of Jaw, etc. {De^ifal Cosmos. Vol. VII.) 
 W. H. Atkinson. Necrosis, etc. {De)ita.l Cosmos. Vol. "\'III.) 
 
 — Paget. Necrosis of the Lower Jaw. [Dental Cosmos. Vol. VIII.) 
 Prof. Gross. Necrosis of Lower Jaw. {De?itnl Cosmos. Yo]. X.) 
 
 T. G. Lewis. Necrosis. {Dental Cosmos. Vol. XI.) 
 C. Heath. Necrosis, etc. {Dental Cosmos. Vol. XII.) 
 C. Fryer. Caries of Hard Palate from Syphilis. {De)itnl Cosmos. Vol. 
 XII.) 
 
 J. H. MrQuiLLEN. Necrosis, etc. {Dental Cosmos. Vol. XII.) 
 R. H. Prkston. Caries and Subsequent Removal of the Whole Inferior Max- 
 illa. {Dental Cosmos. Vol. XIII.) 
 
 J. S. Bailey. Necrosis of the Inferior 3Iaxilla. {Dental Cisnios. Vol. 
 XIII.) 
 
 W. Ferousson. Necrosis of Lower Jaw. {Doital Cosmos. Vol. XIII.) 
 
 T. Bryant. Necrosis of Lower Jaw. {Dental Cosmos. Vol. XIII.) 
 
 S. J. Cobb. Necrosis of Upper Jaw. {Dental Cosmos. Vol. XIII.) 
 
 A. Robertson. Necrosis, etc. {Dental Cosmos. Vol XIV.) 
 
 E. R. Pettit. Caries of Maxillary Bones, etc. {Dental Cosmos. Vol. XTV.) 
 
 Sayre. Necrosis of Jaw. {Dental Cosmos. Vol. XIV.) 
 
 E. van de "Waiikek. Necrosis, etc. {Dental Cosmos. Vol. XIV.) 
 W. Tay. Necrosis of Lower Jaw. [Dental Cosmos. Vol. XVI.) 
 J. Hutchinson. Syphilitic Necrosis, etc. {Dental Cosmos. Vol. XVI.) 
 W. S. Savory. Necrosis from Phosphorus. {Dental Cosmos. Vol. XVI.) 
 
 . Phosphorus Necrosis. {Dental Cosmos. Vol. XVI.) 
 
 . Phosphorus Necrosis of Upper Jaw. {Dental Co.imos Vol. 
 
 XVII.) 
 W. H. Atkinson. Necrosis and Caries. {Dental Co.smos. Vol. XVIII.) 
 
 . Necrosis and Fistula. {Dental Cosmos. Vol. XIX.) 
 
 . Necrosis of the Lower Jaw. {Dental Cos)n.os. Vol. XIX.) 
 
 . Necrosis following Smallpox. {Dental Cosmos. Vol. XX.) 
 
 . Dental Abscesses and Fistula. {Dental Cosmos. Vol. XX.) 
 
 C. F. W. BOdecker. Necrosis. {Dental Cosmos. Vol. XX.) 
 J. E. Mears. Necrosis of Superior Maxillary Bone following Typhoid Fever. 
 {Dental Cosmos. Vol. XXII.) 
 
 . Fistulous Opening in the Shoulder IVoni a Carious Tooth. {Dental 
 
 Cosmos.- Vol. XXII.)
 
 LITERATURE. 657 
 
 G. Bkuiixs. Phosphorus Necrosis of tho Facial Bone>. yhnnal Cos/nos 
 
 Vol. XXIII.) 
 
 ■■ Necrosis of the Maxilla'. {Denial Costnos. Vol. XXIII.) 
 
 • Six Cases of Syphilitic Necrosis of the Jaw. {Dental 0>siiii>s 
 
 Vol. XXIV.) 
 
 — Post. Necrosis of Jaw, etc. {Dculal Cosmos. Vol XXV ) 
 
 A. MoxEY, Necrosis of Upper Jaw in Typhoid Pever. {Denial Cosim.x. 
 Vol. XXVI.) 
 .1. E. Mkars. Pho.sphorus Necrosis. {Dental Cosmos. Vol. XXVII.) 
 
 — HuTCHixsox. Necrosis of Jaw from Administration of Phosphorus. {Den- 
 tal Cosmos. Vol. XXIX.) 
 
 J. H. Martindale. Caries and Necrosis. {Dental Cosmos. Vol. XXXI.) 
 
 G. F. Lydston. The Relation of Tropho-Neurosis to Diseases of the Mouth 
 and Jaws, with Special Eeference to Syphilitic Necrosis. {Dental Cosmos. Vol. 
 XXXII.) 
 
 D. M. SabatkPw Necrosis : Its Microscopical Appearance, etc. {Dental Cosmos. 
 Vol. XXXIII.) 
 
 L. L. Dunbar. Caries and Recurrent Caries of the Inferior Maxillaiy Rone. 
 (California State Odont. Society. 1884.) 
 
 W. H. Atkinson. Necrosis. (Trans. Dent. Soc. of the State of N. Y. 1877.) 
 
 — Balfour. tJber die "Wirkung dcr Phosphordampfe auf die Ziihne, etc. 
 {Der Zahnarzt. 1847.) 
 
 — JtiNGKEN. Tiber den Knochenbrand der Kiefer bei den Arlieitern in den 
 Pho.sphorzvindholz Fabriken [Der Zahnarzt. 1848.) 
 
 — Hklkt. Zur Pathologic des Kieferleidens der Arbeiter in den Pliospbor- 
 ziindholz Fabriken. {Der Zahna.rzt. 1848.) 
 
 J. RouYER. Necrose der Kieferknochen. {Der Za.hnarzt. 1856.) 
 H; Santesson. tJber Phosphornekrose. {Der Zahnarzt. 1857.) 
 
 — HuBE. tJber einen eigenthiimlichen Fall ausgedehnter syphilitischer Zer- 
 storung des oberen Alveolarfortsatzes, etc. {VerJi. d. Deut. Odont. Ges. Bd. II.) 
 
 Fr. Kleinmann. tJber Phosphor-Necrosen, etc. {Deut. Vier. Jahrsch. /. 
 Zahnheilk. 1882.) 
 
 — RiTTER. Ein Fall von Unterkiefernckrose rait todtlichem Ausgange 
 {Dent. Monatssch. f. Zahnheilk. 1886.) 
 
 — Salzer. Ein Fall von Nekrose der Alveole nadi (iangraen dcr Puljia 
 {Odontoskup. 1892.) 
 
 W. R. Grates. A Case of Tulx'rcular Caries of Palatine Plates of Supci'ior 
 Maxillarj' Rones, etc. {Monthly Review of Dent. Snrg. 1891.) 
 
 CHAPTER XL! 1 1. 
 
 H. C. QuiNBY. Interesting Case of Ulceration of tho Lining >reinbrane of 
 the Maxillary Sinrs. {Dental Cosmos. Yol. V.) 
 
 ScuwAR'iv.. Enipyem der Highmoi-shohle. {Dreslaner drztliche Zeitsch. 
 
 1889.) 
 A. NoRDMANX. tJber das Empyem der Oberkieferhohle. (Strassburg, 1890.) 
 W. C. Starbuck. Mucous Engorgement of the Maxillary Sinus. {John- 
 ston's Dental Miscellani/. 1875.) 
 
 D. H. GooDWiLLiK. Case of Sup|iurative Disease of the .Vntruni. {,7<din.'iton's 
 Dental Miscellany. 1 880. )
 
 658 LITERATURE. 
 
 I. B. Davenport. A Case of Antral Disease treated throui;h a Lateral In- 
 cisor. {Johnston's Dental Miscellany. 1881.) 
 
 E. Mawhinney. Diseases of the Antrum. {Dental Review. 1893 ) 
 I. P. AViLSON. Abscess of the Antrum, etc. [Dental Revieio. 1892.) 
 
 F. H. Bo.swoRTH. Various Forms of Diseases of the Ethmoid Cells. {New 
 York Med. Jour. 1892.) 
 
 G. L. MoRGENTHAN. Kecent Contributions to the Diagnosis and Treatment 
 of Empyema of the Maxillary Sinus. {Dental Review. 1882.) 
 
 I. P. Wilson. Pathological Conditions of the Ethmoid Bone Kesulting from 
 Dental Lesions. {Dental Review. 1890.) 
 
 S. P. HuLLiHEN. Observations on the Antrum Maxillare. {Am. Jour, of 
 Dent. Sci. 1842.) 
 
 W. W. H. Thackston. Diseases of the Maxillary Sinuses. {Am. Jour, of 
 Dent. Sci. 1842.) 
 
 C. A. Harris. Diseases of the Antrum. {Am. Jour, of Dent. Sei. 1843.) 
 
 C. A. Harris. Fungous Tumor of the Antrum. {Atn. Jour, of Dent. Sci, 
 1845.) 
 
 II. J. Dillingham. Abscess of the Antrum. {Am. Jour, of Dent. Sci. 1846.) 
 W. H. DwiNELLE. Perforation of the Antrum. {Am. Jotir. of Dent. Sci. 
 
 1848.) 
 J. Weatherby. Abscess of the Antrum. {Atii. Jour, of Dent. Sci. 1848.) 
 W. Fergusson. Disease of the Antrum. [Am. Jour, of Dent. Sci.- 1850.) 
 H. Dubs. Diseased Aiiti'um, etc. {Am. Jour, of Dent. Sci. 1850.) 
 R. D. Addington. Operation on the Antrum. (Am. Jour, of Dent. Sci. 
 
 1850.) 
 
 R. D. CouoiT. Disease of the Antrum. {A7n. Jour, of Dent. Sci. 1850.) 
 W. Cooper. Spontaneous Collapse of the Walls of the Antrum. {A)n. Jour. 
 
 of Dent. Sci. 1850.) 
 
 M. ViouERiE. Cancerous Tumor within the Antrum. {Am. Jour, of Dent. 
 
 Sei. 1850.) 
 
 Mr. Levison. Disease of the Antrum, etc. {Ain.. Jour, of Dent. Sci. 1852.) 
 J. A. GiRALDEs. Diseases of the Maxillary Sinus. {Am. Jour, of Dent. Sci. 
 
 1856.) 
 F. M. Fay. Dropsy of the Antrum. {Penn. Jour, of Dent. Sci. 1875.) 
 J. N. Farrar. Diseases of the Antrum, etc. {Intei-n. Dent. Jour. 1889.) 
 H. S. Chase. Tumor upon the Antrum. {Missouri Dent. Jour. 1869.) 
 H. S. Chase. Polycystic Tumor of the Antrum. [Missouri Dent. Jour. 
 
 1870.) 
 H. S. Chase. Inflammation of the Antrum. [Missouri Dent. Jour. 1870.) 
 T. W. Reed. Diseased Antrum. [Missouri Dent. Jour. 1876.) 
 H. Fo.x:. Pus in the Antrum. {Missouri Dent. Jour. 1876.) 
 L. Browne. Abscess of the Antrum. [Missouri Dent. Jour. 1880.) 
 H. Evans. Abscess of the Antrum. [Missouri Dent. Jour. 1881.) 
 . Abscess of the Antrum not Caused by any Disease of Teeth. 
 
 [Missou7^i Dent. Jour. 1881. P. 509.) 
 
 A. J. Prager. Suppuration in the Antrum, etc. [Missouri Dent. Jour. 1882.) 
 A. W. Harlan. The Antrum Highmorianum. [Archives of Dentistry. 
 
 1885.) 
 
 M. J. Davis. Antrum Disease, etc. [Archives of Dentistry. 1886.) 
 
 J. W. Plummer. Abscessed Antrum, etc. [Archives of Dentistry. 1889.) 
 
 J. Green. Dropsy of the Antrum. [Dental Cosmos. Vol. I.)
 
 LITERATURE. g59 
 
 W. Fergussox. Disease of the Antrum. {Dental Cosmos. Vol. I.) 
 
 H. M. White. Abscess of the Antrum. [Dental Cosmos. Vol. II.) 
 
 H. A. Beamer. Dropsy of the Antrum. {Dental Cosmos. Vol. II.) 
 
 H M. White. Dropsy of the Dental Sac. {Dental Cosmos. Vol. V.) 
 
 T. Bryant. Cyst of the Antrum {Dental Cosmos. Vol. VI.) 
 
 W. T. Bullock. Cystic Tumor of the Antrum. {Dental Cosmos. Vol. VII.) 
 
 H.S.Chase. Encysted Tumor of the Antrum. {Dental Cosmos. Vol. VIII.) 
 
 — Michelson. Zur Diagnose unci Therapie des Empyems der Highmors- 
 hohle. {Berliner Klin. Wochenschr. 1889.) 
 
 O. CuiARi. tibor Empyema Anti'i Highmori. ( Wiener Klin. Wochenschr. 
 1889.) 
 
 — Hartmann. tJber EmpyemderOberkieferhohle. {Dent. Meil. Wochenschr. 
 1889.) 
 
 G. S. Eouke. Polypus of the Antrum. {Dental Cosmos. Vol. VIII.) 
 H. Smith. Disease of the Antrum. {Dental Cosmos. Vol. IX.) 
 
 — Derby. Dropsy of the xiutrum. {Dental Cosmos. Vol. X.) 
 
 C. H. Moore. Antrum of Highmore, Expansion Thereof. {Dental Cosmos. 
 Vol. XII.) 
 
 C. E. Latimer. Diseases of the Maxillary Sinus. {Dental Cosmos. Vol. XII. ) 
 L. F. Hakvey. The Antrum of Highmore and its Diseases. {Dental Cosmos. 
 
 Vol. XIV.) 
 
 Prof. Armsby. Diseases of the Maxillary Antrum. {Dental Cosmos. Vol. 
 XIV.) 
 
 F. Fay. Dropsy of the Antrum. {Dental Cosmos. Vol. XVI.) 
 
 — Grant. Cystic Antral Tumor. {Dental Cosmos. Vol. XVI.) 
 
 — -. Tumor of the Antrum. {Dental Cosmos. Vol. XXII.) 
 
 L. Brown. Abscess of the Antrum. {Dental Cosmos. Vol. XXI.) 
 
 L. Howe. Abscess of the Antrum, etc. {Dental Cosmos. Vol. XXIII.) 
 
 E. Owen. On Maxillary Abscess and Necrosis in Childhood. {Dental Costnos. 
 Vol. XXIII.) 
 
 D. H. Goodwillie. a Tooth Developed in the Antrum. {Dental Cosmos.- 
 Vol. XXVI.) 
 
 D. H. Goodwillie. Abscess of the Antrum of Ten Yeai^s' Standing. {Dental 
 Cosmos. Vol. XXVI.) 
 
 D. H. Goodwillie. Tooth Found in the Antrum. {Dental Cosmos. Vol. 
 XXVI.) 
 
 D. H. Goodwillie. Tlie Antrum of Highmore and Some of its Diseases. 
 {Dental Cosmos. Vol. XXVI.) 
 
 J. S. Marshall. Alveolar Abscess Opening into the Antrum and Nasal 
 Cavity, etc. {Dental Cosjnos. Vol. XXVI.) 
 
 F. Warner. Abscess of the Antrum. {Dental Cosmos. Vol. XXVII.) 
 . Cases of Suppuration in the Antrum. {Dental Cosmos. Vol. 
 
 XXVII.) 
 
 M. Smale. Chronic Suppuration in the Antrum. {Dental Cosmos. Vol. 
 
 XXVII.) 
 
 C. Heath. Diseases of the Antrum. {Dental Cosmos. Vol. XXIX.) 
 
 Schifeers. Catarrh of the Antrum. {Dental Cosmos. Vol. XXX.) 
 
 A. Bronner. Empyema of the Maxillary Sinus. {Dental Cosmos. Vol. 
 
 XXXI.) 
 
 Adelmann. Untersuch. liber Krankhafte Zustande der 01)erkieferhohle. 
 
 Dorpat, 1844.
 
 660 LITERATURE. 
 
 A. Schubert, tibor Empyein der Highmorshohle. {Miiuch. Mc/. \l\ic/irnsrhr. 
 1889.) 
 
 W. Cakk. Disease of the Antrum. {Dental Cosmos. Vol. XXXI.) 
 
 F. Abbott. Disease of the Antrum Due to Dental Complications and its 
 Treatment. {Dental Cosmos. Vol. XXXI.) 
 
 I. P. Wilson. Pathological Conditions of the Air Cavities of the Cranium. 
 Resulting from Dental Lesions. {Dental Cosmos. Vol. XXXV.) 
 
 E. A. LuxDY. Abscess of the xVntrum. (Trans. California State Dent. Ass. 1886.) 
 
 F. Abbott. Diseases of the Antrum. (Trans. Dent. Soc. of the State of 
 X. Y. 1883.) 
 
 M. Kroxthal. Schleimhautcyste des Antrum. {Dcut. Monatssch. f. Zohn- 
 he'dk. 1884.) 
 
 M. Krohxtiial. Empyema Sinus Maxillaris. {Deut. Monatssch./. ZahnheUk. 
 
 1884.) 
 
 ScHXEiDER. Entziindung des Antrum, etc. {Dent. Monatssch./. ZahnheUk. 
 
 1887.) 
 
 C. IvEsciiREiTER. Zur Morphologic des Sinus Maxillaris. Stuttgart, 1878. 
 
 J. A. GiRALDis. tjber die Schleimcvsten der OberkieferhOhle. {Virchow's 
 Arch. 1856.) 
 
 Eeisert. Drei Fiillc von Erkrankung des Antri Highmori. {Deut. Monats- 
 
 M-hr./. ZahnheUk. 1891.) 
 
 M. R. Bkoavx'. Suppuration of the Antrum of Highmore. {Xcw York Med. 
 .hmr. 1891.) 
 
 G. ScHEFF. tJber das Empyem der Highmorshohle und seinen dentalen Ur- 
 -prung. Wien, 1891. 
 
 J. I. Hart. Diseases of the Antrum. (Trans. Dent. Soc. of the State of 
 X\ Y. 1890.) 
 
 C. Partsch. Die Erkrankungen der Kieferhohle. In Htmdb. d. Zahnheilk. 
 von J. Scheff, jr. Wien, 1892. 
 
 ZlEM. Zur Diagnose und Behandlung der Erkrankung der Kieferhohle. 
 
 (Berlhier Klin. Wochenschr. 1889.) 
 
 — Krieg. tJber Empyem des Antrum Highmori. {Med. Correspond. Bl. des 
 Wiirttemb. Arztl. Vercins. 1888.) 
 
 31. Schmidt. Zur Diagnose und Behandlung der Erkrankungen des Antrum 
 Highmori. {Berliner Klin. Wochensch. 1888.) 
 
 — Krause. Discussion iiber das Empyem der Highmorshohle. {Berliner 
 Klin. Wochensch. 1887.) 
 
 L. A. AVeil. Eiterdurchbruch naoh der Fossa canina des Oberkiefers, falschlich 
 als Empyenni Antri Highmori diagnosticirt. {(Jdontoskop. 1893.) 
 
 — Eyssautier. CuiTettage du sinus Maxillaire pour un cas rebelle dabces 
 chronique de cette cavite (Grenoble Imp. 1891) 
 
 P. Bitter. Ein Fall eines ins Antrum hineingewueherten Xasenpoh'pen. 
 {Deut. Monatssch. /. Zahnheilk. 1893.) ' 
 
 M. Schmidt. The Diagnosis and Treatment of Diseases of the Antrum of 
 Highmore. {Br. Jour, of Dent. Sci. 1889.) 
 
 A. W. W. Baker. Abscess of the Antrum. {Br. Jour, o/ Dent. Sci. 1889.) 
 A. B. SiBSOX. Antral Diseases. {Br. Jour, of Dent. Sci. 1893.) 
 H. Sewell. Empyema of the Antrum. {Monthly Review (/ Dental Surgery. 
 1891.) 
 
 F. Semox. Some Points in the Etiology, Diagnosis, and Treatment of Empy- 
 ema of the Antrum. (Trans. Odont. Soc. Gr. Britain. 1889.)
 
 LITERATURE. QQl 
 
 CHAPTER XLIV. 
 
 N. Jacohson. The Early Diagnosis and Treatment of Tumors [Dmlal 
 Cosvios. Vol. XXXI.) 
 
 S. RousH. Differential Diagnosis between Benign and Malignant Growths in 
 the Oral Cavity. {Dental Cosmos. Vol. XXXVI.) 
 
 CHAPTER XL VI. 
 
 T. AV. Brophy. Affections of the Salivary Glands, etc. {Dentnl Review. 
 1891.) 
 J. S. Smith. Cystic Tumor of Upper .Jaw. {Missouri DodalJounnd. 1878.) 
 
 — AVhep:lkk. Large Ranula, etc. {Missouri DentalJotcrual. 1883.) 
 
 C. H. HuxGERFORD. Cystic Abscess in a Child. {Archives of Dentistry. 
 1884.) 
 A. Baker. Den tigerous Cyst. {Archives of Dentistry. 1886.) 
 
 — Bryant. Cyst in the Antrum. (Dental Cosmos. Vol. III.) 
 W. M. GoATEs. Large Ranula. {Dental Cosmos. Vol. VII.) 
 F. Betton. Ranula. {Dental Cos^nos. Vol. X.) 
 
 J. Mason. Cystic Tumors of the Jaws. {Dental Cosmos. Vol. VIII.) 
 
 — Napheys. Ranula. {Dental Cos)nos. Vol. VIII.) 
 
 . Cyst in the Antrum, etc. (Pp. 159, 160. Dental Costnos. Vol. 
 
 IX.) 
 
 — Bertin. Ranula. {Dental Cosmos. Vol. XL) 
 
 — HuLKE. Cy.<tic Tumor of the Ma.xilla. {Dental Cosvios. Vol. XL) 
 
 . Ranula. (Pp. 321, 326, 439, 550. Dental Cosmos. Vol. XII.) 
 
 J. E. Garretson. Ranula, etc. {Dental Costnos. Vol. XII.) 
 
 — HoDGE.s. Dentigerous Cyst. {Dental Cosmos. Vol. XIII.) 
 W. S. BoLLEs. Dentigerous Cyst. {Dental Cosmos. Vol. XIII.) 
 "W. Tay. Ranula. {Dental Costnos. Vol. XIII.) 
 
 — Ramskill. Salivary Calculus 01)structing Wharton's Duct, etc. (Denfal 
 Costnos. Vol. XIII.) 
 
 — Verneuil. Osseous Cyst of tlie Lower Jaw. {Dental Costnos. Vol. 
 XIV.) 
 
 — "Waite. Fatty Tumor in the Situation of Kanula. {Dental Cos^tios. Vol. 
 XIV.) 
 
 C. Heath. Fibro-Cystic Tumor of Lower .Jaw. {Dental Cosmos. Vol. XIV.) 
 Professor Briggs. Fibro-Cystic Tumor of Inferior ^laxilla. {Detital Costnos. 
 Vol. XIV.) 
 
 — GuERSANT. Ranula. {Dental Cosmos. Vol. XIV.) 
 W. M. Barker. Ranula. {Detital Cosmos. Vol. XIV. ) 
 
 J. Machwuerth. Alveolar Cyst. {Dental Costnos. Vol. XV.) 
 
 J. F. Babcock. Cysto-Sarcoma in the Upper Jaw. {Dental Cosmos. Vol. 
 
 XVI.) 
 
 A. W. Stocks. Dentigerous Cyst in the Upper .Jaw. {Dental Cosmos. Vol. 
 
 XVII.) 
 
 M. TiLLAXJX. Acute Ranula. {Dental Costnos. Vol. XVII.) 
 M. Forget. On Ranula. {Detital Costtios. Vol. XVII.) 
 
 .. Sub-Lingual Mucous Cyst. {Dental Cositn^s. Vol. XVII.) 
 
 A. Coleman. Dentigerous Cyst. {Detital Cosmos. Vol. XVIII.) 
 
 . Ranula. {Detital Costtios. Vol. XIX.) 
 
 .^ . Cyst of the Upper Jaw. {Dental Cosmos. W>\. X'X.) 
 
 46
 
 662 LITERATURE. 
 
 N. MuLLEB. On Ranula in jSTew-Bom Children. {Denial Cosmos. Vol. XX.) 
 
 Stokes. Dentigerous Cystic Tumor. {Dental Cosmos. Vol. XXII.) 
 
 . Cyst of the Upper Jaw. {Dental Cosmos. Vol. XXI.) 
 
 . Ranula. {Dental Cosmos. Vol. XXI.) 
 
 W. T. Wheeler. Large Eanula. {Dental Cosmos. Vol XXIII.) 
 
 . Serous Cysts. {Dental Cosmos. Vol. XXIII.) 
 
 . Ranula, etc. {Dental Cosmos. Vol. XXIV.) 
 
 C. B. LocKWOOD. Ranula {Dental Cosmos. ,Vol XXIV.) 
 F. S. Eve. Some Points in the Pathology of Cystic and Encysted Solid 
 Tumoi-s of the Jaw. {Dental Cosmos Vol. XXVIH.) 
 
 A. Baker. Dentigerous Cyst. {Dental Cosmos. Vol. XXIX.) 
 
 E. R. Mtjllett. a Case of Dentigerous Cyst. {Dental Cosmos. Vol. 
 
 XXXV.) 
 
 Rossi. Bemerkungen iiber die an der Spitze der Backenzahnwurzeln 
 
 entwickelten Cysten. {Der Zahnarzt. 1853.) 
 
 A. Hartung. Kiefercyste in Folge abnorm entwickelter Zahne. {Deut. 
 Monatssch . f. Zahnhellk. 1883. ) 
 
 C. KuHNS. Cyste Milchzahngebilde eiithultend. {Deut. Monatssch. f. 
 Zahnhellk. 1885.) 
 
 RiTTER. Cyste am Proc. Alveol. des Oberkiefers. {Deut. Monatsschi-. f. 
 
 Zahnhellk. 1885.) 
 
 Gartner. tJber Ranula. Heidelberg, 1890. 
 
 Netjmanx. tJber die Entstehung der Ranula, etc. {Arch. f. Klin. Chirur- 
 
 (jie. Vol. XXX.) 
 
 F. Bartels. tJber Kiemengangcysten und Kiemengangfisteln. Rudolph- 
 
 stadt, 1891.) 
 
 E. Beneke. Zur Genese der Kiefercysten. Halle, 1891. 
 
 C. BouvET. Etude critique svir la Pathogenic des Kystes des machoires. 
 (^These.) Paris, 1891. 
 
 A. Backer. Notes on the Pathology of a Dentigerous Cyst. {Dublin Jour, 
 of Med. Sci. 1891.) 
 
 Kruse. tJber die Entwicklung Cystischer Geschwiilste im Unterkiefer. 
 
 {Vir chow' s Arch. Bd. CXXIV.) 
 
 C. Fackeldey. tJber Kiefercysten. Halle, 1869. 
 
 Manassein. Zur Lehre von der Spirochiieta Oberiueieri. (Cyste ausge- 
 
 hend von der Highmorshohle.) {Med. Wochenschr. Petei-sburg, 1876.) 
 
 F. S. Eve. Cystic Tumors of the Jaws, and the Etiology of Tumors. {Br. 
 Jour, of Dent. Sci. 1883.) 
 
 T. S. Carter. Dentigerous Cyst. {Monthly Review of Dent. Surg. 1888.) 
 W. "W. Baker. Note on the Pathology of a Dentigerous Cyst. {Monthly 
 Review of Dent. Surg. 1891.) 
 
 Coleman. On Cystic Tumors. (Trans. Odont. Soc. Gr. Britain. 1864.) 
 
 C. Wedl und Heider. tJber sine Cyste des Oberkiefers nebst klinischen 
 Bemerkungen iiber Cysten. {Deut. Vier. Jahrsch. f. Zahnhellk. 1865.) 
 
 Falkson. Cystom des Unterkiefers. {Virehow's Arch. Bd. LXXVI.) 
 
 V. Recklinghausen. tJber die Ranula, etc. {Virehow's Arch. Bd. 
 LXXXIV.) 
 
 J. PARREn>T. Ubor Zahn- und Kiefercysten. {Deut. Monatsschr. f. Zahn- 
 hellk. 1887.) 
 
 Redard. iiber einen Fall von Zahntragender Dermoidcyste. {Deut. 
 
 Mnuai^sahr.f. Zahnhellk. 1887.)
 
 LITERATURE. 663 
 
 J. Parkeidt. Beitrag zur Diagnose, Aetiologie, und H-'handluiig dor Zalm- 
 cysten. {Beat. Monatssch. f. ZaJnihi'Jlk. 1889.) 
 
 W. DiECK. Irritationscyste, liorvorgcrufen durch eineu aUnoim golagerten 
 blcibendeii Zahii. [Dent. Monatssclir. f. Zalinke'dk, 1889.) 
 
 — SciiNKiDEK. Eiupyc'iii dcr Kieferhohlo, etc. (Deut. Muuatsschr. f. Zalui- 
 ki'llK 1890.) 
 
 F. IvAHX. Beitrag zur Keiiiitnis.s dor Kaiiula. Tuliingeu, 1891. 
 
 — Partsch. tJLer Kieforeysteii. {^Deut. MonatsscliY. f. Zahuheilk. 1892.) 
 
 G. KiLiAN. Meine Erfahruugen iiber Kieferhohleneiterungen. {Miinchner 
 Mnl. Wochenschr. 1892.) 
 
 A. Caye. Des Kj'stes dermoides et nnicoules median.s de la languo et du 
 plancher de la bouche. (These. ) Paris, 1892. 
 
 — Bkoesike. Zur Casuistik der C^'stome. Berlin, 1874. 
 
 — Zahn. tjber viele Fiille von Kiemengangcysten. {Dp.nt. Zeltsc.hr. f. C/ii- 
 riirglr. Bd. XXII.) 
 
 A. Kruse. Uber die Entstchung cystischer Gesehwiilste ini Unterkieler. 
 yVireJioiv^s Arch. Vol. CXXIY.) 
 
 — Neumann. Ein Beitrag zur Kenntniss der ilanula. [Lanfienhcck' s Arr.Ji. 
 Vol. XX.) 
 
 — SoNXENBURQ. Uber Sitz und Behandlung der Kanula. [Arch. f. Klin. 
 Chirurgie. Vol. XXIX.) 
 
 F. Buscii. Centrale Epitlielionic Miit C3'stenbildung. { Berliner Klin, Wochen- 
 schr. 1877. ) 
 
 CHAPTEPv XLVII. 
 
 A. E. Baldwin. Tumoi-s of the Mouth and Jaws. {Dental Rcrieu: 1888.) 
 AV. Fergusson. Kecun-ent Osseous Tumor. [Denial Cosmos. Vol. XV.) 
 . Cancer of Upper Jaw. [Dental Cosmos. Vol. XVI. ) 
 
 — . Tumor of Upper Jaw. [Dental Cosmos. Vol. XVI.) 
 
 — Bertolet. Interesting Specimen of Epulis. [Drntol Cosmos. A'ol. 
 XVI.) 
 
 . Tumor of Both Upper Jaws. [Dental Cosmos. \ <•]. X\ I.) 
 
 — . Sublingual Tumor. [Dental Cosmos. Vol. X"\'I.) 
 
 — BxTTLiN. Osteoma of the Superior Maxilla. [Dental Cosmos. \'ol. 
 XVII.) 
 
 F. Mason. Anomalous Tumors Caused by Imbedded Teeth. [Dental Cosmos. 
 
 Vol. XX.) 
 
 J. E. Mears. Spindle-Cell Sarcoma of the Lower Jaw. (Dental Cosmos. 
 
 Vol. XXTI.) 
 
 M. Longstretu. Mj-eloid Sarcoma of Jaw. [Dental Cosmos, ^'ol. XII.) 
 
 E.Mason. Sarcoma of Jaw. — Di^ath. [Dental Ommos. Vol. XII.) 
 
 Heath. Twenty-iive Years' History of a Maxillary Tumor. [Dental 
 
 Cosmos. Vol. XXII.) 
 J. F. Thompson. Carcinoma Sinuilating Kanula. [Dental Cosmos. Vol. 
 
 XXII.) 
 
 N. Sknn. The Pathology and Treatment of Epulis. [Dental Cosmos. Vol. 
 
 XXII.) 
 
 C. Macnamara. Sarcoma of Upper Jaw. [Dental Cosmos. Vol. XXTV.) 
 
 Gaddes. Recun-ent Epulis. [Dental Cosmos. Vol. XXIV.) 
 
 . Ossified Sarcoma of the Lower Jaw. [Dental Cosmos. Vol. 
 
 XXV.)
 
 664 LITERATURE. 
 
 K. TiLLKY. Ostvoiua. {Dentol Csiho-s. ^'ol. XXVIII.) 
 
 C. Heitzmaxn and F. Ahbott. Contrilmtions to the Knowledge of Tumoi-s 
 of the Jaws. {Dental Cosmos. Vol. XXX.) 
 
 A. We!<tlake. a Case of Giant-Cell t5arconia. {Dental Cosinon. \o\. 
 XXXI.) 
 
 A. C Gerster. Ojierative Dissemination. (.Y. Y. Med. Jour.) 
 
 J. Leclerc. Contribution a I'etude des tumeui-.s du mile du palais et de la 
 voute palatine. (Those.) Montpellier Imper. Hamelin Freres, 1892. 
 
 P. S. AViXDMXJLLKR. Beitnig zur Casuistik der Kiefertumoren. Gottingen, 
 1891. 
 
 HiLDEBRANi). Beitrag zur Lehre vun den durch almornie Zahnentwieklung 
 
 bedingten Kiefertumoren. [Dcut. Zeitschr.f. Ctiirun/ie. Bd. XXXII.) 
 
 J. C. Scott. Cancerous Tumor. [Johnston's Doital Miscellany. 1878.) 
 
 G. Law.-^ox. Large Cartilaginous Tiuiior. [Johnston's Dental Miscellany. 
 1878.) 
 
 W. H. Atkixsox. Tumors of the Mouth. (Trans. Dent. 8oc. of the State 
 of N. Y. 1873.) 
 
 H. Maxcock. tJber Geschwiilste des Oberkiefers. [Dcr Zahnarzt. 1856.) 
 
 C. FocK. tJber zwei Fiille von Knochengeschwiilsten am Alveolarfortsatz 
 des Oberkiefei-s. [Der Zahnarzt. 1856.) 
 
 J. RouYER. Uber die Tumoren der Gaumenregion, welche durch Driisen — 
 Hypertrophie gebildet werden. [Der Zahnarzt. 1857.) 
 
 C. Heath. The Diseases of the Jaw. 
 
 — HoFMOKL. tJber Resection des Unterkiefei-s, niit Riicksicht auf 88 darauf 
 beziigliche Krankheitsfalle. ( Wiener Med. Jahrb. 1871.) 
 
 Th. Billroth. Elemente der Allgemeinen chirurgischen Pathologie. 1868. 
 J. Paget. Tumors of the Palate. (St. Bartholm Hosp Rep. 1886.) 
 
 — Allgey'er. tjbercentrale EpithelgeschwiilstedesUnterkiefers. [KUni.^che 
 Beitr. 1886. ) 
 
 O. Weber. Handb^ der allgem. und operativen Chirurgie. Bd. III. 
 
 — Ohlmaxx. Beitrage zur Statistik der Oberkiefergeschwiilste. [AreJi. f. 
 Klin. Chirurgie. Bd. XVIII.) 
 
 A. "Wixiwarter. Beitrage zur Statistik der Carcinome. Stuttgart, 1878. 
 
 — BiRXBAUM. Beitrage zur Statistik der Kiefergeschwiilste. [Deut. ZeitscJt. 
 f. Chirurgie. Bd. XXVIII.) 
 
 — Saurel. Tumors of the Gums. (.4;// .Jour, of Dent. Sri. 1858.) 
 E. C. Chase. Epulis. [Missouri Dent. Jour. 1872.) 
 
 G. Rabitoy. Bone Tumor of Lower Jaw. [Missouri Dent. Jour. 1876 ) 
 G. Lawsox. Large Cartilaginous Tumor of Lower Maxilla. [Missouri Dent 
 
 Jour. 1878.) 
 
 C. E. Nelsox. Dental Tumor of Jaw. [Missouri Dent. Jour. 1882.) 
 
 J. S. Amoore. Sarcomatous Growth in the Upper Jaw. [Mls.souri Dent. 
 
 Jour. 1882.) 
 
 O. J. Coskery. a Case of Sarcoma of Lower Jaw. [Archives of Dentistry. 
 
 1885.) 
 J. A. Wy^eth. Sarcoma of the Lower Jaw. [Archives of Dentistry. 1885.) 
 T. Bryaxt. Tumors. [Dental Cosmos. Vols. V and VI.) 
 J. E. Garretsox. The Tunioi-s of the Mouth. [Dental Cosmos. Vols. VII 
 
 and VIII.) 
 
 . Epulis. [Dental Cosmos. Vol. VIII. Pp. 181 and 448.) 
 
 '■ . Large Epulis. [Dental Cosmos. Vol. VIII. P. 103. )
 
 LITERATURE. 665 
 
 8. J. A. S.vi.TKK. On I'aiiillary 1'iiiiimis of the (iiim. I^Dniinl ('„s»ii,s. 
 Vol. VIII.) 
 
 J. S. Smith. Vascular Tumor. (Drnfal fhsitws. Vol. IX.) 
 
 C. Heath. Osteo-Sarconia of Lower Jaw. {Dcntnl Cosmos. Vol. X.) 
 
 W. Fekgusson. Ivory Tumor of the Upper Jaw. {Denial Cosmos. Vol. X.) 
 
 II. ViRCHOAv. Neuroma. {Dental Cosmos. Vol. X.) 
 
 J. Martin. Epulis. {Denial Cosmos. Vol. X.) 
 
 — Mear.s. Medullary Carcinoma of Antrum. {Dental Cosmos. Vol. XII.) 
 I\. A. KiNLOCH. Sarcomatous Fibroma, etc. {Dental Cosmos. Vol. XII.) 
 S. \V. Gross Horny Tumor of Lower Lip. {Dental Cosmos. Vol. XII.) 
 L. A. Sayre. Fibro-Serous Cyst of Jaw. {Dental Cosmos. Vol. XIII.) 
 
 E. Neumann. Gummata Syphilitica. {Dental Cosmos. Vol. XIII.) 
 
 S. W. Gross. Tumor of the Lower Jaw. {Dental Cosmos. Vol. XIII.) 
 
 J. Syme. I'ber Kiefergcschwiilste. {Der Zahnarzt. 1856.) 
 
 C. Barrow. Uber die nachthcilige Wirkung im Alveolarfortsatz zuriickge- 
 
 bliebener Zahnrestc. {Der Zahnarzt. 1859.) 
 
 C. E. TiiUMAN. Contributions from the Dental Dejiartment of St. Thomas's 
 
 Hospital. Two Cases of Epulis, etc. Two Cases of Abscess Pointing on Face at 
 
 Root of Nose, just below the Eye. Case of Eruption of Canine mider the Chin. 
 
 {Br. Jour, of Dent. Sci. 1893.) 
 W. Thorburn. Tumoi-s of the Jaw and Gums. {Br. Jour, of Dent. Sr.i. 
 
 1892.) 
 S. A. CoxoN. A Case of Cy.«tic Sarcoma of the Superior Maxilla, {Br. Jour. 
 
 of Dent. Sci. 1892.) 
 
 F. F. BuRQHARD. On Some Cases of Epulis. (Trans. Odont. Soc. Gr. Britain. 
 1888 ) 
 
 C. Heath. On Epithelioma of the Jaw. (Trans. Odont. Soc. Gr. Jiritain. 
 1891.) 
 
 J. ArkOvy. On rapilloma of the Oral Cavity. (Trans. Odnnt. Soc. Gr. 
 Britain. 1880.) 
 
 CHAPTER XL VI II. 
 
 Ellenberger und Baum. Ein Beitrag zu dem Kapitel Zahnretention und 
 Zahnrudimente. {Arch.f. Anat. unci Phi/slol 1892.) 
 
 L. A. Weil. Doppelseitige Zwillingsbildung der Mittleren oberen Schneide- 
 ziihne. {Dent. Monatssc/ir. f. Zahtiheilk. 1893.) 
 
 R. Baiime. Zahnniissbildungen. {Deut. Vier. Jahrschr. f. Zahnheilk. 1874.) 
 
 R. Baume. Ein Odontom. {Dent. Vier. Jahrsrhr. f. Zahnheilk. 1874.) 
 
 — Hermann. Anomal gebildete Ziiline. {Dent. Vier. JaJirselir. f. Za]inheilk. 
 1874.) 
 
 J. \ . Schneider. Zwei Fiille von Sehnielzlnsen Zahnniissbildungen. {Deut. 
 Vier. Jahrschr. f. Zahnlieitk. 187K. ) 
 
 ScHWARTZKOPF. Ein Fall von Zwillingsbildung zweier vorderer Sdineidi'- 
 
 ziihne. {Deut. Vier. Jahrxcttr. f. Zahnheilk. 1882.) 
 
 (iEissELBRECHT. Zahnmissl)ildung und dritte Dentition. {Deut. Vier. 
 
 Jahrschr. f. Zah nheilk. 1 882. ) 
 
 MoNTiGEL. Uber zwei Fiille seltener Dentitionsanonialic {Deut. Munats- 
 
 schr.f. Zahnheilk. 1888.) 
 
 Brunsmann. Uber einige Zahnanomalicn i/h.,/ Monats.'ichr. f. Zahn- 
 heilk. 1889.)
 
 666 LITERATURE. 
 
 A. Mayek. Ein Fall von Cementv.TSchiiielzung dreier Zjihne. {DpaiL 
 Monatsschr. f. Zahnheilk. 1890.) 
 
 Herrmanx. Eine Milchzahnanouuilie. (Dnd. Monnts.^c/ir. /. Zalmheilk. 
 
 1891.) 
 
 A. Sterxfeld. Anomalien der Z;diiie, in Handl). der Zahnlieilk., von J. 
 
 Scheff, Jr. Wien, 1891. 
 
 J. Scheff, Jr. Retention ; Eudimentarziihne etc. In Handb. der Zahnheilk. 
 
 Wien, 1891. 
 
 M. ScHLENKER. Schmelztropfen, aussere Odontome Exo.«tosen. In Handh. 
 der Zahnheilk., von J. Schetf, Jr. Wien, 1891. 
 
 Partsch. tjber zwei Falle von Odontomen. {Deut. Monatsschr. f. Zahn- 
 heilk. 1892.) 
 
 B. Salzer. Yerschiedenes au.s der Praxis. {Odontoskop. 1893.) 
 
 A. H. Thompson. The Missing Teeth of Man. {Dental Cosmos. Vol 
 
 XXXVI.) 
 
 M. LiP.>*CHiTZ. Eine seltene Zahnanomalic. [Deut. Monatssc/tr. f. Zahnheilk. 
 
 1893) 
 
 : . A Child with Teeth in its iSTo-'^e {Johnston's De»tal Miscellany. 
 
 1874.) 
 J. A. OsMiTx. Unerupted Teeth in the Pvoof of the Mouth. {.Johnston's 
 
 Den tal Miscel I any 1 880. ) 
 
 . Anomalous Teeth. {Am. Join: of Dent. Sci. 1843. P. 150.) 
 
 . Anomalous Teeth. {Am. Jour, of Dent. Sci. 1844. P. 63.) 
 
 S. Malet. Osseous Union of Teeth. {Am. Jour, of Dent. Sci. 1856.) 
 
 J. J. Patrick. Osseous Union of Teeth. {Am. Jour, of Dent. Sci. 1856.) 
 
 . Osseous Union of Teeth. {Am. Jour, of Dent. Sci. 1857. Pp. 
 
 451 and 600.) 
 
 I. C. Gray. An Odontoid. {Missouri Dent. Jour. 1875.) 
 T. W. PtEED. Union of Teeth. {Missouri Dent. Jour. 1876.) 
 H. L. Sage. Nodules on Teeth. {Missouri Dent. Jour. 1876.) 
 G. V. Black. Odontome. {Missouri Dent. Jour. 1880.) 
 
 E. Schwarzkopf. Union between Both Upper Central Inci.sors with the 
 Laterals. {Missouri Dent. Jour. 1882.) 
 
 U. D. Taylor. Double Teeth. {Dental Cosmos. Vol.1.) 
 G. J. Stivers. Mai-Development of Teeth. {Dental Cosmos. Vol. II.) 
 W. N. Amek. Mal-Position of the Canine Teeth. (Dental Cosmos. Vol.11.) 
 S. H. Guilford. A Dental Anomaly. {Dental Cosmos. Vol. XXV.) 
 
 C. W. Staistox. Ci-ownless Teeth. {Dental Costnos. Vol. XXXIV.) 
 
 V. Jarre. Congenital Absence of Teeth in a Subject Twelve Yeai-s Old. 
 {Dental Co.^mos. Vol. XXXIV.) 
 
 L. H. HoLLAXDER. Demonstration ciniger Pathologischer Kieferpraparate und 
 einiger Zahnanomalien. {Verhand. d. Deut. Odont. Gesell. Bd. II.) 
 
 F. BuscH. Uber Vei-schmelzung und Verwachsung der Zjihue de* ]\[ilchge- 
 bisses und des bleibenden Gebi.<.<es. {Verhand. d. Deut. Odont. Gesell. Bd. V.) 
 
 HoHL. Einiges iiber die Eutstehung der "freien'' Odontome. {Deut. 
 
 Vier. f. Zahnheilk. 1868. ) 
 
 C. Wedl. Untersuchung einer Zahnmis>bildung am Unterkiefer. {Deut. 
 Vier. Jahr.f. Zahnheilk. 1869.) 
 
 J. V. Metnitz. Odontomes. {Dental Review. 1889.) 
 
 Z. M. Kreider. Osseous Union of Two Temporary Teeth. {Am. Jour, of 
 Dent. Sci. 1861.)
 
 LITERATURE. 667 
 
 ■ Osseous Union of Teeth. {Am. Jour, of Dent. Sci. 1858.) 
 
 E. H. AxDREWs. Extraordinary Successive Development of Teeth. {A))i. 
 Jour, of Dent. Sci. 1858 ) 
 
 E. S. Talbot. A Wandering Supernumerary Tooth. [Indep. I'ract. 1884.) 
 W. H. FoLKKR Tooth in Upper Lip. {Dental Coamo.^. Vol. IX.) 
 
 M. GuENiOT. Teeth at Birth. {Dental Co.siuos. Vol. IX.) 
 
 M. Broca. Odontonies. {Dental Cosmos. Vol. X ) 
 
 W. P. EiCE. Dental Anomaly. {Dental Cosmos. Vol. XIII.) 
 
 G. S. FouKE. Osseous Union of Teeth. {Dental Cosmos. Vol. XIV.) 
 
 — . Connate Teeth. {Dental Cosmos. Vol. XV.) 
 
 DE H. Hall. Malposition of a Tooth. {Dental Cosmos. XXVI.) 
 J. A. Daly. Dental Anornalies. {Dental Cosmos. Vol. XXX.) 
 AV. Adams. Dental Anomaly. {Dental Cosntos. Vol. XXXI.) 
 
 F. Abbott. Eare Dental Anomalies. {De?itril Cos»nis. Vol. XXXlll.) 
 C. W. ScHMEDicKE. tjher Verschmolzene Zahue. {De?' Zahnarzt. iSid.) 
 C. W. ScHMEDiCKE. Das Angebliche Verwachsen der Zahnwurzeln mit den 
 
 Alveolen. {Der Zahnarzt. 1846.) 
 
 L. J. Melicher. tjber zusammengewach.sene Zahne. {Der Zahnarzt. 1847.) 
 
 M. HoFi^A. Beschreibung zweier anoinal gebildeten Ziihne. {Der ZuJmarzt. 
 1849.) 
 
 K. Baume. Seltsame Zahnmissbildung. {Dent. Vier. Jahrschr. f. Zahn- 
 heilk. 1872.) 
 
 K. Baume. Zwillingsbiidung. {Dent. Vier. Jahrschr. f. Zahnheilk. 1872) 
 
 — Fripp. Three Cases of Imperfect Dentition in the Same Family. {Jour, 
 of the Br. Dent. A.'<so 1 89 1 . ) 
 
 L. Hollander. Impaction eines Milcheckzahnes tief im Kiefer bei noi-malem 
 Durclibruch des bleibenden Eck/cahnes {Oestr. Ungar. Vier. Jahrsch. 1892.) 
 
 J. Parreidt ^lahlziihne an Stclli; der zweiten Praemolaren. {Deui. 
 Moiiatsschr.f Zahnheilk 1894) 
 
 J, A. Brigos. On Malformation. {Br, Jour, of Dent. Sci. 1889.) 
 
 J. W. Duxkerley. Odontomes. {Br. Jour, of Dent. Sci. 1892.) 
 
 . Odontomes, in Trans. Odont. Soc. Gr. Britain. 1888. 
 
 A. S. UxDERWOOD. A Remarkable Odontome. {Monthly Review of Dental 
 Surgery. 1882.) 
 
 C. S. ToME.s. Description of an Odontome. (Trans. Odont. Soc. Gr. Britain. 
 1871.)
 
 INDEX. 
 
 Ap.kasion, mechanical, 309. 
 
 causes of, 309. 
 
 secondary dentine in, 311. 
 Abscess, alveolar, clinical features of, 455. 
 
 blind (chronic purulent eircumscril)ed peri- 
 cementitis). 451. 
 Absorption of temporary teeth, 2(54. 
 
 of cementura and dentine of temporary 
 teeth, 267. 
 
 of enamel of temporary teeth, 270. 
 Adenitis, lymph, 460. 
 Alveolar process of lower .iaw, 10. 
 
 of upper .iaw, 4. 
 Amelitis, 322. 
 Ameloblasts, breaking up of the, 173, 186. 
 
 definition of the. 126. 
 
 development of the, 171. 
 Ameloma, tumor of the enamel, 554. 
 Anatomy, general, of the teeth, 39. 
 
 of the teeth, diagram of the, 40. 
 
 of the teeth, macroscopical, 16. 
 
 morbid. (See microscopical features of .) 
 Anomalies of the dentine, 241. 
 
 of the enamel, 205. 
 
 of the papilla, 239, 242. 
 Anomalous though not pathological formations 
 
 in the teeth, 44, 205, 239. 
 Anterior dental canal, 2. 
 
 nasal spine, 4. 
 
 palatine canal, 3. 
 Antrum of Highmore, 1, 5. 
 
 blood-vessels and glands of, 7. 
 
 communications between nasal cavityand,6. 
 
 empyema of, 542. 
 
 lining membrane of, 7. 
 
 polypoid growths in, 545. 
 
 shape of, 5. 
 
 variations in size of, 6. 
 
 walls of, 5. 
 Aphtha;, ulceration of the gum, ;%9. 
 Arsenic, the effects of upon the pulps of teeth, 
 
 518. 
 Articulation of the teeth, 34. 
 Atrophy of the pulp, of the nerves of, 427. 
 
 reticular, 419-42.5. 
 
 sclerotic, 418-424. 
 
 Basal ridge orcingulum, 18. 
 Basis-substance of bone, 51. 
 
 of cementum, structure of, 105. 
 
 of dentine, structure of, 41, 73, 80, 86, 133 
 138. 
 
 of enamel, structure of, 91, 96. 
 Bicuspids or premolars, general characteristics 
 of the, 20. 
 
 lower and upper, characteristics of the, 20. 
 Blood-vessels, structure of, 58. 
 
 of the pericementum, 260. 
 
 of the pulp, 43, 44, 248. 
 Bone-tissue, basis-substance of, 51. 
 
 canaliculi of, 50. 
 
 corpuscles of (lacuna?), 50. 
 
 Haversian systems of, 51 . 
 
 lamellie of, 51. 
 
 new formations of in the pericementum, 
 475. 
 
 BOW formations of in the pulp, 289, 292, ,303, 
 307. 
 
 trabeculas of, 50. 
 
 two varieties of, 49. 
 
 Calcification of the enamel, 173. 
 deficient, 210, 216. 
 of dentine, 133. 
 of nerves of the pulp, 429. 
 of pulp-tissuo, 412. 420. 
 Cancer, or carcinoma, 604. 
 
 epithelioma or dermoid, 6(14. 
 medullary, 607. 
 Canine fossa, 1. 
 Canines, cuspids, or eye-teeth, description of, 
 
 19, 26, 28. 
 Caries of the teeth, 48.8. 
 Abbott's views, 489. 
 acute, 496. 
 
 begins as a chemical process, 490. 
 chronic a more chemical process, 495. 
 difference of resistance to, 490. 
 etiology of, 489. 
 micro-organisms in. 493, 495. 
 Nasmyth's membrane in, 493. 
 of a piece of hippo|)otamus tooth, 494. 
 I of cement, 500. 
 
 47 669
 
 670 
 
 INDEX. 
 
 Caries of dentine. 493. 
 of enamel. 491. 
 pigmentation, 491. 
 re-establislies the |irotoplasmic condition 
 
 of the tissues 492. 
 results of investigations, 502. 
 starting-points of, 489. 
 the influence of food on. 489. 
 Miller's views. 503. 
 accompanying phenomena of, 506. 
 of cement, 505, 514. 
 of dentine. 501, 510. 
 of enamel, 5'i3, 508. 
 physical phenomena of, 503. 
 pigmentation of the tissues in, 507. 
 the micro-organisms of, .515. 
 results of investigations of, 516. 
 the healing process in. .517. 
 Carious cavities, examination for, 282. 
 Cementitis and eburnitis, 370, 457, 467. 
 Cementum, the, 43, 101, 110. 
 absorption of the, 267. 
 basis-substance of the, 102. 
 corpuscles of the, 43. 
 haematoidin clusters in the, 463. 
 osteoid, 114. 
 
 the development of, 227. 
 the minute structure of, 101, 108. 
 the minute structure of the neck, 83, 105, 
 
 119. 
 the structure of devitalized, 123. 
 Classification of the diseases of the pericemen- 
 tum, 432. 
 of the diseases of the pulp, 382. 
 Clinical and anatomical features of tumors in 
 general, 546. 
 . Cold and heat in diagnosis, 286. 
 Colloid degeneration of the pulp, 431. 
 Connective tissue, development of, 58. 
 
 varieties of, 46, 
 Constitutional diseases diagnosed by the changes 
 in the teeth and their surroundings, 277. 
 Coronoid and condyloid processes, 12. 
 Cysto-adenoma, 601. 
 Cysts, alveolar, 563. 
 
 bony new formations in, 572. 
 
 classification of, 560. 
 
 definition of, 560. 
 
 dental or dentigerous, 561. 
 
 epithelial, 560. 
 
 in the antrum, 566. 
 
 in the oral cavity, 559. 
 
 inflammatory, 564. 
 
 mucoid, 561. 
 
 papillary vegetations in wall of. 564. 
 
 (ranula), 560. 
 
 Defects, congenital, in enamel, 216. 
 Degenerations and atrophies of the pulp, 412. 
 
 colloid, of the pulp, 431. 
 
 fatty, of the pulp, 431. 
 Dentine, absorption of the, 267. 
 
 anomalies of the, 241. 
 
 basis-substance of the, 41, 73, 80, 86, 133, 139. 
 
 Dentine, calcification of the, 134. 
 
 cannliculi, development of the, 135. 
 canaliculi and course of the, 41, 133. 
 chemical constituents of the, 41. 
 development of the, 129. 139. 
 fibers, development of the, 131. 
 fibers, or "Tomes's" fibers, 42. 
 first trace of papilla of the, 129. 
 formations of globular territories in the, 
 
 135. 
 granular layer of the, 42. 
 interglobular spaces in the, 44, 135. 
 interzonal layer of the, 42. 
 methods of preparing microscopical speci- 
 mens of the. 69, 76. 
 minute structure of the, 69. • 
 nutrition of the, 270. 
 physiology of the, 271. 
 reaction of the, upon fillings, .320. 
 recalcification of softened, 272. 
 secondary formations of, 289, 292, 305, 311. 
 sensitiveness of the, 272. 
 structure of devitalized, 80, 273. 
 tumors of the, odontoma, 553. 
 Development, faulty, 194. 
 of bone-tissue. 64. 
 of teeth in embryos aifected with rhachitis, 
 
 232. 
 of the ameloblasts, 171. 
 of the cementum, 227. 
 of the connective tissue, 58. 
 of the dentine, 129, 139. 
 of the enamel, 148, 180. 
 of the enamel-cord at the sixth week, 149. 
 of the enamel-cord into the enamel-organ, 
 
 149. 
 of the enamel-fibers, 174. 
 of the enamel-organ at two months, 150. 
 of the enamel-organ at three months, 151. 
 of the enamel-organ at three and one-half 
 
 months, 154. 
 of the enamel-organ at four months, 155. 
 of the enamel-organ at five months. 156. 
 of the enamel-organ at si.x and seven 
 
 months, 169. 
 of the lower maxilla, 12. 
 of the upper maxilla, 8. 
 of the stellate reticulum and stratum inter- 
 medium, 161. 
 Diagnosis, general, of the diseases of the teeth, 
 274. 
 heat and cold in, 286. 
 light in, 287. 
 of acute non-purulent apical pericementitis. 
 
 437. 
 of acute non-purulent circumscribed peri- 
 cementitis, 435. 
 of acute non-purulent ditfuse pericemen- 
 titis, 438. 
 of acute non-purulent marginal pericemen- 
 titis, 433. 
 of acute non-purulent partial pulpitis, 385. 
 of acute non-purulent total pulpitis, 386. 
 of acute purulent apical pericementitis, 443.
 
 INDEX. 
 
 t;7i 
 
 Diagnosis of acuto purulent <litl'uso periconien- 
 titis. 444. 
 
 of acuto purulent pulpitis, 38S. 
 
 of alveolar cysts, 563. 
 
 of calcification of the pulp, 41:;. 
 
 of comentitis and oburnitis, 4iT. 
 
 of chronic purulent .ipical poricouioutitis. 
 453. 
 
 of chronic purulent circuinscriboil pori- 
 cementitis (blind abscess), 4")1. 
 
 of chronic purulent ditfuse i)oriccHientitis, 
 454. 
 
 of chronic purulent margin, il puriccniun- 
 titis (pj'orrhica alvoolaris), 447. 
 
 of chronic purulent pulpitis, 392. 
 
 of cysts in the antrum, 545. 
 
 of cysts in the oral cavity, 559. 
 
 of dental or dontigerous cysts, 561. 
 
 of eburnifications and ossifications of the 
 pulp, 416. 
 
 of empyema of the antrum, 543. 
 
 of gangrene of ihe pulp, dry, 396. 
 
 of gangrene of the pulp, moist, 394. 
 
 of hyperplasia of the pulp, partial, 389. 
 
 of hyi>erplasia of the pulp, total, 3'.i0. 
 
 of hyperplastic diffuse pericementitis, 441. 
 
 of hyperplastic partial pericementitis, 440. 
 
 of inflammatory cyst, 564. 
 
 of irritation of the pulp, 384. 
 
 of lymphadenitis, 460. 
 
 of necrosis of the jaw-bone, 536. 
 
 of periostitis, osteitis, and osteomyoli is, 458. 
 
 of ranula, 560. 
 
 of reticular atrophy of the pulp. 419. 
 
 of sclerotic atrophy of the pulp, 418. 
 
 of tumors in general, 549. 
 
 of tumors of the jaws, 573. 
 
 the sense of smell in, 285. 
 
 the sense of touch in, 281. 
 
 transillumination in, 287. 
 Differential diagnosis of acute non -purulent 
 apical pericementitis, 437. 
 
 of acute non-purulent circumscribed peri- 
 cementitis, 436. 
 
 of acute non-purulent diffuse pericemen- 
 titis. 439. 
 
 of acute non-purulent marginal pericemen- 
 titis, 434. 
 
 of acuto non-purulent partial pulpitis, 386. 
 
 of acute non-purulent total pulpitis, 387. 
 
 of acute purulent ai)ical pericementitis, 443. 
 
 of acuto purulent diffuse pericementitis, 445. 
 
 of acute purulent pulpitis, 388. 
 
 of alveolar abscess, 457. 
 
 of calcifications in the pulp, 413. 
 
 of chronic purulent apical pericementitis, 
 453. 
 
 of chronic purulent circumscribed peri- 
 cementitis, 452. 
 
 of chronic purulent diffuse pericementitis, 
 454. 
 
 of chronic purulent marginal pericemen- 
 titis, 449. 
 
 of chronic purulent pulpitis, 393. 
 
 Differential diagnosis of oburnilicatious and 
 ossifications of the pulp, 417. 
 
 of empyema of the antrum, 515. 
 
 of gangreno of the pulp, dry, 3%. 
 
 of gangrene of the pulp, moist, 396. 
 
 of hyperplasia of the pulp, partial, 3U0. 
 
 of hyperplasia of the pulp, total, .391. 
 
 of hyperplastic dift'use pericementitis, 442. 
 
 of hyperplasti..- partial pericomontitis, 440. 
 
 of irritation of the pulp. .^84. 
 
 of lymphadenitis, 461 . 
 
 of necrosis of the jaw-bones, 5i6. 
 
 of ozaena of the nose, 54.5. 
 
 of periostitis, osteitis, and osteomyelitis, 4i)0. 
 
 of reticular atrophy of the pulp, 420. 
 Discoloration of devitalized teeth, 273. 
 Diseases, constitutional, affecting the tissues of 
 the teeth, 277. 
 
 of the antrum, .542. 
 
 of the gums, 363. 
 
 of the maxillary lymph-ganglia, 4tiO. 
 
 of the pericementum and alveolus, clini- 
 cal, 432. 
 
 of the pericementum and alveolus, morbid 
 anatomy, 462. 
 
 of the pulp, clinical, oSO. 412. 
 
 of the pulp, morbid anatomy, 397, 420. 
 Dwarf teeth, 235, 609. 
 
 Eburnificatioxs and ossifications of the pulp, 
 
 413, 423. 
 Eburnitis, 370, 457. 
 
 healing process in, 376. 
 Effects of arsenic dioxide and metallic arsenic 
 
 upon the pulps of teeth, 518. 
 Empyema of the antrum, .542. 
 Enamel, absorption of the, 270. 
 
 anomalies of the, 239. . 
 
 basis-substance of the. 01, 96. 
 
 beginning formation of the, 170. 
 
 boundary between dentine and, 93. 
 
 caries of the, by Abbott, 491. 
 
 caries of the. by Miller, 503, 508. 
 
 congenital defects in the, 216. 
 
 cuticle, or Nasmyth's membrane, 4.3, 92. 
 
 deficient calcification of the, 210. 
 
 fibrilhvof the. 42, 90. 
 
 first trace of the germ of the, 149. 
 
 first trace of the tissue of the, 174. 
 
 granulation of the, 214. 
 
 growth of the, 180. 
 
 living matter of, 90. 
 
 minute structure of, 90, 96. 
 
 nutrition of the, 270. 
 
 of devitalized teeth, 273. 
 
 physiology of the, 271. 
 
 pigmentation and stratification of the, 45. 
 207, 212. 
 
 prisms or rods, 42. 
 
 recalcification, rehardeningof the, 272. 
 
 rods, anomalous arrungoment of the, 209. 
 
 sensitiveness of the, 272. 
 
 striie, the, of Rotzius, 42. 
 
 tumors of the, ameloma, 554.
 
 672 
 
 INDEX. 
 
 Enamel-organ, definition of the, 124. 
 
 five component parts of the. 126. 
 
 folds, convolutions and reduplications of 
 the. 238. 
 
 malformations and malpositions of the, 236. 
 
 what is the ultimate fate of the, 174. 
 Epithelioma, or dermoid cancer, 604. 
 Epithelium, 56. 
 
 function of, 58. 
 
 of glands, 58. 
 
 varieties of, f>7. 
 Erosion of teeth, 316. 
 Eruption of teeth, 261. 
 
 premature, of ill-developed teeth. 233. 
 Examination for carious cavities of teeth, 282. 
 External epithelium of the enamel-organ, 159, 
 161, 165. 
 
 breaking up of the, 166. 
 
 formation of blood-vessels in, 166. 
 External oblique line of lower jaw, 10. 
 
 Fatty degeneration of the pulp, 431. 
 Faulty development of the teeth, 194. 
 
 an interesting case of, 198. 
 
 time of occurrence of, 196. 
 Fibrous connective tissue, general description 
 
 of, 48. 
 Fusion of roots of teeth. 611. 
 
 of crowns of teeth, 611. 
 
 of two teeth, 611. 
 
 Gaxgrkse of the gums, 370. 
 
 of the pulp. dry. 396. 
 
 of the pulp, moist, 394. 
 General anatomy of the human teeth, 39. 
 General diagnosis of the diseases of the teeth, 
 
 274. 
 General features of tumors, 546. 
 General histology, 46. 
 Genial tubercles. 10. 
 
 Granuloma in hyperplastic pericementitis, 472. 
 Groove for facial artery of lower .iaw, 10. 
 Gum, acute inflammation of the, 364. 
 
 anatomy of the, 40. 
 
 chronic inflammation of the, 366. 
 
 diphtheritic ulcers of the, 370. 
 
 gangrene of the, 370. 
 
 hyperaemia of the, 363. 
 
 hyperplasia of the. 365. 
 
 inflammation of the. 363. 
 
 mucous membrane of the, 41. 
 
 papillary layer of the, 41. 
 
 syphilitic ulceration of the. 369. 
 
 the, in scurvy, 370. 
 
 ulceration of the (aphthae), 369. 
 
 Healed fracture of a tooth, 612. 
 Healing process in caries, 516. 
 
 in eementitis, 487. 
 
 in eburnitis, 376. 
 
 in pericementitis, 475, 487. 
 Heat and cold in general diagnosis, 286. 
 Herbst's method of treatinglpulps, 524. 
 Histology, general, 46. 
 
 Horizontal or inferior turbinated crest, 4. 
 Hutchinson's teeth. 194, 217. 
 Hyperostosis of the roots of teeth, 329. 
 
 cause of, 291, 329. 
 
 circumscribed, 332. 
 
 difi'used with roots separated, 333. 
 
 diffused with roots united. 335. 
 
 minute anatomy of the, 338. 
 
 union of two teeth by. 336, 611. 
 Hyperplasia in general, 357. 
 
 of the gums, 365. 
 
 of the pericementum, diffuse, 441. 
 
 of the pericementum, partial, 440. 
 
 of the pulp, partial. 389, 403. 
 
 of the pulp, total. 390. 407. 
 
 Incisive fossa of lower jaw, 9. 
 
 of upper jaw, 1. 
 Incisor teeth, macroscopical anatomy of, 18, 19, 
 
 26. 28. 
 Individual characteristics of the teeth, 24. 
 Inferior dental canal, 11. 
 Inferior maxillary bone,"<J. 
 Inflammation, 348. 
 
 hyperplasia in, 357. 
 
 of the dentine, eburnitis, 370. 
 
 of the gums. 363. 
 
 of the lymph-ganglia, 460. 
 
 of the pericementum, clinical aspect, 432. 
 
 of the pericementum, morbid anatomy, 462. 
 
 of the pulp, clinical aspects of, 380. 
 
 of the pulp, morbid anatomy, 397. 
 
 suppuration in the process of, 358. 
 Infra-orbital foramen, 1. 
 Infra-orbital groove, 2. 
 Interglobular spaces, definition of the, 44. 
 
 formation of, 135. 
 Internal epithelium of enamel-organ, 159, 161. 
 Internal oblique line of the lower jaw, 11. 
 Interzonal layer between dentine and enamel, 
 81. 
 
 betw en dentine and cement. 83. 
 Involution of lower masilk, 12. 
 
 of upper maxilla. 9. 
 Irritation and new formation of dental tissues, 
 288. 
 
 and new formations of the pulp, 289, 384. 
 
 producing hyperostosis of the roots, 291. 
 
 Jaw-bone, lower, 9. 
 
 necrosis of the, 534. 
 
 upper, 1. 
 Jaws, tumors of the, 573. 
 
 Lachrymal or nasal diict, 4. 
 
 Leucoplakia oris, 369. 
 
 Light in diagnosis, 281. 287. 
 
 Lining membrane of the antrum, 7. 
 
 Lobulation of crowns of teeth, 610. 
 
 Lower bicuspids, macroscopical anatomy of, 20. 
 
 central incisors, macroscopical anatomy of, 
 19. 
 
 cuspids or eye-teeth, macroscopical anatomy 
 of, 19.
 
 INDEX. 
 
 673 
 
 Ijuwcr i,iw-bono, '.K 
 
 lateral incisors, inacroscopical anatoiuy of, 
 19. 
 
 meatus of the nasal cavity, 4. 
 
 molars, macroscopical anatomy of, 22. 
 Lymphadenitis, 460. 
 
 Lymph-glands, so-called, structure of the, 5S. 
 Lymph -vessels, structui-o of the, 58. 
 
 of the pulp, 252. 
 
 Malar process, 2. 
 
 Malformations of the enamel-organ, 236. 
 
 of the teeth. 609. 
 Malpositions of teeth, 613. 
 Maxillary tuberosity, 2. 
 Mechanical abrasion, 300. 
 
 secondary dentine in, 311. 
 Medullary cancer, 607. 
 Mental foramen, 10, 12. 
 Mental process, 0. 
 Microscopical features of abscess of the pulp, 
 
 402. 
 of absorption of cementum of temporary 
 
 teeth. 266. 
 of absorption of dentine of temporary 
 
 teeth, 268. 
 of acute caries of dentine (Abbott), 496. 
 of acute cementitis and pericementitis, 468. 
 of acute non-purulent pericementitis, 464, 
 
 466. 
 of acute non -purulent pulpitis, 398, 400. 
 of acute osteitis, 469, 470. 
 of acute purulent pulpitis, 402. 
 of acute ulitis (inllammation of the gums), 
 
 364. 
 of alveolar abscess. 483, 484. 
 of alveolar cysts, 563. 
 
 of amelitis (inflammation of enamel), 322. 
 of ameloblasts. 172, 190, 193. 
 of atrophy of the nerves of the pulp, 427, 
 
 428, 430. 
 of blood- and lymph-vessels in general, 57. 
 of blood- and lymph-vessels of the pulp, 248, 
 
 252. 
 of blood-vessels of the pericementum, 260. 
 of calcification of the pulp, 421, 422. 
 of cancellous bone-tissue, 51. 
 of caries of cement (Abbott), 501. 
 of caries of enamel (Abbott), 492. 
 of cementum, 43, 103, 110. 
 of chronic caries of dentine (.\bbott), 494, 
 
 496. 
 of chronic partial hyperplasia of the pulp, 
 
 403, 404, 406. 
 of chronic purulent pulpitis, 409, 410. 
 of chronic total hyperplasia of the pulp, 
 
 307, 407. 
 of chronic ulitis (inflammation of the 
 
 gums), 366. 
 of cortical bone-tissue, 52. 
 of decay of cement (Miller), 514. 
 of decay of dentine (Miller), 510. 512, 513. 
 of decay of enamel (MiHor), 507, 509. 
 of dentine, 41, 73. 
 
 Microscopical features of development of bone- 
 
 tissuo, Ii5, 66. 
 of development of cementum, 22S. 
 of development of dentine. 129-1,39. 
 of development of enamel, 148-180. 
 of development of enamel-organ, the, 149- 
 
 194. 
 of devitali/.eil cementum, 123. 
 of devitalized dentine, 80. 
 of dissolution of epithelial cord, the, 168 
 
 176. 
 of dissolution of e.xternal epithelium. 165 
 
 167. 
 of dwarf teeth, 2:56. 
 of eburniiis (inflammation of dentine^ 
 
 370, 457. 
 of efifects of arsenic (20 minutes). 521. 
 of ofieets of arsenic (24 hours), 523,527, 
 
 528. 
 of enamel, the, 42, 90, 96. 
 of enamol-fibors. the. 90, 96, 174. 
 of enamel-prisms, the, 99. 
 of epithelial tissue, 56. 
 of external epithelium, 162. 
 of faulty develojiment of dentine, 2a5, 218. 
 
 223, 242. 
 of faulty development of enamel, 197, 201, 
 
 218, 222, 2:^9, 240. 
 of fibrous connective tissue, 49. 
 of fibrous pericementum, 258. 
 of fibrous pulp-tissue. 307,530. 
 of giganticgrowths(teratomaoftlie teeth), 
 
 556. 
 of gum, the, 41. 
 
 of healing process of caries, the, 517. 
 of healing process of pericementitis and 
 
 cementitis, 487. 
 of hyperostosis of roots of teeth. 339-346. 
 of hyperplasia of the gum, 367, 368. 
 of hyperplasia of the pul|i, partial. 403-406. 
 of hy|)erplasia of the pulp, total. 307. 407. 
 of hyperplastic pericementitis. 473, 475. 
 of internal epithelium, the. 162. 
 of interzonal layer between domino and 
 
 cementum, 83. 
 of interzonal layer between dentine and 
 
 enamel, 93. 
 of lymph-vessels of the pule, 252. 
 of muscle-tissue, 53. 
 of my.xomatous pericementum. 256. 
 of myxomatous tissue. 48. 
 of Nasmyth's membrane, 4.3, 92. 
 of neck of the tooth, 84, 105. 115, 119. 
 of necrosis of the jaw-bones. 541. 
 of nerve-tissue, 55. 
 of nerves of the pulp, 249, 253. 
 of normal perieemontum, 256-260. 
 of normal pulp-tissue. 247-25.'5. 
 of odontoblasts. 219. i53. 
 of odontoblasts in developing dentine. l.'?S, 
 
 144. 146. 
 of protoplasm in general. 58. 
 of purulent marginal pericemootitis, 
 
 (pyorrhcea alvoolaris), 478, 481.
 
 674 
 
 INDEX. 
 
 Microscopical features of reaction of the den- 
 tine upon amalgam, 87, 326. 
 
 of reaction of the dentine upon fillings, 
 320. 
 
 of reaction of the dentine upon gold, 322, 
 324. 
 
 of reaction of the dentine upon oxyphos- 
 phate, 325. 
 
 of reaction of the dentine upon tin, 529. 
 
 of reticular atrophy of the pulp, 425, 426. 
 
 of sclerotic atrophy of the pulp, 424. 
 
 of secondary dentine in general, 289-308. 
 
 of secondary dentine in mechanical abra- 
 sion, 311,315. 
 
 of stellate reticulum, the, 164, 192, 193. 
 
 of stratification and pigmentation of the 
 enamel, 45, 207.211,213. 
 
 of stratum intermedium, 162, 192, 193. 
 
 of the reticulum of cementum, 103-121. 
 
 of the reticulum of dentine, 73-87, 89. 
 
 of the reticulum of enamel, 91-99. 
 
 of tumors of the cement (osteoma), 339- 
 346, 555. 
 
 of tumors of the dentine (odontoma), 553. 
 
 of tumors of the enamel (ameloma), 554. 
 
 of tumors of the jaws, 573. 
 
 of tumors of the pulp, 557. 
 Microscopical specimens, preparation of, 69, 128, 
 244. 
 
 Nasal process of upper jaw, 2. 
 Neck of the tooth, structure of the. 83, 105, 119. 
 Necrosis of the jaw-bones, 534. 
 Nerve-fibors, general description of, 55. 
 Nerve-tissue, general description of, 55. 
 Nerves of the pulp, 253. 
 
 calcification of the, 429. 
 Nutrition of the hard dental tissues, 271. 
 
 Odontoblast layer, 44, 249, 253. 
 
 in developing dentine, 131, 139. 
 Odontoma, tumor of the dentine, 553. 
 Osteitis, osteomyelitis, periostitis, 458, 569. 
 Osteoblasts, 257. 
 Ozaena of the nose, 545. 
 
 Palatk process of upper jaw, 3. 
 Percussion in diagnosis, 283. 
 
 difi"erent sounds of, 284. 
 Pericementum, the, 39, 255. 
 
 blood-vessels of the, 260. 
 
 bony new formations in the, 475. 
 
 minute structure of, 255. 
 
 osteoblasts of the, 257. 
 
 two forms of, 256. 
 Pericementitis, acute non -purulent apical, 436. 
 
 acute non-purulent circumscribed, 434. 
 
 acute non-purulent ditt'use, 438. 
 
 acute non-purulont marginal, 433. 
 
 acute purulent apical, 442. 
 
 acute purulent diffuse, 444. 
 
 chronic purulent apical, 452. 
 
 chronic .purulent circumscribed (blind 
 abscess), 451. 
 
 Pericementitis, chronic purulent diffuse, 454. 
 chronic purulent marginal (pyorrhoea al- 
 
 veolaris), 445. 
 classification of, 432. 
 clinical aspects of, 432. 
 diffuse hyperplastic, 441. 
 morbid anatomy of, 462. 
 partial hyperplastic, 440. 
 Periosteum of the alveolus, 39. 
 Periostitis, osteitis, osteomyelitis, 458, 569. 
 Physical examination in diagnosis, 281. 
 Physiology of the hard dental tissues, 270. 
 
 of the senile changes of dental tissues, 273. 
 Pigmentation of the enamel. 212. 
 of the enamel in caries, 491, 507. 
 of the pulp, 425. 431. 
 Polypoid growth in the antrum, 543. 
 Posterior dental canals, 1. 
 Posterior palatine canal, 4. 
 Pregnancy, the teeth during, 277. 
 Premature erui)tion of ill-developed teeth, 233. 
 Preparation of microscopical specimens, 69, 128, 
 
 244. 
 Prognosis of acute non -purulent apical peri- 
 cementitis, 438. 
 of acute non-purulent circumscribed peri- 
 cementitis, 43i. 
 of acute non-purulent diffuse pericemen- 
 titis, 439. 
 of acute non-purulent marginal pericemen- 
 titis, 431. 
 of acute non-purulent partial pulpitis, 386. 
 of acute non-purulent total pulpitis, 387. 
 of acute purulent apical pericementitis, 443. 
 of acute purulent diffuse pericementitis, 
 
 445. 
 of acute purulent pulpitis, 389. 
 of calcification of the imlp, 413. 
 of cementitis and eburnitis, 458. 
 of chronic purulent apical pericementitis, 
 
 453. 
 of chronic purulent circumscribed perice- 
 mentitis (blind abscess), 4.52. 
 of chronic purulent diffuse pericementitis, 
 
 455. 
 of chronic purulent marginal pericementitis 
 
 (pyorrhoea alveolaris), 450. 
 of chronic purulent pulpitis, 394. 
 of eburnifications and ossifications of the 
 
 pulp, 418. 
 of empyema of the antrum, 545. 
 of gangrene of the pulp, dry, 397. 
 of gangrene of the pulp, moist, 396. 
 of hyperplasia of the pulp, partial, 390. 
 of hyperplastic diffuse pericementitis, 442. 
 of hyperplastic partial pericementitis, 441. 
 of irritation of the pulp, 385. 
 of lymphadenitis, 461. 
 of necrosis of the jaw-bones, 537. 
 of periostitis, osteitis, and osteomyelitis, 
 
 460. 
 of reticular atrophy of the pulp, 420. 
 of sclerotic atrophy of the pulp, 419. 
 of tumors in general, 550.
 
 INDEX. 
 
 675 
 
 Pulp of a tooth, the. 43, 244. | 
 
 blood-vessels of the, 43, 44, 246. 
 
 formations of dentine and bone in tho.2Sii. 
 305. 
 
 irritation of the, 289, 384. 
 
 lymphatics of the. 252. 
 
 method of preparing sections of the, 244. 
 
 minute structure of the, 246. 
 
 nerves of the. 253. 
 
 new formations in the. 305. 
 
 odontoblasts of the. 44. 249. 253. 
 
 the llcrbst method of treating exposed, 524. 
 
 tumors of the, 55(3. 
 Pulp-chambers of the tooth. 28. 
 
 measurements of the. 31, 32. 33. 
 Pulp-stones composed of secondary, dentine. 305. 
 
 composed of laminated bone, 306. 
 
 composed of a mixture of regular bono and 
 dentine. 307. 
 
 composed of primary dentine. 308. 
 Pulpitis, acut.e non-purulont. partial, 385. 
 
 acute non-purulent, total. 386. 
 
 acute purulent. 387. 
 
 chronic purulent. 392. 
 
 clinical aspects of. 380. 
 
 etiology of. 380. 
 
 hyperplastic, partial, 389. 
 
 hyperplastic, total. 390. 
 
 morbid anatomy of, 397. 
 Pyorrhoea alveolaris. 445. 
 
 morbid anatomy of. 476. 
 
 Reaction of the dentine upon amalgam, 87, 
 326. 
 
 upon fillings, 320. 
 
 upon gold, 323. 
 
 upon gutta-percha, 323. 
 
 upon oxyphosphate of zinc, 323. 
 Recalcification of softened enamel and dentine, 
 
 272. 
 Re-formation of cementum, 487. 
 Reticular atrophy of the pulp, 419, 425. 
 Roots of teeth, devious course of, 610. 
 
 fusion of. Oil. 
 
 hyperostosis or hyperplasia of the, 329. 
 
 macroscopical anatomj' of the, 18. 
 
 multiplication of, 611. 
 
 Salivary calculi, 275, 448. 
 
 Sclerotic atrophy of the pulp, 418, 442. 
 
 Secondary dentine, 292. 
 
 in the middle of the pirip-tissue, 305. 
 
 in mechanical abrasion, 311. 
 
 similar to primary dentine, 299, 308. 
 
 varieties of, 298. 
 
 witii Haversian canals (vaso-dentine), 303. 
 
 with lamella, 302. 
 Senile changes in the dental tissues, 273. 
 Smell, the sense of in diagnosis. 285. 
 Sounds produced by percussion upon the tooth. 
 
 284. 
 Stellate reticulum and stratum intermedium 
 
 126. 161.163. 
 Stratification of dentine. 136. 
 
 of enamel, 207. 
 
 Subjective phenomena of .acute non-purulent 
 apical pericementitis, 437. 
 of acute non-purulent circumscribed peri- 
 cementitis. 435. 
 of acute non purulent diffuse pericemen- 
 titis. 439. 
 of acute non-purulont marginal perice- 
 mentitis. 433. 
 of acute non-purulent partial pulpitis. 385. 
 of acute non-purulent total pulpitis. 386. 
 of acute purulent apical pericementitis, 
 
 443. 
 of acuto purulent ditluse pericementitis. 
 
 444. 
 of acute purulent pulpitis. 388. 
 of calcification of the pulp. 413. 
 of chronic alveolar abscess. 456. 
 of chronic hyperplastic partial pericemen- 
 titis. 440. 
 of chronic hyperplastic total pericementi- 
 tis, 442. 
 of chronic purulent apical pericementitis, 
 
 453. 
 of chronic purulent circumscribed perice- 
 mentitis, 452. 
 of chronic purulent diffuse pericementitis, 
 
 454. 
 of chronic purulent marginal pericementi- 
 tis, 449. 
 of chronic purulent pulpitis, 393. 
 of eburnifications and ossifications of the 
 
 pulp. 416. 
 of empyema of the antrum. 544. 
 of gangrene of the pulp. dry. 396. 
 of gangrene of the pulp, moist. 395. 
 of hyperplasia of the pulp, partial. 390. 
 of hyperplasia of the pulp, total. 391. 
 of irritation of the pulp. 384. 
 of lymphadenitis. 461. 
 of necrosis of the jaw-bones, 536. 
 of periostitis, osteitis, and osteomyelitis, 
 
 459. 
 of reticular atrophy of the pulp. 420. 
 Sublingual fossa. 10. 
 Submaxill.ary fossa. 11. 
 Superior maxillary bones. 1. 
 Supernumerary teeth. 610. 
 Synopsis of the development of the teeth, 
 
 124. 
 Syphilitic ulcers upon the gum, 369. 
 Systemic derangements diagnosed by the teeth 
 and their surroundings, 275. 
 
 Tartau in diagnosis, 275. 
 
 forms of, 275. 
 
 green. 276. 
 
 in pregnancy, 277. 
 
 in pyorrhoea alveolaris, 448. 
 
 white and yellow. 275. 
 Teeth, anomalies of the papilla of the. 242. 
 
 and gums sis indicators of the general 
 health. 275. 
 
 breach of the continuity of the crown of, 
 612.
 
 676 
 
 INDEX. 
 
 Teeth, changes of the tissues of, by general dis- 
 eases, 278. 
 
 description of their surfaces, 17. 
 
 devious course of roots of, 610. 
 
 discoloration of devitalized, 273. 
 
 distinguishing features between the per- 
 manent and temporary, 24. 
 
 distinguishing features between the upper 
 and lower, 25. 
 
 double papillae of. 235. 
 
 dwarf, 235, 609. 
 
 faulty development of, 194. 
 
 forms of, 16. 
 
 fusion of crowns of, 611. 
 
 fusion of roots of, 611. 
 
 fusion of two, 611. 
 
 healed fracture of, 612. 
 
 hyperplasia, or hyperostosis of the roots of, 
 329, 609. 
 
 individual characteristics of the, 24. 
 
 lobulation of the crowns of, 610. 
 
 maeroscopical description of the, 16. 
 
 malformations of, (309. 
 
 malpositions of the, 613. 
 
 multiplication of roots of, 611. 
 
 numbering of the, 25. 
 
 percussion in diseases of the, 283. 
 
 supernumerary, 610. 
 
 syphilitic or Hutchinson's, 194, 217. 
 Teratoma of teeth, or gigantic growth, 556. 
 Tissue, bony or osseous, 49. 
 
 cartilaginous, 49. 
 
 connective, 46. 
 
 epithelial, 56. 
 
 fibrous. 48. 
 
 general description of, 46. 
 
 muscle, 52. 
 
 myxomatous, 47. 
 
 nerve, 55. 
 Touch, the sense of in diagnosis, 281. 
 Transillumination in diagnosis, 287. 
 Tumors, their clinical and anatomical features 
 in general, 546. 
 
 ameloma, of the enamel, 554. 
 
 classification of, 550. 
 
 covering skin or mucosa of, 547. 
 
 Tumors, definition of,',546. 
 
 domarkation of, 547. 
 
 diagnosis of, 549. 
 
 etiology of, 546. 
 
 growth, benignity and malignity of, 546. 
 
 hyperplasia of the roots of, 329, 555. 
 
 infection of remote tissues and organs by, 
 548. 
 
 odontoma, of the dentine, 553. 
 
 of the pulp, lymphomyeloma, 557. 
 
 of the pulp, myeloma, 556. 
 
 of the teeth, 553. 
 
 pain of, 547. 
 
 prognosis of, 550. 
 
 reaction upon adjacent tissues, 547. 
 
 teratoma, or gigantic growth, 556. 
 
 ulceration of the surface of, 548. 
 Tumors of the jaws, angioma, 584. 
 
 carcinoma or cancer, 604. 
 
 cavernous angioma, 587. 
 
 chrondroma, 582. 
 
 cysto-adenoma, 601. 
 
 epithelioma or dermoid cancer, 604. 
 
 fibro-myeloma, 591. 
 
 fibroma, 577. 
 
 globo-myeloma, 597. 
 
 lipo-fibroma, 582. 
 
 lobular angioma, 584. 
 
 medullary cancer, 607. 
 
 myeloma, 589. 
 
 myxoma, 573. 
 
 myxo-fibroma, 575. 
 
 myxo-myeloma, 590. 
 
 osteoma of jaws, 581. 
 
 osteoma of roots, 329, 555. 
 
 osteo-myeloma, 595. 
 
 papilloma or warty tumor, 599. 
 
 spindle myeloma, 598. 
 
 Upper central incisors, 18. 
 
 bicuspids. 20. 
 
 cuspids or eye-teeth, 19. 
 
 lateral incisors, 18. 
 
 molars, 21. 
 Ulitis, acute inflammation of the gums, 363. 
 
 chronic inflammation of the gums, 366.
 
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