i,-p:|ir;.W(;U«i'l.;i_{^,; <5? o 1^1 ^(!/0JI'IV3J0>^ c VJ 5 i^mwm//. &Aavaflii# 3WV ^UIBRARY^/ ^ ^iHOJIlVJJO^ ^OFCAIIFOS'^ ^K /' — \.% > ,^\^tDK|VER% .^WE■UNIVER5/A oe ,». Iv \ F±- ^ ^(?AJiVJjfiinS^'^ ^^AHVJign-^- ^X7inNY.^m>^ v5>.lOSANCEli AWEUNIVERS/a ^•lOSA^Elfx^ '^/^a3AiNn-3WV N^llIBRARY(9/^^ so ^' ^Mf•UNIVERS/^ ^vlOSANCElfX/ ^OF-CAIIFOI?^ ^ <^^UIBRARYQ/'^ ^^llIBRARYQc. ^^OJIIVJ-JO"^ '^«!/0JllV3J0^ ^\\El)NIVERS//, ^lOSANCElJ O V^ ,0F CAllFOf?^;, ^OFCAIIFOI?^ ^^•A«v«flmV^ W^ElMIVERy/A •<^rjinn.'v.cm>S^ o ^1 Ifel i ^/sa]AiNn3V^^ '%ojnvojo^ '^ o %a3AlNn-3Wv ^OFCAUFOI?^ '^•^oxunmi'^ ^\^EUNIV[RJ•/A o o '^/5«3AINn3ViV' C3 ?13DNVS01^ vvlOSANCElfj> o %a3AlN(13WV ^^HIBRARYQ^^ ^^UIBRARYQa, ^WJIWD-JO"^ ^.yOJITYJ-JO^ >- CD ?130NVS01^ ^■lOSANCnfXj> so ■%a3AIN(l-3WV^ ), the spongy tissue. This forms the principal mass of the enamel organ, and its transparent basis-substance is occupied by cells with stelliform radiating processes. The bodies of the cells inclose an oval nucleus ; the processes unite to form a net- '^ work, the meshes of which become more narrow from within outwards, and are in relation with an inter- * Fig. 13. -^Transverse section of the enamel organ of an incisor from a human foetus, tiie section taken from the vicinity of the reflection of the cap, where the organ has already become quite thin, (a) Enamel cells (ex- ternal [?J epithelium), with the gradually more obliquely disposed formative cells (Ersatzzellen), which ultimately assume a liorizontal direction, and become spindle-shaped ; (/;) multiradiating flattened cells, which form a net- work by means of their connecting processes, and belong to the spongy layer; (c) layer of spindle-shaped cells, with oblong nuclei, analogous to those adjoining the layer of enamel cells; [d) groups of cells belonging to the external epithelium, and lying in sac-like cavities ; between the groups are the openings of capillary bloodvessels. The papillie of the dental sac, on account of their oblique position, are represented obliquely within the sec- tions ; (f) lax connective tissue of the dental sac. Magnified 400 diameters. 64 ANATOMY AND PHYSIOLOGY, Fio. 14.* mediate layer composed of horizontally disposed spindle-shaped cells. Outside of the latter appears {e) a group of cells, called the external epi- thelium, which invest the papilite pro- jecting into the enamel organ from the wall of the dental sac (Fig. 13). f The dental sac, from the floor of which proceeds the dentinal germ, is developed opposite the surface of the latter, and in- vests it and the enamel germ, forming a connective tissue envelope around the two, the continuity of which is broken only at that part which has been de- scribed as the constricted portion or neck of the enamel germ, and is connected with the mucous layer of the epithelium. It * Fig. 14. — Injected bloodvessels from the dental sac of a new-born child. The larger ones lying outside form a network, with elongated meshes. In- teriorly, delicate capillaries are given off and form anastomotic loops, here and there, directed toward the enamel organ. Magnified 30 diameters. f The spong}^ tissue was formerly considered to be a gelatinous connective tissue, until Huxley and KoUiker demonstrated that it is to be classed with the epithelial structures. Opinions are still divided as to the manner in vvliicli the enamel is developed out of the enamel cells. One theory, which I also uphold, maintains that it is by the direct calcification of the enamel cells, and Waldeyer (S. Strieker's Handbuch der Gewebelchre) adduces, as strong evidence in support of this view, the occurrence of enamel cells and fragments of enamel prisms in intimate connection, the latter remaining adherent to the former in the form of processes. According to his view pet- rifaction (petrifiziren) of the enamel cells commences in the investing zone, while the axial portion of the protoplasm retains its softness for a time, and in is-olated cells forms a kind of process (Tomes' Processes of the Enamel Cells). The other view, which Kolliker furmerly held, is ba^ed upon the idea, that the enamel is a cuticular structure. Guillot, Robin, and Magitot, as the I'esult of their investigations with reference to this subject, assert that the teeth and their appendages are developed in the submucous tissue, entirely free and independent of all other tissues. Max Eeichert, also, was inclined to this erroneous view (Dubois-Reichert's Archiv, 18G9), according to whom, the enamel organ originates from the corium, and not from the epithelium of the mucous membrane of the mouth. The gelatinous tissue, together with the stellate cells of the enamel organ, he regards as connec- tive tissue. Kollmann has recently published a work, agreeing essenti- ally with KoUiker's theories (Entwicklung der JMilch- und Ersatzzahne, Zeitschr. f. wiss. Zoologie, Bd. 20). DEVELOPMENT OF THE TEETH. 65 is closed, at a quite early period, in the manner already de- scribed, before there is the least trace of the tooth cap. It be- comes richly supplied with bloodvessels and nerves. That por- tion of the sac, particularly, which invests the enamel organ, becomes elevated into rows of papillary excrescences which are covered by the cells of the external epithelium of the developing enamel organ. The wall of the sac is divided into a compact pe- ripheral or outer, and an inner lamina of a more lax tissue. It is traversed by numerous interlacing bundles of nerves, and the bloodvessels also are very abundant ; the larger of these are distributed in the outer, and the smaller in the inner lamina. As they pursue a generally straight course, they give rise to oblong meshes (Fig. 14). In that lamina of the dental sac which is in relation with the enamel organ, capillaries extend into the corresponding papillse, where they form anastomotic loops. These vascularized papillae are so intimately united with the enamel organ, that, together with the anastomotic loops, 4pl^^,^/hi&Mj> they remain adherent to the enamel organ j, s'^'lf^'^*/) after the dental sac has been detnched uyjO^^i-^ j, '<-k! (Fig. 15). The dentinal germ receives bloodvessels and nerves from that portion of the dental sac with which it is in contact, and becomes developed into one or several papillne or prominences, according to the number of tubercles which the crown is to present. Consequently the rudiments of canine teeth present one, and those of molar and bicuspid teeth several papill;i3. Well-developed dentinal cells with their processes, such as have been described in connection with the pulp, are observed at a comparatively early period. Large vascular twigs extend up and down from the base of the germ, and ramify in various directions towards its surface, where * Fig. 15. — Injected capillaries which remained adherent to the enamel organ of a bicuspid tooth, from a calf, the dental sac having been detached. The anastomotic loops have been torn from their connection with the vessels of the dental sac, and reach almost to the layer of enamel cells. Magnified 30 diameters. 5 QQ ANATOMY AND PHYSIOLOGY. Fig. 16.* they terminate in loops. The latter pursue a straight course in young germs (Fig. 16). The connective tissue of the germ is very soft, contains numerous cells, and be- comes exceedingly cloudy on the addition of acetic acid. The dentinal cap, ■which primarily is exceedingly thin, is blended with the enamel cap, while, from the be- ginning, the enamel and dentine are devel- oped in opposite directions. The dentine is formed by the deposition of new layers from without inwards, while the enamel, as above demonstrated, is developed in a similar manner from within outwards. The enamel germ of a permanent tooth, which has a single root, is developed, at an early period, upon the lingual side of the milk teeth, in the form of a cul-de-sac. It commences in the form of a direct depression of the mucous layer of the epithelium from the dental groove, between the facial and lingual lips of the dental ridge, and has a common origin with the enamel germ of the milk tooth (Fig. 17). The follicle presents lateral folds, which not unfrequently occur in large numbers. The closed" terminal portion of the follicle was recognized by Kol- liker as the enamel germ of the perma- nent tooth. The connecting branch of the follicle, which extends outwardly towards the face, is in direct communi- cation with the external epithelium of the enamel orfjan of the deciduous tooth. * Fig. 16. — Injected terminal loops from the pulp of a permanent incisor of a new-born child. The vessels pursue a straight course. The loops are partly single and partly complex. Magnified 30 diameters. f Fio. 17 shows a follicle of mucous cells extending from the dental ridge to the enamel germs of the milk and permanent teeth ; from a human embryo of three months' growth. The cells of the raucous layer of epithelium dip DEVELOPMENT OF THE TEETH. 67 The connection of the outer with the inner epithelium, as well as a general view of the developing crown, the tooth cap, and the dental sac, together with the parts in the immediate vicinity, may be observed in sections of the jaws of embryos of a suitable age, which have been decalcified by means of diluted hydro- chloric and chromic acids. The inner epithelium commences at the base of the dentinal germ (Fig. 18), and extends along the Fig. 18.* down into tlie substance from the dentul groove (a) of an incisor of the lower jaw, and resemble, somewhat, a tubular gland with lateral ottViicots. At about the middle of the follicle, which is lined throughout with cylindrical cells, it is connected by a transverse process {/>) witii the external epithelium of the enamel organ, the spongy layer of which is represented (<•]. The inferior closed portion of the follicle is the enamel germ of the permanent incisor tooth. Magnified 80 diameters. * Fig. 18. — Sagittal ^ection of a lower jaw from the embryo of a dog, showing an incisor within its dental sac. (a) Facial lip of the dental ridge; (6) epithelium ; (c) corium, with papillae in the dental ridge, and cavities of transversely divided vessels; {d) enamel germ of the permanent incisor containing an aggregation of epithelial cells; its connection with the enamel 68 ANATOMY AND PHYSIOLOGY. entire outer surface of the dental cap. The thickness of the pulp bears a direct relation to that of the cap ; that is to say, the thicker the former, the thinner the latter ; and the pulp rests upon the floor of tlie dental sac. The latter has a rounded form, corresponding with the developing dental crown, lies be- neath the facial lip of the dental ridge, within the maxillary- groove, and is intimately connected with the exceedingly vascu- lar and nervous submucous connective tissue of the gum, and with the layer of connective tissue which lines the maxillary groove.* organ of the decidiious tooth does not appear in the section ; (e) anterior, (e') posterior, osseous lamelhi of the jaw with rounded summits; (/) completed enamel of the dental cap ; in the section it is separated, somewhat, from the (9) layer of enamel cells; (A) retiform connective tissue of the dental sac; (i) outer epithelium of the enamel organ completely investing the papillae of the dental sac; {k) spongy layer of the enamel organ; (I) completed dentine of the cap; (>«) layer of dentinal cells ; (n) dental pulp with wide vessels in its interior. Magnified 20 diameters. * The mode of development of the dentine is so far determined that we know positively that the dentine is developed from the dentinal cells. We may also readily demonstrate that, as soon as the connection of the dentinal with their formative cells occurs, the calcification of the contents of the dentinal cells begins ; that their principal and accessory processes remain attached and are transformed into dentinal fibres, and that a constant depo- sition of calcareous salts into the cells takes place from the blood. Bj' the continuous transformation of formative cells into dentinal cells, the process goes on, and new layers of dentine are deposited constantly by progressive calcification. Kolliker (op. cit.) maintains another view, a modification of the last, namely, that the calcified substance, which is found between the dentinal fibrils (basis-substance, or matrix, of the dentine), is to be considered an excretion from the dentinal cells, and consequently is not a product of the immediate calcification of the latter. Another question arises, viz., how do the globular masses originate, and what relation do they bear to the normal development of the dentine? The globular masses found on the inner surface of the dentine of the teeth of children are permeated by dentinal canals, and in accordance with the first theory may be considered to be the result of a coalescence of separate groups of calcified dentinal cells. There are two possibilities, in regard to the globular masses which are intercalated between the systems of dentinal canals, without being pierced by them, namely: that in these localities the processes within the groups of calcified cells were prematurely destroyed, or that, in consequence of an arrest of development, tlie process of calcification of the dentinal cells progressed merely to the formation of globules of cal- careous salts. DEVELOPMENT OF TUE TEETH. 69 4. The dental cap, considered as the aggregate of calcified dentinal and enamel cells, maintains during its development the shape given to it by the arrangement of the cells ; it increases in thickness, and eventually becomes the crown of the tooth ; contemporaneous with the growth of the latter the enamel organ gradually becomes thinner, and finally shrivels up completely. When the development of the crown is accomplished, that is, when no new layers of enamel are formed, the growth of the radical portion of the tooth, from the edge of the crown, com- mences ; the dentinal cells adopt a more horizontal position, and consequently the dentinal canals also assume a more hori- zontal direction. At the margin of the crown the dental sac contracts, and upon its inner surface the formation of the cement is effected, increasing gradually as the formation of the root advances ; the lower segment of the dental sac becomes, there- fore, the root-membrane of the tooth. Contemporaneous with the latter processes occurs the formation of Nasmytlis enamel membrane, which is interpreted in various ways. This membrane, called by Ivolliker the cuticle of the enamel, is considered by him to originate in this manner, viz.: that an additional coherent layer (cuticle) is secreted by the enamel cells, after the completion of the formation of the enamel, to serve as a protection for the whole. Waldeyer regards it as the product of the cornification (Verhornung) of cells. J. Tomes holds the opinion, that the membrane belongs to the cement, because it is continuous from the crown upon the cement, as ma}'^ be demonstrated on teeth which have been treated with dilute hydrochloric acid ; moreover, the membrane is thickened in the depressions upon the crowns of the molars, and in these localities distinct bone-corpuscles likewise occur. These argu- ments, together with data furnished by comparative and patho- logical anatomy, uphold the latter view, in my opinion. In the development of teeth with irregularities in the enamel, the adap- tations of the dental sac and the enamal organ to depressions in the crowns may easily be demonstrated, and there remains, finally, an outer covering of cement upon the masticating sur- faces of the crowns. The case illustrated in the Atlas, Fig. 9, where the radical cement passes without interruption into a 70 ANATOMY AND PHYSIOLOGY. well-marked coronal cement, whicli covers the entire masticating surface and insinuates itself between the folds of enamel, is ex- plained by the latter theory, 5. The growth of the pulp root and the contiguous zones of the dentine keeps pace with the formation of the cement which takes place externally to the latter. While the growth of the dentine in thickness gradually diminishes, that of the cement increases. As the peripheral portions of the dentine are always formed first, it will readily be understood why an incomplete root presents at its extremity a sharp margin and a dome-shaped cavity, called by the dentists an unclosed root. The formation of the root is completed when its canal no longer presents a funnel-shaped expansion at its extremity. 6. The development of the osseous walls of the teeth is first indicated by an osseous dental groove, which is more fk.. 19.* distinctly marked upon the lower jaw, and is inclosed by a facial and lingual lip. It is shallow and flattened posteriorly (Fig. 19). As this groove becomes deeper and wider, lamellar projections appear upon its interior wall, the first making its appearance between the two dental sacs of the incisors. At about the same time, flattened spinous processes also appear toward the upper margins of both the labial and lingual walls (Fig 20 a). These processes grow towards one another and gradually complete the continuity of the wall. In this way an osse- ous case, of a fine spongy tex- ture, is formed around the den- tal sac, which gradually con- tracts,but remains permanently open externally. It may be demonstrated separately, and is called the bont/ socket, or alveolus of the dental crown. The size, position, and re- * Fig. 19. — Lower jaw of a human foetus, at the commencement of the third month of pregnancy, seen from above, in order to give a view of the groove in the bone, which becomes flattened from before backwards. The coronoid processes and cond^yles are already indicated. Natural size. f Fig. 20, a. — Macerated left half cf the inferior maxillary arch, from a Fig. 20. a, b.f DEVELOPMENT OF THE TEETH. 71 spective distances of the sockets from each other can be demon- strated to the best advantage in sections of decalcified jaws, corresponding with their curves. All the cells are equidistant from the edge of the gum, while their distance from the inferior margin of the lower jaw decreases from before backwards, that is, the socket of the middle incisor is most distant, and that of the second molar is nearest, which relation corresponds with the growth of tlie bone in depth from before backwards (Fig. 20 b). When the growth of the root commences, and the corresponding segment of the dental sac becomes the root-membrane from which the cement originates, a partial process of resorption takes place in the osseous coronal sockets. This is but a tem- porary process, and continues only so long as the crown is in an embryonic condition. As far as I know, Tomes was the first to call attention to the important circumstance, to be considered later, namely, the fact that resorption of a portion of the walls of the alveoli ensues in order to prepare the way for the passage of the teeth through the gum. 7. The formation of the twenty osseous alveoli of the crowns is nearly completed in the eighth month of pregnancy, only the facial walls of the alveoli of the canine teeth, and the posterior Avail of the second deciduous molar, particularly in the upper jaw, remaining, for the most part, membranous. Consequently the osseous septum between the second deciduous and first per- manent molar is wanting. Since the posterior are considerably wider than the anterior alveoli, it will be seen that the facial lamina of the alveolar process of the upper jaw describes a wide fa>tus, at the seventh month of pregnancy. View from the lingual side. The partitions or septa for the incisors are partially formed ; the facial wall of the canine tooth still presents a gap. The septa for the milk molars are indicated by slight ridges; that for the first permanent molar is already per- ceptible towards the coronoid process. Natural size. Fig. 20, b. — Left half of the inferior maxillary arch, from a new-born child ; decalcified by means of dilute hydrochloric acid, and bisected by an incision corresponding with its curve. The incised surface of the outer half is exposed to view ; the dental sac and contents are removed. The separate walls for the dental sacs of the milk teeth are completely developed ; the septum for the first permanent molar is seen to be partially developed within the coronoid process. Natural size. 72 ANATOMY AND PHYSIOLOGY. and semicircular curve, internal to which lies the narrower semi- elliptical bow of the lingual lamina. In the lower jaw the lamiuiB of the alveolar process extend nearly parallel to each other, from before backwards ; the anterior segments extend from the median line outwards ; behind the alveoli of the canine teeth they bend abruptly backwards, and thus describe curves similar to the letter S ; the posterior extremities of the two rami of the lower jaw consetiuently present a greater divergence than those of the upper. If the inferior maxillary arch be examined from below at this same period of development (the eighth month), in its relation to the superior arch, both jaws being left in their natural posi- tion so that the suture of the palatal processes and the symphisis of the lower jaw lie in the same perpendicular plane, the greater divergence of the posterior segments of the inferior arch will be perceptible. A profile view presents a notable projection of the upper beyond the lower jaw, an appearance occasioned in part by the fact that the mental process is not yet developed. The alveoli for the cj-owns of the incisors are broader on the facial than on the lingual side. While they expand, with the growth of the crown, their orifices upon the alveolar ridge become contracted, because the facial and lingual walls, as they are de- veloped from below upward, incline toward each other. The alveoli of the canine teeth are characterized externally by a prominent ridge, the canine eminence, and generally bulge more than the other sockets. Their facial walls in the upper jaw are almost entirely ossified at the commencement of the second month after birth. The openings leading to the oblong alveoli of the milk molars, particularly that of the second molar, are wide at first, but later contract gradually. In the first months after birth, the facial and lingual walls, together with the septa between the alveoli, are developed from below upward, and in- cline toward each other. The margins of each of the sockets, in the course of their development, present a concavity, at first usually slight, but still perceptible, which is the result of com- mencing resorption. These taken together give rise to the festooned appearance of the edges of the alveolar borders. The FIRST DENTITION. 73 latter conformation is exhibited first of all and most distinctly bj the alveoli of the incisors. First Dentition. — The growth of the root in length keeps pace with the process of resorption at the alveolar borders. The crown presses against its membranous covering, and becomes perceptible to the touch externally, as the so-called tooth prom- inence (Zahnpille). In consequence of the continuous pressure of the crown upon the vessels and nerves of the summit of the dental sac, the latter undergoes complete atrophy ; the inter- lacing bundles of connective tissue acquire a dried and tense appear- ^'*^' "^'^ ance and a yellowish color. That part of the gum Avhich is in im- mediate relation with the dental sac undergoes a similar process, its numerous vessels being subjected to extreme tension (Fig. 21). The membranous coverings gradually become thinner, and at last trans- parent, when the edge of an incisor, or the tubercles or cusps of the canine and molar teeth, are exposed to view. On account of the constant onward pressure of the crown, which is com- mensurate with the advancing growth of the root, the gum neces- sarily recedes and, after the eruption of the crown is completed, attaches itself to the neck of the tooth, by which means its sub- mucous la^'^er maintains its connection with the dental sac, which latter becomes the root-membrane. The preparation for the eruption of the central incisors is manifested by the above-mentioned process of resorption, which gradually becomes more evident, upon the lingual and facial walls of their alveoli, by an increase in the concavity of their margins. Recently cut incisive edges of the central and lateral deciduous incisors present two shallow indentations. The re- sorption upon the alveolar margins of the lower incisors is much * Fig. 21. — Injected gingival bloodvessels of the prominence (Zahnpille) over the molar of a new-born sheep. View from above. The vessels con- verge toward the summit, where a capillary network is presented. Magni- fied 5 diameters. 74 ANATOMY AND PHYSIOLOGY. more evident at first than it is on those of the upper. The re- sorption of the latter, however, soon follows, and commonly is more conspicuous on the facial than on the lingual walls of milk teeth. The central incisors advance perpendicularly, while the lateral incisors present a lateral inclination of the facial coronal sur- faces, which is more decided when still inclosed within their bony capsules than is the case after their eruption ; they must, therefore, during the latter process, be twisted considerably toward the median line of the jaw. The first milk molai's generally are cut in the first months of the second year, and not unfrequently earlier in the upper than in the lower jaw. When the masticating surfaces of these teeth have already advanced to their proper level in the dental range, their roots are barely half formed, and the extremities of the latter present a wide cavity and a sharp edge. While the canine teeth are still deeply imbedded in the jaw, within their alveoli, they present the most notable inclination of all the teeth, their crowns being inclined toward the median line of the jaw, and their necks laterally. As. they approach the summit of the alveolar ridge, they experience a slight lateral inclination in order that they may advance in the space between the lateral incisors and first molars. Another peculiarity of the canines is afforded by the fact that they lie farthest from the alveolar ridge and consequently are obliged to traverse the greatest distance in order to reach it. There is, however, another cir- cumstance which is very much in their favor, namely, that the resorption upon their alveolar margins extends higher in the upper, and deeper in the under jaws than is the case with the remaining teeth. When their eruption has progressed so far that the coronal extremities have reached the level of those of the adjacent teeth, the roots have barely attained half their final length. The second upper molars not unfrequently make their appear- ance before the corresponding lower teeth. With these, the first set of teeth, the milk or deciduous set is completed, gener- ally by the end of the second, or occasionally not until the end of the third year. FIRST DENTITION. 75 When the crowns of all the milk teeth have attained their full growth and proper relations, tlie growth of the roots is still more or less incomplete, in proportion to the early or late eruption of their respective crowns. Even the extremities of the roots of the central incisors are scarcely closed at this period. The periods at which the eruption of the milk teeth com- mences and terminates vary considerably. While, in rare cases, children enter the world with their lower central incisors already cut, sometimes the latter do not make their appearance until the end of the first year after birth. As has been observed before, the eruption is completed generally at the end of the second year after birth, though, frequently, it is prolonged many months beyond this period.* It would be an interesting point to determine the normal in- tervals between the eruption of the different kinds of teeth, since, from the longer or shorter intervals, an approximate con- clusion might be deduced concerning the growth of the jaw in its different dimensions; variations, however, in this respect are presented in the same individual. In general, it may be said that the interval between the completed eruption of the central and the lateral incisors, and between that of the latter and the first molars, is about ten or twelve weeks for each kind men- tioned, while that between the eruption of the first molars and canine teeth is prolonged to twenty or twenty-four weeks ; the second molars succeed the canine teeth after a similar period. The intervals before the appearance of the canine teeth and second molars, therefore, are about twice as long as those be- tween the first mentioned kinds of teeth. In regard to the eruption of the teeth in the upper and lower jaw respectively, it is the rule that the lower incisors appear * The eruption of the deciduous teeth usually takes place at about the following ages: Central incisors, 7th month. Lateral incisors, ..... 9th " First molars, 12th " Canines, ...... 18th " Second molars, . . . . 24th " T. B. H. 76 ANATOMY AND PHYSIOLOGY. first, and generally the upper ones succeed them in a very short time. The reverse is the case, frequently, -with the molars. Second Dentition. — The eruption of the first, molars ushers in the shedding of the teeth. They appear in the seventh year and genei'ally in the upper jaw earlier than in the lower. Toward the end of the second year, the crowns of those in the upper jaw are situated high up in the maxillary tuherosity, and those in the lower jaw, in the coronoid process, and as the de- velopment of the jaws progresses, they descend towards the dental range. The alveoli of the crowns undergo a process of gradual resorption in the vicinity of the summits of the latter, and contemporaneously with this process, the growth of the radical portion commences. For ^^''•"•* some time hefore the emergence of the first molars, the margins of their alveoli have undergone a considerable amount of re- sorption, but are still separated from the alveoli of the second molars by partially membran- ous septa (Fig. 22). Concur- rent with the emergence of the teeth, the alveoli for the roots in the upper jaw form three broad, cup-like depressions, sepa- rated from one another by projecting partition-walls or septa. In the lower jaw are found two similar shallow, flattened de- pressions. Generally, at this period of their development, the roots present remarkably sharp edges and broad cavities. * Fig. 22. — Eight half of the upper jaw of a child between five and six j'ears of age. View of the palatal surface. The process of resorption is seen to have made considerable progress upon the margins of the coronal alveolus of the first permanent molar (near a), and the latter communicates with the coronal alveolus of the second permanent molar. The three de- pressions at the bottom of the cavity correspond with the three incompletely formed roots belonging to the detached tooth ; (ft) incisive fissure which is met with, sometimes, in adults. Upon the lingual wall of the alveolar process, and corresponding to the localities of the lateral incisor and first molar of the milk set, openings are visible for the corresponding permanent teeth, produced by the process of resorption. Natural size. SECOND DENTITION. 77 When the coronal cusps of the first molars have reached the level of those of the deciduous molars, their roots are scarcely more than a few millimetres in length. The subsequent growth of the roots in length and of the jaws in depth is a compara- tively rapid process. * The shedding of the teeth involves all the milk teeth, and commences as soon as the crowns of the permanent teeth, through reason of the development of their roots, draw near to the alveoli of the milk teeth. A series of phenomena then en- sues in the alveoli, and in the milk teeth themselves, which have been embraced under the general term resorption.- This process manifests itself by a loss of substance wdiich commences in the alveoli of the milk teeth, then usually attacks the apices of their roots, and finally the entire roots and, in many cases, involves a large portion of the crowns. Generally this process attacks the milk tooth upon the side towards the advancing crown of the permanent tooth, though frequently it commences at many points simultaneously, and gives rise to pitted or funnel-shaped depressions, grooves, or irregular facets, looking like the effects of corrosion, all of which are characterized by their rough, ex- posed surfaces and sharp edges. We are indebted to Tomes for the first thorough histological investigation and correct inter- pretation of the various phenomena presented by this process of resorption. If we examine closely a portion of the cement of the root of a deciduous tooth which has been affected by this process, we find what at first appears to be a simple depression; under the micro- scope, however, this is found to be made up of a number of smaller, cup-shaped excavations, which, seen from above, are bounded by sharp, elevated laminte and, upon still closer examination, dis- play, in suitable places, a network of projections in each micro- scopic cavity. The bone-corpuscles, together with the interme- diate substance, undergo a decomposition ; first of all, a molec- ular cloudiness occurs in their immediate vicinity, and also in the intercorpuscular substance ; the radiating bone-canaliculi become indistinct, disappear, and the bone-corpuscles, deprived of their radiating canaliculi, are isolated w^ithin the cavities which become more clear by the solution of the substance con- 78 ANATOMY AND PHYSIOLOGY. tained in them, and in which the network of delicate projecting himincTG gradually disappears ; the walls of contiguous cavities become thinner, and finalljr are entirely absorbed (Atlas, Fig. 112), As the same process is repeated, and gives rise to larger and smaller gi*oups of such indentations (Resorptionsalveolen), the cement substance in the affected localities is entirely de- stroyed, so that, finally, cross-sections present an excavation with an irregularly notched boundary. The same process also takes place in the dentine when simi- lar indentations are produced by resorption and occasion a roughness of the surface. Not merely those portions adjacent to the cement are attacked by this process, but the inner por- tions also, which inclose the root canal (Atlas, Fig. 111). Resorption of the milk tooth is frequently accompanied by a new formation of osseous substance, a phenomenon of frequent occurrence with new formations, that is to say, involution by the side of evolution. The new formation and resorption can readily be studied in that portion of the cement where no rows, or, still better, where a single row of bone-corpuscles occurs. In addition to the in- dentations produced by resorption already described, which quite frequently are coated with the remains of the organic basis- substance, cross-sections also present clear, hemispherical, sharply defined masses imbedded in the cement ; these are either separate or grouped together, and gradually extend be- yond the boundary of the cement even into the dentine, and not unfrequently assume a radiating arrangement. The central portion of these masses contains irregular cavities, which denote the points where the process of resorption com- menced. The osseous substance, which encroaches considerably upon the dentine, is always sharply defined ; the corpuscles, like- wise, either singly or in groups, are inclosed by a bright cap- sular layer (Atlas, Fig. 110). Such corpuscles resemble young, immature bone-corpuscles, the canaliculi of which have not yet formed their mutual connections. Not unfrequently the cor- puscles are irregularly formed, elongated ; present several long offshoots, or are large, without any definite form, as if resulting from a blending together of separate ones. As they increase in SECOND DENTITION. 79 volume, and lose their proper characteristics, they assume an appearance like that of gaps, resulting from interstitial resorp- tion, and filled with amorphous calcareous salts, and all the more so from the fact that very decided evidences of resorption are found in their vicinity. The newly-formed osseous substance is immediately subjected to a peripheral resorption, while the capsule of the corpuscles thickens, and the latter, finally, are destroyed. The cloudy, granular, discolored substance contains a greater or less amount of fat, which is the remains of the disintegrated tissue. When the resorption of the milk teeth has progressed so far that a small portion only of the crown remains, the enamel, likewise, becomes eroded and resorption indenta- tions make their appear- ance in it also (Fig. 23). Tomes has also observed the development of osse- ous substance upon the outside of the enamel. If a milk tooth, in which resorption has made some progress, be sepa- rated from the jaw, a loose, spongy substance remains adherent to it, which a long time ago, was claimed by Laforgue and Bourdet to be the absorbent organs. It was supposed that the latter secreted a fluid capable of dissolving the substances of the tooth. Tomes made a microscopic examination of this pa- pillary organ, and states that its surface is made up of peculiar multiform cells, each one being composed of several smaller cells, the number varving from two or three to as many as four- teen or fifteen. Some few deviating forms bear a strong re- semblance to the cells, described by Kblliker as myeloid cells. * Tio. 28. — Kesorption indentations which penetrate from the surface of the enamel toward the deeper layers, resembling, in the manner in which they are grouped together, glandular lobes, and tilled with a cloudy, gran- ular mass. The contiguous portion of the enamel is in its normal condition. Magnified 250 diameters. 80 ANATOMY AND PHYSIOLOGY. Each hemispherical depression of the absorbent surface of tlie tooth is occupied by such a cell as has been described. Beneath the surface of the papillre, there are commonly found nucleated cells and free nuclei, and, in the deepest layers, a fibrous tissue in the process of development. According to my experience upon this point, which indeed is limited, these compound cells (Tomes) are not of constant occur- rence; I have not been able to discover them in some eases, but have perceived merely aggregations of single cells of connective tissue. Hohl has succeeded only in one case in discovering a few gigantic cells, and he is of the opinion that the large cells described by Tomes are nothing but nests of cells with connective- tissue capsules. How the destruction of the hard substances of the tooth is accomplished by these cells, we have no clear con- ception ; to me it seems more probable that a fluid is secreted by the cells, which dissolves the hard substance, than the theory, held by some, that these cells 'are of a parasitic nature, that is to say, that the dental substances are eaten up, as it were, since the cells absorb the latter. Possibly amoeboid movements may be the occasion of the wasting of the tissues. The so-called absorbent organ, however, induces also an os- seous formation, already described, since the cement, notwith- standing its partial resorption, evinces, on the other hand, a pro- ductive activity which results in the development of osseous sub- stance within the dentine and upon the exterior of the enamel. When the cells of the milk teeth are absorbed, those of the per- manent teeth are completed.* * The organ of resorption probably is developed from the connect! \'e tissue of the root-tnembrane of the milk tooth, and from the medullary matter of the adjacent osseous tissue, and is, essentially, a granulation tissue, similar to that which we find in many inflammatory affections of the bone, or in tumors which are developed in the osseous substance. We also find, on the one hand, upon the periphery of sarcoma, cancer, &c., a resorption of the contiguous bone, and on the other hand, frequenth^ a growth of trabecular osseous tissue. Therefore, during the shedding of the teeth, an hyperajmic condition occurs in the root-membrane and the medullary matter of the bone adjacent to it; the activity of the cells becomes augmented, in conse- quence of which the whole process of nutrition is carried on more rapidly than under ordinary conditions ; the j'oung, more vigorous cells supplant the older, enfeebled ones. In the organism of youth, also, we find that in the SECOND DENTITION. 81 When the resorption of the milk tooth is completed with the exception of a certain portion, variable according to local cir- cumstances, its alveolus has, for the most part, disappeared, and that of the permanent tooth occupies its place. This, however, is not always the case, particularly when the milk teeth are shed prematurely, or the permanent teeth occupy anomalous posi- tions, and in such cases there remains upon the summit of the alveolar process an oval or circular channel, in the centre of which is found a conical osseous papilla, which is to be consid- ered as the remains of the bony substance which, in its growth, occupied the pulp-cavity (Atlas, Fig. 3). Fig. 24.= growth of bone, there occurs upon one side resorption, and upon the other pri)dLicti(jn, as for example, in the flat bones of the skull, resorption occurs on the inner surface, growth on the outer surface which is in relation with the galea aponeurotica. Again, in the tibia, resorption takes place in the central medullarj^ canal, and growth upon the periosteum and epiphyses. These processes, too, explain the increase in size of the cranial cavity and central medullary canal of the tibia. * Fig. 24. — Set of milk teeth with the corresponding permanent teeth still imbedded within the jaw. The tirst permanent molars («) have already emerged from the jaw both above and below, so that the second dentition has commenced. Profile view from the right side. The somewhat inclined crowns of both permanent incisors are visible behind the extremities of the roots of the milk incisors. The crown of the upper canine tooth (b) presents 6 82 ANATOMY AND PHYSIOLOGY. Fig. 2.1 * Before passing to the consideration of the separate teeth, it is to be premised that the permanent teeth in the upper jaw are arranged somewhat differently from those in the under jaw, in their rehitions to the milk teeth, and also that the dif- ferent kinds of teeth present varia- tions in this respect (Fig. 24). Commonly, toward the end of the fourth year, small, barely per- ceptible apertures appear in the under jaw, behind the central milk incisors, and adjacent to the lingual alveolar margin ; these gradually enlarge so as to admit the incisive edges of the per- manent central incisors between their smooth borders. In the meantime, similar apertures become visible behind the lateral incisors. When the edges of the permanent central incisors have reached the level of the lingual alveolar margin, the edges of the lateral incisors are still some millimetres deeper, and are inclined somewhat toward the medium line and backwards (Fig. 25). Since the total breadth of the crowns of the two perma- nent incisors is greater than that of the corresponding milk a marked inclination, and is situated high up in its alveolus; the lower per- manent canine (c) likewise occupies a deep position. The crowns of the per- manent bicuspids are grasped by the diverging roots of the milk molars. The mental foramen (rf) is seen between the first and second milk teeth. The crowns of the second permanent molars, inclosed within their alveoli, are imbedded in the maxillary tuberosity and coronoid process. Natural size. * Fig. 25. — Front view of the lower jaw at the commencement of the process of shedding the teeth, showing the relative positions of the anterior milk and permanent teeth. On the left side, the two milk incisors and canine were left in their natural positions, with reference to the permanent teeth lying posteriorly and inferioriy. The process of resorption is i'arther advanced in the extremit}' of the root of the central incisor, than it is in that of the lateral. On the right side, the milk teeth have been removed ; the permanent teeth lie within their alveoli in an inclined plane. The notched edges of the permanent central incisors have reached the alveolar margin, those of the laterals being situated about two millimetres lower down ; the latter teeth, also, are inclined somewhat toward the median line, although to a less degree than the conical crowns which are deeply situated and inclosed within their alveoli. Natural size. SECOND DENTITION. 83 teeth, the eruption of the former, side by side, would be impos- sible, so long indeed as the milk canine teeth remained in situ, if provision were not made to secure sufficient space, as will be shown farther on in connection with the subject of the growth of the jaw. Similar phenomena attend the cutting of the permanent inci- sors of the upper jaw, with the exception that, in consequence of the greater difference in size between the milk and permanent incisors, the upper permanent lateral, before it is cut, has a still greater inclination than the , under one toward the median I ^^ i llJ Njff line and posteriorly. Hence still more space must be pro- vided in the upper jaw than in the lower, for the eruption of the permanent incisors (Fig. 26). The first bicuspids generally are the next to take their places in the dental range ; it is not an infrequent occurrence, however, for their eruption to precede that of the lateral incisors ; the second bicuspids usually succeed the canine teeth. The alveoli of the permanent bicuspids of the lower jaw are situated between the anterior and posterior root of each milk molar. As the in- closed crowns of the permanent bicuspids, taken together, occupy less space than those of the milk molars with their diverging * Fia. 26. — Pront view of the upper jaw, of a child seven years of age, presenting an abnormal dentition. The central incisors have descended to the level of the dental range ; the edges of the lateral incisors are situated seven millimetres higher up; the latter also are still inclined somewhat toward the median line and backward, and consequently have not yet com- pleted their slight rotation. The crowns and the already completed roots of the permanent canine teeth are situated high up in the anterior segment of the septum between the nasal and maxillary cavities, and are inclined toward the median line. The extremities of the roots of the milk canines («, a), the crowns of which are afiFected with caries, are already absorbed. The first permanent bicuspid on the left side {b) has descended nearly to the level of the dental range, while the first milk molar on the right side (c) is not yet shed, and retains, between its roots, the first permanent bicuspid, the radical portion of which is developed to a slight degree. Natural size. 8-i ANATOMY AND PHYSIOLOGY. roots, space is reserved anterior!}', after the eruption of the first permanent bicuspids, for the permanent canine teeth. As the second lower milk molar is considerably larger than the first, while the second lower permanent bicuspid is of nearly equal size Avitk the first, the roots of tlie first lower milk molar undergo a more notable resorption. In consequence of the fact that the permanent bicuspids are embraced by the roots of the milk molars, as if by forceps, it is necessary to exercise especial care in connection with the extraction of the latter, for if it becomes necessary to extract the milk molar on account of its unsound- ness before resorption of its roots has commenced, the crown of the permanent molar will necessarily be extracted at the same time, because it is so tightly embraced by the roots of the milk tooth (Atlas, Fig. 15). The permanent canine teeth remain w-ithin their temporary alveoli very deeply imbedded in the under jaw, with their long diameters inclined towards the median line, until the eruption of the perfectly developed permanent incisors is completed, and the first permanent molars with their roots are entirely formed; the milk molars, however, have not yet been shed. When, in consequence of continued resorption of the root, the milk canine tooth becomes so loose that it falls out, the permanent canine tooth necessarily is slightly tilted laterall}- on its long axis, be- comes more upright, and enters directly into the space left vacant by the lower milk canine. Since, however, the latter space is too small, the space reserved after the succession of the first bicuspid now comes into play. The position of the upper canine teeth in their temporary alveoli, is analogous, that is to say, their long diameters are inclined somewhat toward the median line, and the developing roots, together with the large rounded crowns, are implanted in the osseous wedge (Knochenzwickel) between the facial wall of the upper jaw, and the septum of the nasal cavity and antrum of Highmore. The canines, when inclosed in their bony capsules, occup}^ the highest position of all the teeth in the upper jaw, and their crowns experience, in their de- scent, a slight lateral tilting, by means of which their crowns acquire a more perpendicular direction. AVhen the first molars have emerged completely, the prepara- SECOND DENTITION. 85 tions for the eruption of the second molars are completed. The jaws have increased in length in their posterior segments, and oval apertures are perceptible upon the summit of the alveolar process behind the first molars. In the lower jaw, these apertures are at the base of the coronoid processes and, in the upper jaw, in the upper part and to the outside of the tuberosities. From the posterior margins of these apertureg extends a more or less distinct, shallow, short, narrow, bony groove, which is known as the posterior dental groove. About the end of the eighth year the apertures enlarge, and the coronal cusps of the second molars may be seen at the bottom of them. If the facial wall of the jaw and the corresponding segment of the rounded alveolus be removed, the lateral portion of the incomplete crown will be ex- posed. The subsequent phenomena attending the growth of these teeth are similar to those attending the development of the first molars. The process, however, is slower, their eruption not being completed until the twelfth or thirteenth year, making an interval of five to six years between the eruption of the first and second molars. The above-mentioned posterior dental groove, ascending from the base of the coronoid process, and bending upwards like a bow over the tuberosity, bears a striking resemblance to the dentnl groove in the jaw of a three months' foetus. It is cov- ered with a delicate mucous membrane. At a later period there appears in the posterior segment a small crypt (Alveole) about the size of a millet-seed, which is intended for the tliird molar, or wisdom tooth. A spicula of bone, the unabsorbed remains of the outer extremity of the alveolus, frequently is found, at this period, attached to the outer edge of the aperture pro- duced by resorption, and continues to obstruct the entrance to the alveolus of the second lower molar. Concurrent Avith the expansion of the crypt-like depression for the Avisdom tooth, an osseous lamina is developed behind the alveolus of the second molar, the alveolar septum, which gradually becomes more prominent. About the twelfth year the alveolus of the wisdom tooth, shaped like a shallow dish, attains the size of a small lentil, but still is situated high up in the tuberosity of the upper, and in the base of the ascending coronoid process of the lower jaw. As the growth of the posterior segments of the jaws is 86 ANATOMY AND PHYSIOLOGY. advanced considerablj, Avliicli process takes place much more slowly than in the earlier years, the alveoli of the wisdom teeth begin to advance, and finally reach the level of the dental range. In the meantime the alveoli of their crowns have become deeper and wider, and the coronal cusps become perceptible in the apertures upon the alveolar processes and gradually become larger by resorption. Their eruption occurs, as is well known, a few years before or after the twentieth year of life. The opinion is entertained by some that the germ of the wisdom tooth is derived from a process of that of the second molar. But the facts which have been mentioned that, as the growth of the posterior segment of the jaw advances, the mucous membrane becomes extended over the posterior dental groove, and that the development of the alveolus of the wisdom tooth occurs within the latter, are much more in favor of the view that the germ of the wisdom tooth, like those of the other teeth, is the product of the, formation of a sac and papillae directly from the epithelium and corium of the mucous membrane. I have been unable to obtain histological evidence in proof of the latter theory, yet I consider it, nevertheless, as probable. Ac- cording to the recent statements of Kollmann,* the enamel germs of the second and third molars are not developed directly from the epithelium of the oval cavit}', but from the enamel germ of. the first molar. f * Op. cit. f The second dentition sometimes does not commence until the second or third decade. D. Fricke, of Liineburg (Deutsche Vierteljahressch. f. Z., 1869), saw two girls, one eighteen and the other sixteen years old, both of whom still retained all the twenty milk teeth which were worn away very much. [The permanent teeth usualh' appear at about the following ages, and in the following order : First molars, ^. . . . 6th to 7th year. Central incisors, . Lateral incisors, . First bicuspids. Second bicuspids, . Canine, . Second molars, Third molars, 7th to 8th 8th to 9th 9th to 10th 10th to 11th 11th to 12th 12lh to 14th 17th to 21st T. B. H.] THIRD DENTITION. 87 Third Dentition. — The possibility of the occurrence of a third dentition is doubted, and even openly denied by many. Its opponents assert that cases of presumed third dentition are merely instances in which the teeth have not emerged, but have remained imbedded within the jaw until the occurrence of senile resorption of the alveolar processes. Deceptions may easily occur in regard to them, particularly among the ignorant, as will be evident from reference to the section upon the retention of teeth. On the other hand, however, we ought not to persist in the denial of the occurrence of a third dentition, on the ground that it is contrary to the current physiological doctrines. The writers of former times,* Aristotle, Eustachius, and Al- binus, mention a repeated renewal of the teeth. In recent times, Fauchard, Bourdet, J. Hunter (the latter observed a third set of teeth in both jaws). Van Swieten, Haller, collected several such cases from different writers. Hufeland describes a case which came to his knowledge. In the one hundred and six- teenth year of life, new teeth were said to have made their ap- pearance ; six months after the loss of these, new molars appeared in each jaw. Serres observed two cases in the Hopital de la Pitie ; one of a man thirty-five years old, whose two lower cen- tral incisors fell out, and were replaced after a few months ; the other of a man seventy-six years old, who, during convalescence from a bilious fever, experienced pain and swelling in the gum of the under jaw, which disappeared on the eruption of a tooth with several eminences in the place of the second molar on the left side. The margins of the alveoli had not yet disappeared in this old man. C A. Harrisf has no doubt that a third dentition does occur in extremely rare cases, and instances a number of examples where individuals, who for a long time had been toothless, ac- quired several teeth, or even an entire set, in extreme old age. According to the authority of Dr. Bisset, of Knayton, twelve molars made their appearance in a woman ninety-eight years old. Harris himself observed two cases, the second of which is * Carabelli's and Linderer's Geschichte der Zahnheilkunde. f Principles and Practice of Dental Surgery. Phil., 1850. 88 ANATOMY AND PHYSIOLOGY. ■\vortliy of note, uhcre four central incisors made their appear- ance, one after the other, on one side of the upper jaw. Such teeth, he remarks, seldom lie in alveoli, and have either no roots or stunted ones. He thinks it not improbable that duplicatures of the mucous membrane occur during the healing process which ensues after the extraction of one or more teeth. M. Carre relates the case of a woman eighty-five years old, who cut a left upper canine, and a few months later, a left lateral incisor and first bicuspid on tiie right side in each jaAv.''' Heider reported a case of multiple formation of a dwarfish canine tooth in a wo- man not very old.f If we admit the occurrence of a third dentition in very rare cases, it is by no means necessary to assume, as Harris thinks, the origin of a new dental germ after the permanent teeth have been detached, since it cannot really be denied that germs may lie dormant for many years in the animal organism, until they are subjected to favorable conditions which enable them to develop. The possibility that during a long series of years a germ may remain dormant in the lateral folds of the enamel gum, cannot be rejected on theoretical grounds. Kollmann even asserts that the germs for such a late dentition have their origin in the ear- liest years of childhood. The fact that the crowns only are formed while the roots are stunted is clearly due to the small depth of the jaws in old age. Groavtii of the Jaws. — Ossification of the up2:)er jaw com- mences at a very eaidy period. SappeyJ describes five centres of ossification. As the ossification advances, sutures make their appearance, which directly disappear again. The most con- spicuous suture, easily distinguished both in the foetus and in the first years after birth, and even later, is the sutura incisiva, which extends from the foramen incisivum across to the septum, between the alveoli of the lateral incisor and canine. In rare cases it is also continued upon the facial wall of the upper jaw, between the above teeth, and can be traced into the nasal pro- cess as far as the inner portion of the inferior margin of the * Med. and Surg. Reporter, 1860. t Vide Anomalies of Formation. X Anatomic Descriptive, 2d ed. GROWTH OP THE JAWS. 89 ovbit. The alveolar portion of the upper jaw is divided by it into a smaller anterior segment, which includes the sockets of both incisors, and a larger posterior segment, which contains the remaining sockets. In such cases its analogy with the os incisivum of mammals is evident. The deformity known as wolf's jaw denotes a persisting fissure between the intermaxil- lary bone and the rest of the alveolar process. In luire-lip these bones are united, but the fissure of the upper lip persists, corres- ponding in its position to that of the junction of the bones. If the two upper jaws are not united at the palatal suture, the de- formity known as cleft palate results. These malformations are considered to be the results of arrest of development, the cause of which is unknown. The lower jaw is formed very soon after the collar-bone. Ac- cording to Sappey (op. cit.), it has two centres of ossification, which make their appearance about the thirty-fifth day. In the foetus, the lower jaw is divided into two halves, which are not wholly united until some time in the course of the first year after birth. With a deformity of a median fissure of the lower lip, a persistence of the median separation of the lower jaw is observed only in a slight degree or not at all. The direction of the groivth of the under jaw may be ascer- tained in part from the direction of the rays of bone. The latter may be seen in an embryo, extending along the facial wall from the head of the articulating process, which, as yet, projects scarcel}'' above the level of the alveolar border, and in front of the margin of the ascend inir ramus, in horizontal and somewhat oblique directions towards the anterior segment of the maxillary arch ; the latter are joined by those descending from the coronoid process which, as yet, is but slightlj^ devel- oped. The first-mentioned rays become closely compacted, es- pecially in the vicinity of the lower border of the jaw, which thereby increases in thickness. The inferior dental canal pri- marily is open above like a groove. The growth of the lower jaw is most conspicuous upon its facial wall and inferior border. The radiation of the bone is not distinctly marked on its lingual surface, where are formed instead imbricated lamelliTe or delicate networks of trabeculne. Another centre of ossific radiation 90 ANATOMY AND PHYSIOLOGY. daring embryonic life, which easily escapes observatioTi, is beneath the mental foramen. Here the osseous trabecuhe are arranged in a crescentic form around the inferior margin of the foramen. A similar radiation, with the convexity of the cres- cent turned downwards, may be seen about the infraorbital for- amen in the upper jaw. Towards the end of the third, and the beginning of the fourth month after birth, the articular process of the under jaw in- creases considerably in length, and the formation of the neck portion takes place. By a corresponding growth of the cor- onoid process, the saddle-like concavity of the sigmoid notch becomes more distinctly marked. At about this period, a third system of osseous rays is met with, Avhich at a later period becomes more apparent, and extends downwards from the head of the condyle to the obtuse angle of the under jaw. At birth, the lower jaw generally is still separated into its two halves. The facial surface of the future symphysis presents a triangular, fibro-cartilaginous portion, in which several ossiiic centres appear during the first months after birth. Coincident with the latter occurs the union of the two halves, together with the formation of the mental process ; the former takes place from below upwards and is completed at the period of the eruption of the central incisors. At birth, the angle of the lower jaw presents only a slight bend. Upon the convexity of this curve the osseous substance is deposited subsequently in such a manner that the vertex of the angle gradually becomes more pointed (during a year or year and a half). The angle formed by the junction of the hor- izontal and ascending rami changes but little during this time, but in the subsequent years it gradually becomes smaller by the deposition of bone in increasing proportion from the head of the condyle towards the vertex of the angle, while the ascend- ing branch, at the same time, gradually increases in length. Previous to the eruption of the second milk molar, the growth of the posterior segment in length makes considerable progress. When the growth necessary for the milk teeth is completed, a delicate, porous, osteophyte-like osseous layer is observed upon the posterior segment of the inferior maxillary arch, and also GROWTH OF THE JAWS. 91 upon the tuberosity of the upper jaw. The growth in tliick- ness takes phice principally upon the inferior border of the lower jaw, that in height is displayed in the fan-shaped ossific radiation in the alveoli, and likewise in their ascending septa. The spongy substance of the bone between the alveoli and the maxillary Avail is not developed at first, and the latter lie in juxtaposition until the growth of the bone in thickness is con- siderably advanced, when the spongy substance makes its ap- pearance. In the first and second years after birth, the exter- nal and internal oblique lines, together with the spina ment. int., &c., are rendered more prominent by means of increased mus- cular action. Changes in the Jaws during the Second Dentition. — Hunter* was the first to assert that in the portions of the jaws in which the milk teeth are placed growth ceases after the completion of the first dentition. Foxf agreed with him substantially. They reached this conclusion by measurements of macerated lower jaws. Delabarre,J on the other hand, endeavored by means of clinical observations to establish the fact of the growth of the bone in length after the first dentition. He asserts that, at the age of five to six years, the milk teeth separate from each other, and says, that those people with whom this does not occur are liable to have an irregular second dentition. Fox had recog- nized this occurrence before Delabarre, but did not give to it the same significance, for he states, "the anterior portion of the jaw undergoes scarcely more than an alteration in form ; it adapts itself to the permanent teeth there situated, and scarcely receives any increase in size." Th. Bell§ asserts emphatically that no reliance can be placed upon the comparison between jaws of different individuals. The only way to get at the truth of the matter is to examine the same jaw at different ages, and then compare the various results. " This," says Bell, "I have repeatedly tried, and do not hesitate to say that the ten front permanent teeth occupy a somewhat wider arch than the milk teeth which preceded them." C. A. Harris || coincides with * Natural History of Teeth. f Natural History of Human Teeth. J Seconde Dentition, 1819. § Anatomy, Physiology, and Diseases of the Teeth, 1835, 2d ed. II Op. cit. 92 ANATOMY AND PHYSIOLOGY. Bell's opinion, and states that the transverse and perpendicular dimensions of the anterior portions of the bone continue to aug- ment until the completion of the second dentition, and even during youth. J. Tomes inclines to Hunter's opinion, and op- poses the idea of an interstitial growth of the bone. According to Hiiter,* the growth of the inferior maxillary arch in its perpendicular dimensions is chiefly periosteal, while horizontally it is the result of the expansive osseous groAvth. In his opinion no notable growth takes place after birth in the whole of that part of the lower jaw between the third grinders (first permanent molars). Welcker's measurements, also, con- firm this statement. HiAter opposed the idea of an interstitial growth of bone, -while Rich. \ olkmann, long since and again recently, t advocated its occurrence. C. Ruge| and Julius Wolff,§ also, are in favor of the same view. I, myself, agree with the latter, for the reasons already given. There can be no doubt that, as already stated, an enlargement of the maxillary arch is produced chiefly by the deposition of osseous substance upon the facial surface, and also by resorption ■which takes place upon the lingual surface. In this way the front teeth are pushed forward, and the back teeth outwards. This change of the location of the teeth, however, is conceivable only in case resorption also takes place in the interior of the bone, since, otherwise, the teeth, covered as they are by new layers upon the facial surface, must finally be pressed nearer the lingual surface, which evidently is not the case. An inter- stitial ri'.so7'ption must, therefore, take place. Fox advocates, to be sure, a change of form in the maxillary arch during its growth, but this is true only of the upper jaw. If we compare, he says, the jaw of a child with that of an adult, a marked dif- ference Avill be observed ; that of the child has nearly the form of a semicircle, while that of the adult presents a semi-ellipse. These changes in the maxillary arches will be considered at greater length farther on.|| In order to ascertain tlie relative growth in the under jaw, we * Virchow's Arcliiv, 9 Bd. f Centralblatt fur med., Wiss., 1870. + Virchow's Archiv, Bd. 49. § Ccntnilblatt fiir med., Wiss., 18G9. II Vide p. 95, et seq. GROWTH OF THE JAWS. 93 must first endeavor, if possible, to select points that are not liable to change, from which to make our measurements. It is self-evident that absolute accuracy is impossible, and that ap- proximate results only can be obtained. The unavoidable errors of observation acquire greater importance the smaller the dis- tances which are to be measured. The longitudinal dimensions are much less diflficult to ascertain than the transverse and perpendicular. I instituted a series of measurements of forty-five children's skulls, with reference to the growth in length of the inferior maxillary arch, partly also with the view of ascertaining the in- dividual differences, making use of a thin slip of paper slightly moistened and accurately adapted to the peripheral surfaces. Measurements taken by means of a pair of compasses give a sector, wlien applied to a curved object, which may be the same with different curves. The mental foramen is taken as a fixed point for measurements upon the anterior segment of the lower jaw ; it must, however, be remembered that the locality of this aperture is not constant. In the under jaws of adults its ante- rior margin falls sometimes in a line between the two bicuspids, at times directly under the first, or under the second bicuspid, and at others on a line with the posterior coronal surface of the second bicuspid. -These variations, even in a small series of under jaws, give an error of from three to four millimetres. Disregarding the latter, and employing the measurements of the peripheral distance from the line of junction of the two halves of the under jaw (Avhich may easily be marked with a pencil) to the anterior margin of the mental foramen, we found that, in a five months' foetus, the distance measured 10 mm.; in new-born children, 12 to 13 mm.; in children from 4 to 11 months old, 15 to 18 mm.; in others from 1 to 7 years old, it remained about the same, 18 to 19 mm. ; in four cases, one a child 1 year 5 months 27 days old, who had cut the central incisors, it reached a length of 20 mm. ; in one 1 year 10 months 10 days old, with a first molar cut, 21 mm. ; in a child 5 j^ears old, with its complete set of milk teeth, 21 mm. ; in one 6 years 1 month old, with a large set of teeth, 23 mm. ; from 7 to 12 years, inclusive, it varies from 22 to 24 mm., and in comparative 94 ANATOMY AND PHYSIOLOGY. mcnsurements of adults' under jaws, between 23 and 29 mm. If we disregard extreme cases, we find the most notable growth of this part of the under jaw during the first months of life, and an interval of rest after the eruption of the milk teeth, and again an increase during the shedding of the teeth, amounting to at least 3 mm. In order to meet the objection, that no account was taken of the thickness of the facial wall, separate measure- ments Avere made after the removal of the facial wall ; they showed, however, as indeed was anticipated, no material diiference. Further measurements were made, in the same manner by means of a slip of paper, of the Avhole length of the facial sur- face of the under jaw from the junction of the halves, which Avas marked, to the most prominent point of the condyle, which may be done as long as the latter does not project very far above the level of the alveolar margin. This peripheral boundary measures, in a foetus of five months, 40 mm. ; in one of 7 months, 43 mm.; in a new-born child, 45 to 52 mm.; it increases until the fourth month to 58 mm.; till the seventh month to 62 mm. ; till the first year to 67 mm. ; till the end of the second year, after the eruption of the first molar, to 77 mm, ; in the fourth, fifth, and sixth years, with the entire set of milk teeth, from 78 to S5 mm. ; in a child seven years old, with the first permanent molar, to 100 mm. After this age such measurements cannot be made with precision. If Ave subtract from the latter the measurements of the anterior segments of the tAvo halves of the lower jaAv, made from the median line as far as the anterior margin of the mental foramen, Ave obtain a series of measure- ments for the posterior segments, from the last-named margin to the prominent point of the condyle. This latter series gives an increase of from 30 to 77 mm., while Ave found that the anterior segments increased from 10 to 23 only. The total increase rep- resented by the quotients of the latter, 2.56 and 2.3 respec- tively, presents a difference Avhich is due to the greater degree of groAvth of the posterior segment of the jaw. J. Tomes em- ployed also the tubercles on the lingual surface of the lower jaw, which serve for the attachment of the genio-hyo-glossus and genio-hyoideus muscles, as a point from which to take meas- urements. According to my experience, however, these tuber- GROWTH OF THE JAWS. 95 cles are, often, so indistinct in the foetus, and likeAvise in the new-born child, and vary so much in form, size, and height in chihlren, and particularly in adults, that the value of such measurements appears doubtful, and all the more so in the case in hand, from the fact that the calculation involves such small quantities. Measurements of sets of teeth, taken on the facial margin of the alveolar border, from the line of junction of the jaws across the necks of the teeth to the posterior portion of the neck of the second bicuspid, gave for half the set of lower milk teeth, 32 to 34 mm.; the peripheral extent of the permanent teeth, measured in the same manner, varied from 32 to 37 mm. In many cases, therefore, the size of the under set of milk teeth conforms exactly to the corresponding segment of the perma- nent set ; in some cases the former may even be larger, but generally the reverse is the case. Just as the new layers of bone are deposited upon the facial Avail of the growing maxillary arch, and resorption takes place upon its lingual surface, so in the development of the posterior segment of the jaw, deposition of new osseous layers takes place upon the posterior surface of the articular and osseous process, while anteriorly upon the coronoid process and condyle resorp- tion of the osseous substance ensues. G. M. Humphrey* has proved this fact experimentally. He introduced wire ligatures through the middle of the ascending ramus of the lower jaw of a young pig, near the anterior and posterior margins of the ramus, and ascertained that, after the expiration of a certain interval, the front loop was loose and projecting, while the back one lay deeply imbedded within the posterior portion of the ramus. He states that a somewhat analogous process occurs in the upper jaw, and, on the whole, agrees with the views of J. Tomes. In order to illustrate the changes which take place in the arch of the milk teeth, in comparison with that of the permanent teeth, the arches formed by a permanent and milk set and that of the outer alveolar plate of a seven months' foetus, placed one * Triinsactions of the Cambridge Philosophical Society, vol. xi, part 1. 96 ANATOMY AND PHYSIOLOGY. inside the other, were emploj'ed as a basis for measurements. The commencing and terminal points of the measurements were as follows : The centre of the space between the edges of the two central incisors, and the points of the intersection of the posterior coronal with the masticating surfaces of the crowns of the second permanent bicuspids and milk molars, and, in the seven months' foetus, the point of junction of the two halves of the jaw, upon the facial alveolar margin, and the outer extremity of the alveolus for the second milk molar. As they were made upon a well-developed set of milk teeth and a large set of a man twenty-two years old, they are not the mean measurements and have no claim to a very general application. Fig. 27 In the upper jaw (Fig. 27), it will be seen that the curve a, a', obtained by the above measurements in a seven months' foetus, is very nearly the segment of a circle ; in the milk set, 6, 6', it describes a concentric arc of a circle ; in the permanent set, on the other hand, it has changed into the segment of an * Fig. 27. — Diagram illustrating the changes in the dental arch during the growth of the upper jaw. (a), lowest point in the junction of the anterior portions of the two segments of the upper jaw, from a foetus in the seventh month ; (6), central point of the space between the edges of the two central incisors of a set of milk teeth; (c), the same of a permanent set; («'), pos- terior and external termination of the alveolus for the second milk molar; (//), point of intersection of the posterior coronal with the masticating sur- face of the second milk molar; (c/), point of intersection of the posterior coronal with the masticating surface of the second permanent bicuspid. Natural size. GROWTH OF THE JAWS. 97 ellipse, f, c' . We find, further, that the point a has advanced to b and finally to c, anteriorly, while posteriorly the displace- ment of a' to h' measures the same as that of a to h, but that the point c' is displaced comparatively farther outwards; in other words, a, b = a', b\ but b, c <. b,' e' . The permanent second bicuspid occupies a more outward position towards the face than the permanent central incisor. A similar method was applied to the lower jaw (Fig. 28), and it was found that, in corresponding segments, the increase in growth is less than in the upper jaw, and that the curves con- FlG. 28.* tinue nearly parallel, that is tosay «5 = a'<^', and 5 c=5'c' nearly ; the second permanent bicuspid is placed only a little farther ex- ternally than the second milk molar, and does not, as is the case in the upper jaw, undergo a notably greater facial displace- ment than the central permanent incisor. If a moderately well-developed set of permanent teeth be chosen and compared with a large, well-developed set of milk teeth, the curves b, b' and c, c' coincide, and the latter curve may be met with even smaller than the first. ■^ Fig. '28. — Diagram illustrating the change in the dental arch, during the growth of the lower jaw ; a, the highest point in the line of junction of the anterior surfaces of the two segments of the lower jaw in a foetus of seven months. The rest of the letters indicate corresponding points with those in the last figure. Natural size, 7 PART II. PATHOLOGY. I. IRREGULARITIES IN THE FORMATION OF TEETH. The teeth are subject to manifold anomalies which are de- serving of careful consideration, since, in addition to the mere theoretical interest which they possess, many require a special operative treatment. They present for particular consideration abnormal conditions in respect of size, number, arrangement, position, and structure. The permanent teeth will be considered first, since their irregularities are the more important and of more frequent occurrence. 1. Irregularities of Size. Excessive size, so great as to constitute a disfigurement, is seldom presented by the entire rows of permanent teeth, more frequently by the front ones alone. With this condition, the crowns of the upper central incisors are particularly conspicuous, in consequence of their very great extent of surface, while their roots remain comparatively short and stunted. Sometimes the excessive size of the upper central incisors is compensated for by the lesser, retarded growth of the laterals. Occasionally the excessive growth involves both the crowns and the roots of the canine teeth, which then resemble the fangs of animals. Disproportions in size between the jaw and teeth are accom- panied by corresponding changes in the arrangement of the latter which will be considered at length in subsequent pages. Excessive growth is limited to one or another tooth, and must not be confounded with the excessive size occasioned by the coalescence of two teeth, the incisors, for example, a mis- take very easily made, since the longitudinal groove which is IRREGULARITIES OF NUMBER. 99 produced by the coalescence of the teeth is perceptible on the roots only, and not upon the blended crowns. On the other hand, teeth may not attain the average size, and still there may be no interruption in the contiguity of the dental range. If, however, the maxillary arch is too wide, in proportion to the dental arch, intervals occur now and then be- tween the teeth, especially between the front ones. These in- tervals will be so much the more conspicuous, if cither of the front teeth is unusually small in comparison with the others. They occur most frequently between the two upper central, and lateral incisors, and more rarely betAveen the lower centrals. The interval between the two upper centrals is often so wide, and occasions such a disfigurement that Heider was required frequently to fill up the abnormal space by the insertion of a tooth. In many cases, these large intervals are occasioned by the prolonged retention of a large milk incisor, which prevents the normal advance and approximation of the two permanent incisors. Generally, however, they are due to the great resist- ance of the alveolar septum, or the suture which unites the two segments of the upper jaw. Wisdom teeth, particularly, are liable to be stunted in their growth. In many children, milk teeth are found so uncommonly large and strong, that they may easily be mistaken for permanent teeth, and on the contrary, in others, they are remarkably small, and at times, the milk incisors, for example, do not afford surface enough for the application of an ordinary pair of children's forceps, without danger of grasping the contiguous tooth at the same time. When the milk teeth are too large, the incisors, in particular, frequently overlap one another on account of the deficiency of space. Milk canine teeth, both in the upper and lower jaw, sometimes are unusually long and pointed. 2. Irregularities of Number. Deviations from the normal number occur more frequently ■with the permanent than with the milk teeth, and a number of teeth less than normal is observed more often, perhaps, than the opposite condition. J. Tomes, on the contrary, asserts that an excess of the normal number is perhaps more common. 100 PATUOLOGY. Tlic excess of tlie normal number of teeth is either alsolute^ that is to say, there are more than the thirty-two normal teeth present ; or it is relative if there is an excess of one or another kind, while the total number does not exceed, and, indeed, may even be less than the normal number. If it is desired to enumerate accurately the number of teeth in a set, it is not sufficient to give merely the total number of teeth existing, but the different kinds of teeth should be enumerated sepa- rately, and then all the teeth together. An adult may have the requisite number of thirty-two teeth, and still present both a deficiency and an excess of one or more teeth. It may happen that the upper jaw contains two supernumerary lateral incisors, while the wisdom teeth are Avanting. Hence the total number is not altered but remains thirty-two, and yet there is an excess and a deficiency of two teeth to be specified. Siqjernumerajnj teeth may be divided into two groups, those which can be ranked with one or another of the .members of the dental series, and those which differ in form from the latter, called the conical teeth (Dutten-oder Zapfenziihne). Those belonging to the first group are, most frequently, inci- sors and bicuspids. Sometimes five, and in very rare cases, six incisors instead of four are met with in one jaw. The super- numerary tooth usually is a lateral incisor, and generally is so well arranged in the series that this anomaly easily escapes ob- servation, especially in the under jaw. An extra canine tooth has been observed, but it is a very un- common occurrence. Tlie cases in which a milk tooth is re- tained in later life in close proximity to a permanent one, evidently do not belong to this class, but are liable to be misin- terpreted by an inexperienced observer. Ileider observed a remarkable case, that of a woman who had several canine teeth in succession, which, to be sure, Avere stunted in their growth. Three months after he extracted the well- developed canine, which had become diseased, a hard body, resembling the latter, made its appearance in the upper part of the socket, upon the external surface of the gum. It was of the size of a rice-kernel, and its extremity Avas covered with enamel. About the same interval having elapsed after the extraction of the IRREGULARITIES OF NUMBER, 101 latter, a second, and finally a third appeared, so that in the course of a year three such canines, each provided Avith its root, were extracted from this woman's jaw. When three, instead of two, bicuspids are met with, the supernumerary one gener- ally stands inside tlie dental range, towards the tongue, crowded into the space between the two normal bicuspids, so that to- gether they form an equilateral triangle. In rare cases, three bicuspids are met with on each side, but scarcely ever three in the upper and under jaw at the same time. Wisdom teeth are sometimes duplicated, one standing within, and the other without the dental range. The latter is always the supernumernry tooth, occurs upon the outer side of the one in the range, and generally has a much smaller crown and a stunted, roundish root. Super- numerary molars are extremely rare, and still more rare is their arrangement in the normal den- tal row, as in the case of a set, belonging to a negro, which, be- sides four molars in each maxil- lary segment, contained a supernumerary bicuspid, making altogether five teeth more than in the normal condition (Figs. 29 and 30). This case suggests further inquiry, whether super- numerary molars occur more frequently, and anomalies of posi- tion more rarely, and also whether the anterior segment formed by the inferior dental arch is more circular, and the jaws longer, in the negro than in the Caucasian race?t * Fig. 29. — Shows supernumerary molars in the upper jaw, from the skull of H negro (for the use of which the author is indebted to Prof. Langer). The set of teeth is remarkably well developed and regular. Behind the three large, well-developed molars, upon the right side, the wisdom tooth is placed in the dental range ; on the left side it has not yet protruded, but is imbedded in the tuberosity, and may bo seen in the opening made in the part. Two- thirds natural size. f J. Mummery (Transactions of the Odontological Society of Great Britain, New Series, vol. ii) ascertained that with the Ashantees, the 102 PATHOLOGY. An excess of normally-shaped milh teeth is occasioned, usually, by one or another supernumerary incisor. Fig. 30.* The second group of supernumerary teeth includes the so- called conical teeth, which can be ranked Avitli neither of the four kinds of teeth. They resemble most the canine teeth in form, though there is no danger of confounding the two. In most cases the crown, as well as the invariably single root, is conical, and the three dental tissues are well developed ; the inhabitants of Dahomy and a few neighboring tribes on the west coast of Africa, the dental arches are very wide, and adduced the frequent occurrence of supernumerary teeth among them as a noteworthy fact. He observed six cases, in each of which there was a fourth eztra molar in the upper jaw, in five of the cases on both sides, and in the other on one side; three cases of an extra third upper bicuspid on one side; an extra upper canine tooth in a regular position on each side, and an extra well-developed right upper central incisor. In the under jaw he did not meet with a single example of a supernumerary tooth, but the third molars were frequently larger than the second. * Fio. 30 shows three supernumerary teeth in the lower jaw, from the same negro's skull. The arrangement of the dental row is regular. On the left side, and lingual surface, between the two bicuspids, lies a supernumerary bicuspid, which is twisted so that its lingual coronal surface is turned towards the median line of the jaw. The wisdom teeth on both sides are located behind the three large molars. Two-thirds natural size. IRREGULARITIES OF NUMBER. 103 Fig. 31. t exposed upper surface is encircled, sometimes, by transverse grooves; the pulp-cavity is elongated into a single dental canal. In rare cases the crown is three-sided, resembling a pyramid, in ■which cases the root, also, presents similar surfaces, but the planes of the coronal surfaces correspond to the edges of the roots (Atlas, Fig. 1).* Sometimes these teeth are disproportionately short and thick, but ordinarily they are slender, and present many variations in respect of size. Their locality is variable ; they are placed either among the permanent teeth in the dental range, or, as is generally the case, stand upon one side of the latter. They are found implanted between the central upper incisors (Fig. 31), or between the upper centrals and laterals, frequently be- hind the centrals or laterals, or in pairs on the palatal por- tion of the upper jaw, and also at the side of the bicus- pids or molars in both the upper and lower jaws. They seem never to occur in the vicinity of the lower incisors. Their eruption takes place during the first or second dentition, or in the interval between the two. J. Tomes reports two cases, which occurred in his practice, of supernumerary conical teeth * Fox, Nat. Hist, of tins Human Teeth, p. 69, with instructive illustrations. t Fig. 31 shows a supernumerary tooth situated at the right side of the median line and between the central incisors of the upper jaw. It has a conical crown, is well covered with enamel, and somewhat worn away trans- versely at the extremity. The incisors upon the right side slightly overlap, while those upon the left side stand within the dental range. The right segment of the dental arch extends about three millimetres more posteriorly than the left, on account of the insertion of the supernumerary tooth. The latter probably emerged sooner than the right incisors, and produced only a slight variation in the dental arrangement, on account of the breadth of the maxillary arch. Two-thirds natural size. (The author is indebted to Prof. Langer for the use of this specimen.) 104 PATHOLOGY. in children five years of age. In most cases, however, they belong to the second dentition, and are permanent. The ques- tion as to whether they are secondary developments from the germs of milk or permanent teeth may be answered negatively, inasmuch as they differ in shape from normal teeth. Reasoning from the latter point of view, it is more probable that they are independent dental germs, products of the superficial mucous membrane, and do not originate, like the permanent teeth, from secondary germs. As their eruption is coincident, generally, with that of the per- manent teeth, they are more likely to interfere with the regular arrangement of the latter when the maxillary arch is too narrow or too short, and are the origin of a variety of anomalies in the position of teeth. As they occasion a disfigurement, and inter- fere with articulation when they are situated in the palate, in which case also the tongue is especially liable to injury, further, as they favor the occurrence of caries when they are placed by the side of bicuspids or molars, and, finally, as they are of no particular service, if allowed to remain, it is customary to ex- tract them. A thorough acquaintance with them, therefore, is indispensable to the practitioner. In cases where the super- numerary teeth are well arranged in the dental row between the central incisors, or occupy the position of lateral incisors, it is the common practice to allow them to remain, since in the former case a disfiguring oblique position of the permanent teeth is to be anticipated under any circumstances, and in the latter it can- not be expected that the sockets of the supernumerary teeth will be filled up by a lateral displacement of the remaining teeth. The treatment is to be determined only by a careful considera- tion of the circumstances in each case. The extraction of such teeth from their alveoli is attended with no difiiculty, on account of the favorable form of their roots, but the adaptation of the forceps is sometimes interfered with in certain localities. Deficiency of Teeth. — Cases of the absence of all the perma- nent teeth certainly are very rare. Linderer* reported the case * Zahnlieilkuiule, p. 137. IRREGULARITIES OF NUMBER. 105 of a woman fifty years of age, who never had any teeth. The examination of her mouth gave no grounds for doubting the truth of her assertion. J. Tomes* relates one or two simihir cases, though in his practice he has never met with a person who did not present some indication of second teeth. Carabelli,t also, never observed such a case ; and he asserts that the entire absence is an improbable, though not an impossible occurrence. Heider, in the course of twenty-three j^ears, never met with an instance of total deficiency. Sometimes, though rarely, very inanij of the permanent teeth are wanting, the wdiole set containing but a few teeth. Such cases now and then come under the observation of extensive practitioners and are referred to in nearly all the larger works on dentistry. Fox saw a young woman about twenty years of age, who retained the central milk incisors of the under jaw and, in the upper jaw, all the milk incisors except one lateral, which had fallen out. He also relates a case in which there were only four teeth in each jaw, and still another, in which there was but one incisor in the upper jaw. J. Tomes relates an instance where there was one molar on each side of the upper and lower jaw. These four molars, together with four incisors, two in each jaw, composed all the permanent teeth. It is a curious fact that the milk teeth presented no peculiarities in regard to their number, or the time at which they were shed, according to the statements of the patient and his friends. The absence of single permatient teeth is not of rare occur- rence. The utmost caution is requisite in judging in a given case, whether a tooth is wanting naturally or has been detached, since the statements of patients are exceedingly untrustworthy; sometimes they cannot remember wdiich teeth, if any, have been extracted. A thorough examination of the teeth, which remain, of the sockets and jaws, is necessary before coming to a decision. Especial attention should also be given to the fact whether such defects are hereditary or not, for it often happens that the same tooth is deficient M'ith several members of the same family. Individuals are met with, now and then, wdio have only one * Op. cit., p. 206. t Anatomie des Mundes, p. 127. 106 PATHOLOaY. large incisor in the upper jaw, Avliich mars considerably the sym- metry of the dental range. When this is seen, it may be as- sumed, almost with certainty, that the second incisor, now missing, formerly stood in its place, and was lost by a blow, fall, &c., soon after it was cut. Heider mentions a case which occurred in his practice, where a surgeon, after extracting an upper cential milk incisor, the root of which was entirely ab- sorbed, mistook the projecting extremity of the permanent in- cisor for the broken root, seized it, and consequently extracted the entire immature, secondary tooth. Afterwards the parents brought the latter secondary tooth to him, to be replaced in the child's jaw, but this, of course, was impracticable, with the root only half developed. Many similar mistakes are liable to be made with the rest of the milk teeth, and the fact that these pass unnoticed in so many cases, accounts for the frequent deficiency in the number of the secondary teeth, particularly when it is considered that the gaps which remain after the extraction of teeth at such an early age are entirely effaced by the approximation of the suc- ceeding teeth, so that the dental range presents a complete ap- pearance, and, in such cases, many are entirely ignorant of the fact of the loss of a tooth, thinking nature failed to produce a secondary tooth. In many cases the lateral incisors are wanting upon one side only, but a deficiency upon both sides is of more common occur- rence. Of the canines, sometimes one is absent in the upper or under jaw, or both are wanting and, almost always, are concealed within the jaw, as in the case, Atlas, Fig. 4. Sometimes only one bicuspid is present upon one or both sides, and generally that is the first ; the second bicuspid is often absent, but usually it is concealed in the jaw, its eruption being prevented by Avant of space, since it is obliged to emerge between the first bicus- pid and first molar. As is well known, sometimes the upper, and, at others, tlie under wisdom tooth is out of sight entirely, perhaps on account of the non-formation of the germs, or, it may be that they, lie imbedded in the jaw and are prevented from emerging in consequence of want of space, which latter is fre- IRREGULARITIES OF NUMBER. 107 quently the case with the lower wisdom teeth, on account of the marked projection of the coronoid process in front. The inspection of the rehations of the locality and thorough examination of the neighboring sockets and portions of the jaw w^ill indicate whether disproportion of space hinders the develop- ment of the tooth, or whether the latter is actually wantino-. By a careful examination of the jaw with the finger, the bulging corresponding with the location of the concealed tooth may frequently be felt distinctly, and often furnishes presumptive evidence in regard to the position of the latter. Operative in- terference should very seldom be decided upon at once ; an attempt should not be made to provide room by the removal of permanent or milk teeth which stand in the way, until, after repeated examinations, there remains no doubt about the exist- ence of a concealed tooth, the position and development of which may be assumed to be normal, with a considerable degree of probability, upon the ground of the prominent bulging of the jaw which has been mentioned. The absence of all the milk teeth is allowed to be an occur- rence of extreme rarity. J. Tomes* has never had the oppor- tunity of examining such a case, either in a living subject or in a prepared specimen. He was informed, recently, by a gentle- man, that a member of his family, a female about fifteen years of age, had been from the time of her birth, and was then, en- tirely edentulous, and that the lower part of her face preserved the appearance usually presented by a child before the eruption of the teeth. A diminution in the ordinary number of milk teeth is not so rare ; generally in such cases the lateral incisors are absent. In regard to this anomaly, however, it is to be borne in mind that the deficiency of one or another tooth may only be appar- ent, since, in consequence of the contracted space their erup- tion may be utterly impossible, or else they can emerge only partially. Suppuration of a dental sac or alveolus, which occurs in scrofulous children particularly, involves, of course, the de- struction of the corresponding tooth, and deserves mention in connection with the subject of the deficiency of teeth. * Op. cit , p. 39. 108 pathology. 3. Irregularities of Arrangement. A. Irregularities in the Arrangement of the Entire Dental Archf'S. — In the deviations of the set from the normal position, ■which occur in the Caucasian races, either the upper or the loAver jaw, or both together, are more or less elongated ante- riorly ; their alveolar processes describe an unusually broad or narrow, oval or circular arch ; the undulatory curves of the dental arches are more shallow or deeper than is the case ordi- narily; the six anterior sockets of one or both jaws are more everted or inverted ; the teeth, implanted in these sockets, have very long or short, broad or narrow crowns, and the latter are ■well or badly arranged ; the dental arch presents an abnormal internal or external curvature, together with a frequent Avant of symmetry between the two halves of the jaw ; the molars pre- sent an excessive mesial or lateral inclination, and the ascending ramus of the lower jaw is too short or too long. These exam- ples of the principal irregularities which occur in the position of sets of teeth, give rise also to various deviations from the normal conformation of the mouth. a. Sometimes all the incisors and canine teeth, particularly those in the under jaw, instead of being arranged side by side, in the form of an arch, are placed in a straight line so that the canine teeth meet the bicuspids nearl}^ at right angles. The lower half of the face thus loses its oval curve, becomes broader, and gives rise to the flat mouth. A less degree of this irregu- larity is produced very frequently by a slight overlapping of the crowns of the lower incisors. b. If the middle portions of the two alveolar arches project forwards considerably, and, at the same time, are everted, then the canine teeth and incisors, implanted in these portions, will also project obliquely forwards, and this gives rise to the so- called negro mouth (os gethiopum). As, with this irregularity, the front teeth in closing come together obliquely, or not at all, the pressure and counterpressure necessary for their fixation cannot take place, and consequently such teeth emerge gradu- ally from their cells, appear to grow longer, and finally fall out much earlier than others. IRREGULARITIES OF ARRANGEMENT. 109 c. The alveolar process of the upper jaw is often unusually deep and very prominent; the teeth implanted in it being very long and generally broad, the incisors and canines are pushed outward so far, that between them and the under teeth there is left a vacant space, in some cases five or six lines in width; frequently the palatal arch forms a sharp curve and is narrow, and the upper bicuspids and molars are everted, al- though to a less degree than the front teeth, so that merely their internal coronal cusps and the outer coronal edo;es of the corresponding under teeth come in contact; in these cases, the labial fissure is wide and the upper lip usually very short ; the inferior maxillary arch presents a contracted appearance ; when the mouth is closed, the lower lip lies behind the upper front teeth, and the lower incisors impinge upon the posterior gingival portions of the upper teeth. As with such an arrangement of the dental arches, and such a misshaped mouth, a person ex- poses nearly all the upper teeth, together with the anterior por- tion of the upper gum, especially in speaking and laughing, this deformity is usually call the grinning mouth (Fletschenmund). J. Tomes* calls attention to the fact that, in most of these cases, the molars are unusually short, and finds that there is a short alveolar process, and a short rectangular ascending ramus of the lower jaw. This conformation he regards as probably the primary cause of this deformity. G. Prochaska,f in a skull presenting an irregularity in the position of the teeth, in Avhich the lower incisors stood three lines behind the upper ones, when the jaws were approximated, observed that the convexity of the superior alveolar arch, in comparison with that of the under jaw, was unusually great. d. Sometimes the lower incisors and canine teeth are half an inch in advance of the corresponding teeth of tlie upper jaw, and, in such cases, the crowns of the lower front teeth fre- quently are so deep as entirely to conceal the upper incisors, when the jaws are closed. The prominent under lip oveidaps the contracted upper one, and the chin is thrown forwards. * Op. cit., p. 124. f Observ. Anat. de Decremento Dentiura, 1800. 110 PATHOLOGY. This deformity is produced by a want of relationship between the superior maxillary arch, which is shorter, and the inferior, which is longer, than in the normal condition, and by an exces- sive development of the alveolar portion of the lower jaw. According to Gynnel, a natural, partial luxation, which takes place at the articulation of the lower jaw, is also to be taken into account, as contributing to its production. The deformity of the mouth which it occasions is called " underhung " (das Hundemaul) (la ganache of the French). e. AVhen the six upper front teeth are placed directly over the lower ones, so that their respective incisive margins meet edge to edge, there results the so-called upriglit set, one of the most frequent irregularities, and accompanied, usually, by the flat mouth. This position of the teeth is very favorable for masti- cation, for, in biting, the teeth act in a perpendicular line and become firmly pressed into their sockets, and the masticating surfaces operate to the best advantage, while the teeth are not so likely to be loosened as is the case when the front teeth are everted ; on the other hand, they are subjected to more Avear from attrition, so that the incisive edges and points become transformed into small masticating surfaces. /. Another irregularity of the dental arches occurs when the incisive margins of the front teeth meet edge to edge, but both the upper and under incisors are inverted, producing a sort of channel, opening outwards, where the dental arches are in con- tact. In these cases, the chin projects very much, and the lips are considerably retracted. The mouth shaped by this irregu- larity is called, from its resemblance to that of an old person, the Seville mouth (os senile). g. Cases in which the mouth remains open continually, in which the sets of teeth stand apart, form a very disagreeable and trou- blesome deformit3^ Many people cannot bring together the anterior portions of the two rows of teeth, so that between the upper and under incisors there remains a space from two to ten millimetres in width. This space, between the two rows of teeth, gradually becomes smaller from before backwards, as far as the second molars, the masticating surfaces of the latter being partly, while those of the wisdom teeth are wholly in contact IRREGULARITIES OF ARRANGEMENT. Ill with those of the opposite teeth. This repulsive arrangement of the two dental arches is due, generally, to a short articular process of the lower jaw, as a result of which the anterior seg- ment of the inferior maxillary arch and the chin assume an unusually depressed position. Less frequently, the reason may be found in an irregular conformation of the alveolar process, the posterior alveoli of which are much higher, in- stead of lower, than the anterior ones. Still more rarely is it due to a curve or an oblique direction of the lower jaw from behind forwards and dowuAvards. It might be attempted also to refer this deformity to the crowns of the last molars, but as the latter are always found unusually low, it is evident that the evil will not be remedied by filing or by extracting them. h. C. Langer* mentions a form of want of relationship between the dental rows which occur in giants ; the jaws are developed in height nearly in proportion to the rest of the body, and the size and shape of the lower jaw, especially, assume really mon- strous proportions, the latter exceeding in its development that of the upper jaw to such an extent that its dental row frequently forms a Avide arch which envelops that of the latter. The smaller the cranium so much the more marked is this monstrosity of the under jaw. i. In cases of asymmetrical development of the two halves of the same jaw, the set of teeth presents a distorted appear- ance, and projects more or less, either obliquely upwards or downwards upon one side or the other. To recapitulate, the irregular (abnormal) sets comprise, a, those Avhich are flattened in front ; h, those in which both the upper and lower ranges project ; c, those in which the upper row is most prominent; f?, those in which the lower is most prominent; e, the upright sets ; /, those in which both rows are inverted ; g, those in which the two rows are separated in front ; 7i, those in which the lower row is too broad; i, the distorted sets. These include the principal forms, between which innu- merable varieties may occur. The latter are the more frequent, since complex cases occur so often, Avhich combine irregularities in the position of the entire set with those of separate teeth, * Sitzungsber. der Wiener Akad. d. Wiss. vom, 1 Juii, 1869. 112 PATHOLOGY. B. Irregularities in the Position of the separate Permanent Teeth. — The irregularities in the position of separate teeth may arise from several causes : 1. From the growth of the jaws being absolutely insufficient in proportion to the space required in the maxillary segments for the corresponding teeth. It has been shown in connection with the growth of the jaws, that the an- terior portions of the maxillary arches grow comparatively less than the branches upon either side, subsequent to the eruption of the milk teeth, and, therefore, it is easy to understand that irregularities in the position of the anterior permanent teeth are of more frequent occurrence; 2. From a disproportion be- tween the very wide maxillary segment and the small crowns of the teeth ; 3. From an interruption in the process of shedding the teeth ; when a milk tooth is retained, the corresponding per- manent tooth is forced to take another position ; 4. From an irregularity in the process of shedding the teeth, that is, when one or another tooth is shed and replaced prematurely, the adja- cent secondary tooth is compelled to adopt another position; 5. From the early removal of a permanent tooth, in which case the socket cicatrizes and, consequently, the adjacent permanent tooth, which has not yet emerged, is compelled to assume an- other position ; 6. From the existence of an unabsorbed alveolar cicatrix, resulting from the premature shedding or extraction of a milk tooth, which forces the secondary tooth to take another position ; 7. From an anomalous position of the milk tooth, which necessitates an irregular position of the permanent tooth ; 8. From the partial or complete occupation of the place of a per- manent by a supernumerary tooth ; 9. From an exostosis upon the alveolar process, especially upon its posterior segment ; 10. From abscesses of the alveoli of the milk teeth ; 11. From the presence of tumors within the jaws, collections of pus, kc. Commonly the following irregularities are presented : The long diameter of the tooth is inclined too much externally or internally towards the median line of the jaw or laterally, and frequently, if there is sufficient space to allow it, the tooth assumes a nearly horizontal position. The tooth may undergo a quarter or half revolution upon its long axis. The intervals between certain teeth and the adjacent ones may either be too IRREGULARITIES OF ARRANGEMENT. 113 ■wide or too narrow, and in the latter case the teeth sometimes partially overlap their neighbors either upon the facial or lin- gual surfaces. Central Incisors. — A slight degree of irregularity in position is presented by an unusually wide separation of the adjacent teeth, which occurs less frequently with the lower incisors. These large intervals, which frequently amount to a deformity, in many cases are occasioned by the protracted retention of a large milk incisor, which prevents the normal emergence and approximation of the two permanent incisors. Generally, how- ever, they are due to the firmness of the suture which unites the two segments of the upper jaw. Twisting of the central incisors upon their axes is by no means of rare occurrence. This Fig. 32.* may take place in the direction of the median line or laterally, to various degrees, 45°, 90°, and, in rare cases, even 180°. Ac- cording to the manner and extent of the revolution, the labial sur- face becomes turned towards the adjacent central or lateral incisor, and, in rare cases, it is changed so as to look towards the tongue. The torsion is generally lim- ited to one central incisor, but instances are recorded in which each has experienced a twisting upon its axis (Fig. 32). By a lateral inclination of the central incisors the crowns fre- quently overlap. Sometimes the central incisors are inserted more or less towards the hard palate, or the lips. In many cases one of them stands outside the range anteriorly, and the other * Fig. 32 shows a twisting of both central upper incisors, occasioned, probably, by a hyperostosis in the palatal suture. The labial surfaces of both pormaiient central incisors are turned laterally, the lingual towards the median line ; the lateral milk incisors are twisted laterally at an angle of nearly 45° ; the milk molars are in their normal positions ; the first permanent tooth has emerged. The maxillary arch is narrow. Natural size. (From a plaster cast, for the use of which the author is indebted to Prof. Strasky.) 114 PATHOLOGY. posteriorly, so that the loAver incisors are inserted between the two -when the jaws are closed. The upper incisors are frequently inclined posteriorly. The causes of these mal-positions are numerous. The reten- tion of the central milk incisor or its root, the premature ap- pearance of the lateral perma- nent incisor, which offers an im- pediment to the growing tooth, 1 or perhaps an arrest of develop- J ment in the corresponding por- j I I L-^juiiA-iic^ tion of the jaw, or a super- ^^ ^^ numerary tooth (Fig. 33), may be cited as predisposing causes. As the tooth during its growth must adapt itself to the space provided for it, so does its eruption ensue regularly, or a mal- position occur in accordance with the dimensions of the space it is to occupy. Lateral Incisors. — The axial torsions of these teeth occur almost always in such a manner that their labial surfaces are turned, to a slight degree only, towards the median line of the jaw, or laterally, and consequently are overlapped by, or them- selves overlap, the lateral borders of the central incisors. The torsion may amount to 90°, and in rare cases it reaches 180°. The lower laterals are more frequently the subjects of slight rotations than the upper ones. When the latter are in- volved, their axes are directed towards the canine teeth or the ' central incisors. It frequently happens that they are implanted * Fig. 33 shows a displacement of the upper front teeth on the right side, produced by a supernumerary tooth. The front teeth upon the left side of the broad upper jaw were quite normally arranged, while upon the right side a conical supernumerary tooth (a) occurred within the dental range, adjacent to the left central incisor ; this pressed the right central in- cisor [b) forwards and upwards. The lateral incisor (c) is twisted upon its axis, so that its labial surface is turned laterally. The milk canine tooth {d) is retained, and the permanent one [e) is implanted without the dental range, toward the face. Natural size. (From a plaster cast, for the use of which the author is indebted to Prof. Strasky.) IRREGULARITIES OF ARRANGEMENT. 115 Fig. 34 * at the side of the dental range, either upon the facial or lingual side, the latter nial-position being most marked in narrow wedge-shaped upper jaws. In the latter, which couinionly are asymmetrical, the lin- gual surfaces of the central incisors face each other, and the lateral in- cisors are implanted behind the den- tal range at a greater or less dis- tance from the palatal suture (Fig. 34). Marked mal-positions of the front teeth are produced very often by the presence of supernumerary teeth in the anterior portion of the upper jaw, since the latter are the first to make their appearance and interfere with the eruption of the nor- mal teeth (Fig. 35). In the under jaw it is not uncommon to find the lateral incisors implanted upon the lingual side of the dental range; sometimes they stand directly behind the central incisors (Atlas, Fig. 138), and Fig. 35.t * Fig. 34. — A wedge-shaped narrow upper jaw of a young person, in which both lateral incisors have emerged upon the lingual side of the dental range, in consequence, perhaps, of some interruption in the development of the jaw, or, it may be, from the protracted retention of the lateral milk in- cisors. The right milk canine tooth has fallen out. (From a plaster cast.) Two-thirds natural size. f Fig. 35 shows an asymmetrical conformation of the upper jaw in which two supernumerary teeth are implanted behind the displaced incisors. The right nuixillary wall bulges forwards in front, and, between the first molar («) and the second bicuspid (6), presents a flexion towards the median line. A deviation of the dental arch, therefore, occurs at this point, and the front teeth on this side, the canine (c) and the laterally twisted lateral in- cisor, stand in a straight line. The central incisor, upon the right side (e), which has not emerged completely, is located upon the median line. The 116 PATHOLOGY. Fl'i. -Mk* at other times they present a combination of axial torsion and mesial or lateral inclination (Fig. 36). Probably the most frequent predisposing causes of these irregularities of position are to be found in the development of the osseous tissue in the anterior seg- ment of the jaw, which may be too slow to correspond with the growth "^ of the permanent teeth, or may be arrested, or abnormal in its dimen- sions. The developing crowns will be found, even within the dental sacs, in abnormal positions. A protracted retention of the lateral milk incisors or canine teeth, or the premature cutting of the permanent canines, may occasion irregularities, and the latter may crowd the lateral incisors, before they are properly and firmly fixed, towards the median line of the jaw, or towards the tongue, and sometimes may even occasion resorption of the extremities of the roots of the latter teeth. If the canine tooth emerges upon the lingual side of the dental range, it may press the lateral incisor towards the lips. Canine Teeth. — Irregularity in the position of these, especi- ally of the upper ones, occurs frequently ; they are situated more or less without the dental range and overlap the lateral in- cisor or first bicuspid, either upon the facial, or, more rarely, left central incisor is implanted upon the left side, and the left lateral incisor upon the lingual side of the left canine tooth (/). (From a plaster cast.) Two-thirds natural size. * Fig. 36. — Anterior segment of the lower jaw. View from the lingual side. The two lateral incisors are implanted behind the centrals, are twisted and inclined towards the median line of the jaw, and, together with the centrals which are inclined laterally and considerably ■worn away upon their coronal edges, inclose a quadrilateral space. As the lateral incisors are implanted behind the dental range, and their edges are below the level of the masticating teeth, they have not been emploj'ed in mastication and, indeed, do not in the least present any indications of abrasion. These irreg- ularities of position were produced by an interrupted development of the jaw and, perhaps, a premature eruption of the canine teeth, which are very much worn away upon their coronal extremities. Natural size. IRREGULARITIES OF ARRANGEMENT. 117 upon the lingual surface. In the latter case, after the complete emergence of the crown of the canine tooth, there occurs an outward displacement of the lateral incisor or first bicuspid. The inclination of the axes of the canines usually is tow'ards the median line of the jaw. They are frequently twisted upon their axes to a slight degree and, in rare cases, present quarter and half revolutions. A quarter revolution of the crown, be- fore it has cut through the gum or before the formation of the root is completed, may prevent the eruption of the tooth, since the facio-lingual diameter of the crown in this position is rela- tively too great to enter between the lateral incisor and first bicuspid. The canine tooth, therefore, remains concealed , ^^^'" ^'* ' b a within the jaw, on account of its abnormal torsion. Some- times the canine tooth aban- dons its proper place entirely, and is found by the side of the central incisor (Fig. 37), in which case the lateral incisor is located either upon the lin- gual or lateral side of the displaced canine tooth, rarely, the canine tooth is inserted between the two bicuspids. "f The frequent irregularities in the position of canine teeth may readily be explained when we consider that their normal eruption is provided for by the vacant spaces which remain Much more * Fig. 37 shows a displacement of the upper left canine («) to the side of the central incisor. Posterior to the former is an alveolar cicatrix, prob- ably the remains of the socket of the lateral incisor which emerged subse- quently to the canine. Upon the right side, the canine occupies its normal position ; the lateral incisor (&) is stunted ; the bicuspids upon either side retain their normal positions. IS'atural size. (For the use of this specimen the author is indebted to Dr. Friedlowski.) ■j- The museum of the Harvard Dental School contains a cast taken from the mouth of a young woman, in which the left inferior lateral incisor and canine are transposed, the canine being turned so that its labial surface is presented towards the central incisor and the median line, while its lingual surface is presented towards the lateral incisor and backwards. Another cast of the lower jaw of a person about sixteen years of age pre- sents the canines between the second bicuspids and first molars. — T. B. H. 118 PATHOLOGY. Fig. 38.* — 6 between the first bicuspids and lateral incisors, after the latter have already assumed their positions, and that these spaces are too narrow when the growth of the jaw in length is sus- pended. A premature or de- layed eruption of the perma- nent canines, a protracted re- tention of the milk canines, sometimes even to the third decade of life, or the inser- tion of a supernumerary tooth in the dental range, may also give rise to these displace- ments (Fig. 38). Bicuspids and Molars. — The first bicuspids seldom, the second more frequently, are met with without the dental range and generally in the so-called small or anterior oval cavity. A prem- ature loss of the second milk molar promotes the advance of the first permanent molar, in consequence of which the second permanent bicuspid is forced to emerge either upon the facial or lingual side of the dental range. In many cases, one or both bicuspids are twisted in such a manner that their cusps become located anteriorly and posteriorly, instead of externally and internally (Fig. 39). Insufficient space is, almost always, the predisposing cause. * Fig. 38 shows displacement of both canines produced by the reten- tion of the milk canines, and by the presence of a supez'numerary tooth. The upper jaw is broad and has an irregular conformation. The central in- cisors are slightly inclined to the left side, where the milk canine [a), worn away by attrition, is seen, adjacent to the central incisor, while the lateral is located upon the lingual surface behind the milk canine ; the permanent canine (b) is in the dental range, in front of the first bicuspid. Upon the right side, the lateral incisor is in the dental range ; the permanent canine (c) is inserted without the dental range, towards the face; the milk canine, the crown of which is considerably worn away, is crowded towards the tongue. Between the canine and the first bicuspid, on either side, is a supernumerary tooth (rf), the crown of which is very much worn away. Behind the central incisors are seen lunated folds of mucous membrane. Two-thirds natural size. (From a plaster cast, for the use of which the author is indebted to Prof. Strasky.) IRREGULARITIES OF ARRANGEMENT. 119 Fig. 3!>.t An axial revolution of 180° is extremely rare. AVerner* states that in those cases, in which the milk molars are retained with the permanent bicuspids, the latter assume an oblique position. J. Tomes observed a dis- placement of the bicuspids, resulting from caries of the milk molars, which was followed by an alveolar abscess, and also axial rotations of the second bicuspids, occasioned by the retention of the palatal root of the second milk molar. The lower bicuspids sometimes stand so far opart, in consequence of the great abundance of room, that a person unacquainted with the true condi- tion will be convinced either that teeth existed previously, or are to appear, in this interspace. The notable derangement which supernumerary teeth occasion in the position of the nor- mal teeth, when they occur in the anterior segments of the jaws, may also extend so far as to involve the bi- cuspids, particularly the « second, which generally in such cases are implanted towards the tongue (Fig. 40). Fig. 40.t * Anomalien der Zahnstellung. Inauguraldissertation, Giessen, 1868. f Fig. 39 shows a segment of the right half of the upper jaw. The two bicuspids are placed close to one another with their facial surfaces twisted posteriori}' about 90° ; the first is crowded somewhat externally, and is in contact with the second, which is pressed slightly towards the tongue. Natural size. J Fig. 40 shows marked displacement of the upper incisors, canines, and bicuspids, occasioned by two large supernumeriiry teeth. The two central incisors are implanted upon the lingual side of the dental range, the left slightly overlapping the right in front; the left lateral incisor (a) is located outside the dental range towards the face; behind the right lateral (b) is located the first bicuspid. Two conical supernumerary teeth (c) and (d), which are worn away upon the crowns, have emerged on the side towards the lips. The first bicuspid on the right side (e) is twisted several degrees towards the median line of the jaw, the second is inserted upon the lingual 120 PATHOLOGY. An arrest of development in the posterior segments of the jaws sometimes occasions a displace- ment of the three molars, by which they are inserted so as to form a triangle. Wisdom teeth, especially those in the under jaw, when their roots are imbedded in the coronoid process, not infrequently are in- clined anteriorly to a considerable degree towards the second molars, with the posterior coronal surfaces of which their masticating surfaces come in contact. Frequently their crowns present a lingual, and, more rarely, a facial inclination. In the upper jaw, the wisdom teeth are inserted sometimes high up towards the tuberosity, 'and the masticating surfaces may even face posteriorly. Slight displacements of these teeth with- out the dental range, generally to the lingual side, are of fre- quent occurrence. Marked irregularities in the position of the molars, accom- panied, at times, by deformity of the upper jaw, are produced by a hyperostosis upon the alveolar process (Fig. 41). f side of the dental range. Upon the left side, the bicuspids are separated somewhat from each other by an angular interval which opens externally, and in which projects the coronal portion (/) of the canine tooth. Two-thirds natural size. (From a plaster cast, for the use of which the author is in- debted to Prof. Strasky.) * Fig. 41 shows a narrow upper jaw, as if compressed from side to side. Plaster cast. The six front teeth, with the exception of the left lateral inci- sor which is implanted upon the lingual side of the dental range, are ranged in contiguity so as to form a very narrow arch, the arms of which are nearly parallel to each other. Three molars present a curved arrangement forwards and outwards. The extremity only of the crown of the first right molar (?) has emerged. Distinct folds of the mucous membrane are perceptible, and also hyperostoses on the lingual aspect of the posterior segments of the al- veolar process, which diminish the breadth of the channel-like cavity formed by the high arch of the hard palate. Two-thirds natural size. •f In the Dental Review (1859), a curious instance is mentioned of the mal- position of a wisdom tooth between the upper incisors. A. zur Nedden (Deutsche Viertelj. f. Z., 18G8), obtained a plaster cast of an upper jaw in IRREGULARITIES OF ARRANGEMENT. 121 Irregularities in the Position of Milk Teeth. — The milk teeth are very rarely met with without the dental range, and only in those cases in which all the milk teeth are very large, when, in consequence of a deficiency of space, the incisors overlap. In many cases the sharp edges of the upper incisors are inclined very much towards the tongue, and the canines, uncommonly long and pointed, are crowded towards the face. In extremely rachitic individuals, abnormal positions of milk teeth are frequently met with, since in these cases the growth of the jaws in length is retarded by a hj'perplasia of the con- nective tissue in the bone (Atlas, Figs. 144 and 145). In the latter case, moreover, it is to be observed that, although the process of decalcification has made such progress in the bony structure that the latter has become flexible and may be cut with a knife, it has not in the least affected the crowns and the growing roots of the teeth. The development of the tooth, there- fore, continues, notwithstanding the notable interruption to the growth of the bone. If the rachitis does not become very de- cided until after the milk teeth are cut, then the permanent teeth, still inclosed in the dental sacs, may be displaced from their normal positions. Abscesses of the periosteum of the root, which occur particu- larly in scrofulous children and sometimes after cutaneous erup- tions, may produce considerable destruction of the bone, dis- which a molar occupied the place of a central incisor, neither of the normal incisors being present. All teeth which are inserted upon one side of the dental range, or overlap the anterior or posterior contiguous teeth either upon the facial or lingual surface, are very liable to be atfected with caries, because, even with the utmost cleanliness, the particles of food cannot be removed entirely from the intervals between the teeth. Moreover, it is a very difficult matter to apply to them the ordinary methods of treatment, for a tooth, which is in- serted externally, cannot be reached upon the inside, and one situated inter- nally cannot be reached upon the outside, on account of the close proximity of the adjacent tooth. Therefore they require peculiar and extremely diffi- cult methods of treatment. When a bicuspid is twisted to the amount of 90°, the operative treatment is attended with still greater difficulties, because the surfaces of its roots are directed outwards and inwards, and consequently offer greater resistance by reason of their more numerous points of contact with the walls of the alveolar process; 122 PATHOLOGY. placements and partial destruction of the milk or permanent teeth, which are still inclosed in the dental sac. C. Irregularities in the Position of Separate Permanent Teeth which are Imbedded ivitlnn the Jaw. — It sometimes hap- pens that a tooth, during its development, acquires a more or less inclined or horizontal position, and consequently, when its development is completed, projects but little, if anj, beyond the alveolar wall. The causes of these extremely curious devia- tions of position can be ascertained only by a special anatomical examination of each individual case. As a general rule, it may be assumed that the change of position must occur prior to the development of the root. The growth of the latter, modified by the local relations, takes place in an opposite direction to that of the incisive margin or masticating surface of the tooth whose position is changed, i. e., if the masticating surface is inclined forwards, the root grows from before backwards. These irregu- larities include a great variety, and all the predisposing causes which have been mentioned previously are equally applicable to them. J. Tomes* illustrates a case in which the crown, as well as the root of the right central incisor, is imbedded in an oblique position within the bone, beneath the floor of the nasal cavity, its normal position being occupied by a supernumerary tooth, which, it is obvious, prevented the emergence of the incisor. Figs. 2 and 3 of the Atlas illustrate a case in which a well- formed lateral incisor occupies a horizontal position in the angle formed by the floor of the antrum and the nasal process of the upper jaw, its incisive edge projecting through an oval opening with smooth edges, at the side of the apertura pyriformis. The cause of this displacement is obvious in the presence of an irregu- larly formed tooth Avhich is inclosed in a smooth-walled osseous capsule, and projects near the edge of the alveolar process, and, perhaps, is the rudimentary lateral milk incisor, since its posi- tion is directly over that which a milk incisor should occupy ; or it may be the shapeless mass of a supernumerary tooth. The canine teeth, more frequently than any others, are the subjects of total displacement, a fact quite easily understood ; the upper canines are more frequently displaced than the lower, * System of Dental Surgery, p. 183. IRREGULARITIES OF ARRANGEMENT. 123 as the front teeth of the upper jaw require more space. Albinus* describes a case with a canine situated between the nasal cavity and the orbit on either side, whose crowns were directed upwards. J. Hunterf reports a similar case. Wait observed a case where the radical extremity of a canine pierced the gums externally. J. Tomes| gives a series of illustrations in which the permanent canine is displaced behind the dental range, the root being curved very much, or placed across the dental arch, with its apex directed towards the median line of the palate, its crown towards the cheek and projecting slightly, or in a horizontal position, with the coronal apex in front and the root extending posteriorly or into the floor of the nasal cavity. The succeeding series of figures will serve to illustrate the causes of partial or complete perma- nent embedment of the canine teeth within the jaw. In the case. Fig. 42, the retention of an upper milk canine occasioned a twisting of the croAvn of the permanent tooth, and forced it to assume an oblique position, pointing towards the median line, so that its eruption progressed to a slight degree «= " only behind the dental range. In the under jaw similar conditions are met with. In Fig. 43 the retained milk canine tooth produced an axial revolution of the developing crown of the permanent canine, as in the pre- ceding case, and has inclined it towards the horizontal line, so * Adnot. Acad., i. f Nat. Hist, of Teeth. J Op. cit. § Fig. 42 shows the incomplete eruption, upon the palatal surface of the alveolar process, of the crown of the right upper canine which has an oblique direction towards the median line. (The specimen is from a young subject, and for the use of it the author is indebted to Dr. Friedlowsky.) The per- manent incisors and the temporary canine have been detached by maceration. The slightly projecting crown of the permanent canine tooth (a) has given rise to a sharp-edged opening, the result of absorption, upon the alveolar process, and, in the same manner, the corresponding portion of the alveolus of the lateral incisor (6), and also that of the milk canine (c), has been ab- sorbed. The first bicuspid was slightly twisted by the curved root of the permanent canine which is imbedded within the jaw. Natural size. 12-i PATHOLOGY. that its extremity only has emerged beneath the alveolar margin. A forward inclination and quarter revolution on the part of the first bicuspid may also produce an axial revolution of the growing canine, and entirely prevent its eruption (Fig. 44). Fig. 43.* Goethe observed! in an osteological preparation in the pos- session of Rapp, in Stuttgart, 1797, a total displacement of a bicuspid which was located in the nasal cavity beneath the margin of the orbit, its roots firmly attached to a small, round, plaited osseous mass ; it extended obliquely downwards and * Fig. 43 shows the anterior segment of the lower jaw in which the left canine tooth is placed horizontally beneath the alveolar margin. The coronal extremity has emerged upon the lingual wall of the lower jaw (a). The labial surface of the crown is upwards. The root is turned obliquely out- wards, projects beyond the labial wall of the jaw, and has given rise to re- sorption in the corresponding portion of the wall {b). A portion of the posterior wall of the alveolus of the left lateral incisor has been removed by resorption ; the superior circumference of the alveolus of the milk canine (c) is still well preserved. Natural size. f Fig. 44 shows a segment of the lower jaw from which a portion of the facial wall was removed in order to display the left canine and first bicuspid, which are not yet cut. The canine remains in a pez'pendicular position, and its radical extremity (a) reaches to the inferior border of the lower jaw; its labial surface is directed forwards and inwards, and its coronal and radical portions are in contact with the first bicuspid {b) which, also, is imbedded within the jaw, its internal coronal cusps alone being slightlj- exposed, and is inclined anteriorly and twisted on its axis to the extent of a quarter of a turn. Natural size, ■j Schweizerreise. IRREGULARITIES OF ARRANGEMENT. 125 backwards, and emerged from the palatal portion of the upper jaw behind the incisive canal, where its crown was but slightly exposed upon the surface of the palate. J. F. Meckel* met with an upper second bicuspid, the crown of which pointed directly upwards. The first bicuspid was detached at an early period, and there was a large gap between the canine and first molar. An abscess of the root- membrane of the first milk molar fig. 4.5.t may have given rise to the rota- __,^- j t^gf/ tion of 180°. A nearly hori- zontal position of the second left bicuspid in the upper jaw, as shown in Fig. 45, in all proba- f £ j,^ j^^,^,^ ,^^ bility was occasioned by an in- flammation of the periosteum of the root of the first molar, which was followed by a destruction of the corresponding portion of the alveolus and, without doubt, occurred at an early period while the process of shedding the milk molars and eruption of the bicuspids Avas in progress. The cicatrization, which encroached upon the territory of the second permanent bicuspid, may have been the cause of the deviation of its coronal portion, in consequence of which the masticating surface became directed backwards and slightly downwards. The tooth emerged in the gap in the dental row, while the growth of the radical portion took place in a direction forwards and a little upwards. By the removal of the alveolar wall it was ascertained, further, that the roots of the first and second bicuspids were not blended together, since their extremities had been kept apart by a thin osseous lamina. Abnormally short jaws sometimes contain several permanent teeth imbedded within them in irregular positions, w^hich do not * TabulsB Anat. Path. Fasc, iii. f Fig. 45. — Facial view of the left upper jaw. The second bicuspid has a nearly horizontal position, its masticating surface being directed towards the anterior facial roots of the second molar ; the crown and neck lie in the upper part of the alveolar process, within an excavation which probably resulted from an alveolar abscess of the first molar. Two-thirds natural size. (For the use of this specimen the author is indebted to Prof. Langer.) 126 PATHOLOGY. make their appearance until tlie occurrence of senile atrophy of the alveolar process, and then only partially emerge (Fig. 46). Fig. 40.* The ivudom teeth are more frequently the subjects of a total displacement. The reason for this is quite obvious, from the fact that they are the last to take their places in the dental series and therefore have reserved for them that space only which remains vacant at the posterior extremity of the jaw. In the upper jaw an axial displacement, by which the masticating surface becomes directed posteriorly, is the most frequent. If the coronal portion is bent from its normal position, so as to * Fig. 46 shows a bicuspid upon the right and left side imbedded within the short, distorted upper jaw of an old person. On the right side, behind the alveolus of the canine tooth (a), the alveolar process becomes prominent and presents two cavities, at the bottom of which are seen the two coronal cusps of a bicuspid (6), with the longitudinal groove between them extending from side to side. Finally, this segment of the jaw also presents the wisdom tooth imbedded within the maxillary tuberosity in a horizontal position, with its crown directed posteriorly and its roots inserted between those of the second molar, as may be seen upon the buccal surface of the maxillary wall. Upon the left side cicatrization has taken place in all the alveoli. The crown of the bicuspid, however, which is imbedded within the jaw in an oblique position, may be seen through the openings resulting from re- sorption in the bulging portion of the alveolar process, while its radical portion (c) forms an oblique projection upon the buccal surface of the jaw. The lower jaw corresponds to that of extreme old age and is edentulous, with the exception of one bicuspid. Natural size. (For the use of this specimen the author is indebted to Dr. Friedlowski.) IRREGULARITIES OF ARRANGEMENT. 127 describe an arc of 90°, the growth of the roots takes phice from behind forwards, in a more or less horizontal direction, and the latter come in contact Avith those of the second molar, some- times even blend with them, so that the second and third molars, by the coalescence of their roots, form an inseparable whole (Atlas, Figs. 18 and 19). If now the growth of the roots of the wisdom tooth continues from behind forwards, the croAvn neces- sarily emerges posteriorly and, consequently, induces a partial resorption, varying in extent, of the maxillary tuberosity of tlie upper jaw. The crown of the wisdom tooth may also be in- clined externally or internally, and the roots be pLaced across the jaw in a more or less horizontal position. The rotation sometimes amounts to 180°, so that the masticating surface is directed upwards and the roots downwards. In the lower jaAv, an inclination of the crowns of the wisdom teeth from behind forAvards, is most common, in Avhich cases the growth of the roots takes place in the ascending ramus. Wer- ner* also mentions cases which came under his observation where the lower wisdom tooth assumed a nearly horizontal position, the roots being inclined obliquely dowuAvards and backwards, and the crown forwards, so that only the posterior and upper portion of the crown was visible. Sometimes the germ of the coronal portion of this tooth is displaced so far posteriorly, that the crown of the tooth becomes imbedded within the ascending ramus of the lower jaw, reaching nearly to the level of the sig- moid notch. Finally, the crown of the wisdom tooth may be the subject of a rotation on its transverse axis to the extent of 180°, in which case the inverted crown is grasped by the roots of the second molar. f D. Retention of Teeth ivithout Displaceme7it. — Cases are fre- quently met Avith, Avhere completely developed permanent teeth remain during life, partially or entirely inclosed Avithin the jaAV, in the places where their development took place. The position of such teeth is not really anomalous, and becomes irregular * Op. cit. f Compare the instructive illustrations given by J. Tomes, op. cit., p. 192 et seq. 128 PATHOLOGY. only because it persists during the later periods of life. Those teeth are most frequently the subjects of this irregularity, which, as their growth continues, should occupy the spaces left vacant by the already developed adjacent teeth, namely, the canines and second bicuspids. The canine tooth, as we know, is obliged to insert itself between the permanent lateral incisor and first bi- cuspid, after the latter have taken their positions in the dental series, and the second bicuspid enters the interval left vacant between the first molar and the first permanent bicuspid which have already emerged. If, therefore, from any cause a dispro- portion exists between the above-mentioned intervals and the circumference of the crowns of the teeth which are to occupy them, the complete eruption of the canine or second bicuspid will be prevented partially or entirely. An instructive case is illustrated in the Atlas, Fig. 4, where both canine teeth are imbedded within the lower jaAv and are slightly twisted upon their axes, the right towards the lateral in- cisor and median line of the jaw, the left laterally towards the first bicuspid. The development of the radical extremities of both canines, in the direction of their long diameters, was possible only to a certain extent, and they are bent at nearly right angles, each in a difi"erent direction. The case, therefore, is quite com- plicated, as it illustrates not only a retention of both canines within the under jaw, but also an axial revolution and a deviation in the direction of growth of the radical extremities. The extent to which the incisors are worn away indicates that the specimen belonged to a person of advanced age, and so it may be assumed that, had all the adjacent teeth become detached and an atrophy of the alveolar process ensued, the coronal extremities of both the imbedded canines would have made their appearance. Pos- sibly the prolonged retention of the milk canines occasioned the axial revolution of the permanent teeth and, consecutively, pre- vented the eruption of the latter, but this point cannot be de- termined. Wisdom teeth, especially those of the under jaw, are most fre- quently subject to retention. The space necessary for their eruption in the maxillary arches, which so frequently do not grow to a suflScient length, is preoccupied by the teeth which IRREGULARITIES OF ARRANGEMENT. 129 have made their appearance, and, therefore, there is no room left for the wisdom teeth. Sometimes the upper second molar is' crowded so far backwards towards the tuberosity, that the fur- ther descent of the third becomes impossible. In the same way, the space in the lower jaw becomes diminished when the second molar is crowded close up to the ascending ramus. In addition to the disproportion between the lengths of the maxillary and dental arches, special causes, which are not readily distinguish- able, also occasion the retention of the wisdom teeth. Some- times, during the process of cicatrization which ensues after the detachment of the first upper molar, the second molar acquires a forward inclination which prevents the emergence of the wis- dom tooth, since the posterior external root of the former im- pinges upon and opposes the advance of the crown of the latter (Fig. 47). b Fig. 47.* Fig. 48.t Fig. 49.t * Fig. 47 show.s an obstacle to the descent of the right upper wisdom tooth, in a facial view of the posterior segment of the upper jaw. The first molar was detached some time previously ; the second is inclined anteriorly, and the extremity of the posterior facial root (a) has a corresponding deviation posteriorly, and presses against the descending masticating surface of the wisdom tooth, the facial surface of which {b) has been exposed by the removal of the alveolar wall. Two-thirds natural size. f Fig. 48 shows the union of the roots of the upper second molar on the leftside, with those of the wisdom tooth, as seen from the facial side. The posterior facial root of the second molar, which has been filed away to show the root canal, impinges upon the anterior facial root of the wisdom tooth, and is united to it hy means of cement; in the same manner, the lingual root of the second molar is united with the anterior facial root of the wisdom tooth by means of a quite thick layer of cement. These teeth were extracted on account of chronic inflammation of the root-membrane and suppuration of the gum. Natural size. (For the use of this specimen the author is indebted to Dr. Jurie Gustav.) J Fig. 49 shows a union of the posterior facial root of the upper second 9 130 PATHOLOGY. Sometimes a union of the roots of the second upper molar with those of the -wisdom tooth, also, prevents the descent of the latter. In such cases the wisdom teeth are found in a normal position, but are situated one centimetre higher than usual (Figs. 48 and 49). Teeth which are retained within the jaw frequently make their appearance unchanged in the later periods of life, when their emergence is promoted by the loss of the other teeth and by the changes which take place in the jaws in old age. People who are ignorant of this fact interpret the occurrence falsely as an evidence of remarkable vigor, when, in reality, it is only an indication of old age. These teeth always emerge very slowly, and are rarely of much value to the possessor. 4. Irregularities of Structure. These involve either all the teeth in common, or a part of them, most frequently, however, separate teeth or only their coronal or radical portions. In general terms, they comprise growth in an abnormal direction ; excessive, stunted, or arrested develop- ment of the dental tissues ; the coalescence of two dental germs and the blending of roots; monstrous malformations of the crowns and roots, and double malformations of the teeth. a. Flexions and Torsions of the Crowns and Roots. — In rare cases, teeth which have single roots are bent at right or more obtuse angles in the coronal portions or in their immediate vicinity, while the roots, in these cases frequently stunted, retain their normal positions. With the crowns of incisors, rec- tangular flexions are most frequently observed, their incisive edges being directed forwards or backwards, or inclined to either side. When the crown of an upper incisor is bent towards the lips, the palatal surface of the tooth is directed downwards, and upwards Avhen the flexion is towards the tongue. The reverse is the case with the incisors of the lower jaw. molar on the left side with the blended facial roots of the wisdom tooth. View from the facial side. Natural size. (For the use of this specimen the author is indebted to Dr. Friodlowski.) IRREGULARITIES OF STRUCTURE. 131 The development of a crown which is the subject of this dis- tortion may go on to completion ; exami- nation of the enamel, however, in the vi- ^^' '__ ^"' '' ' cinitj of its terminal portions, will show a variation from the normal arrangement of the layers, inasmuch as the enamel is thicker at the vertex of the angle of flexion, while the margin of the enamel is furrowed in some cases, and raised into a fold in others (Figs. 50 and 51). Sometimes cleft-like gaps, lined with very thin layers of enamel, are met with, which likewise indicate irregularity and interrup- tion in the development of the enamel. These circumstances justify the assumption that the flexion takes place prior to the completion of the formation of the enamel cap of the crown. The growth of the roots may continue in the normal direction after the occurrence of flexion of the coronal portions. These flexions should be studied carefully by practitioners to whom such teeth are presented for the purpose of being straight- ened, because the distortion can neither be removed nor im- proved, and there is nothing to be done except to extract the tooth affected. Care should be taken not to confound cases presenting this deformity with those in which normally formed teeth assume an oblique or a nearly horizontal position, and which, under favorable circumstances, may be treated with suc- cess. A careful examination of the teeth and jaws, and par- ticularly the existence of slight irregularities upon the crown of the tooth in question, for example, notable bulging upon either * Fig. 50. — Lateral view of an upper central incisor. The crown is com- pletely developed ; the extremity of the short, thick root is turned towards the lips. On the edge of the enamel, on the lingual surface, rises a sharp ridge, corresponding to which, upon the labial surface, is a constriction. Natural size. t Fig. 51. — Lateral view of a lower central incisor. The crown is bent at a right angle, so that the incisive edge, with its three denticles, is directed towards the lips. The lingual surface is turned obliquely upwards. In the vicinity of the neck of the tooth, at the part corresponding to the vertex of the angle of the flexion, a distinct layer of enamel is presented, which resem- bles a flattened nodule and, when examined with a lens, seems to be sepa- rated from the enamel of the crown by a narrow zone of dentine. Natural fcize. 132 PATHOLOGY. surface of the horizontally placed crowns, a very narrow neck, and a marked mobility of the tooth under slight pressure, will indicate, with a considerable degree of probability, the existence of a flexion of the crown at an angle with the root. Flexions of the roots are met with near the necks, in the middle portions, or at the extremities, and Fig. 52.=^ Fio. 53.t are of various dcgrecs. Those of a moderate degree are limited to a slight S-shaped curvature ; those of a higher degree present a step-like deviation (Atlas, Fig. 7), or a sharply defined bend of the axis of the tooth (Fig. 52). Flexions at the extremities are the most common, and are single, double, or zigzag (Fig. 53). The pulp-cavity is inclined in correspondence with the flexion of the crown, and the root-canal, in conformity to the flexion of the roots, presents one or two deviations from the straight course. The continuity of the dentine is uninterrupted, as its canals adapt themselves to the direction of the deviating portion. Axial torsions of the crowns present an appearance such as would be produced by twisting the coronal portion about its axis, so that the corresponding surfaces of the crown and root do not lie in the same planes. Such irregularities of formation are met with only in teeth with single roots, particularly in canine teeth, but also in bicuspids. They are twisted from 90° to 180°, so that the facial surface of the crown is turned towards the tongue, which, however, does not prevent the root from re- taining its normal position. Deficiency of space, at the time when the crown is just formed, may, with reason, be assumed to be the cause of this phenomenon, while, during the subsequent expansion of the contracted space, the root would be enabled to develop in its normal position. Similar circumstances, namely, the adaptation of the growth of the root to the varying space * Fig. 52. — Lateral view of a central upper incisor, which presents a sharply-defined flexion in the upper half of the root. Natural size. f Fig. 53. — Lateral view of an upper central incisor, which presents a double flexion towards the extremity of the root. Natural size. IRREGULARITIES OF STRUCTURE. 133 provided for the latter, may also be the cause of the spiral twisting of roots which is met with. From the appearances which are found upon the bent crowns and roots, there can be no doubt that the direction of growth of the tooth may be altered by external influences, and in the fol- lowing manner : either the crown undergoes a more or less dis- tinct deviation in the direction of its growth, prior to the comple- tion of its development, or a deviation takes place subsequently, in which case it occurs at the neck, or in the vicinity of the middle or the extremity of the root. The process may be con- ceived of as occurring in the following manner. The develop- ment of the formative cells of the enamel, upon the surface of the enamel organ, is arrested in some parts by external influ- ences, while, in others, a proliferation of the cells ensues. Simi- lar influences induce a variation in the arrangement of the den- tinal cells which become inclined in one or another direction. J. Tomes* first directed attention to that remarkable irregu- larity of formation, which he describes as " dilaceration of par- tially-developed teeth from the formative pulp," and considers it to be the result of a forcible displacement of the cap of developed dentine from the pulp, the development of the dentine being continued in this abnormal position. That the incisors and bicuspids are the subjects of dilaceration, he explains by the fact that they are more exposed to accidental influences. In many cases, external mechanical influences apparently do give rise to flexion of a tooth during its formation ; in such instances, however, sufficient evidence must be adduced to show that the blow or kick, and the like, really occurred during the process of formation of the tooth. Generally, however, patients are unable to recall any such occurrences, which may have been mechanical causes ; indeed such a cause often is not in the least to be thought of in cases in which the bent crown has emerged only partially or not any. Evidently, also, dilaceration, resulting from a kick, blow, or fall, could not have been intended in the sense that portions of the soft dental tissues are ruptured ; in that case a circumscribed cicatricial tissue could be demonstrated, * Lectures upon Dental Phys. and Surgery, and System of Dental Surgery. 134 PATHOLOGY. which, however, is not the fact, for only a displacement of the dental tissues is met with. With this view of the subject the term " dilaceration" was not well chosen. In particular cases it is quite possible that continued pressure of a tooth already cut upon one whose development is interrupted, or whose eruption is retarded, may give rise to a flexion or dis- placement of the coronal portion. The singular fact, that up to the present time these coronal flexions have been observed only in teeth with single roots, cannot be satisfactorily explained. Flexions, at the commencement, in the middle or at the ex- tremity of roots, evidently cannot be caused by any accidental external influences, but always are induced by the contracted proportions of the space provided for them, of which mention has been made. In many cases a want of proportion between the depth of the jaw and the length of the root gives rise to a flexion, as also may the retarded eruption of a tooth, which compels the root, as its growth continues, to turn off" at an angle. The facial or lingual wall, especially of the under jaw, may also exert an influence, if the roots, growing in an irregular direction, strike against the wall. Flexions of the crown or neck have a deceptive resemblance to a united fracture of a tooth, and have been regarded as such, as in the case described by H. Hertz ;* but the principal evidence in proof of the occurrence of a fracture, the formation of a callus, is wanting in these cases. f h. Excessive Growth upon the Crowns and Roots. — The lesser irregularities coming under this head comprise chiefly the so- called enamel nodules^ which are of small size and, also, occur in particular localities. Most of them are hemispherical superficial growths, varying in size between diminutive nodules barely visible to the naked eye and those two to four millimetres in diameter. They are located upon the necks of teeth with mul- tiple roots, at a slight distance from the boundary of the enamel, or even upon or between the roots (Atlas, Figs. 23, 25, and 26). They have a white, polished, pearly, clear, rounded appearance, * Virchow's Archiv, Bd. 38. f C. "Wedl, uber Knickungen und Drehuiigen an den Kronen und Wurzeln der Zahne, Deutsche Viertelj. f. Z., 1867. IRREGULARITIES OF STRUCTURE. 135 always are attached by the flat surface of the spherical segment, and, not infrequently, are united with the zone of the enamel by a narrow, spinous, sharp lamina. Heider and I, up to the present time, have observed well-formed enamel nodules only upon the molars of the upper ja'w; and have never met with them upon teeth with single roots, but J, Tomes* gives an illustration of a case in which a large nodule of enamel is at- tached to the neck of a tooth with a single root. Occasionally ridges of enamel are met with on the molars of the lower jaw, which, commencing at the boundary of the enamel on the neck of the tooth, are prolonged directly between the anterior and posterior roots, but without forming nodular en- largements. Although these enamel nodules are of rare occurrence, still they are more common than is supposed, since, on account of their unusually small size, they are liable to escape observation on teeth which have just been extracted and are covered with blood. It is obvious, that the nodules or ridges which are met with upon the molars are the results of localized continuations of the development of the enamel between the already devel- oped basal portions of the roots, and are produced by the strip of the enamel organ which has persisted longer than the rest. If a section be made through an enamel nodule, it will be found that the enamel forms a thick layer upon a truncated cone of dentine (x\tlas, Fig. 24). In many nodules, cross-sec- tions of the enamel have a light color and indicate a normal formation, while others present an abundant deposit of pigment and an irregular arrangement of the prisms. The dentinal cone is a direct prolongation from the dentine of the neck or root, and contains dentinal canals which assume a regular ar- rangement and a radiating course. Occasionally one or more empty spaces or cavities are met with which are filled with mi- nute granules of calcareous salts. With reference to their structure, the enamel nodules are to be reo-arded as lateral offshoots from the teeth, and are to be classed with the small dentiform excrescences which are met * System of Dental Surgery, Fig. 102. 136 PATHOLOGY. witli, sometimes, upon the facial or lingual surfaces of the molars, especially those of the lower jaw. In many cases, particularly upon the upper milk molars, a cusp, covered with enamel, is met with upon the lingual aspect of the neck, the apex of which projects through the gum as if it were isolated, and may lead to the false supposition that it is a new tooth which is just emerging. An excess in the number of roots is not uncommon. Super- numerary roots sometimes are stunted in their growth, at others, they are completely developed, and occur either in the form of lateral offshoots, or are produced by a division of the flattened roots, as is the case, particularly, Avith the lower incisors and canines (Fig. 54), the upper bicuspids, and upper and lower molars. It is very uncommon to find two completely separate roots upon the upper incisors and canines, or upon the lower bicuspids, that is to say, upon the teeth which properly have, single, con- ical roots (Fig. 55). A partial division at the radical extremity of a lower bicuspid is extremely rare. Supplemental roots, consisting of lateral offshoots which are located in the region of the neck of the tooth and attain scarcely one-third the length of the normal root, are met with, though rarely (Figs. 56 and 57). Roots which arise from a division are always conical, in other words, cross-sections of them are circular. Carabelli* observed an extremely rare case, in which all the bicuspids of a skull had three roots. The upper ones were seen to possess three entirely distinct roots, and the existence of the same number upon those of the lower jaw was indicated by deep depressions corresponding to them. Bicuspids, first ones especially, with three roots, are frequently met with, in which cases the arrangement of the roots is similar to that of the roots of the molars, but they stand close to one another, so that the teeth are more easily extracted (Fig. 58). Sometimes the upper bicuspids have two separate, divergent roots (Atlas, Fig. 6) ; the divergence, in some cases, being so great, that ex- * Anatomie des Mundes. IRREGULARITIES OP STRUCTURE. 137 traction of the teeth is accomplished very seldom without frac- ture of one of the roots. The occurrence of upper molars with five, and lower ones Fig. 54* Fig. 55.t Fig. .'^6.+ Fig. 57.§ Fig. 58. [| with four roots is accounted for by a division of all the flattened roots belonging to them. When the upper molars have four regularly formed roots, the two flattened ones, as is the case normally, are placed upon the outside, and the rounded ones, opposite the first, upon the inside. Consequently the second internal root is to be regarded rather as a supplemental one, that is to say, not the result of a division. Sometimes all the lower molars have a third root which is roundish and located internally, towards the cavity of the mouth. It gives to the lower molar a form similar to that of an upper and might, therefore, lead to a confounding of the two ; but they may be distinguished by the fact that, in the lower molar, this third root always arises from the inner surface of * Fig. 54 shows a longitudinal section of a canine, with two root-canals in the divided root. Canines are also met with, in which a single root pre- sents two root-canals. Natural size. t Fig. 55 shows a lower bicuspid with two hroad roots : the latter are of equal length, separate, flattened, and marked by a shallow groove. Natural size. J Fig. 56 shows an upper central incisor with a short, conical supple- mental root, arising from the neck of the tooth. View of the labial surface. Natural size. § Fig. 57 shows a much worn lower incisor, the lingual surface of which is bevelled, and upon its neck is located a short, conical, supplemental root. Natural size. II Fig. 58 shows the anterior surface of an upper bicuspid, with three distinct, slightly divergent roots, and a normally formed crown. Natural size. 138 PATHOLOGY. the base of the posterior root, and never from the middle por- tion of the neck of the tooth, as is the ease with the rounded root of the upper molar. Five entirely separate, completely formed roots also are met with (Atlas, Fig. 11), in which cases, the fifth, which is located upon the lingual side, is not the result of a division into three roots, but is a supplemental formation. Both upper and lower molars with more than five roots have also been observed, but such cases, it is evident, are the result of the union of two molars. Under the head of excessive formations are also to be con- sidered the unusually long or thick 7'oots, as well as, in most cases at least, the unusually divergent or curved roots, and finally the condyloid or nodular enlargements, which are met with at the extremities of roots and are not to be confounded with hypertrophy of the cement. The length of the roots may be excessive either absolutely or relatively, i. e., in proportion to the depth and thickness of the jaw. In some cases, the second bicuspids, or the first and second molars, are inserted to an unusual depth into the floor of the antrum of Highmore, where they form hump-like prominences, and their extraction is likely to occasion quite serious injuries. The three roots of the upper molars frequently present an excessive thickness and divergence. Sometimes the roots of the lower molars are very broad, and separated by unusually wide intervals. The extraction of the latter teeth is the more difficult when the two adjacent teeth are still present in the jaw. It is not uncommon, in teeth with several roots, to find that the development of the latter, in respect of size, is in an inverse proportion, i. e., if the internal ones are well developed, the two outer ones are found to be stunted, and vice versa. Curves of all or of separate roots, which are absolutely or relatively too long, occur in every conceivable form, and a knowledge of them is of special interest to the practitioner, since very slight deviations may be important obstacles in the way of extraction. For a long time, therefore, practitioners have devoted their attention to these curves of the roots, and the student will find in every manual of dentistry descriptions and illustrations of such irregularities. IRREGULARITIES OF STRUCTURE. 139 111 rare cases, an incisor or canine root is curved posteriorly like a hook, or the radical extremities of upper and lower teeth with multiple roots converge in the shape of a bow which, some- times, forms a hook-like curve with a very decided bend (Atlas, Fig, 5). It is not uncommon for the extremities of each of the roots of wisdom teeth to present a strong curve, or for one of them or all of them blended together, to be bent like a hook (Atlas, Fig. 10). A quite uncommon irregularity is that in which one root is inserted between two others of the same tooth, as the thumb may be inserted between the index and middle fingers (Atlas, Fig. 14). The condyloid enlargements upon the extremities of the roots, when they are due to irregularities of formation, are to be ascribed to a hyperplastic process which takes place subsequent to the completion of the root extremities. Of such a character are the larger or smaller pisiform nodules Avhich occupy the ex- tremities of the roots of the lower molars, and offer serious ob- stacles to the extraction of these teeth. Pisiform, condyloid enlargements are also met with, though very rarely, upon the extremities of the radical portions of the upper molars. Among the excessive formations in the dentine of the root, may be included the concentric dentinal formations (comp. den- tinal new formations), when they are located in the root-canal, near the apex, in very young teeth. c. Defective Formation of the Crowns and Roots. — Stunted crowns are indicated by a diminished superficial area, and by the fact that the incisive edges, eminences, and cusps are less marked than is usually the case. The enamel layer frequently is unusually thin, or forms an incomplete investment. The enamel cap is not everywhere smooth upon its outer surface, the pol- ished appearance peculiar to it and its transparency are, in a measure, lost. The four upper incisors, and, more frequently, the two lat- erals, sometimes present, upon their lingual surfaces, deep longi- tudinal grooves, which commence upon the roots and extend to the ends of the crowns. Upon the same surfaces of these teeth, it is not uncommon to find deep funnel-shaped depressions, or pits, surrounded by a fold-like elevation of the dental tissues. 1-iO PATHOLOGY. To the practitioner, these grooves and pits have an important signification, from the fact that they almost always are the seat of the commencement of caries, though the latter very frequently continues unrecognized until, finally, a hluish spot becomes per- ceptible through the facial surface of the incisor. The crowns of the upper lateral incisors, also, often possess narrow, stunted incisive edges, in comparison with the well-developed ones of the centrals. The crowns of the wisdom teeth, especially of the upper ones, are most frequently stunted in their growth. When the upper wisdom teeth are duplicated, the normal, well-developed tooth is located in the dental range, while the supernumerary one is located without the latter, upon the buccal side, and at- tains scarcely two-thirds the size of the other. A diminution in the number of roots is produced by a partial or complete blending together of the separate roots of a molar. In this manner, molars with two, and single roots are formed, upon which, however, the outlines of the roots, which should have occurred normally, are more or less distinctly indicated. When the three roots of the upper first molars are united they acquire a pyramidal form (Atlas, Fig. 12). In many cases, however, merely the extremities of the two external roots are united, leaving a cleft-like interval, occupied by the septum which necessarily must be removed with the teeth when they are extracted. When the two external roots are united in their entire length, a deep longitudinal groove extends along the external surface. Less frequently the extremity of the internal rounded root is united "with the two external ones. When the extremities of the three roots are united together, the latter form an annular inclosure around the septum which is inserted into the space intervening between them. It is evi- dent, that such teeth cannot be extracted without fracture of the septa between the roots (Atlas, Fig. 63). The roots of the first lower molars, in many cases, are united throughout into single, wedge-shaped roots, the lines of junc- tion upon the outer and inner surfaces being indicated by grooves. Coalescence of all the roots is met with most frequently on IRREGULARITIES OF STRUCTURE. 141 tlie molars, since there is, usually, insufficient space for their normal development. Generally the roots are grooved through- out, indicating the parts where union has occurred. "When the roots are completely united, which is more likely to occur with the upper wisdom teeth, the single root assumes a generally rounded appearance without any grooved markings, but the ex- tremities may diverge and be inserted in the jaw in the form of a trident, a condition which renders the extraction of such a tooth impossible without fracture of the ^^^■^^■'^ socket (Fig. 59). In most cases the coalescence of the roots of a molar tooth is due partly to an unusually short or narrow maxillary arch. The union is formed by cement, which partially or entirely prevents the development of the partition walls of the socket between the roots. In certain in- stances, ^Yhere the roots are separated by normal intervals and are united by osseous substance, we may assume the occurrence of a hyperplastic growth of cement from the dental sac. Frequently the distributio7i of the enamel over the surface of the coronal dentine is not uniform ; here and there, it is de- fective, Avhile the denthie, corresponding with the very distinct depressions and grooves upon the crowns, either is entirely un- protected or covered merely by a thin layer of enamel; on the other hand, the enamel is disproportionately thick in some lo- calities ; for example, upon the dental cusps and eminences where the enamel occurs in the form of pediculated nodules. These appearances are presented generally by the greater num- ber of the teeth in a set and, not uncommonly, are hereditary. The permanent teeth are more frequently, and the milk teeth more rarely, the subjects of these conditions; they are most conspicuous upon the incisors, canines, and upper first molars, and are met with less frequently upon the lower first molars * Fig. 59 shows a stunted upper wisdom tooth from the right side. The masticating surface of the crown presents four blunt cusps. The roots are united into one cylindrical root, the extremity of which expands into three short prongs, so tlMt the tooth could not be separated entirely without break- ing away a portion of the alveolar process. Natural size. (For the use of this specimen the author is indebted to Dr. Friedlowski.) 142 ' PATHOLOGY. and bicuspids. The appearances presented by the malformed enamel in these cases are very characteristic. The surface of the enamel otherwise smooth, frequently is studded like a thimble, with numerous minute pits, some of which extend as far as the dentine ; sometimes it is traversed by transverse grooves which are bounded by ridges. In such instances, however, it is to be borne in mind that, although the external enamel layers present numerous pits, the internal layers Fir., co.'^ towards the dentine are invariably found to be smooth (Fig. 60). The thickened deposits of enamel occur upon the crenated incisive edges of the incisors where fenestrated open- ings are met with which dip down as far as the dentine. Such teeth present a trans- versely grooved appearance. The cribriform, foraminated enamel upon the crowns of teeth with multiple roots is commonly limited to the masticating sur- faces, where, also, are located the papilliform thickened deposits of enamel. I^ot infrequently half the crown is destitute of enamel, only the portion adjacent to the neck of the tooth being covered. These defects in the formation of the enamel are generally included under the head of Atrophy in the manuals of dentistry, but this latter term is incorrectly applied, since defective forma- tion and atrophy are not identical. f * Fig. 60. — View of the interior of the enamel cap of a fully formed molar, from the jaw of a young person ; its outer surface was studded with numerous depressions ; the cap was isolated by means of a fifty per cent, solution of sulphuric acid. The central portion of the grinding surface pre- sents a bifurcating fissure, to the right of which is a cavity the result of a suspension of the process of enamel formation at this point. Witliin the parietal wall is a groove (a), having the character of a sort of suture, where, likewise, the development of the enamel was interrupted for a certain period. Magnified two diameters. f These malformations are considered, without reason, by many practi- tioners, to be caused by hot drinks, sweet and sour articles of food, the use of acid preparations for the teeth, or other medicaments. They are referred, also, to a scrofulous diathesis by some who, however, adduce no plausible reasons for such an opinion. The truth is, that the only explanation which can be relied upon is to be attained upon anatomical grounds, and this way IRREGULARITIES OF STRUCTURE. 143 It is the general opinion that teeth of this kind, with so many depressions upon their coronal surfaces giving to them a disa- greeable appearance, are very liable to be affected with caries at an early period, but they may, however, be preserved with proper care and cleanliness. •Recently-cut molars are met with occasionally in which, whether they are the subjects of the enamel defects just de- scribed or not, the continuity of the enamel at the bottom of the grooves is interrupted, so that a fine probe may be inserted into the fissures which remain, as far as the dentine. In these cases, evidently, the development of the enamel has been defec- tive, since the enamel caps, which should cover the prominences of the teeth and form continuous layers in the grooves between them, present interruptions in their continuity. Defectively developed enamel is characterized histologically by the granular cloudiness of separate portions in which the structure is more or less altered and irregularly jagged borders are directed towards the normally developed enamel. With this condition, the enamel is capable of less resistance and easily crumbles. Very frequently, abundant deposits of dark-brown or blackish-brown pigment are observed, which render the structure of the enamel quite unrecognizable in places. was Huggested long ago by Bourdet (De I'art du Deiitiste, 1757, p. 79), who treated of such deformities under the name of Erosion, and considered them to be due to rachitis, scorbutus, loYhich are interpolated in the neighborhood of the globular sub- stances in the deeper layers of the malformation, care being requisite in order to avoid confounding interglobular spaces filled with calcareous salts, with bone-corpuscles. The origin of this monstrous tooth can only be conjectured. This much, however, may with reason be admitted; that the in- terlacing of the systems of dentinal canals is explained by the existence of numerous new formations of dentine (odontomes), extending in various directions into the pulp; for the same reason, also, the pulp-cavity is represented merely by cleft-like gaps. From the abundant and very irregular folding of the enamel organ, the conical prolongations, extending inwards, re- sulted. As before observed, I agree with J. Tomes, in consid- ering Nasmytlis membrane to be a continuation of the cement layer and, also, a rudimentary osseous tissue, so that to my mind, the occurrence of an osseous substance, in an advanced stage of development, is readily explained. There can scarcely, indeed, be any doubt but that, in this case which, clinically, was carefully studied, a dislocation of the germ of the wisdom tooth occurred during the growth of the second molar, in consequence of a deficiency of space, whereby the former, instead of assuming a position behind, became lo- cated beneath the second molar ; the subsequent formation of its crown prevented the development of the radical portion of the molar tooth and, in all probability, was the general exciting cause of the whole mischief. In the imperfectly formed crown of the second molar, both the dentine and enamel, as well as the cement, became developed in abnormal directions, and the growth of the separate tissues in some parts was excessive and in others defective. The fact, that the growth of the malformed tooth continued beyond the ordinary period until its eruption, is confirmed by the demonstrable, well-preserved bloodvessels con- tained in the connective tissue fringes of the exterior, and that the deformed mass was penetrated by the wisdom tooth lying beneath it, is indicated by the cavity presented by the under surface of the deformed tooth, which is a cast of the crown of the wisdom tooth. 166 PATHOLOGY. In view of the great interest of his case, Dr. Steinberger, at intervals of several months, prepared three plaster casts of the surface of the lower jaw, and kindly loaned me the models. The illustrations given in Figs. 68 and 69 correspond with the Fig. 68* Fig- C9.t first two periods and show the variation in the cavity, which was occupied by the malformed tooth, and the change in the position of the wisdom tooth. If a horizontal plane be projected posteriorly from the masti- cating surface of the second bicuspid tooth, and the distance from the posterior coronal border of the latter to the anterior border of the wisdom tooth, in the visual plane, in other words, if their distance from each other upon the longitudinal plane, at the first period, be measured and compared with the distance at the second period, it will be found, that the longitudinal dis- * Fig. 68. — Plaster cast of a right half of a lower jaw, showing, posterior to the alveolar cicatrix of the first molar, a cavity from which the malformed second molar was removed by operative means. At the bottom of the cavity maj' be seen the wisdom tooth displaced to one side. The cast was taken soon after the operation. Two-thirds natural size. f Fig. 69. — Plaster cast of the same segment of the right lower jaw, taken several months after the removal of the malformed tooth. The di- mensions of the cavity have diminished, and the crown of the wisdom tooth has reached a higher level and moved towards the median line. Two-thirds natural size. (For the use of both casts the author is indebted to Dr. Stein- berger.) IRREGULARITIES OF STRUCTURE. 167 tance between the two teeth = sixteen millimetres has remained unchanged, but that on the other hand, the masticating surface of the wisdom tooth has been raised about nine millimetres and lies only three millimetres below the level of the second bi- cuspid. The wisdom tooth, however, has also been displaced from the outside inwards, so that it is but a few millimetres to the outside of its normal position. The dimensions of the cavity present a considerable diminution in the later period ; the lon- gitudinal diameter being about twelve millimetres, the transverse about six millimetres ; the approximation of the facial to the lingual maxillary wall has been brought about by the process of cicatrization, the contraction of the cavity being analogous to that of the alveoli subsequent to the extraction of teeth. J. Tomes* reports a very similar case. The deformed molar of the lower jaw, likewise located over the wisdom tooth, was several times larger than the latter, the development of which Avas retarded. The nature of the case was not rightly under- stood, consequently a portion of the jaw was removed. Analogous malformations are met with in animals, and have been observed in the horse by Etienne Geoffroy St. Hilaire, and Rousseau. I am indebted to Prof. Bruckmiiller, of the Vienna Veterinary Institute, for an extremely rare example of a malformed left molar from a horse. The colossal tooth at- tained about the size of an orange and, evidently, was located within the dental range, for upon the anterior and posterior sur- faces are to be seen, in directions oblique to each other, the abraded surfaces produced by friction with the contiguous sur- faces of the adjacent molars. The monstrous formation pre- sents one surface, convex, rough, studded with numerous denta- tions, and another, excavated, and polished in appearance, corresponding to the masticating surface. The latter presents a substance composed of enamel and dentine, which is trans- versely disposed from the outside to the inside, one to five mil- limetres in width, sharply defined, and divides the excavation into two unequal portions. The remainder of the tooth is composed of finely porous osse- * Op. cit, p, 2L'4. 168 PATHOLOGY. ous substance and dentine. Fig. 70* The enamel extends from the masti- cating surface (Fig. 70), into the substance of the tooth, where it forms nar- row zigzag folds, which are accompanied by the dentine. Towards the lower portion, the periph- eral cement penetrates to various depths. The pulp-cavity is wanting, its upper portion being filled with osteo-dentinal masses, which distend the Avails of the cavity. 4. J. Tomesf also mentions partial deformities of the croum in the form of excrescences. An outgrowth of this kind came under his observation, upon the anterior surface of an upper central incisor, and consisted of imperfectly developed and ir- regularly arranged dental tissues. He also states, that a case described by Salter in the "Pathological Transactions," under the title of a "Warty Tooth," comes under this head. 5. Fissures. — During the development of the tooth, it hap- * Fig. 70 shows a carious, malformed left molar from a horse. (For this specimen the author is indebted to Prof. Bruckmiiller.) Sagittal section. The smooth, masticating surface (a) has a polished appearance, is deeply ex- cavated and divided into two unequal portions by a substance composed of enamel and dentine, which extends from below upwards. One of the two abraded surfaces, produced by friction with the anterior and posterior adja- cent teeth, is visible, [b). The osseous substance is, comparatively, more abun- dant than the other tissues, and forms the mass lying upon either side, like a kernel in a shell, in which mass are imbedded striated markings of dentine, (c) At the outer part of the substance forming the shell, osseous tissue (rf, d) is met with, which is united with irregular folds of enamel (c), and in- ternally to the latter, with dentine. Confused masses of dentinal tissue (/), however, which are traversed by canals, are met with, also, in immediate connection with the cement. The occurrence of caries upon the superficial portion of the grooved masticating surface has left jagged, discolored cav- ities. Two-thirds natural size. t Op. cit., p. 227. IRREGULARITIES OF STRUCTURE. 169 pens, sometimes, that the continuity of the enamel cap becomes interrupted, and the dentine appears to penetrate into the cleft- like gaps of the enamel. The dentine, also, is developed beyond its normal limits in many places, and hence another source of cleft-formations. The fissures in the enamel are sharply cut and filled with dentinal globules (Atlas, Fig. 32). In most cases, the growth of the dentine does not extend into the fissures, and we find merely cleft-like gaps in the substance of the en- amel cap. The dentine may, however, attain a higher grade of develop- ment in the fissures, as is illustrated by Fig. 33 in the xVtlas, where the crown and root of a wisdom tooth present an appear- ance as if they had been divided by a longitudinal section, and a flattened plate of dentine had been introduced into the fissure, where it had continued to grow and become firmly adherent. Fissures in the roots are due to defective union of the two rad- ical halves. A fissure in the neck extending into the root- canal, and surrounded by a layer of enamel which extends perhaps to the bottom of the cleft (Atlas, Fig. 27), sometimes occurs, though it is extremely rare. 6. Monstrous outgrowth of Dentine and Cement [osteo-odon- toma) upon the Root. — Rare tumors of this description are de- veloped, during the formation of the roots, from a circumscribed portion of the radical pulp. The hard tissues of the tumor comprise bone and dentine, but, as the crown is not involved, enamel is not found (Atlas, Figs. 28 and 29). The cortical tissue of the tumor is composed of cement, beneath which is found a comparatively thin, but normally formed layer of den- tine ; immediately internal to the latter expands the abundantly vascularized osseous mass which forms the principal component of the tumor and, from the fact that it is encompassed by den- tine, must have originated from the pulp of the root. Heider,* who previously described this malformation, was inclined to regard it as an instance of the fusion of a normally formed wisdom tooth with a malformed supernumerary dental germ. In my opinion, the supposition of a supernumerary dental germ * Mittheiluniren des Centralv. deutsch. Zahiiiirzte, 1860. 170 PATHOLOGY. cannot be entertained, from the fact of the entire absence of all traces of enamel in the tumor. Heider was unable to obtain any history of the case. Th. Billroth reported a case "which may be classed under this head, from Langenbeck's Clinic in Berlin.* A girl, sixteen years of age, complained for several months of a swollen and painful cheek on the right side. During the same period, the second right (large ?) molar of the upper jaw acquired an ob- lique position and a slight displacement inwards, and at the same time, a hai^d mass made its appearance upon the outside, which the patient supposed to be another tooth. She was utterly ignorant as to the length of time during which the latter irregularity had existed. On examination, the external wall of the antrum was found to be distended, where an indistinctly defined, hard tumor, the size of a walnut, could be felt. Neither the tooth nor tumor were movable. With a stout Eno-lish for- ceps, both were seized and extracted together. The mass was of a bony hardness, the size of a walnut ; its upper surface was very uneven, warty, and entirely destitute of soft parts, the whole tumor presenting an appearance as if it had been wedged into a sort of large alveolus. The tooth was firmly attached to the tumor, its roots apparently being entirely imbedded in the new formation. No second crown could be discovered any- where. The surface of a section resembled very much the pol- ished surface of an agate. Microscopical examination showed it to be made up principally of dentine, with cavities and canals, and bone-corpuscles, which were of extremely irregular forms. No enamel was to be found. 7. Double or Twin-formations. — The essential characteristic of these is, that instead of a single, there is formed a double dental germ, Avhich remains inclosed in a single dental sac, and as a result of this, a partial or complete fusion of the twin- formations ensues. There are, consequently, two crowns and two radical portions belonging to the same kind of tooth. Herein lies the distinction between twin-formation and the fusion of two teeth. Sometimes the development of one of the * Yiichow's Archiv., Bd. viii. IRREGULARITIES OF STRUCTURE. 171 pair is considerably retarded, and, ultimately, it may present such a deformity, that the form of the crown, or root, -which should denote the kind of teeth to which it belongs, is unrecognizable, and, therefore, the basis is lost for determining whether or not the case is one of twin-formation. The only cases of twin-formation in man, as far as I know, which have been observed up to the present time, are those of wisdom teeth, and such a one is described in the Atlas, Fig. 20. "Whether they occur with other kinds of teeth is a question to be decided by more extended investigations. Animals, also, occasionally present deformities of this kind, and A. Friedlow- sky reported* an instance of twin-formation of the left tusk of an elephant, the one on the right side being stunted in its grow'th ; the former is composed of two of unequal size, the larger of which is wound around the smaller in the form of a long spiral ; the anterior segments of both roots and the greater portion of the bodies are fused together, but the apices of the tusks are separate. 8. The parenchyma of the embryonic dental pulp degene- rates in various Avays which are imperfectly understood. The unique case observed by Robinf may, as Virchow| states, be regarded as one of fibrous degeneration ; in this case, there Avas found upon the lower jaw of a child, two and a half years of age, apparently a fibrous tumor, in Avhich papilliB with quite distinct dentine and enamel could be recognized. VirchoAV designates Leisering's case, observed upon the lower jaw of a calf, as a myxomatous proliferation of the dental germ. This was developed in the vicinity of the sixth molar, forced the dental wall asunder, and made its appearance as a free polypoid tumor, three inches in length and seven and a half inches in breadth. It presented upon its surface papilliTe, which here and there were covered with quite firm enamel and dentine and, besides, was composed of connective tissue, blood- vessels, dentinal cells, &c. 9. A very remarkable series of phenomena is presented by * Sitsungsber. der Wien. Akad. d. Wiss., 1869. f Mem. de la Soc. de Biologie, 1863. J Krankhafte Gescliwiilste, Bd. ii, p. 57. 172 PATHOLOGY. dentigerous cysts, where several germs, belonging to the same kind of teeth, (?) are contained within a capsule of connective tissue. Nelaton found eight bodies in a dental cyst, and pro- nounced the case one of multiple dental formations within a sino;le alveolus. Broca modified the latter view, and asserted that the eight bodies were not dental follicles, but dental germs which arose from an eight-fold division of the original dental germ. Imperfectly Developed Teeth in a 3Iultilocular Ovarian Cyst. — In concluding the subject of anomalies of formation, I will add some observations with reference to teeth, which, though they do not come within the province of the dentist, still deserve an interest on his part ; but I must express my regret that I have been unable to obtain more than the following single case of teeth in ovarian cysts. Dr. Weinlechner extirpated, with a successful result, a multilocular ovarian cyst, about the size of the fist. The largest cyst, oval in shape, measured 7.5 cen- timetres, in its long diameter, and Fig. 71.* iuclosed a disk of bone twenty- seven millimetres in diameter, attached to a cushion of dermal tissue which was the seat of a growth of hair. Into this disk are inserted three teeth which are surrounded by a fold of mucous membrane. The contiguous ex- ternal skin may be divided into two portions, one covered with woolly hair and flattened, conical, * Fig. 71 shows three upper teeth implanted in a slightly convex disk of bone and, behind these, a pad of skin with long hairs. Taken from a multi- locular ovarian cyst. The middle tooth is the largest; its crown corresponds with that of a permanent molar ; its roots, resembling those of wisdom teeth, are bent in the shape of a bow. The long diameter of the oblong crown measures eleven, and the short diameter eight millimetres. The adjacent milk molar to the left has an inclined position ; that to the right also cor- responds with a milk molar. The three teeth are surrounded by a smooth mucous membrane, which extends to the pad of dermal tissue and becomes continuous with the external skin which is furnished with hair. Natural size. IRREGULARITIES OF STRUCTURE. 173 comparatively large papilloe, and the other furnished Avith tufts of glossy, dark pigmented hair. This dermal tissue presents a thickness of four millimetres in its thickest portion, and is con- tinued in the form of a thin layer over the cyst-wall, the latter being about one millimetre or less thick. Numberless hairs also are implanted everywhere in the thin layer of skin. By the removal of the periosteal layer of the bone together with the hairy cushion of skin, a very singularly-formed osseous framework was brought into view beneath, forming a continua- tion of the osseous plate into which the three upper teeth are inserted (Fig. 72). This plate, which is to be considered as the rudimentary upper jaw, presents an outer, i. e., turned towards the cyst-wall, convex and smooth, and an inner, con- cave, uneven surface. Upon the latter project the roots of the teeth. Upon the " '^ continuation of the osseous framework behind the rudimentary upper jaw rise two perpendicular, tolerably thick, compact, slightly curved, osseous laminpe, which terminate in blunt- pointed processes that incline towards each other. The basal portions of the laminte are united in the direction of the dental plate and partially, also, upon the opposite side ; and hence an incomplete excavation is formed, which is filled with an unctuous, fatty mass (cerebral?), and lined with a separablefibrous mem- brane ; adherent to the anterior portion of the excavation are two black pigmental masses of lax connective tissue, the size of millet-seeds, containing several groups of epithelium cells with black pigment together with cords containing pigment (belonging to the choroidea?). Several apertures also found here probably serve for the passage of bloodvessels and nerves. In two other cysts rudimentary fragments of the jaw were found in the form of osseous plates in which teeth were implanted. * Fig. 72 shows an osseous framework presented by the previous specimen. Posterior view, a, a, blunted, convergent, terminal extremities of the two elevated osseous laminae. At the bottom of the cavity are three apertures for the transmission of bloodvessels and nerves. Natural size. 174 PATHOLOGY. The larger plate has a discoid form, a diameter of nearlj'' two centimetres, and is from 0.5 to 4 millimetres thick. The ex- terior surface, i. e., the surface turned towards the cjst-wall, is smooth and slightly convex, while the interior is occupied by several irregular osseous protuberances. From one sharp edge of the plate projects the crown of a milk molar (Fig. 73), which, on close inspection, presents a defect in the enamel ; the outer segment of the crown and roots, also, is wanting, and a gives to it, w^ien viewed from the ex- ternal wall of the plate, the appear- ance as if it had been split longitudi- nally. Upon the other side of the plate rises a perpendicular process of bone which has a cylindri- form shape, is excavated at the upper part and, upon one side of its base, presents a shallow cavity which is traversed by several osseous trabcculiB. Upon either side of the process is a minute foramen and a groove for the afferent bloodvessels and nerves. The greater portion of the osseous plate, in this case, as in the one previously described, was covered with a cushion of skin and a growth of hair. Again, in a third cyst, with a small, flattened fragment of the upper jaw, two teeth, in this case still concealed Avithin the gum, were found, next to a tegumentary cushion, having conical papillce flattened upon two sides and covered with hair. The membrane stretching over the crown presents an appearance exactly like that which is found at the time of the eruption of a normal tooth, that is to say, clouded interlacing bundles of fibrous tissue, without perceptible vessels, and nuclei, form the principal portion. One of the teeth, a bicuspid (Fig. 74), presents a hook-like bend at the extremity of the root, and a notable peculiarity. If, namely, the general course of the thin * Fig. 73 shows an osseous plate taken from a second cyst of the same ovary. View of the internal surface directed towards the cyst-cavitj-. At (a) is inserted an imperfectly-developed lower milk molar ; [h), perpendicular process of bone (rudimentary ascending ramus of the lower jaw). Natural size. IRREGULARITIES OF STRUCTURE. 175 cement be traced, it will be seen, that it invaginates the dentine near the extremity of the root, where it is continued as a sharply- defined luminous zone (globular masses with interglobular spaces) between the ^"" 'i* outer and inner dentinal segments. The ' ' ' dentinal canals, commencing at the pulp- '> - cavity, terminate at the luminous zone in anastomotic loops, or in its interglobular [ ; • f^-"^^' spaces. The pulp-cavity and canal are of nearly equal breadth, and inclose a ! pulp, presenting the condition of net-like ' atrophy. The enamel is well developed. In my opinion, the condition presented by the dentine, in this case, is an indication of the occurrence of an interruption to the dentinal develop- ment ; in the interval, the process terminated with the forma- tion of globular masses, and subsequently the growth of den- tine ensued in a regular manner. The second milk molar of the same cyst presents upon its neck a distinct defect, with sharp edges, in appearance as if a file had been used upon the crow^n. A sclerosed, clouded mass of connective tissue was ad- herent at this point. Without doubt, more extended investiga- tions, with reference to the teeth contained in ovarian cysts, will prove a fertile field for the study of anomalies of teeth. The imperfectly-developed bicuspid mentioned by Richard Owen"}" also presents an anomalous formation similar to that of the upper bicuspid in the figure. * Fig. 74 shows a section of an upper bicuspid from a third cyst of the same ovary. The crown, neck, and commencing portion of the root are well: developed. The apex of the root presents a strong flexion. In general the tooth has an ajipearance as if a fresh cylindrical piece of dentine had been inserted into the tooth prior to the closure of its root. Magnified 4 diameters. f Odontography, Plate 124. 176 INFLAMMATIONS. 11. IXFLAMMATIOXS. Dental Pulp. — When we consider the great amount of ill usao'e to which the teeth are subjected, Ave may well wonder that primary or idiopathic inflammations of the pulp are not of more frequent occurrence. J. Tomes goes so far even as to say that, in ninety-nine out of a hundred cases, the diseased action is con- sequent upon perforation of the pulp-cavity by caries. Heider,* also, expresses a similar opinion. The difficulties attending the recognition of an idiopathic in- flammation are rendered still greater from the fact that, in making the diagnosis, caries is to be excluded, and this is a difficult matter to determine in not a few cases. Again, an in- flammation of the periosteum of the root may be misinterpreted as one of the pulp. A third element of difficulty lies in dis- tinguishing between a commencing inflammation and the hyper- aesthesia of the pulp which is occasioned by a congestive condi- tion. When the objective symptoms are Avanting and it becomes necessary to depend upon the subjective ones exclusively, then the course which the disease takes can only decide the point. If the aff'ection presents decided intermissions, and hypera?sthesia of other organs, also, occurs, there will be good grounds for excluding inflammation. If Ave trace the history of an inflammation of the pulp, occa- sioned by so-called perforating caries, and, first of all, the pain, it Avill be found that the latter is localized primarily, and sub- sequently extends to the neighboring teeth, and even over the whole side of the face. The partially exposed pulp is sensitive to external influences ; a current of air, cold water, acid sub- stances, Avhen brought into contact Avith it, give rise to painful sensations, while pressure upon the tooth is Avell borne, provided the exposed pulp is not pressed upon. The intensity of the pain varies according to the irritability and age of the indi- vidual ; frequently it is more severe during pregnancy or at the • * Zeitschrift der k. k. Gesellsch. dcr Wiener Aerzte, 1846. Abhandl. liber Zahnschnierz. SUPPURATIVE INFLAMMATION. 177 menstrual period. In most cases, the inflammation becomes suppurative, i. e., the circumscribed portion of the surface of the pulp presents a purulent coating, while the latter often has an oedematous appearance or is covered with a limpid adhesive fluid. If there is no obstruction to the escape of the pus, when it is formed, there will be notable remissions in the piercing, dragging, throbbing pains ; frequently, indeed, a complete in- termission, and the patient is only reminded of the affected pulp by pain induced by special exciting causes. The acute form then passes into the chronic. In cases where the pulp-cavity is not yet exposed by the carious process, and the pulp is shut in by a thin layer of dentine merely, external influences may still produce their effects, even when indirectly applied. In such cases, that con- dition is presented, which dentists term odontalgia nervosa ex carte. "Inflammation," says Heider, " does not appear to be present, for the accessions of intense pain occur without any warning, and even with great intensity, but frequently, however, intervals occur, during which there is entire freedom from pain. Cold applications, which diminish the pains induced by inflam- mation, increase them in these cases. " A considerable period having elapsed," he continues, " after the appearance of a dark spot and the subsequent destruction of the crown of the tooth at the part corresponding to the dis- coloration, the tooth becomes sensitive to changes of tempera- ture ; heat and cold occasion slight and transient pains, and hence the patient is careful to avoid cold and hot food and drinks, and that side of the jaw, upon which the carious tooth lies, is no longer employed in mastication, because the pressure, even of the particles of food which are forced into the carious cavities in masticating, now causes quite severe pain. After this state of things has continued a longer or shorter period, a pain suddenly occurs in the pulp, usually after biting something, of such severity as not infrequently to bring tears into the eyes, and if it continues very long it becomes intolerable. In a few minutes, its severity diminishes to a more tolerable degree, but it is still quite severe and continues, perhaps, for an hour, with exacerbations and intermissions, and finally ceases by degrees, 12 178 INFLAMMATIONS. ■when an interval, usually brief, of freedom from pain ensues, but soon it is reproduced, for now the pulp-cavity is exposed, and all external agencies act directly upon the nerves. The patient, however, is not always free from severe pains until the opening of the pulp-cavity ; frequently, after the occurrence of transient slight pains, a mild attack is succeeded by a more acute and lasting toothache, with intermissions of hours, or half a day." Inflammation of pulps which have been denuded by penetra- ting caries, may be circumscribed or general. The former is found in those cases especially where the perforation of the hard tissues by the carious process is confined within narrow limits ; only a portion of the body of the pulp is implicated, perhaps the extremity of a papilla of a bicuspid or molar. The most prominent indication is the redness, Avhich is due either to a hyperremic condition of the bloodvessels, or to the imbibition, by the pulp-tissue, of the coloring matter of the blood, which is deposited from the red blood- corpuscles. Inter- mediate between the congestive and diffusive, stands the hemor- rhagic redness which occurs in the form of reddish points or spots. The borders of the extravasation generally fade away im- perceptibly in the parenchyma of the pulp. In cases of circum- scribed inflammation, the redness is limited to a portion of the body of the pulp, and diminishes from the periphery towards the centre ; it involves one or another root, or perhaps only the broader portion. The intensity of the redness varies between a light rose red and a deep blood red, frequently mixed with gray, which preponderates more or less. When the inflamed pulp is accompanied by an oedematous enlargement, it acquires a yellowish-red appearance, and, attended by a superficial sup- puration, is of a pale greenish-yellow color. The increase in the volume of the pulp, when swollen from the effects of inflammation, is restricted to certain limits by the resisting dentinal capsule, within which it lies, and the view has often been expressed, that the resistance of the capsule is the cause of the intense throbbing and lancinating pains. Though it cannot be doubted that the inflammatory toothache is modified by local relations, still, on the other hand, we think it should DENTAL PULP. 179 be remembered in this connection that intensive neuralo-ias occur under the most varied anatomical relations. The swellino- of the pulp, in cases of circumscribed inflammation, is limited to one or another portion, but a circumscribed swelling can hardly be determined in many cases, and is best recognized in those cases where the inflammation occurs in an atrophic pulp. With reference to their duration, inflammations are divided commonly into acute and chronic, both of which present various degrees of intensity. The more acute the case, so much the more rapidly is the parenchyma destroyed, and the more chronic the case, the more moderate are the symptoms and the lono^er are the intervals between them. In the former case, the oro;an also undergoes a relative decrease in its consistence, and may even become transformed into a soft, pultaceous mass. The suppurative process is developed, almost always, as a se- quence of caries, and is limited to the superficial layer of the body of the pulp or of the root portion corresponding to the carious locality ; the suppuration manifests itself in the form of a greenish-gray or greenish-yellow, semi-fluid, thready covering, containing pus-corpuscles as its characteristic morphological elements. The latter, for the most part, have undergone fatty degeneration, so that on treating them with acetic acid, the numerous nuclei are obscured by the presence of the fat-gran- ules; indeed, it is not an uncommon occurrence for the corpus- cles to be so shrivelled and degenerated that they are no longer recognizable. The fluid basis of the purulent mass is rendered turbid by the fat-globules suspended in it, which latter, also, are presented in agglomerated granular masses. By adding acetic acid, the mucus is precipitated in the form of a cloudy, string;^ mass. Cases are met with frequently, where not a single pus-cor- puscle, but mere agglomerations of shrivelled, turbid nuclei im- bedded in a mass resembling coagulated albumen, are to be found, in the superficial, apparently purulent, substance. If the examination is extended from the purulent, infiltrated portion of the pulp to the deeper layers, it will readily be seen, in acute cases, that a proliferation of the cells of the paren- chyma has taken place and may be traced into the internal por- 180 INFLAMMATIONS. tions even far do-\vn into the root-pulp. In order to show this, it is well to place sections of such pulps in paraffine, glue, or some other suitable substance. The connective-tissue cells of the pulp, especially in young individuals, sometimes present a marked proliferation. For instance, binucleated, roundish, and spindle-shaped cells, are frequently observed, as the principal forms, and these, together with many others derived from them and variously shaped, occur in such large numbers that they are closely compacted, especially in the vicinity of the focus of in- flammation. Finally, still more closely packed, agglutinated, elementary organs are found, consisting, usually, of a round nucleiform body surrounded by a layer of protoplasnT which be- comes exceedingly small. If we examine the bloodvessels, structural changes may be discovered at the points where they pass into the focus of in- flammation, as follows : A swollen and lax condition of the fibrous sheaths of the small arteries and veins ; a cloudiness of the sheaths, occasioned by scattered or aggregated fat-granules, or by larger or smaller nuclei, often in clusters, which not infre- quently surround the entire vessel, whereby the characteristic elements of the bloodvessel are lost, and it can only be recog- nized by its continuity. Albrecht* called attention to the no- table increase in the volume of the vessels and to their direc- tions, which, instead of being in straight lines, are exceedingly tortuous. t * Krankheiten der Zahnpulpe, 1858. ■j- This condition is observed especially in connection with chronic inflam- mation. The prolonged and frequently repeated, augmented pressure of the blood occasions a diminution of the elasticity and contractility of the vas- cular walls; coincident with the proliferation of the connective-tissue ele- mentary organs, the vessel loses a certain amount of its basis-tissue which has become succulent; after expansion, it cannot recover its former length or transverse diameter, but becomes longer and wider, acquires lateral flexions, and frequently varicose expansions which, when they lie superfi- cially, easily rupture and give rise to the above-mentioned extravasations of blood; the latter subsequently occasion pigmental degeneration and cloudi- ness. When the vessels are permanently expanded, disturbances of the circula- tion are more liable to occur. The interchange of materials in proper DENTAL PULP. 181 The bundles of nerve-tubes in the vicinity of the focus of in- flammation, also, present evidences of structural changes. The most notable indication is afforded by the cloudiness produced by deposits of fat-granules which, partly disseminated and partly aggregated, are deposited between the nerve-tubes and also in their interior (neuritis). The fat-granular metamorpho- sis does not uniformly involve the medullary matter even of one bundle of nerves, that is to say, the nerve-medulla of indi- vidual nerve-tubes is unaffected by fatty degeneration. Some- times, groups of oval or round nuclei, analogous to those in the bloodvessels, are met with in the fibrous sheaths of the nerves, and indicate a proliferation of the connective-tissue elementary organs (Atlas, Fig. 80), Hence it may be concluded that the occurrence of inflamma- tion in the nerve-bundles of the pulp, whether it results in a fatty degeneration of the nerve-medulla or in a cell prolifera- tion of the interstitial connective tissue of the bundles, necessi- tates a disturbance of the conductibility of the axis-cylinder, which is manifested by a sensation of pain. The protoplasm of the dentinal cells, in the vicinity of the focus of inflammation, is rendered cloudy by fat-granules ; their cohesion becomes lax, and gradually they undergo complete dis- integration. In cases which run an acute course, the fatty metamorphosis is more intensive and extensive than in chronic cases, and, co- incident with this, occurs the production of a lax condition of the pulp-tissue, and subsequently dissolution ensues, so that, finally, there remains merely a discolored membrane adherent to the still intact wall of the pulp-cavity and prolonged into the root-pulps and containing the shrivelled remains of the pulp. From a general view of the phenomena attending an inflam- mation of the pulp, it appears that the anomaly in the inter- amounts, can no longer continue, so that excretory elements are retained, which in turn occasion still further impairment of function. In consequence of the stagnation of the blood, both the red and white corpuscles become necrotic; the former yield tlieir coloring matter to the fluid in which they are immersed, and the pulp becomes impregnated with the coloring matter of the blood. 182 INFLAMMATIONS. change of material is manifested by an augmented supply and diminished witlidrawal of the blood, an increased transudation, and an accumulation of excretory materials : further, by a pro- liferation of cells which form the stroma of the pulp and the connective-tissue investments of the bloodvessels and nerves, and by an abundant development of pus-corpuscles or unusually large, rapidly shrivelling nuclei, which prolifications, together, induce a partial or complete disorganization of the parenchyma of the pulp. Acute inflammation of the pulp frequently results in a gan- grenous destruction ; usually this is a sequence of caries of the milk and permanent teeth, but it also occurs after inflammation of the root-periosteum and, more rarely, is developed independ- ently. As is the case with other organs, two principal forms of gangrene of the pulp are distinguished, the so-called moht and di-y. The former is characterized by a dirty deep red, brown- ish-red, reddish-gray or greenish-gray discoloration ; a diminu- tion of the consistence to that of a thick, pultaceous mass, which has a decided penetrating, fetid, characteristic gangren- ous odor. Sometimes, also, the pulp becomes transformed into a pulpy, unctuous, caseous, disintegrated mass, with a nauseating odor. The inflammatory character of the changes in the tissues may be recognized, unless the gangrene has made too great progress, and, for this purpose, it is well to commence the investigation in the root proper and to continue it in the direction of the coronal pulp. The sheaths of both the nerves and bloodvessels exhibit the above-mentioned prolifications, which increase pro- portionately as the gangrenous focus is approached, and finally cover the whole field of view. The evidences of fatty degene- ration, also, are apparent in rapidly increasing progression. Here and there, the contents of the nerve-tubes are disinte- grated. The walls of the bloodvessels have a fat-granular ap- pearance and disintegrate as if they had been macerated; the oblong nuclei of their organic muscular fibre layers are scat- tered in confusion. Where the gangrenous destruction is com- plete, a dirty yellow, brownish-yellow molecular detritus is found, containing, generally, numerous interposed, long, bow- DENTAL PULP. 183 shaped, fatty acid crystals, similar to those found in the sputa in gangrene of the lungs. In the so-called dry gangrene^ nothing is left of the pulp but a blackish-brown, brownish-red, tinder-like, shreddy or mem- branous, slightly moist mass, which only partially fills the pulp- cavity, the remaining space being occupied by a gaseous fluid. The principal histological elements comprise red or dark-brown, cylindrical masses (necrotic blood) inclosed within still recog- nizable sheaths (bloodvessels), dirty yellowish or brownish ag- glomerations of nuclei, diminutive pigment grains, crystals of hgematoidin. In most cases there is no perforation of the pulp-cavity, though caries has preceded the gangrenous condition of the pulp. In certain cases filling the tooth may be the predisposing cause. The primary gangrene appears to occur particularly in teeth which have been worn away by attrition. Besides these causes there are general, obscure, injurious external agencies which also promote the occurrence of gangrene in the inflamed pulp. When the red coloring matter of the blood-corpuscles transudes through the intact vascular walls, or escapes from the corpuscles after the rupture of the latter, it penetrates the dentine and im- parts a reddish color to the teeth,* which generally is first noticed upon the neck of the tooth, where the enamel about the dentine terminates. In many cases the redness, which is a pale rose color, is limited to a short streak upon the neck in the vicinity of the root, and fades away towards the latter. In other cases the redness is more intense, and spreads towards the extremities of the roots, being more marked, generally, upon one side than upon the others. The coloring may, how- ever, be most decided even upon a portion of the root. If sections are made to show the amount of the redness pre- sented by the diff'erent dentinal layers, now and then instances are met with where the inner dentinal zones, towards the pulp- cavity or canal, exhibit very slight or no redness ; next to this is a broader or narrower middle zone of a brighter tinge, which * M. Heider und C. Wedl iiber gerotbete Zahne: Deutsche Viertelj. f. Zahnheilk. 18G3. 184: INFLAMMATIONS. passes into the weaker color of the outer zone. Sometimes the inner dentinal zone is the most highly colored. Tliin sections furnish a clear idea of the relative amounts of the coloring substance in the different dentinal zones. The dentinal canals are filled with the red coloring matter, from their origins even to their most delicate ramifications, while the basis-substance, apparently, is not colored in the least. The coloring matter presents the red hue of the blood and has the appearance of a homogeneous, not granular, substance filling the canals. It is evident that these appearances are not due to the phenomena of interference, from the fact that sections of normal teeth do not present such discolorations. As is well known, similar colorings may be produced artificially, e. g., by means of carmine, madder, Prussian blue, blood-red, &c. It may quite readily be shown by experiment, that the cement takes up none of the coloring matter. If the latter is allowed to act from the pulp-cavity, the dentine becomes colored, while this does not ensue if the root of the tooth is surrounded by the coloring matter, a fact which is self-evident if the root-canal is closed.* The varying degrees of redness presented by the different dentinal layers may be referred to various causative conditions. * We immersed dried human teeth, the crowns of which were broken off, in the fresh blood of a rabbit diluted with about one-fourth the amount of water, upon which a layer of oil was poured in order to prevent evaporation. About forty-eight hours afterwards, the dentinal surfaces were exposed and found to be colored more or less, in some places a deep red, in others a pale rose-red. Sections were made, which showed the red coloring matter de- posited within the dentinal canals. In order to solve the question, whether the red color is imparted to the dentine in a direction from the root-canal or from the cement layer, i. e., from the inside or from the outside, the following experiment was made. A glass tube, six inches in length and of a suitable diameter, was fitted to an opening into the pulp- cavity of a lower molar. Eabbit's blood was then in- troduced into the tube until a column stood above the pulp-cavity. Further, some teeth, which were quite intact, were placed in fresh rabbit's blood, the openings of the canals at the extremities of the roots having previously been closed with sealing-wax. The result of the two experiments was conclusive. In the first case the dentine acquired a very deep red color, while in the latter not even a trace of discoloration was perceptible in several sections of the teeth. DENTAL PULP. 185 It is to be remembered tbat the middle dentinal zone is traversed by more numerous ramifications of canals than the inner one. Our perception of the red color of the dentine must be the effect of the totality of the reddened canals which are visible to a certain depth through the basis-substance. If the latter presents various degrees of transparency, then the red coloring will also exhibit corresponding modifications. The reddish-yellow, rose- red or gray-red, or reddish-gray color of the different teeth, and the various shades in the several dentinal zones, are not due to casual variations in the coloring matter of the blood, nor to the diminished imbibition of the latter (one can satisfy him- self, even by inspection, of the uniform coloring of the tubules), but within certain limits are dependent upon the degree of trans- parency of the dentinal basis-tissue. With caries of the teeth, with atrophy of the dental pulp, the dentine, as is well known, presents a dirty white, sometimes yellowish-gray color, particu- larly towards the pulp-cavity and dental canal, in localities, in fact, which the caries has not attacked. Accompanying this condition there is diminished transparency of the basis-sub- stance in the inner dentinal zone, which obstructs the perception of the coloring matter within the canals. The degree of redness depends, also, upon the disposition of the reddened canals. If the dentine is arranged in such a manner that only small por- tions of the canals are presented to view, as it Avere in cross- section, then the sensation of redness produced will be less marked than if they are arranged with their long dimensions exposed to view, so that a larger quantity of the coloring matter is presented to the retina. Since the dentinal canals inclose the ramifications of the pro- cesses of the dentinal cells, it appears much more reasonable to assume a process of imbibition by the latter, rather than capil- lary attraction. The occurrence of reddened teeth is confined principally to such as are carious, whose pulps present a deep-red color or ex- travasations of blood, which latter correspond in location to the reddened portions of the dentine. It is, also, a well-known fact, that when incisors are treated with arsenic or caustic paste pre- vious to the operation of filling, their crowns acquire a rose-red 186 INFLAMMATIONS. color in the course of a few weeks or a month after the operation of filling. This discoloration often occurs without any symptoms ; frequently, however, it is attended by symptoms of a congestion, and this is tiie case alwa^'s with teeth whose pulps were not re- moved after the application of caustic paste.* Moreover, red- colored teeth are observed also as a post-mortem appearance, after cholera, typhus, and death by suffocation. Rose-red teeth, with a variation in the shading upon the different sides, occur also as a variety of formation. f Chronic Inflammation of the Pulp. — The anatomical appear- ances which characterize this affection comprise a more limited extension of the usually pale redness ; diminished succulence and greater consistence of the tissues; limited, usually not very pronounced, proliferation of the connective-tissue elementary organs in the portions denuded by the carious process ; some- times superficial suppuration; in many cases, an atrophic condi- tion of the pulp, particularly net-like atrophy in which extrava- sations of blood are commonly found ; a secretion of a serous fluid with an offensive odor like that of macerating bone, which however does not properly belong to the fluid, but is generated by the putrefaction of the organic constituents of the dentine. The paroxysms of pain are less severe and less prolonged as a rule. Indeed there may be no pain, if there is no obstruction to the escape of the usually thin serous or purulent fluid upon the surface of the exposed portion of the pulp. Heat, cold, chemical or mechanical injuries of the exposqd portion, always produce an uneasy sensation which may be increased to severe pain. Chronio Abscesses in the Pidjj, independent of Caries, are very rare. The case illustrated in the Atlas, Fig. 51, of calci- * [The pulp often dies as the result of the use of arsenic to obtrude sensitive dentine, even when it is left in the cavity of decay but a short time. In these cases the tooth almost always becomes reddened. For this reason, in this country, the use of arsenic, except to devitalize the pulp, has been almost if not entirely given up. Even when it is used for destroying the pulp, un- less a free opening is made through the walls of the pulp-cavity that the fluids may And exit, intiltration of the dentine and discoloration follow. — T. B. II.] f Heider aus der Praxis: Deutsche Yiertelj. f. Z., 1862. ABSCESSES IN THE DENTINE. 187 fication of the root-pulps of a grooved molar of the upper jaw may, perhaps, be regarded as a case in point, where the coronal pulp contains, besides calcareous deposits, a cyst-like, spherical, quite large cavity, with smooth walls, which is separated bv a transverse membranous expansion from an analogous cleft-like cavity extending to the bottom of the pulp-cavity. There is, to be sure, no actual proof that the cavity in question is that of an abscess ; but the only other probability is that it is the cavity of a serous cyst. Still more rare is the occurrence, in man. of an excavation of the coronal portion, extending hdo the dentine^ as the result of an abscess. Th. Bell * reported a single case which came under his observation. A physician suffered, for a long time, from severe pain in the right side of the upper jaw, apparently referable to the second molar tooth which, however, presented no* external evidences of disease. After some time had elapsed, an inflammation of the root-membrane ensued, and the tooth became loosened a little. It now was obvious that this tooth was the source of the pain, which finally became in- tense, and so it was extracted ; as its exterior presented no in- dications of disease. Bell divided it with a saw, at the upper part of the crown, and found a completely circumscribed cavity in the dentine ; the surface Avas white and apparently sound and unbroken. The rest of the tooth did not present the least evidence of disease, excepting that the root-membrane, which had been inflamed for a long time, had also begun to suppurate. It seems, remarks Bell, that the inflammation arose primarily in the dentine, from some local cause ; that the bloodvessels of the dentine (of the pulp, rather) developed suppuration, and ab- sorption ensued in consequence of pressure, and, in this way, a cavity was produced for the reception of the pus. We shall frequently have occasion to refer, in the following pages, to the fact, that pus produces a "usure," a wearing away (usurire) of the dentine. In the teeth of large mammals, abscess cavities will be found quite frequently in the dentine^ if one only takes pains to search for them. ■^ Op. cit. , p. 173. 188 INFLAMMATIONS. The tusks of elephants, on account of their large size and great projection, are exposed to manifold mechanical injuries, and it is, also, a Avell-known fact, that it is not an uncommon occurrence, in working ivory, to find bullets imbedded in the tooth, which then presents pathological changes, that render it unsuitable for the purposes of the ivory turner. The attention of Goethe* was attracted long since to the changes in ivory which are produced by bullets imbedded within it ; he speaks of cavities in the diseased limits, which are partially lined by a delicate membrane. We are indebted to J. Tomesf for the very thorough descrip- tion of cavities of this nature in two tusks. The dentinal sub- stance in each of the two tusks presented a newly-formed cavity, having no connection with the pulp-cavity, nor indeed any out- let. One of them was quite empty, dry, and contained a small quantity of a desiccated membranous mass, or a fluid, which was apparent in the most dependent portion of the cavity, where it had become inspissated. In the other case, the cavity was broader, also without any outlet, encompassed by dentinal sub- stance and lined with a dried membrane ; here and there, small spinous processes of dentinal substance projected from the walls of the cavity. The dentine encompassing the cavity had a veined appearance like mai'ble, occasioned by the different di- rections assumed by the dentinal tubules, and also was traversed by numerous canals of the character of bloodvessels and visible to the naked eye. The lining membrane of the cavity was de- tached and macerated in water, and proved to be a fibro-cellular tissue. According to these statements. Tomes appears to have taken no notice of the new formation of osseous substance around the abscess-cavity. | Albrecht holds the view, for which there are grounds, that the vessels in the dentine of the second case can have been formed only by the prolongation of the vessels of the pulp. He assumes, then, that vaso-dentine does not occur in the tusk of the elephant. According to R. Owen,§ small bloodvessels ex- * Osteologische Mittheilungen, 1798. f Albrecht, Krankli. d. Zahnpulpe, p. 23. X Compare New-formations. I Odontography. ABSCESSES IN THE DENTINE. 189 tend forward in the axis of the tusk as far as its apex, and the bloodvessels may, also, penetrate, even to the dentine, from those of the root-membrane, if the abscess-cavity be located near the outer surface. By the kindness of Prof, von Schroff, I had the opportunity of examining segments of elephants' tusks which were labelled ulcers. They contain extensive abscess-cavities in the dentine, apparently entirely shut in, of the size of a pigeon's, a hen's, even of a goose's egg and, here and there, present irregular parietal sinuations. The cavities are lined by a desiccated, dirty-yellow, brownish-yellow, dark-brown and black mass. The portions adjacent to the cavities have a mottled look, and con- sist, principally, of vascularized osseous tissue, Avhich forms a layer of varying thickness encompassing the abscess-cavities, dips more or less deeply into the dentine, and presents in sec- tions various sinuations and islands (Fig. 75). If we trace the Fig. 75.* process of resorption of the ivory from the side of the en- croaching osseous tissue, it will be observed that both the main * Fig. 75 shows a section from the tusk of an elephant, containing a large abscess-cavity which upon one side approaches to within six millimetres of the periphery. It presents various cup-like excavations and is lined with an adherent, dried, dirty brownish-yellow mass. That portion of the wall which incloses the inferior segment of the cavity, is transformed into an ununiform tissue (a) (osseous tissue) to a depth of five to ten millimetres, the line of demarcation between it and the normal dentine being sharply defined. This tissue has a wavy outline, a spotted and striped appearance, and its consistence is less than that of normal dentine. Two-thirds natural size. 190 INFLAMxMATIONS. trunks and the lateral branches of the dentinal canals present numerous varicous expansions, Avhile portions of them are trans- formed into jagged, elongated cavities, or give place to a glob- ular, transparent substance. In other portions, large, multi- radiating bone-corpuscles have encroached upon the dentine, or vascular canals have become surrounded by concentric layers of osseous substance. From the wall of another abscess-cavity, conical processes, one-half to one millimetre broad at the base and two to four millimetres in length, project into it, and are composed partly of a minutely lobulated (kleindrusig), globular mass, together with bone-corpuscles, and partly of den- tinal canals, anastomosing without irregularity in various direc- tions and, here and there, forming tufts which extend in the direction of the axis of the conical process. A condition, also, is presented which essentially bears a close analogy to that observed by Tomes. The new hard formations upon the wall of the abscess (abscedirenden Wand) form a re- parative tissue which tends to replace the substance lost by the suppurative process, and probably their development would have gone on still farther, so that they would have diminished the area of the cavity, had they been supplied with fresh formative material by the bloodvessels. As I had only sections at my disposal, I was unable to make special investigations with refer- ence to the origin of the bloodvessels, which are the necessary antecedents to the production of both the new dental and osse- ous tissues and, also, of the suppurative process. In all proba- bility, the newly-formed bloodvessels Avere outgrowths from those of the pulp. The elucidation of this question remains for future special investigation. The chronic inflammation of the periphery of the abscess (Abscesshaut), in these cases, led to the production of solid tissues (osseous and dentinal), both of which must have been developed from cells. But even if we are willing to admit that the bloodvessels of the new-formed substances are derived from other pre-existing ones, still the appearance of the new osseous and dentinal substance in the wall of the abscess-cavity con- tinues to be an extraordinary phenomenon, and the assumption in relation to their appearance, that the cell-life of the con- DENTAL PULP. 191 ncctive-tissue parietes of the abscess is exalted to a diflferentia- tion, as in embryonic life, is open for discussion, since, indeed, we cannot by any means presuppose that the germs of the formative cells are transported to the part with the blood. As a general rule, as has been shown above at considerable length, injlammalion of the pulp imparts a reddish color to the dentine. Albrecht* observed dark-colored portions of dentine in localities corresponding to small defects which were visible in the lining of the wall of the pulp-cavity and extended as far as the enamel layer. It was observable, however, that the dark color Avas confined principally to the dentinal canals, and was much less perceptible in the intervening substance. The affected tooth, he says, undergoes a change of color, under these cir- cumstances, the dentinal substance becomes gray-black and as- sumes the condition of a gray, pulverous, structureless mass, which is perceptible through the enamel layer, the latter re- maining intact for a much longer period. Apparently, he ob- served no circumscribed defect in the dentine upon the inside, and, indeed, this is found only very rarely in conjunction with a discoloration of the tooth. Dr. Steinberger informed me, that he could call to mind only a single instance which occurred in Heider's practice, where the dentine had become softened by the extension of gangrene from the pulp-cavity. In this case, Heider exposed and filled the cavity, and succeeded in preserv- ing the tooth. Cases of this kind may possibly have given rise to the supposition of the occurrence of caries interna (compare Anomalies of the Secretions). Chronic inflammations in the pulp lead to various forms of atrophy, among which, chronic fatty degenerations and calcifi- cations are to be mentioned especially. The new-formations, which are consequent upon an irritation of the elementary organs of the pulp, include those of dentine, osseous substance and connective-tissue cells (sarcomatous proliferations). f The return to an entirely normal condition is very exceptional, and whenever there seems to be a probability of such an occurrence, frequent relapses will undeceive one. In fact the pathological * Op. c'it., p. 21. f Vide New-formations. 192 INFLAMMATIONS. germs of the cells persist, and the latter are called into renewed activity under the influence of trifling causes. Chronically in- flamed pulps may, also, become gangrenous and transformed, partially or entirely, into a fetid, pultaceous mass. An important affection, which frequently occurs as a sequel of inflammation of the pulp, is that of the periosteum of the root, a fact easily explained, when the relations of the bloodvessels and nerves are taken into consideration. This membrane be- comes swollen, abscesses are formed, generally at the extremities of the roots, and the pus finds an exit into the substance of the gum or into other regions, to be mentioned farther on. Gums. — According to the locality and symptoms, there is dis- tinguished a superficial inflammation of the gums, which is con- fined to the outer mucous-membrane layer, and a general paren- chymatous inflammation which is not limited to the outer, but attacks, as well, the deeper layers. The character of these in- flammations is controlled by the genetic conditions which are the foundation of the processes, and its determination presents manifold difficulties. The mere form, independent of all other clinical evidence, aff"ords insufficient grounds for an opinion as to its character. Individual peculiarities modify the general eff"ect of the disease, and the combinations of diff'erent processes produce a variability in the phenomena. In many cases it is possible merely to make distinctions with reference to the course of the disease, that it is acute or chronic. Every inflammation of the gums may give rise to a superficial or deep destruction of the substance of the gum and, likewise, may cause a destruction of neighboring tissues. In catarrhal inflammation of the gum, the latter assumes a rose-red color which is most apparent upon the free edges; sub- sequently, white spots appear and disappear, which are produced by the exfoliation of the epithelium. The gum feels uniformly, though not notably, swollen, smooth, and hot. The patient complains of annoying sensations of itching, tickling, and burn- ing, which are diminished temporarily by grinding the teeth. A livid gray, mucilaginous, frequently puriform secretion col- lects in the pockets formed by the gum, and oozes out, when the finger is pressed along its border. GUMS. 193 This inflammation occurs most, frequently upon the labial surface of the incisors and canines of the lower jaw, and more rarely upon the same surface of the corresponding upper teeth. In the latter case, the covering of the hard palate of the affected side becomes involved. Still more rarely are the gums of the bicuspids, and almost never are those of the molars attacked. The affection either is limited to the gums of a few teeth merely, or invades those of all the incisors and canines of one jaw, less frequently of both jaws, and never those of all the teeth of either jaw. The inflammation ma^^ continue months and even years, par- ticularly upon the lower jaw where the secreted fluid accumulates Avithin the pockets formed by the gums. In cases of unusually long duration, it spreads to the periosteum of the root, gives rise to resorption of the margin of the alveolus and loosening of the tooth in its socket. The more acute forms, in most cases, are due apparently to the same causes which generally give rise to catarrhal conditions, to excessive variations in temperature, damp and cold weather, &c. Another very frequent cause, particularly of inflammation of the gums of the incisors and canines, is the prolonged, con- tinually-repeated mechanical injury^ to which these teeth are subjected in closing the jaws, when several molars and bicuspids are wanting. With the latter condition the incisors and canines are pressed together more firmly in chewing and experience slight movements in their sockets, whereby the gums and root- membrane become irritated and swollen. As the mechanical injury continues, a process of resorption of the margins of the alveoli, also, is induced, the tooth becomes loose and finally falls out. An accumulation of tartar with its rough outer surface, also, produces a mechanical irritation of the margins of the gums and gives rise to a chronic catarrh, while the secretion of the latter, on the other hand, occasions an increased formation of tartar. Each process, consequently, promotes the development of the other. In cases where caries has destroyed the greater part or the whole of the coronal portion of the tooth, the sharp edges of the 13 19-i INFLAMMATIONS. cup- shaped carious cavity become a sourne of irritation of the margins of the gums ; the putrid products of decomposition, which result from the carious process, also have a similar effect. If the neck of the tooth, also, or a portion of the root is destroyed by caries, the gum loses its support, becomes detached, inverted, and acts as an additional constant source of irritation. With tobacco chewers and those who smoke filthy pipes and strong cigars, especially if the}^ do not pay proper regard to cleanliness, the tobacco juice becomes an important source of irritation. Catarrhal inflammation is observed, also, as an accompaniment of catarrh of the intestinal tract. The character of the catarrhal secretion is essentially modified by the constitutional peculiarity of the individual. In tubercu- lous people, generally a very abundant, frequently puriform, secretion is observed, and the affection is usually very obstinate, wdiile with individuals who are healthy in other respects, it dis- appears directly on the removal of the irritating cause. Super- ficial ulceration of the gums is a not uncommon sequel of a neglected or obstinate catarrhal inflammation ; such ulcers are flattened and covered, at the base, with a firmly-adherent gray mass ; they heal finally without leaving a perceptible breach of substance. If the old epithelium, even in the minor catarrhal affections, is not removed, but, remaining adherent, becomes mixed with the debris of food, and if, in addition, there is also a gastric catarrh, the cells become disintegrated, their contents thickened, and between the layers are found the familiar fermentation fungi (mucor), which are very abundant in mucus, under the favorable conditions afforded especially by individuals present- ing evidences of impaired nutrition, e. invested by straight fibrous ~ "" "^ ^ tissue. In other places, devel- '^•^1 ^' ^ (" i}}< opment has progressed to the r - formation of minute osseous trabecul?e of various forms, containing jagged bone-cor- ~~ puscles and presenting, upon their peripheral portions, superposed roundish formations (Fig. 97). The opinion formerly entertained that the tumor merely dis- tends the bone, forces the external layer outwards, is disputed by Virchow on the ground that these tumors sometimes attain such magnitude, that, if there is merely a distention, it would be impossible for the bony shell to continue unbroken. It is much more probable that a new- formation of osseous substance takes place upon the outer surface from the periosteum, in the same manner in which the apposition of fresh layers ensues in growing bone. In the case cited, a complete destruction of a portion of the maxillary wall ensued from resorption. In the upper jaw, also, the fibromata attain quite large dimen- sions. Several of the tumors which I have had the opportunity of examining contained so many calcareous deposits that the surfaces of sections through them communicated a gravelly feel- * Fig. 97. — Section from the central portion of the same fibroma. Straight bundles of fibrous tissue include fusiform cells containing oblong nuclei, and interlace with one another. Nests of ovoid cells are imbedded here and there. The highly-refractive calcified portions have a homogeneous appear- ance and a roundish or elongated form {n). The isolated trabecule have the character of young, imperfectly-developed, osseous substance, and are surrounded by roundish, nucleated formative colls (A). The basis-substance, in many places, has a coarse granular appearance; the jagged bone-corpus- cles are more or less minute, and notched cavities filled with amorphous calcareous salts are brought into view here and there. Magnified 400 diameters. SARCOMATA OF THE JAWS. 343 insT. Dr. Friedlowski showed me a skull, from the anatomical collection, which presented a breach involving the facial wall of the antrum of the left side, a portion of the horizontal plate of the superior maxillary bone, and of the inferior turbinated bone. The second molar on the left side was inclined anteriorly, and the alveolus of its anterior facial root was entirely destroyed. The alveolar process was wanting, from the canine as far as the second molar. The breach in the bones extended upwards to the vicinity of the zygomatic arch and was bounded everywhere by sharp edges. The tumor which occupied the smooth-walled cavity corresponded in character to those above described, ac- cordinor to the statements of Dr. FriedloAvski. Since these tumors may be enucleated, resection may be avoided in suitable cases. Sarcomata of the Jaws. — Without taking into considera- tion those which are developed from the alveolar process and have been treated of in the preceding pages, sarcomata are of frequent occurrence, especially in the lower jaw, in the form of simple, cysto-, and osteo-sarcomata. The cysto-sarcoma is developed in the spongy tissue of the bone, which is very abundant in the lower jaw. A portion of this tissue undergoes complete resorption, and in its place occur sarcomatous masses and cyst-like cavities of various dimensions, some being very small while others are tolerably large (Atlas, Fig. 143). The larger cavities are lined with a separable, con- nective-tissue membrane, the internal surface of which is covered with a coating of small cells.. Reddish, succulent proliferations of a roundish, tuberculated, nodulated, mulberry-like form, pro- ject into these spaces which are filled with a thin, yellowish, yellow-brownish, or a thick, viscid, stringy, ropy fluid. In the case illustrated in the Atlas, Figs. 142 and 143, the sarcomatous mass has a quite remarkable structure. There is a fibrillated stroma of connective tissue ; in this are imbedded vesicular and tubular cavities which, here and there, subdivide and everywhere are lined with cylindrical epithelium, the Avhole presenting the appearance of a utricular gland with many terminal vesicles as if detached by constriction. These adenoid masses inclose multifariously-siuuated cavities which attain con- 344 NEW-FORMATIONS. siderable size in consequence of the secretion of a fluid on the part of the colunnar epithelial cells and their proliferation. The adenoid structuie is apparent -wherever a sarcomatous mass is to be seen, and is wanting Avherever a dense, firm, fibrous, connective substance occurs, as in the cicatricial gum corres- ponding to the . usually have a li";ht or gravish-brown color, v penetrate the entire thickness of the enamel at first only in the thinnest portion near the neck of the tooth. It happens, sometimes, that a portion of the summit of the still hard dentine, with a brownish-yellow pigment deposit cor- responding with the carious locality, remains unaffected, while the rest of the dentine is destroyed by the boiling dilute sul- phuric acid. It has not yet been determined whether or not a casual, unusually great power of resistance on the part of the dentine is to be assigned as the reason for this occurrence. If we select a series of teeth which are affected with caries in its earlier stages and belong to the different periods of life, and treat them with very dilute hydrochloric acid, it may readily be of the enamel are to be observed ; these are not the results of abrasion or caries, but are to be regarded as defects in the formation of the enamel. Magnified 2 diameters. * Fig. 100 — Interior view of the enamel-cap from a molar affected with chronic caries. The latter occurred in the crucial groove. The wall cor- responding to the masticating surface presents a few gaps and several dark spots ; the enamel tissue in the vicinity of the former and in the latter had a dirtj'-grayish and reddish-brown color, and is fissured and full of excava- tions; the carious attection is more extensive upon the inner than upon the outer surface. Magnified 2 diameters. APPEARANCES PRESENTED BY CARIOUS ENAMEL. 381 demonstrated that the portion of the detached enamel membrane corresponding to the carious locality has undergone a perceptible thickening. The transparent membrane, moreover, where the transition into the carious portion is apparent, is clouded, brit- tle and variously stained. The colors vary between gray, grayish-brown, brownish-yellow, syrupj^-brown, reddish-brown, and reddish-yellow. With regard to the cnrious localities, it is to be borne in mind that one has to do not only with the mem- brane of the enamel, but also with the organic remains of the enamel. The frequent gray cloudiness presented by the detached mem- brane is found to be due to a uniformly-diffused mass of granules of nearly equal size and arranged side by side and over one another at uniform distances. The molecular mass is the so- called matrix of leptothrix buccalis which is united so intimately with the enamel membrane and the organic remains of the enamel that together they form an inseparable whole. The thickness of the matrix varies, and the thickening of the mem- brane is due, in a great measure, to the latter; the brittleness and friability of this membrane, also, is occasioned by the super- position of the matrix. As proof that the latter appertains to the leptothrix may be adduced the fact that it is not uncommon to find tufts of leptothrix threads hanging from the edges of the granular mass. The brown portions present light or dark-brown, transparent, homogeneous masses which are fissured in such a manner as to display a lamina composed of irregular polygons. The perfora- tion of the enamel-membrane, mentioned above as resembling the nerves of a leaf, presents a strong resemblance in its con- figuration to the brown mass in question ; the latter, however, is thicker and proceeds from the enamel which is deprived of its calcareous salts, transformed into a homogeneous mass and foraminated. The familiar mosaic appearance produced by the transverse division of some of the prisms is beautifully shown, in some cases, after the extraction of the calcareous salts from carious enamel. Some of the prisms contain a homogeneous, highly refracting, light or dark brown, and others a granular, mass of 382 ANOMALIES OF THE SECRETIONS. a similar color (Atlas, Fig. 84). The persistence of the contours of the enamel prisms in places after treatment Avith acids is un- explained, at present. Possibly it may be due to the prolifera- tion of a leptothrix mass into the decalcified enamel. The carious enamel sometimes, also, is transformed into a coarse-granular, brown mass ; now and then the granules are blended together and are to be regarded as the organic remains of the shrivelled enamel-prisms. The mass is intimately united with the enamel-membrane, upon the outside of which, in many places, is located the matrix together with the attached threads of leptothrix. When the deposits of pigment impart a blackish-brown color to the carious enamel, the prisms are no longer distinguishable. After the extraction of the calcareous salts from the enamel, there is left, sometimes, a brittle, friable, blackish-brown mass which presents sharp and angular edges when broken. In the later stages, the enamel-membrane acquires a syrupy-brown discoloration. When the carious enamel presents superficial greenish spots, this color is participated in by the externally-attached matrix of leptothrix, the enamel-membrane and even the organic re- mains of the enamel-prisms, to a varying degree. If so-called eroded, cribriform, foraminated [honeycombed], and, consequently, irregularly-developed enamel, Avhich is af- fected with commencing caries, be decalcified, the enamel-mem- brane Avill display an alveolate appearance, i. e., it presents round, sharp-edged pits of various sizes, within which the mem- brane is thinner and perhaps wanting entirely, here and there, and a leptothrix-mass has taken up its abode. Between the light-colored alveoli lies a yellow, syrupy-brown substance. In many cases, the remaining organic matter of the enamel from the teeth of old persons, which are aifected with commencing caries, presents the appearance of a diffluent, coagulated, trans- parent, structureless, effused substance, in the interstices of which is lodged a molecular, dirty-gray leptothrix mass. Usually in the course of the process, an undermining caries of the enamel is met with, ^. c, the caries is more extensive in the deeper layers of enamel than is apparent externally upon APPEARANCES PRESENTED BY CARIOUS ENAMEL. 383 the surface, jnst as if the process commenced in ^' • ^'^l'' 1 Left, . „.^ ; Riglit, . ^'^1 Left, . 906 809 467 403 1st Molars, . . . C Superior, . . 4,499 ] [ Inferior, . 2 97':! i P^'S-ht, . ^'-"^ 1 Left, . 1 Ofi r Right, . . -''-''' iLeft, . . 1,189 1,084 1,092 1,034 2d Molars, . . . f Superior, . . 3,615 } [ Inferior, . ■.«MS;'': 838 837 938 1,002 3d Molars, . . . C Superior, . . 1,924 \ (Inferior, . . 470 429 513 512 Total, . . . 20,000 20,000 20,000 Superior, . 13,1.36 f Right sid 6,864 t Left " e face, . . 10,151 Inferior, . . 9,849 400 ANOMALIES OF THE SECRETIONS. tained that caries may be observed as early as the third and fourth year, and that its frequency increases in regular progres- sion from this period up to the twelfth year, the period at which, on the average, the last milk tooth becomes detached. In respect of 7'ace, notable diiferences are observed. Broca, and more particularly Mummery, carefully examined large col- lections of skulls, for the purpose of ascertaining the frequency of dental caries. The latter found a percentage of 41.66 as ex- pressing the frequency of caries among those of the ancient Egyptians, 2.94 among those of the ancient Britons with elon- gated skulls, 21.87 among those with round skulls, 28.67 among those of the Romano-Britons, 15.78 among those of the Anglo- Saxons. Among the modern races, he obtained the lowest per- centage from those of the Esquimaux, natives of the northern coasts of America, New Zealanders, and inhabitants of the northern parts of the East Indies. In Europe, the results show a percentage in favor of the Sclavonic race. In connection with the peculiarities in the structure of the teeth according to race may be considered those which are manifested according to family. It is a familiar fact to all dentists, that children's teeth very frequently resemble those of the father or mother and, therefore, that many defects and mal- formations of the teeth are hereditary in a family, e. g.^ the ab- sence of the upper lateral incisor, the oblique position of a certain tooth, the shape of the teeth, spots upon them, &c. In the same way, also, is the familiar and curious fact to be explained, that with children of the same family the corresponding teeth become carious in the same order, at similar points and at a certain age. Many are inclined to ascribe the differences in respect of the frequency of caries, to locality and the articles of diet. Climatic and geological peculiarities, or the Avater, are assigned as the causes, though authoritative grounds cannot be adduced in sup- port of these views. Mummery endeavored to establish a par- allel between the ordinary food of the different races and the per- centage illustrating the frecjuency of caries, but definite results cannot be drawn from these data. As a matter of course, ade- quate nutritive material is just as requisite for the formation and maintenance of the teeth as it is for the rest of the body, FREQUENCY OF CARIES. 401 whether it be of an animal or vegetable nature. If it be true that geological and climatic conditions, and the means of sub- sistence Avhich are connected with the same, have such a pre- ponderating influence in respect of the frequency of caries, then it is impossible to explain the fact that foreigners belonging to different races, who are exposed to the same conditions with the native inhabitants, still retain the typical structure of their teeth as well as that of their bodies, and continue to furnish the pro- portion of dental caries peculiar to their race. This is found to be the case with the isolated Sclavonic races of Austria and the descendants of the Celtic race in France.* Popular customs promote or retard and may even give rise to caries. Steinbergerf remarks, in this connection, that the crowns of the upper milk incisors, especially in children of the lower classes, are mostly or entirely destroyed by caries even in the second or third year of life, while the lower incisors are scarcely ever so extensively affected and the molars, usually, are still entirely sound. It is found in such cases that the children have been accustomed for months and even years to use a suck- ing-bag containing cracker or white bread which is first soaked in milk and then in a weak solution of sugar. In this way, he says, all the conditions necessary for the rapid formation of vinegar are afforded ; the sugar acts during the process of its fermentation, and the action of acid in statu nascenti is much more intense. Tobacco-smoke or juice is considered by many to be a pre- servative, or a means of preventing caries, though it is not stated whether the secretion of the gums acquires an alkaline condition or the proliferation of leptothrix is diminished. On the other hand, it is quite common to find teeth with a sooty covering, * As geological, climatic, and social conditions exercise a predominant influence upon the growth and development of the A'arious races mentally as well as physically, it is evident that the development of the dental organs cannot fail to be controlled by the same causes. In this country, which is annually receiving large numbers of foreigners by emigration, the typical traces of race are usually effaced after the lapse of a generation or two, the descendants possessing all the peculiarities, and their teeth apparently being as liable to caries as the teeth of Americans generally. — T. B. H. t Deutsche Viertelj. f. Zahnh., 1862. 26 402 ANOMALIES OP THE SECRETIONS. from tobacco-smoke, upon the lingual surface and, at the same time, an extensive carious affection of the facial surface of the neck. An enumeration has been made of the articles of diet -svhich are said to tend to increase the frequency of caries, such as fruit, food which has become sour, curdled milk ; but sugar is regarded as the most injurious. Larrey* asserted that teeth are acted upon by a solution of sugar, the enamel acquiring an opaque appearance, the tooth readily crumbling and becoming almost gelatinous. In this connection, stress is laid upon the affinity of the sugar for the lime with which it enters into com- bination. Marchand denied the accuracy of these experiments, and asserted that no perceptible changes can be detected in teeth which have lain for weeks in a solution of sugar. It has also been stated by English writers that the natives of the East Indies eat a large amount of sugar and with a mere vegetable diet have very good teeth ; to be sure, they keep their teeth very clean. Magitot recently experimented with sugar and ob- tained a result corresponding with that of A. Westcott (1843), namely, that sugar exercises no direct, i. e., in the condition of sugar, injurious effect upon the teeth, since solutions of sugar occasioned extensive destruction of the tooth only after some time (two years) had elapsed, when the solutions were left alone or materials were added to them which acted the part of ferments. The fermentative process gives rise to the development of lactic acid and, subsequently, butyric acid and a few of its derivatives, as propionic and valeric acids, &c. Mantegazza, of Pavia, ex- perimented in another way ; he placed teeth, which had pre- viously been dried and weighed, in solutions of sugar of various degrees of concentration, in distilled Avater and in saliva which was removed directly from the mouth, and, after a few days, noticed an acid reaction of the fluid which contained traces of lime ; the teeth had lost in weight. His conclusions coincide pretty nearly with those of Magitot. Various occupations are directly or indirectly injurious. It is a well-known fact that the teeth of confectioners and cooks * Gaz. Med. di Milano, 1844. EFFECTS OF CARIOUS TEETH ON THE BODY. 403 are very apt to be aiFectecl, and it is supposed that the dust from the sugar enters into combination with the mucus of the gums and the deposits on the teeth, and occasions an acid fermentation. Richardson calls attention, in his lectures, to the fact that dental caries is exceedingly common among the fur-dyers, since the teeth are acted upon by the fumes of the nitric acid which is employed for cleansing and imparting a yellow color to the furs. The fumes produce a dryness and irritated condition of the oral mucous membrane of the tongue and fauces ; as a rule there is constipation, pain in the occipital region and a sensation of constriction of the chest. The drying-room, in which are placed the damp skins impregnated with the nitric acid, is filled with the fumes of this acid. The teeth lose their enamel and, occa- sionally, are entirely destroyed. The fumes of ammonia, also, and the dust occasioned by beating the dried skins, exercise an injurious action. • . Many diseases of the general system promote the development of caries, especially those during the existence of which the mixed saliva generally acquires an acid reaction, including many forms of dyspepsia, cancer of the stomach, diabetes, scrofula, rachitis, phthisis, and aphthae. Effects of Carious Teeth upon the Rest of the Body. — Although, in many cases, it is hardly possible to decide abso- lutely whether the caries is the result or the cause of a certain affection, still approximate results may be obtained from the observation of cases in which a healthy condition is restored after the removal of carious teeth. Every dentist has oppor- tunities enough for observing cases of this kind. The effects are manifested in adjacent or more distant organs with which the mixed saliva comes into contact. The sharp edges of carious teeth sometimes give rise to ulcerations having a cancerous appearance upon the oral mucous membrane, the tongue, or lips, a fact readily explained since the wounded parts are constantly exposed to the foul products of decomposition, resulting from the carious disease. Listen ascribed a number of local and general affections to the presence of carious teeth or decomposed fragments of teeth. The consecutive inflamma- tions of the pulp, root-membrane, gums and periosteum, the ab- 404 ANOMALIES OF THE SECRETIONS. scesses in the alveoli and jaws, have been considered in the pre- ceding pages. Listen also considers caries of the teeth to be a frequent cause of swelling of the tonsils, intense and long-con- tinued headache, various digestive derangements and gastralgias, which affections disappear as soon as the offending carious teeth are removed. Caries of Reinserted Human Teeth. — As a rule, the necks of these, and especially of the front teeth of the upper jaw, become the seat of the disease which generally affects their entire circumference. This fact is easily explained when we consider that the gum does not become attached to the neck, and hence accumulations of the secretions occur more readily. The dentine in the above locality acquires a dirty-j^ellow, brownish- yellow, dirty-brown discoloration and undergoes a superficial cartilaginous softening which spreads beneath the enamel-layer adjacent to the neck, and the enamel acquires an eroded appearance. The deposits of pigment, consequent upon the carious pro- cess, may be traced to a depth of 1 to 2 millimetres into the dentine; s_-^!^?f adjacent to the pigmented portion occurs a dark zone which adjoins another, in many cases, very light zone. Upon close examination of the dark zone and its transition into the pigmental and light portions, respectively, the same changes are found as in ordinary caries of the teeth. The canals are filled with rows of minute grains which gen- erally have a roundish, in some Fig. 101/ * Fig. 101 illustrates a carious affection of the dentine of a reinserted human incisor. The portion of dentine examined still retained sufficient consistence to allow a thin and polished section to be prepared. At the upper surface (a) are sharply defined cavities ; these were filled with masses of lep- tothrix which have fallen out. Next in order is a granular, cloudy portion where the canals, which are more clearly visible beyond (b), are filled with grains arranged in rows like strings of pearls. The interglobular spaces (c) are clouded by accumulations of dirty-brownish molecules. Magnified 500 diameters. CARIES OF REINSERTED HUMAN TEETH. 405 cases, an elongated, rod-like shape, are very clearly distinguish- able from the intermediate substance and, when they are of larger size, form chains like strings of pearls (Fig. 101). If the calcareous salts be removed from dentine of this description, by means of hydrochloric acid, and heat be applied until the pro- cesses of the dentinal cells are set free, knotty swellings make their appearance upon them, in precisely the same manner as in ordinary carious dentine. The processes, here and there, are beset with grains of leptothrix ; quite a large portion of the granular mass in the canals and clouded intertubular tissue, how- ever, is composed of fat, as is shown by the fact that it forms a large number of drops on the addition of hydrochloric acid. The interglobular masses are light in some places ; in others they present a molecular cloudiness and, sometimes, a dirty-brownish discoloration. The outer surface of the Softened, cartilaginous dentine pre- sents very distinct perforations which ex- tend to a considerable depth into its sub- stance. These form the chief abode of the masses of leptothrix which occupy the manifold excavations and may be traced in the irregular pouches which dip down deeply along the course of the dentinal canals (Fig. 102). The den- tinal fibres, beset with an abundance of grains of leptothrix, form free projections beyond the borders of the section, when there is a marked degree of cartilaginous softening, and in cross-sections display, here and there, a notable thickening. A violet color may readily be imparted to the leptothrix mass by means of iodine and hydrochloric acid. * Fig. 102 shows softened, cartilaginous, carious dentine, from a reinserted human tooth. Proliferations of leptothrix-matrix have taken place from irregular, pouch-like excavations into the dentine, along the course of the canals. Maa:nified 500 diameters. 406 ANOMALIES OF THE SECRETIONS. In addition to the above, mycelium tubes, similar to those of oidium albicans, are met with, sometimes, upon the surface of the decomposed dentine. Caries, as is well known, frequently makes rapid progress in the dentine of reinserted teeth. I observed a case where, in fourteen days after the insertion of a pivoted tooth, the dentine in the vicinity of the pivot was found to have acquired a deep black color, to the depth of about one-third of a millimetre. Brown and light spots pervaded the dentine. The eroded border of the enamel presents cup-shaped exca- vations and numerous cracks which extend in short segments along the undulatory courses of the enamel fibres, or form a network. In the vicinity of the affected portions, the enamel has a mottled, clouded appearance, the prisms have a dark or black-brown color, with a reddish tinge, now and then, and are in the process of disintegration. Caries of Teeth made of Ivory from the Hippopotamus. — Thomson calculated the specific gravity of this ivory to be 1.866, and the amount of its organic substance to be 33.41 per cent. The caries, which frequently is very extensive, does not confine itself to the artificial teeth, but spreads beyond the groove which serves for the reception of the alveolar arch. The discolorations are very marked, being sometimes light-colored, at other times, dark-brown ; the cartilaginous softening is so extensive that sections may readily be made. The loss of sub- stance may be quite considerable, both upon the necks and lat- eral portions of the crowns, and hemispherical defects, sometimes, are formed upon adjacent teeth, in the same manner as in natural teeth ; it is obvious, therefore, that the carious process spreads from one artificial tooth to its neighbor. Caries generally com- mences upon the facial and lingual surfaces, and upon the mo- lars ; it originates in the grooves where it forms irregular exca- vations and, also, in the vicinity of cracks in the dentine and about those portions Avhere pivots have been inserted, or plates have been adapted. The yellow, light, or dark-brown pigmental degeneration com- mences upon the carious surface and extends into the dentine to a depth of a few millimetres. Next to this portion arc dark EXPERIMENTS UPON TEETH. 407 and light zones and, beyond the hitter, the contents of the den- tinal canals present transverse breaks, in many places. Some- times the dentinal fibres or processes of the dentinal cells dis- play such uniform transverse fissures that one might imagine them to be thallus-threads, composed of minute articulations ; in other places, however, the irregularity of the clefts does not admit of such an interpretation. The manner in which the met- amorphosis in the dentinal canals within the dark and pigmental zone takes place is quite evident. Minute, sometimes glittering grains, arranged closely together in rows and following the di- rection of the canals, and, towards the outer surface, rod-like bodies, isomorphous with Bacteria, are inclosed in the canals. Sections, which have been decalcified and heated until the isola- tion of the dentinal fibres has been effected, establish the fact beyond any doubt that a fatty degeneration has ensued in the affected dentine and that a proliferation of leptothrix has taken place within the canals. The dentinal fibres, frequently thick- ened to five and ten times their normal size and presenting varicous swellings, are beset with grains of leptothrix. A violet color is produced by the latter in the dentinal canals, on the addition of iodine and acid to thin sections. Sections of the softened, cartilaginous dentine, made in a di- rection perpendicular to that of the canals, present appearances exactly similar to those found in carious reinserted human teeth or in ordinary caries of normal teeth, i. e., we find, besides the normal canals which are considerably thickened, have a glitter- ing appearance and are surrounded by a light halo, groups of others, inclosing, sometimes, a finely-granular mass, the con- tents of which assume a more or less distinct violet color on the addition of a solution of iodine and acids. In artificial teeth in which the dentinal canals have a direction parallel to that of the carious surface, caries extends into the substance, independent of the course of the dentinal canals. Experiments upon the Teeth -with various Substances. — A. Westcott (1843) and Allport (1858) made special investi- gations in order to determine the effects of acids and other sub- stances upon the teeth. Their results coincided in showing that mineral and vegetable acids affect the enamel in such a way that 408 ANOMALIES OF THE SECRETIONS. it may easily be scraped off. The former, also, ascertained that salts, whose acids have a stronger affinity for lime than for their own bases, likewise act upon the teeth ; that vegetable substances only act when they undergo acetous fermentation, as sugar, for example, and that the action of animal substances is very slow, if, indeed, they exert any action, even in association with very advanced decomposition.* Magitot submitted teeth to the action of acids, salts and al- bumen, during certain, quite long intervals (up to two years), and asserts that he produced conditions analogous to caries. He obtained positive results Avith lactic acid in the proportion of 1 : 100 parts of water. The teeth were alloAved to remain in this fluid for two years, when it was found that their roots had become flexible, gelatinous, as it were, and shorter ; the enamel was chalky, friable, separated from the coronal surface in places and readi-ly reducible to a Avhite powder by trituration. The whole dental mass presented a general brownish color. Teeth which were covered with resin, with the exception of one portion, became affected with penetrating caries, in some cases to a depth of 3 to 4 millimetres. A solution com]30sed of a gramme of lactic acid to a litre of w'ater made no perceptible effect upon teeth which were kept immersed in it for two years. According to his experiments, butyric acid produces very nearly the same effects as lactic acid ; the color produced by the caries, also, is analogous. It is a fixed acid not susceptible of fermentation. With citric acid, also, there was no indication of fermentation, and he found its deleterious action to be quite intense, so that, at the expiration of two months, it was quite marked even with a solution of 1 : 1000 parts of water. He states that this acid is more injurious than any others which act upon the teeth. It occasions no discoloration, which leads to the conclusion that it naturally induces a white caries. From experiments with malic acid and cider, he found that the former, in the proportion of 1 : 100 parts of water, acts with more energy than the latter. * Leber und Rottenstein iiber Caries, p. 68. EXPERIMENTS UPON TEETH. 409 Magitot repeated the experiments of Berzelius and Dumas, of decalcifying teeth by subjecting them to the action of carbonic acid, as it occurs in Seltzer water which, usually, contains one volume of water to five volumes of gas. The enamel became friable, the dentine became softened. When equal -volumes of water and gas were employed, he was unable to detect any chanoje in the teeth which were immersed in the solution durinof eight days. For reasons which may readily be understood, he is of the opinion that acidulated waters do not act upon the teeth. Teeth which were allowed to remain in fluid containing /er- menting alhuminoid substances acquired a general and uni- formly softened condition in the course of two 3^ ears ; the roots became transparent and soft, the enamel friable and opaque. Teeth which were protected entirely, excepting at one point, presented the characters of true caries at the exposed part. During the putrefaction, fatty acids formed, of the acetic and benzoic series ; the putrid odor suggested butyric and valerianic acids. A solution of alum (1 : 100 parts of water), which at the end of two years had an acid reaction, had not affected the roots in the least during this period, while the enamel lost its glazed appearance, became opaque and had the appearance and brittle- ness of a layer of chalk ; the dentine and the cement were not in the least affected. The action of a solution of hinoxalate of potash (1 : 100 parts of water) was very similar to that of the solution of alum, that is, it was limited to the enamel. Acetic acid (1 : 100 parts of water) induced a very peculiar change in teeth which were allowed to remain in it for two years. The roots became softened throughout, flexible, yellowish and considerably thinner, while the coronal portions remained unaf- fected. The enamel retained its polished appearance and firm- ness. Tartrate and hitartrate of potash (1 : 100 parts of water), also, left the enamel intact and attacked the cement and dentine, but their action penetrated to a less depth than that of acetic acid. A solution of chloride of sodium (1 : 100 parts of water), con- 410 ANOMALIES OF THE SECRETIONS. taining a few drops of creasote, manifested no action upon the teeth. Tannin (1:100 parts of water) acted upon the cement and dentine, but not in the least upon the enamel. Magitot divided the substances, according to his experiments, into four groups : 1. Those which attack all the dental sub- stances ; 2. Those which occasion a disorganization of the enamel exclusively ; 3. Those which act exclusively upon the dentine and cement ; 4. Those which induce no change in either of the three dental tissues. Unfortunately, Magitot neglected to make histological exam- inations of the teeth in which caries was induced artificially, as this would be necessary in order to establish the identity between natural and artificial caries, Leber and Rottenstein repeated a number of Magitot's ex- periments, with these modifications, however, that they dimin- ished the duration of the action and, as it appears, allowed the substances to act only upon the entire surfaces of the teeth and not upon separate portions. They took exception to the ex- periments of Magitot and showed that the results are not due to the acids alone, but, also, to the decomposition of the organic substance of the tooth, to putrefaction and fermentation, and that the effects produced by the low vegetable and animal organ- isms which are developed in the latter processes, also, are to be taken into account. They were unable to satisfy themselves that the mere action of acids produces changes exactly similar to those observed in caries. Their experiments with tartaric and acetic acids, oxalic acid and alum gave results different from those reported by Magitot in regard to the non- affection of the enamel and cement respectively. Caries of the Teeth of Animals. — I have had an oppor- tunity of examining only a few carious teeth from the horse, which were furnished to me by Prof. F. Miiller. As is Avell known, caries of the teeth is a very rare occurrence Avith ani- mals. They were cases of so-called dry, chronic caries, with no evident, separable, cartilage-like, softened layers in the dentine or cement. In one premolar, the carious affection was presented in its CARIES OP THE TEETH OP ANIMALS. 411 early stage, in the form of a blackish-brown, circumscribed spot, tlie size of a lentil, upon the much worn, excavated, grinding surface, and made its first appearance on the prominent fold of enamel. The carious pigmental degeneration extended, in many places, through the entire thickness of the enamel, as far as the line of junction with the dentine, and, in well-marked localities, was indicated by an intense sap-brown color, the line of demar- cation being well defined. The enamel prisms appeared to be filled with a molecular mass which I did not consider to be lep- tothrix, since the surface of the enamel was found to be smooth, and without any deposit upon it. Where the caries was more extensive, in the tray-shaped abraded, grinding surface, and involved, also, the bony and den- tinal tissues, the encroachment of the affection upon the den- tine was so slight that cross-sections presented merely a narrow streak of carious, blackish-brown discoloration. No finely granular contents were visible in the dentinal canals adjacent to the affected portions, and no leptothrix-mass was attached to the latter. The strong bony tissue of the premolar became undermined by the carious process in such a manner, that carious cavities were met with at a considerable depth below the grinding surface. Here, also, the light-brown discoloration involved only a few rows of bone-corpuscles which, together with the interglobular sub- stance, were uniformly pervaded. The exterior of the carious bony tissue of the tooth was free from leptothrix; the peripheral layers of the latter tissue, as well as of the carious dentine, had a more homogeneous, trans- parent appearance ; it is still undecided if it be allowable to re- gard this as a slow process of decalcification. Theories op Caries. — From the historical account whicli has been given, it is evident that the theory of caries has been sought for chiefly in three directions ; some have given promi- nence to the vital, others to the purely chemical and to the parasitic processes, and still others have advocated divers views, based upon various combinations of the latter processes. Formerly, the knowledge of the structure of the tooth was so defective that there was no anatomical basis for the study of 412 ANOMALIES OF THE SECRETIONS. the carious process, and, until the fourth decade of the present century, when the histology of the tooth became determined by degrees, it was impossible for an accurate investigation of the structural changes in the carious tooth to be made. In order to complete our knowledge of the subject, however, a gap re- mained to be filled up, until within the last ten years, namely, the establishment of the history of the development upon a sound basis. As soon as these preliminary results were ob- tained, it became possible, with the aid of the improvements in optical instruments, to trace the process in its different phases. The writers of the earlier times, for the most part, were vi- talists, since they professed to recognize a life in the tooth and appear to have referred the destructions attending dental caries, resembling, in the general appearances, the gangrene of other organs, to a vital process. As soon, however, as organic chemistry furnished the analyses of the tooth and secretions of the mouth, although these are still unsatisfactory, and explained the process of fermentation with its manifold products, it became necessary, in connection with the decalcification process in dental caries, to take into account the action of acids developed in the secretions or in fermenta- tion. Hence arose the chemical theories. During the past ten years, our knowledge with reference to the marked diffusion of parasites and their injurious efi'ects upon the animal economy has gradually increased ; search was made for such animated beings in the carious tooth ; they were found, or were supposed to have been found, and hence the parasitic theory was constructed. Then came the fusionists, some of whom attempted to com- bine the vital and the chemical theories of dental caries and considered the latter to be a reaction, of the nature of an inflam- matory process, on the part of the hard dental tissue which is chiefly affected, the dentine, and, at the same time, retained the views with regard to the agencies in the process of decalcifica- tion. Another class combined the effects of chemical agents with those of parasites. Still another class endeavored to unite all these theories and, therefore, assumed the occurrence of several kinds of caries. • It was admitted that the caries is de- THEORIES OF CARIES. 413 pendent, in most cases, upon external agencies and extends from the outside towards the interior, but, on the other hand, it was asserted that the same process may also take place in the opposite direction and hence caries which is developed from the pulp towards the exterior was described as caries interna. Since we know that an interchange of material takes place in the dentine and cement during life, as is proved by the occur- rence of atrophies, hypertrophies and new-formations., and that the dentine possesses a degree of sensibility, we cannot reject absolutely the idea of a reaction on the part of both hard tissues against the effects of external agents. Some authors seem to have had an intimation of this idea, since they were inclined to consider the textural changes in carious dentine as vital pro- cesses. There can be no doubt that the sensibility, sometimes increas- ing to actual pain, of the dentine, when deprived of its protec- tive covering, is a vital action, and that this becomes diniinished when the most sensitive, the peripheral portion, is destroyed by an external agent. These facts, however, are by no means suf- ficient to enable us to draw a conclusion in favor of the reac- tionary power of dentine in parts which are attached by caries. The thickening and varicous swellings of the dentinal fibrils were ascribed to a vital process by J. Tomes, E. Neumann and H. Hertz. The former asserts that the outlines of the forma- tive cells are restored by the diseased condition ; E. Neumann goes still farther and observes a proliferation of cellular elements of the dentine in sections which have been colored with carmine, and hence establishes an analogy between dental caries and in- flammatory and ulcerative processes in the soft parts. Leber and Rottenstein merely state that, in cross-sections especially, the contents of the Avidened canals are seen to be broken up into rod-like segments which, sometimes, are separated by slight in- tervals. They did not find, nor have I succeeded in observing the prominent nucleiform bodies in the thickened dentinal fibrils, after coloring the specimen with carmine, as they were described and illustrated by Neumann. The increased transparency of the dentine around the focus of caries and the still problematical calcification of the dentinal 414 ANOMALIES OF THE SECRETIONS. fibrils are regarded by J, Tomes as attempts on the part of na- ture to arrest the progress of caries. The carious dentinal cone is interpreted by Magitot as an evidence of a reaction on the part of the pulp against the agent which acts from the outside. This condition of irritation, he says, is manifested, on one side, by the production of secondary dentine and, on the other, by a molecular deposit in the dentinal canals Avhich become obliter- ated. He, therefore, regards the latter appearance, also, as a vital process. Although it cannot be denied that the living pulp does react against external agencies, still the interpretations of the above- named writers, according to which an inflammatory process of the pulp manifests itself in carious dentine in the different ways already mentioned, are incorrect, as Leber and Rottenstein have shown. Carious dentine of reinserted human teeth and of arti- ficial teeth made from the ivory of the hippopotamus presents the sanie appearances as are found in ordinary caries, in respect of the pigmented, dark and light zones, the granular condition of the dentinal fibrils, the thickening and varicous enlargement of the latter. The phenomena ascribed to odontitis, therefore, do not really belong to it. Dentinal new-formations, which are developed upon the wall of the pulp-cavity at a point corresponding to the carious locality in the dentine, can be induced only by an irritation in the con- tiguous portion of the pulp ; they are an expression of the efforts of nature, a reparative tissue, to compensate for the peripheral destruction. They are particularly^ frequent in connection with caries with a tendency to a chronic character. Numerous cases present no trace of such repair, although the dentine presents all the appearances which have been mentioned. Inflammatory affections of the pulp generally do not make their appearance until the dentine has suffered a considerable loss of substance, or, as is the case frequently, until the pulp is covered by a thin layer of dentine, merely, or a perforation into the pulp-cavity has occurred. There are no grounds, then, for ascribing the changes in the dentinal fibrils to an inflammatory irritation of the pulp. It is a familiar fact, that dead animal tissues undergo a THEORIES OF CARIES. 415 marked fatty degeneration under certain circumstances. In pathological cases, a fatty metamorphosis of organs is frequently met with, and this fact has been adduced, in some cases, to prove that fat is formed by the transformation of protein substances. It is not singular, therefore, that fat may also be deposited, under favorable circumstances, in dead dentine ; indeed it is found interposed in the dentinal canals in the form of drops. On the other hand, there is abundant proof that fungi pene- trate living, dying, and dead animal tissues, and there is a fungus, probably belonging to Mucor, Avhose spores sometimes are found in drinking-Avater, and which, by proliferation in the dead bone and dentine, produces a considerable loss of substance. * This fungus has no connection with caries of the tooth and occurs casually in carious teeth which are kept in water. Quite as little is the part taken by the Protococcus dentalis, described by Klenke as occurring in association with a special form of caries, which he termed vegetative decay of the teeth (Zahn- verderbniss). I have met with tliis in a single instance; its relation to dental caries has not been confirmed by any writer ; it is an accidental occurrence, like the Puccinia graminis in the favus crust. Leptothrix buccalis, on the contrary, occurs so frequently in connection with dental caries and so clearly lodges, here and there, in the cartilage-like, softened, decalcifying dentine, that Leber and Rottenstein went so far as to state that the variations in the course of caries must depend upon the part taken by the fungus proliferation in the carious process. The proliferations of the elements of the fungus without doubt penetrate and ex- pand the dentinal canals, but, according to my observations, this cannot occur until the decalcification of the dentine is complete, or, at all events, until the first stage of this process. I have never detected a proliferation of fungus in the deeper layers of the still hard, carious dentine, and, in my opinion, the death of a certain amount of dentine, in consequence of the action of the acid, is necessary before it is possible for the proliferation of * C. Wedl : Ueber einen ira Knochen unci Zahnbein keimenden Pilz. Sitzunffsber. der kais. Akad. d. Wiss. zii Wien, 18fJ4. •il6 ANOMALIES OF THE SECRETIONS. the fungus to occur. The extension of caries, in the dentine, therefore, according to mj view, is effected by the acid and not by the fungus. If the acid be neutralized by the saliva, e. g., on the lower incisors, caries does not occur, notwithstanding the presence of thick layers of leptothrix, such as are met with in tartar. Leptothrix has no direct connection with the origin of caries; previous to the formation of a carious pit on the neck of the tooth, I have been unable to find any deposit of leptothrix upon the exterior, or any rows of leptothrix-grains in the in- terior, of the dentine. The grains which occur in the dentinal canals in chronic caries are minutely-divided fat. The action of an acid, therefore, I consider a fundamental condition of the occurrence of caries in all cases where there is evidence of a decalcification, however slight. In other cases, where no evidence of the latter has been furnished (in a manner, indeed, not to be relied upon, as in the caries carbonacea, as it is termed by dentists), the chemical process is still in darkness. Although the action of acids is admitted, still our knowledge is not yet sufiicient to enable us to answer the questions, whether one or several acids, what form of the same, how and where they are formed ? The constituents of the mixed saliva vary, not merely in dif- ferent persons but, also, in the same individual. Its well-known property of converting insoluble starch into dextrine and grape- sugar, which latter may enter upon an acetous fermentation in the presence of a ferment, was turned to account by Leber and Rottenstein, who concluded that the acid reaction in the oral cavity is due principally to the acetous fermentation of particles of food. If it is proper to give such prominence to the latter, then it will be impossible to understand why caries of the teeth is such a very rare occurrence with animals, which are unable like men to remove the particles of food that remain between the teeth. Many races of men, who certainly are not very careful in observing cleanliness of the mouth, e. g., the Esqui- maux and New Zealanders, furnish a very small percentage. In well-marked chronic caries, the remains of food manifest no perceptible action ; in so-called central caries, also, a cartilaginous softening of the dentine ensues without the co-operation of the THEORIES OF CARIES. 417 remains of food. With many derangements of the intestinal tract an acid or saline taste is observed, entirely independent of the food. Acid sputa, increased acidity of the vaginal or vesical mucous membrane attest that mucous membranes of themselves may furnish an abnormal acid secretion. Magitot considers the saliva to be the active agent in the production of caries, when the former becomes the vehicle of acid substances. Leber and Rottenstein state that, if it is true that fungi play any part in the acetous fermentation within the oral cavity, a point, however, which remains to be proved, they are inclined to ascribe the action to leptothrix, and assert in common with Oehl, that in all probability lactic acid is formed in the acetous fermentation. Spence Bate* holds the view, that in consequence of a decomposition of the dentinal fibrils within the tubes, carbonic acid is set free ; the latter in statu nascenti, is brought into contact with the calcareous salts of the tissue, which then become decomposed with the development of acid. The acid which is set free, he says, is phosphoric and not lactic acid. In my opinion, especial consideration is claimed by the secre- tion of the gums, which comes into immediate contact with, and forms a partial viscid covering of the teeth. It is found, often- times, to be acid without the presence of the debris of food. When the secretion is unusually abundant, as, for instance, with children, young persons and, especially, with women during pregnancy, caries assumes a more or less acute character. It is not uncommon, remarks Tomes, with persons who have many carious teeth, to find the gums swollen, very vascular, and covered Avith a coating of thick, adhesive mucus which may be drawn from the gums in long strings. He mentions a case where the teeth were rapidly destroyed by caries and, coincident with this process, the salivary secretion was scanty in amount ; at a later period, the whole of the remaining teeth were almost simultaneously attacked near the edge of the gum, producing around each tooth an annular belt of softened tissue. He states that when there is an abundant flow of saliva and a free secre- * Odontological Society of Gre:it Britain Keports, 1865. 27 418 ANOMALIES OF THE SECRETIONS. tion of mucus, the latter is fouml clinging to the teeth, instead of becoming dissolved in the saliva, and that the mucus must be regarded as furnishing the agent by which the dental tissues are decomposed. Tomes' conclusion, that the gum when irri- tated may furnish an acid secretion, Avhich he regards as justified by the fact that caries already existing is promoted by the in- sertion of cotton between the teeth, is invalid, as Leber and Rottenstein have shown, since these results may be due to the fact that the cotton, being a porous substance, necessarily favors the processes of decomposition and fermentation which are in progress in the vicinity. I have frequently met with tumefaction of the gum and papillary hypertrophy in association with dental caries in the cadaver ; these, to be sure, may, in part, be con- secutive affections, still the frequent coincident occurrence of an affection of the gum is deserving of notice. When there is a diminished secretion of oral fluids and from the gum, as is the case in old age, caries assumes a well-marked chronic course. In those localities, where only a slight action of the secretion of the gum is possible or the latter is removed readily by the movements of the tongue, caries is a rare occur- rence. When the caries is acute and the crown is destroyed, its progress in the roots is a slow process, in consequence of the fact that the action of the secretion of the gum becomes less direct. While the greatest prominence is given to the action of the abnormal secretion of the gums, it must not be assumed that the influence of the anomalies in the secretions of the salivary and mucous glands and of the mucous membrane of the oral cavity is underrated, as, indeed, is sufficiently apparent from the preceding observations. Injurious effects, however, as a general rule, are to be ascribed to the debris of food only in cases where the structure of the tooth is defective or there is a carious breach of substance. It must be acknowledged that our knowledge with regard to the quality of the secretions of the oral cavity is imperfect and, at all events, it is a question whether the injurious effects are due to them alone or rather to the products of their decomposi- tion. It is not known whether a larger or smaller amount of an acid (perhaps lactic, and with regard to which organic chemistry THEORIES OF CARIES. 419 teaches us that it occurs frequently in partially-decomposed animal fluids) shortens or prolongs the process, or if different acids modify, in various ways, the course of caries. The presence of lactic acid, particularly, is assumed since C. Schmidt, of Dorpat, has succeeded in demonstrating the frequent occui'- rence of this acid in the usually acid juice (Saft) obtained from long bones affected with osteomalacia. It also remains to be decided whether butyric, valeric, or formic acids, which H. Fischer obtained from strongly-alkaline or acid pus, do not occur as products of the decomposition of the puriforra secretion of the gums. If the continuity of the enamel membrane is interrupted by fissures in the enamel, or has become brittle and friable in conse- quence of the presence of leptothrix masses, and acids have access to the enamel, then the calcareous salts within the prisms are reached quite readily since the organic investments of the latter are capable of offering only slight resistance ; indeed, we learn by chemical analysis that the organic substances of the enamel amount to scarcely more than three per cent. Primarily, the action of the acid is confined to narrow limits, and it may be assumed upon good grounds that a simple solution of the cal- careous salts does not take place, but that the acid enters into combination with the latter and the newlj'^-formed salts, destitute of an organic cement, readily become disintegrated. If we con- sider that the acid spreads in the course of the groups of enamel fibres, it will readily be understood that, on the one side, the action is confined to definite limits and, on the other, an under- mining of the adjacent portions of the enamel ensues. If the continuity of the enamel prisms is broken, the normal transpar- ency of the enamel, at the corresponding part, is destroyed and a white spot makes its appearance. If the action of the acid is slow, we find a more abundant deposit of pigment. Possibly, decalcification and putrefaction occur in common in this case. When a circumscribed breach of substance has been efi'ected in the enamel, materials entering from the outside, tenacious mucus, leptothrix and particles of food, are more likely to be- come impacted in the jagged excavation which then affords a more favorable locality for the action of acid ; with this condi- 420 ANOMALIES OF THE SECRETIONS. tion, the acid continues its deleterious action undisturbed by tlie neutralizing property of the salivary fluid, and its effects are manifested by a yellowish discoloration of the adjacent portions of the dentine, even while the latter is still covered by a thin layer of enamel. • As will be evident, the larger the carious cavity in the enamel and the smaller the aperture leading to it, so much the greater will be the danger that the dentine will be extensively involved. As the dentine contains 28 per cent, of organic matter, the pro- cess of decalcification in it takes place quite rapidly leaving be- hind the organic residue, the so-called dental cartilage. In con- sequence of the action of the acid, death of the affected dentine ensues, and its decomposition, in which, as above observed, lep- tothrix buccalis is the active agent, takes place from the exterior towards the central portions. A carious cavity is formed in the dentine, usually larger than that in the enamel ; this affords a receptacle for particles of food, which frequently cannot be reached except with difficulty, and hence readily becomes the seat of acetous fermentation. The shape of the carious cavities in the enamel and dentine depends partly upon the location in the tooth and partly upon the quality of the enamel and dentine. Near the neck of the tooth, the carious excavations are flattened, while those upon the masticating surfaces of the molars are always very large in comparison with the orifices leading to them. The thicker and more compact the enamel, the greater resistance does it offer and the more extensive is the destruction of the dentine beneath the enamel ; in these cases, therefore, the cavity is always very deep, while flattened cavities occur where the enamel is thin and has a more lax structure. The greater the extent of the ex- posed dentinal surface, the more extensive will be the portions affected. The cause of the very marked carious pigment deposits in the enamel and dentine remains undetermined ; it cannot lie in the organic, changed matter alone, since the discoloration is mani- fested with equal intensity in both tissues, and between the latter there is a marked difference in respect of the percentage of or- ganic matter which they contain. When the action of the acid THEORIES OF CARIES. 421 upon the enamel and dentine takes place slowly, the intense, carious pigmental degeneration does not extend to a great depth, the cartilaginous softening is limited to a narrow zone, and the disintegration ensues so gradually that the proliferating lepto- thrix buccalis could not possibly penetrate except to a very short distance. The distinction between caries of bone and of dentine is il- lustrated by caries of the cement which is characterized, also, by its progress from the exterior towards the central portion of the tooth and by a progressive deposit of pigment, together with a peripheral softening. In the premolar of the horse, where the vascularized osseous substance forms such thick layers, the pro- cess is the same as in the cement of human teeth, with the ex- ception that in the former it assumes a well-marked chronic character. The death of the osseous substance spreads, gradu- ally, from the exterior without any manifestation of an inflam- matory reaction. Since, then, caries gives evidence of its dependence upon ex- ternal causes in all three dental tissues, the question arises, what processes occur in connection with the very rare softening and melting down of the dentine in the direction from the pulp- cavity towards the periphery ? A case has been related (com- pare p. 191) where a central softening of the dentine occurred without any trace of ordinary caries. Leber and Rottenstein,* also, report a case of so-called central caries, where a bluish dis- coloration appeared upon three incisors without any trace of caries. By means of holes made in two of them, the entire in- ternal portions, as far as the enamel, were found to be com- pletely softened, decomposed and of a brownish hue ; even the roots Avere deeply excavated. The third tooth was not touched. The patient recollected that she had a fall, in her childhood, striking upon the teeth, and that this was followed by a swell- ing of the face. Leber and Rottenstein express no opinion as to the cause of the destruction of the dentine in this case and state that such cases ought not to be confounded with ordinary dental caries. - A. Scheller, of Warsaw,t reported two cases of * Op. cit., p. 11. t Deutsche Viertelj. f. Zahnh., 1870. 422 ANOxMALIES OF THE SECRETIONS. this description, the second one of which is of especial interest and is simiLar to that of Leber and Rottenstein. He expresses an opinion that the central caries of the teeth is to be regarded as a process of decomposition which is engendered by the disor- ganization (Verjauchung) of the pulp. The condition found in gangrene of the pulp (compare p. 183) points to the presence of a fatty-acid as a product of decompo- sition ; it may be possible, then, that a fatty-acid is formed in the necrotic pulp, capable of destroying the dentine. Magitot ascertained (compare p. 408 et seq.) that butyric and lactic acids are very similar, in respect of the mode and degree of their action upon the teeth. At all events, the so-called central caries cannot be regarded as a variety of ordinary caries, but, obviously, must be classed with the inflammatory affections of the pulp. " In proof of the occurrence of an internal caries, which has been classed with caries of bone," says Ileider, " the foul, some- times exceedingly nauseating odor occasioned by carious teeth has been taken into account and referred to a secretion from carious dentine. But," he continues, "the peculiar, purulent odor never occurs except with a patent pulp-cavity and arises from the gangrenous pulp ; while the foul odor of carious teeth, when the pulp-cavity is closed, is occasioned by the putrefying debris of food, which accumulates in such cavities, and disap- pears if the latter are kept clean. The preceding must not be confounded with the foul odor occasioned by the accumulation of the secretion of the gum between the teeth and, perhaps, by coagulated blood, or is communicated by plugs of cotton in the cavities." The carious process may be checked, but it cannot be cured. An acute form may become chronic, and an arrest may ensue ; this is a particularly common occurrence, as has been observed before, on the carious roots, upon which, however, it is possible, always, to discover a carious superficial layer containing deposits of pigment. Duval* and various other authors have applied the term caries, * Magitot, op cit., p. 30. THEORIES OF CARIES. 423 ■which resembles a ^^usure^'' (Usur), to a partial defect which occurs upon the neck of the tooth, and has been described as wedge-shaped (comp. p. 253). Although Magitot admits that these defects present all the appearances of a true usure, still he •has pronounced them to be instances of healed caries of the neck of the tooth or dry caries, without, however, adducing any reasons in support of this opinion. The healing process is said to be induced partly by the resistance of the pulp and partly by the removal of the injurious exciting cause. The action of the acid requires a certain length of time, whether the secretions of the gums, the lips, the buccal raucous membrane or the debris of food, act as its vehicle, and this period is shorter or longer, as the local relations are more or less favorable for the reception of the acid vehicle. Hence caries makes its first appearance in the pits and grooves or on the contiguous and facial surfaces of the teeth. The effects of equivalent acid vehicles vary in the different kinds of teeth in the same individual and, also, in those of dif- ferent persons. The frequency of caries is diminished under the following circumstances: a, if the effect of the acid is neu- tralized, as is the case upon the lower incisors which are bathed in saliva almost constantly, and upon which deposits of tartar are very common. The deposition of the latter, probably, pre- vents the occurrence of the carious process in the contiguous locality, but still chronic caries may be in progress upon one surface, while the deposit of tartar takes place upon another ; b, if the position of the teeth is corrected so that their contigu- ous surfaces correspond with the normal arrangement; c, if the teeth receive proper care and they are protected against the action of injurious agents; d, if the tooth is constructed in a solid manner and its surface presents a normal smoothness; e, if all the teeth and the oral mucous membrane, together with the glands, are regularly constructed with reference to the modi- fications engendered by race and hereditary tendencies. The last-mentioned factor is the most important element in the determination of the frequency of caries in general and is intimately connected with the structure of the entire organism. 424 ANOMALIES OF THE SECRETIONS. The quality of the nutritive material has only a secondary im- portance. The structure of the individual tooth has an essential influ- ence upon the course of caries, and the teeth may be divided into groups with reference to their power of resisting the dis- ease. Our present methods of investigation are not yet perfect enough to enable us to determine with exactness, the individual differences in the degrees of hardness of the enamel and dentine, the knowledge of which is of importance in determining the treatment and prognosis. A. Alphons, of CracoAV,* divided the teeth into six classes, with reference to the treatment of caries by filing and filling. Heider communicated to me his vicAvs upon this point as fol- lows: With regard to the predisposing conditions in the struc- ture of teeth which are attacked by caries, it is found that bluish or grayish-white teeth, with a slight polish, very frequently are attacked simultaneously by acute caries, while, on the other hand, yellowish-white teeth, with smooth, polished enamel, usually are affected by chronic caries only, and in isolated cases. The first- named kind of teeth is furnished with less solid enamel and less compact dentine, as is indicated most decidedly by the use of the file and excavator. Some teeth can be operated upon with great ease, even with inferior files, and leave upon the file a large quantity of dentine, reduced to a white, unctuous mass, while, on the other hand, the second named kind of teeth off"ers great resistance to the action of the file and is affected only to a slight degree, comparatively speaking, even by the best files, upon which they leave only a scanty, white, powdered mass of dentine. The enamel and dentine, therefore, present two varie- ties in quality, the gradations of which determine the varying susceptibility of the teeth to caries. If it is true, as Gladstone cites from Lasseigne, in his lectures,t that the molar teeth contain a greater amount of mineral sub- stance than the incisors, and that, with increasing age, the teeth present, especially, a large decrease in the amount of carbonate, * Deutsche Viertelj. f. Zahnheilk., 1867. t Qiuirterly Journal of Dental Science, 1857. THEORIES OF CARIES. 425 as compared with that of phosphate of lime, then we should have several datas as to the course of the carious process according to the kind of tooth affected and to the aoje. From the foregoing observations, it appears that caries of the teeth is a process which has its origin, chiefly, in the abnormal se- cretions of the gums and, likewise, in those of the rest of the oral mucous membrane and of the salivary glands, and, commencing at suitable points upon the exterior of the tooth, spreads in the direction of the pulp-cavity. In consequence of the decomposi- tion of the secretions, acids are formed which extract the cal- careous salts from the hard tissues and give rise to a disinte- gration of the afl'ected portions of the latter, in which no inflam- matory reaction occurs. The destructive process is promoted, essentially, by the accumulations of secretions and particles of food, and opportunity is aff"orded for the proliferation of lepto- thrix buccalis, in the dead and softened dentine. The exclusion of an acid in the development of well-marked chronic caries (caries sicca, carbonacea of writers) is not established upon scientific grounds. 426 NEUROSES. YII. NEUROSES. Under this head we have to consider the disorders of sensi- bility Avithin the territory of the trifacial nerve which, as we know, is a mixed nerve, being composed, for the most part, of sen- sitive, but, also, containing motor and secretory fibres. The por- tion of its territory of particular interest to us includes the branches of the second and third divisions, which supply the teeth and gums on the corresponding side, but, at the same time, it is necessary to keep in view the territory of the other ramifi- cations, the points of their origin, together with the numerous anastomoses and ganglionic communications throughout the en- tire course of the nerves, in order to appreciate fully the com- plicated morbid phenomena of nerve-life. In consequence of the obscure nature of the subject and our present imperfect means of observation, only a few anatomical changes in the nerves and ganglions in neuralgias are recognized. I had the opportunity of examining a series of nerves which were resected by Schuh for the relief of facial neuralgia, and satisfied myself that, in the majority of cases, it is possible to demonstrate disordered conditions both in tlie neurilemma and in the nerve- tubes. In the former, an hypersemic swelling occurs, and the in- terstitial connective tissue of the nerve-tubes acquires a finely granular cloudiness ; in the latter, a finely granular metamor- phosis of the medulla is observed. The latter abnormal, refrac- tive, protruding contents, however, are found only in separate tubes or in a small group of tubes, while the remaining tubes contain a perfectly normal medulla. In old chronic cases, pig- mented granular spots are found in the neurilemma, and a crum- bling disintegration of the greater portion of the medulla is ob- served. The grains which fill and protrude from the nerve- tube, sometimes, are quite large, glittering, and roundish, at others, minute molecules; the axis-cylinders, when removed, present similar grains which are adherent and collected to. EXCITING CAUSES OP NEURALGIAS. 427 gether in clusters. In one instance, I found quite large, highly refractive, roundish bodies, symmetrically arranged in longitu- dinal chains and resting upon separate nerve-tubes. These were entirely soluble in hydrochloric acid and, therefore, were calca- reous grains. They were also found interspersed in the inter- stitial connective tissue. These appearances which have been described clearly indi- cate that, in most cases, a netoritic process [neuritis] ensues, which pursues a more or less active course and, in protracted cases* induces an obliteration of the nerve-medulla. Rosenthal* also mentions knotty swellings of resected branches of the trifacial nerve (consisting of connective tissue and interposed nerve-fibres), like the knots which are met with in the divided nerves after amputations. We know nothing in regard to the affections of the ganglions in the course of the trigeminus, in connection with neuralgias; in one instance, in a case of prosopalgia, I found an evident pathological change in the Gasserian ganglion. f The ganglions on both sides presented numerous calcareous grains of various forms. The ganglionic cells contained abundant deposits of pigment. The ganglion of the affected side presented a quite noticeable swelling, and the bloodvessels of the connective tissue, which invested it and surrounded the nerve-bundles of the nodu- lar enlargement, were very full of blood, so that there could be no doubt of a previous exudative process in this ganglion. An inflammatory affection at the point of origin of the trifacial nerve was observed by Bensow, and Beveridge described a new- formation upon the trunk of the fifth nerve. These inflammatory processes in the continuity of the trifacial nerve are consecutive in most cases, and may have their focus of irritation (Reizungsherde) at the periphery of the branches of the second and third divisions, the consideration of which is involved in our present subject. The following are the exciting causes of neuralgias within the precincts under consideration ; a, chronic inflammation of the pulp, since this and its products * Handbuch der Kinderkrankheiten, p. 490. f Schuh Ueber Gesichtsneuralgien, p. 19. 428 NEUROSES. maintain a constant irritation of the pulp-nerves; b, new-forma- tions of hard dental tissues within the pulp, inasmuch as they irritate the remaining nerves of the pulp, under certain circum- stances; (?, proliferations of cement at the extremities of the roots, whereby the nerves which enter the teeth are bent more or less from their proper course or the same nerves at a dis- tance from the apices of the roots, together with the nerves of periosteum of the root, are irritated; d, chronic inflammation of the root-membrane, with its sequelae, particularly in the vicinity of the apex of the root; e, new-formations of the root-mem- brane when they encroach upon the precincts of the nerve- branches; /, periostitis, especially in the grooves or the foramina which serve for the transit of the dental nerves ; g, osteophytes, which occasion an irritation of the periosteal nerves ; h, tume- faction of the mucous membrane and periosteum of the antrum of Highmore give rise to pain and even a neuralgia of the pos- terior, superior dental nerves (Schuh) in otherwise sound teeth, which circumstance Luschka explains by the fact that the dental nerves pass through complete bony canals in some places, but in others lie in very shallow grooves in the bone, so that they are in immediate contact with the tissue of the periosteum, and, if the latter be removed, they become exposed; i, anomalies of position, whereby resorption of one or another root or of the crown of the adjacent tooth, is occasioned by the growth of the roots of the displaced tooth, and the contiguous portion of the root of the former is subjected to a continual irritation ; k, teeth which re- main imbedded within the jaw sometimes irritate the dental nerves of other teeth by the growth of their roots ; I, inflamma- tory irritation of the gingival nerves which cover the coronal por- tions of teeth during the first dentition ; m, inflammatory irrita- tion of the gingival nerves in connection with the difficult erup- tion of teeth during the second dentition, especially of the wis- dom teeth ; n, tumors of the jaws, inasmuch as they sometimes occasion an irritation of the dental nerves ; o, foreign bodies which have penetrated into the pulp ; p, lesions produced by unsuccessful extractions of teeth. When such peripheral foci of irritation exist, as the resected nerves in facial neuralgia show, the trunks, from which the IRRADIATION OF THE PAINS IN NEURALGIAS. 429 dental nerves are given off, become inflamed, their sheaths are found in an hypersemic condition, and hence the possibility is afforded for communicating nerves, which are contained in a common fibrous envelope, to become involved. Moreover, it is readily explicable that hyperesthesia is induced by inflammator}'' swellings in localities where the radiation of the divisions of the trifacial nerve is confined to a contracted space. Hyrtl* calls attention to the fact, that the branches of this sensitive cranial nerve traverse tightly-inclosed, long canals in the bones, as the infraorbital, alveolar, zygomatic branches, &c., and, therefore, on the occurrence of nutritive disturbances of their sheaths from rheumatism or congestion, with thickening and tumefac- tion, they are subjected, necessarily, to pressure which is mani- fested by sensations of pain. Rosenthalf states that periostitis, involving portions of the bones through which the passage of the trifacial nerve takes place, is a frequent exciting cause, and says neuralgia of this nerve is due, most frequently, to exposure to cold. Without detracting from the influence of the latter, I am convinced, nevertheless, that in most cases there is a primary neuritic con- dition [neuritis] of a peripheral branch of the trifacial nerve, and that the exposure to cold simply furnishes a cause for the farther extension of the previous inflammatory condition in the course of the branches of the nerve. Peripheral irritations of the trifacial nerve, as we knoAV, fre- quently arise at the point of exit of the nerve from tlie cranial cavity, in consequence of inflammatory affections or tumors at the base of the brain, and a thorough examination is required in order to determine whether the focus of ii-ritation is centric or peripheric. In this case, it is supposed, of course, that the patient refers the pain to the periphery and not to the irritated portion of the nerve. Another and frequent source of error, in the determination of the focus of irritation, arises from the irradiation of the pains, by which is meant that they extend far beyond the limits of the * Topograph. Anatomie, 5 Aufl., I, p. 3-15. t Op. cit., p. 193. 430 NEUROSES. seat of irritation and, sometimes, are more severe than the pain felt at the original focus of irritation. In these facts, we have an explanation of the inexact and varying statements of patients with regard to the locality of the pain, whereby the surgeon is not a little perplexed in deciding upon the resection of one or another nerve. Further proof of the difficulty attending the localization of the focus of irritation is furnished by the fact that resection of painful branches of the trifacial nerve, in most cases, affords only temporary relief from pain, which rarely continues longer than a year. Resection of a sensitive nerve really effects nothing but an interruption of its conductivity and, as soon as the latter is restored by the regeneration of the nerve, the pain is renewed and becomes as violent as it was previous to the operation ; hence it is proved that the focus of irritation was not detected and that it must have been located somewhere else than in the resected portion; the irritation persisted after the resection, but consciousness of it was lost since its connection with the brain Avas cut off. Another important question arises: Is there any point to which the pain is referred constantly ? Schuh,* after very ex- tensive observations, came to the conclusion that the fixed pain is wanting very frequently, although Yalleix maintains the op- posite view. It is described by the patients, he says, as dull, heavy, gnawing, dragging and somewhat burning, and is not perceived throughout the entire course of the nerve or branch, but is limited to a circumscribed locality. Usually, it is not very severe and, sometimes, it continues, with varying intensity, for hours or days together. I am disposed to agree with Schuh, since it is a physiological fact that the sensibility of nerve-fibres may become blunted, at least for some time, if they are sub- jected to severe or continued irritation. If, however, we find no continually painful locality, it becomes a more difficult matter to ascertain the locality of the focus of irritation. If the clinical phenomena indicate such a fixed point, they may be divided into those which are confined to the focus of * Ueber Gesichtsneuralgien, 1858, p. 3. REFLEX PHENOMENA. 431 irritation, local or 'primary^ and into periodical or secondary. The most prominent symptom is the disorder of sensibility, which we term pain. Besides the sensitive fibres of the trifacial nerve, its motor and secretory fibres and even those of other nerves are attacked by reflex action through the small reflex centres, the ganglions, or through the central nervous system. Fibres of the sympathetic, also, become involved in the irritation. With regard to the localities from which the pain radiates in the paroxysms, Schuh observes, they originate either at the points where the sensitive branches of the fifth pair emerge from the canals or grooves of the bone and enter the soft parts of the face, in the peripheral, terminal ramifications in the skin, mucous membrane, or teeth, or, finally, where the terminations of the two divisions of the nerve join or communicate with one another. Among the painful points determined by Schuh and Valleix, the following may be mentioned, in the present connection : a, the point of exit of the infraorbital nerve from the infraorbital canal ; 6, the gum of the upper jaw in which the anterior, mid- dle or posterior dental nerves are the seat of the affection ; c, the condyle of the jaw, when the pain appears to be located in the inferior dental nerve, in most cases, and particularly at the point of its entrance into the dental canal ; d, the point of exit of the mental nerve on the chin. The reflex i^henomena have reference both to the motory and secretory fibres. The motor symptoms are manifested, chiefly, in the facial muscles, by clonic or tonic contractions. According to the statements of Schuh, with intensely painful neuralgias, especially when the cause is seated within the cranial cavity, it also happens that, not only the muscles of the face and eyes, but nearly all the muscles of the body are thrown into a state of tonic contraction, so that the patients appear rigid and immov- able, like a statue, and retain, perfectly, the position in which they were at the moment of the attack. The rigidity of the muscles continues until the paroxysm of pain ceases. Very rare cases have been observed where the sensibility of certain points was so acute that the sudden and unexpected contact of anything would even cause the patient to fall, with loss of con- sciousness and convulsions. 432 NEUROSES. The affection of the secretory apparatus is manifested upon the surface of the skin, by perspiration in the region of the face, and an increased secretion, subsequent to the paroxysm, from the mucous membrane and corresponding glands, as the mucous, salivary, and lachrymal glands. Irritation of the fibres of the sympathetic is effected through the ganglions Avithin the territory of the trifacial nerve, namely, in the eye through the ciliary ganglion, in the ear through the spheno-palatine and otic ganglions, in the secretory apparatus on the floor of the oral cavity, through the submaxillary ganglion.* It is necessary to refer in this connection to a special exciting cause of facial yieuralgia, which, in my opinion, is of great im- portance, namely, the extraction of teeth. Schuli observes that it is particularly noticeable, that very many patients date the origin of their suffering from the time of the extraction of one or several decayed teeth. Although he suggests caution in ac- cepting this statement, he is convinced, nevertheless, from ex- tensive observations upon the subject, that the extraction of un- sound teeth, especially if the operation is performed with vio- lence or is repeated at one sitting, sometimes is the cause of neuralgias, in consequence of the stretching and laceration of the delicate nervous filaments. Many well-informed persons, who were accustomed to observe, carefully, their sensations and conditions of body and have stated confidently and positively that they were able to distinguish a difference between the tooth- ache which they felt before, from the slight and soon increasing * Through irritation of the sympathetic nerve the uterus is broug"ht into close relation with the teeth. It is a well-known fact that pains of the teeth often occur during pregnancy as well as during certain inflammatory atfec- tions of the uterus, and cases have been recorded of recovery from pains and symptoms of disease in the uterus upon the extraction of one or more teeth. In a large number of cases of diseases of the uterus, the teeth are seriously affected by caries. Out of more than twenty-five patients suffering from uterine disease, in a hospital for diseases of women in this city, examination of their mouths showed extensive caries of the teeth in all but one. This is a subject which needs thorough investigation. At the present time, our knowledge is so limited that we cannot say with much assurance how much the teeth and the uterus aflect each other in the reciprocal action of condi- tions of disease. — T. B. H, FACIAL NEURALGIA CAUSED BY EXTRACTION. 433 neuralgia wliich occurred a few hours after the extraction of the tooth, would admit no other exciting cause than the one in question. If we consider the fact that, in connection with caries of the teeth, the pulp becomes inflamed and entire bundles of nerves manifest evidences of degeneration, while, in the neuritic pro- cess, which occurs in neuralgia, single nerve-tubes only are affected in the manner already described, there are grounds, in my opinion, for the assertion that the two processes present anatomical differences, and that the darting pains in facial neu- ralgia are due to the affection of the separate nerve-tubes. If we consider, also, that, after amputation of the limbs, sensi- tive nerve-tubes sometimes grow in large numbers from the sur- faces of the transversely-divided nerves, as I proved* in the year 1855, it is probable, that an analogous process occurs in nerves which have been lacerated in the extraction of teeth ; indeed we have an intimation of such an occurrence in the pains in the sockets from which teeth have been extracted. If, noAv, a predisposition (Diathese) to the development of new-formations of nerves of this description exists in an individual, or if, in con- sequence of unskilful extraction, the nervous branches which supply the teeth are not separated from their attachments to the main stems, but are badly bruised and crushed, and the main stem itself is injured more or less, the condition of irrita- tion which is produced in the nerves may, sometimes, induce a proliferation of the sensitive fibres. Actual proof of this sup- position remains to be established in the future. With regard to the diathesis, we may call to mind that such a condition has been established for the new-formations of dentine, cement, periosteum of the root and gum, and we may, upon good grounds, speak of a progressive new-formation, t. e., of one which extends to the adjacent tooth. It is quite reasonable, therefore, to assume a diathesis for the proliferation of nerves after their laceration. Premising this, it is quite easy to un- derstand that the extraction of teeth for the relief of facial neu- ralgias only aggravates the evil. * Zeitschr. d. Gesellsch. d. Aerzte zu Wien. 28 434 NEUROSES. From this point of view, I regard the suggestion of Dobbelin* as a fortunate one, namely, to substitute another operative treat- ment in place of the resection, which necessitates deep incisions and, indeed, affords relief for a few months only, when the focus of irritation is located in the nerves of single teeth. He cites a series of cases which occurred in his practice, where he produced a complete cure of facial neuralgia, particularly of the infra- orbital nerve, by exposing the pulp-cavity with a trephine and killing the nerves of the root in all non-carious bicuspids and molars, and by killing the nerves of the coronal and radical pulp in cases in which perforating caries had occurred. One case is particularly instructive, where the infraorbital nerve together with a portion of the upper jaw around the infraorbital foramen had been removed, but without a successful result ; he trephined all the bicuspids and molars which remained in the jaw, and effected a cure. With the multiplicity of the above-mentioned foci of irritation of the dental nerves (comp. p. 427) and the indefiniteness of the painful sensations, it frequently happens that nothing is left in the way of treatment, but to destroy, experimentally, the supposed focus of irritation in an affected tooth or in a root. The result, then, will confirm or disprove the correctness of the sup- position. It is self-evident that, in an isolated case in which the experiment is attended with a successful result, we must be on our guard and avoid the false conclusion, 'post hoc, ergo propter hoc. If, however, in a series of observations we find that the same favorable effect ensued in equivalent cases, or a complete and permanent cessation of the symptoms followed the removal of the centre of irritation in individual cases, or a notable abate- ment was observable, then in one case the supposition is raised to a certainty, and in the other it is reduced to a mere proba- bility, or the latter, even, may be questionable. When the nerves of the gum are subjected to a severe irrita- tion by the advancing crowns during the first dentition, pain of a radiating character is developed in the sensitive organism of the child, reflex phenomena occur in the form of convulsions or * Deutsche Viertelj. f. Z., 18G8. ABSTRACT OF CASES. 435 epileptiform paroxysms ; in a series of well observed cases, these symptoms disappeared immediately after the division of the irri- tated nerves of the gum with the lancet. Hence, in these cases, the centre of irritation without doubt was located within the gum. Upon pure theoretical grounds, also, the above-men- tioned consecutive irritations of the central nervous system must have their origin in the irritated nerves of the gum. The recorded observations of many observers, also, shoAv that anomalies in the second dentition, in children of a nervous tem- perament, sometimes occasion neuralgias, convulsions and epilep- tiform paroxysms, and, therefore, it is evident that, in such cases, the physician should not neglect to examine the condition of the teeth. An unusually difficult eruption of the wisdom teeth may be the cause of similar symptoms and even of mental aberra- tion. The following series of cases, which I have endeavored to make quite extensive in consequence of the great importance of the subject, will serve to illustrate the preceding observations with reference to the focus of irritation, when it is situated in the dental nerves. Breithaupt* reported a case of prosopalgia caused by an im- pacted canine in the upper jaw. The affection was removed by the extraction of the tooth. Forgetf observed a case of neu- ralgia which was occasioned by a wisdom tooth in the axis of the jaw. IIesse| met with a case of neuralgic pains in the lower jaw, induced by a wisdom tooth which was imbedded within the jaw in an oblique position, with its crown directed towards the molar in front of it. The molar was removed, the pain ceased and the patient soon recovered. F. H. Thomson§ observed a case of facial neuralgia resulting from the concrescence of the roots of the wisdom and second molar tooth, which prevented the descent of the former. Esquirol reports the case of a woman who recovered from insanity after a crucial incision was made in the gum in order to promote the eruption of the wisdom tooth. Ashburner relates the case of a young man, seventeen * Deutsche Viertelj. f. Zahnh., 1861. f ^es Anomalies dentaires, 1859. X Gazette des Hopitaux, 1856. g Dental Eeview, 18G0. 436 NEUROSES. ycavs of age, who was afflicted with delirium, destructive mania and delusions. Incisions were made in the gum covering the wisdom teeth, and recovery ensued in a week. Forget cites a case of severe dental neuralgia, caused by a wisdom tooth, the crown of which Avas inclined anteriorly and exerted a strong pressure upon the second molar. The affection led the patient to commit suicide. He jumped from the upper story of a house, tetanus succeeded and, finally, death. Hancock observed a re- covery from trismus and pain under the right ear, after the ex- traction of the first molar. Dbbbelin cites a case where tetanus occurred simultaneously with the extraction of a tooth. Ben- sow* had under his treatment a young man suffering from very severe neuralgia in the upper first molar which, evidently, was free from any disease. Extraction proved to be useless, and the patient died on the fourth day after the operation. Exami- nation after death showed nothing worthy of observation in the mouth ; the brain was healthy ; at the origin of the fifth nerve, a collection of pus, the size of a mustard-seed, was found. I am inclined to question whether this was not the result of the un- avoidable injury to the nerves of this tooth in extraction, which were in a condition of hypertesthesia.f * British Journal of Dental Science, 1867. f J. Tomes (System of Dental Surgery) states that two cases came under his notice in which epilepsy was consequent upon diseased teeth, the most prominent feature being exostosis of the roots. " A lad, a farm laborer, from "Windsor, was admitted into the hospital for epilepsy. The usual remedies were tried for six weeks without effect. His mouth was then examined, and the molar teeth of the lower jaw were found to be much decayed, and of some of these the fangs only remained. He did not complain of pain in the diseased teeth or in the jaw. The decayed teeth were, however, removed, and the fangs of each were found to be enlarged and bulbous from exostosis. During the eighteen months that succeeded the removal of the diseased teeth, he had not suffered from a single fit, though for many weelvs previous to the operation he had two or three per day. This is a case of singular in- terest, inasmuch as there was no complication of maladies, and lience there could be no doubt as to the cause of the disease, seeing that it immediately subsided when the teeth were removed ; and it is further useful in showing that a sufficient source of local irritation to induce functional derangement may exist without pain being felt in the part where the irritation is applied." "A similar but less marlved case occurred shortly afterwards, in the person ABSTRACT OF CASES. 437 Fox* relates the follo>ving case : " The patient was a young ladj, twenty years of age : for more than a year she had suf- fered from deepseated pain in the face, and in the teeth and gums. The pain gradually extended to all the teeth, and one by one all those of the lower jaw, with the exception of the four incisors, were removed. During this time every kind of medical treatment had been resorted to, but without affording her any alleviation to her sufferings. At the time the patient consulted Mr. Fox, she was only able to take fluid nutriment, for the teeth of the upper jaAv Avere so tender that the slightest touch caused extreme pain. There was a constant flow of saliva from the mouth, and the palpebrre of one eye had been closed for nearly two months [and Avhen opened the sight of the eye was affected]. The most painful tooth was extracted. This was the first molar of the upper jaw, situated under the eye, the palpebrpe of which had become closed. The fangs of the tooth were much enlarged ; its removal was attended with great bene- fit, and two days after, the affected eye could be opened. This only afforded partial relief, and eventually all the teeth were removed, when the patient Avas at length relieved from her suf- ferings." This case, probably, was one of a progressive prolif- eration of cement, where the process advances from one tooth to another, and, in my opinion, it would have been a suitable case for the method of treatment recommended by Dobbelin (comp. p. 434). Thomsonf describes a case of prosopalgia re- sulting from exostoses of the roots of the wisdom teeth. of a policeniiin. He had fits, which were greatly relieved by the removal of an inferior wisdom tooth, the subject of caries and of exostosis." With reference to the first case, an essential point in the argument for the stated source of local irritation is wanting, in my o[)inion, namely, that it was possible to bring on the fits by irritation of the decayed teeth. It is, also, to be borne in mind that, as Kosenthal observes (1. c, p. 311), particular caution is enjoined, both in respect of the prognosis and the estimation of the results of treatment, by the frequency of recurrences, even after a remis- sion of the paroxysms for several years. Again, no little importance is to be attached to the fact that the regulation of the diet, which obtains in the hos- pital, exercised a beneficial influence in diminishing the frequency of the fits with the two epileptics. * Vide Hulme's Lectures, Dental Eeview, 1862. f Glasgow Med. Journal, 1867. 438 NEUROSES. Hilton* reports the case of a man whose hair, upon the left temporal region, became gray, as a result of a carious affection of a lower molar. He suffered from neuralgia in the left side of the face, for the relief of which he was treated in various ways without success. He wore a wig, as the rest of his hair was black. The carious, lower second molar was extracted and the neuralgia disappeared almost entirely. It is not stated whether the hair upon the temple became black again, since the patient was not seen again. Von Stellwagf regards it as probable that irritations in remote portions of the trigeminus nerve may be transmitted through the ciliary system to the nervous apparatus which serves for the reception of luminous impressions, occasion an increased excita- tion in this and, by producing hyperemia and inflammation, give rise to amaurosis (amaurosis trifacialis of Beer). " It is a well-known fact," he says, "that it is, by no means, an uncom- mon occurrence for intense irritations of one or another division of the trifacial nerve to lead to hypercesthesia, and later to hypercemia and inflammation in the territory of the ciliary nerves.'' " Hypertesthesia of the ciliary nerves| may also be in- duced by exfoliation of an alveolar process, abscesses in the roots of a tooth, and the impaction of foreign bodies in an alveolus." He cites the following cases in his notes. Galen- zowski cured a complete amaurosis which occurred in conjunc- tion with a most violent, intermittent neuralgia in the temporal region, face and, especially, in the eye, by the extraction of a cari- ous bicuspid upon the root of which there was a splinter of wood that had produced an irritation of the dental nerves. (I once found a splinter of wood which entirely filled the root-canal of a carious tooth and, evidently, was a fragment of a tooth-pick.) Teirlink relates a case where an impacted fragment of a tooth in the upper jaw of a woman occasioned frequent attacks of odontalgia, which were accompanied, at different times, by in- tense pain in the eyes, intolerance of light, a profuse secretion * Lancet, 1861. f Ophthalmologie vom naturwiss. Standpunkt, ii, p. 657. X Ibid., p. 321. ABSTRACT OF CASES. 439 of tears, dimness of vision, contraction and immobility of the pupil. All treatment Avas unsuccessful until the fragment was removed, when the pain ceased immediately. Hay observed a case where a man, who had overworked himself at a fire, suffered from an excessive intolerance of light Avhich continued even in a dark room. The uncomfortable sensation seemed to start from one of the upper incisors. Tapping upon this tooth with a key produced most violent, twinging pains. Upon the extraction of this tooth, an abscess was found in the root. Recovery ensued after the removal of the tooth, and six years afterwards there had been no recurrence of the affection.* Hutchinsonf observes that far too little attention is given to the condition of the teeth as the possible cause of functional or nutritive derangements in the globe of the eye or in the cerebral centres of vision, and remarks especially upon the importance of taking advantage of every opportunity to clear up the subject of the possibility of the evil effects of stumps of teeth which are left in the jaws. In confirmation of this opinion, I will cite the following cases. Dr. EmraeuchJ suffered for fourteen years from notable conges-* tions in the region of one eye, profuse secretion of tears and in- tolerance of light. These symptoms were increased by slight errors of diet. He found a carious tooth upon the side corres- ponding with the affected eye. Almost immediately after the extraction of this tooth, the symptoms referable to the eye be- gan to abate and, in a short time, they disappeared entirely. Teirlink mentions tAvo cases. A first upper bicuspid was ex- tracted from the jaw of a young man, for the relief of very severe toothache; the patient stated that he suffered from quite severe pains in the eye upon the same side, and, on another day, he came with a complaint that his sight was affected. The pupil was very much dilated. Extract of opium and opium ointment were inserted in the alveolus and effected a contraction of the pupil and restoration of sight. A woman complained of * Comp. also von Stellwag's Lehrbiicli der Augenheilkunde, 4 Aufl., p. 854. f Ophthalmic Review, 1866. J Dublin Medical Free Press. 440 NEUROSES. defective vision and excessive secretion of tears. After the extraction of a carious root, the sight Avas restored gradually and the excessive lachrymal secretion ceased. Hancock* re- ported three cases. A lad, eleven years of age, on Avaking from sleep one month previously, found that he was entirely blind. Previously he had nothing the matter -with his eyes, and when he went to bed on the preceding night he could see dis- tinctly. Treatment had availed nothing. The pupils were dilated, the iris was motionless and did not respond to the ex- citation of light. He was unable to distinguish light from darkness. Upon examination of the teeth, Hancock found them tightl}' wedged and crowded together. Two permanent bicuspids and four milk molars were extracted; the same even- ing, the boy could distinguish light from darkness, and in the following morning he was able to make out objects. From this time the boy's sight improved, and eleven days after the opera- tion, he was discharged well. A man came to the Westminster Ophthalmic Hospital on account of amaurosis of the right eye, which had existed for eight months and came on suddenly. He •could distinguish between light and darkness; the pupil was dilated and fixed. Medical treatment did no good. The second upper molar on the right side was found to be diseased, and it was extracted. Two days afterwards, he was able to distinguish objects, although imperfectly. A few days later, he returned home, cured. A patient, twenty-two years of age, had been affected with strabismus for three years. A ptosis had existed about a fortnight. The left eye was closed. The affection came on suddenly, without pain, either in the head or eye. After treatment had been employed without success for nine days, two carious teeth were found in the left side of the upper jaw, which were not painful. The affection had assumed an in- termittent character. In the morning, the eye was open; towards noon, the lid dropped down and, at evening, it resumed its original position. In four days after the administration of quinine, the ptosis was cured, the strabismus was improved, so that, in fact, no operation was done. Kemptonf observed a * Lancet, 1859. f Dental Review, 1861. ABSTRACT OF CASES. 441 case, Avhere a woman had suffered for a fortnio-ht from severe pains in the right temporal region, which extended over the nape of the neck, sometimes affected the side of the face, and were accompanied by shooting pains in the globe of the eye. Cold applications within the mouth and externally alleviated her suffering. There was no toothache. The lower right wis- dom tooth was extensively carious, and the gum was swollen. During the extraction, she experienced a severe pain across the right side of the head, which lasted a few seconds, but no pain in the locality from which the tooth was removed. The neuralo^ia disappeared. De Witt,* in a man who stated that he had been nearly blind in the right eye for twelve years, so that he could merely dis- tinguish light from darkness, found a cavity filled with white metal in the first bicuspid, and a fistulous opening in its alveolus. Upon the removal of the filling, a foul-smelling, sanious matter escaped from the cavity of the tooth. Three weeks later, when the right eye had recovered so that it performed its functions nearly as well as the other, the sensitiveness of the gum re- turned and, at the same time, the vision again became affected. The tooth was then extracted, and the amaurosis disappeared immediately (?). Six days afterwards, the patient was able to see Avith the right eye as well as with the left, except that small objects were not clearly recognizable. De Witt remarks that the amaurosis had its origin in an irritation of the fifth nerve. Cases, also, are recorded which indicate the efi'ect of diseased teeth upon the hearing. Certain sounds, such as a creaking noise, produce sensations in the teeth. Carious teeth sometimes occasion paroxysmal pains in the ear. The following case came under the observation of Harvey. A man, twenty-two years of age, suffered for three years' from attacks of neuralgia in the ear, which, occasionally, were accompanied by a foul-smelling discharge from the external meatus and lasted several hours. The most intense pain was felt in the direction of a carious Avisdom tooth. This was extracted and the neuralgia was cured. Vautierf reported a case of facial neuralgia and deaf- * American Journal of Medical Sciences, 1868. f Gazette des Hopitaux, 1860. 442 NEUROSES. ness, which was cured by the extraction of an upper wisdom tooth. J;imes Salter, in his instructive article upon nervous affections induced by diseases of the permanent teeth,* expresses the opinion that, next to the branches of the trigeminus, the cervical and brachial plexuses are most frequently affected by an irrita- tion of the teeth. He cites a series of instructive cases. Thomas Bellf reported two cases in point. In one, the patient had suffered for a year from irregular paroxysms of pain which was felt, at first, in the ear and, afterwards, extended across the neck and shoulder and along the arm, producing impairment of motion in the hand and fingers. Bell ascertained that, two years previous to that time, the lower second molar had been broken off, in an attempt to extract it, and the roots were still in the jaw ; the anterior one had emerged, partially, from the socket and lay upon the gum, in an oblique position ; the pos- terior root Avas still firmly imbedded and, evidently, occasioned considerable irritation in the surrounding parts ; pressure upon this root increased the pain which, in a measure, assumed the character of the paroxysmal pains from which the patient had suffered so long. The stumps Avere removed and the paroxysms did not return. In a second case, there was slight impairment of motion in the right arm, with occasional pain and the peculiar sensation of formication Avhich is felt Avhen pressure is exerted upon a nerve. Finally, the patient noticed that a paroxysm was accompanied by an acute pain in the lower second molar upon the same side. This fact led to a careful observation of the succeeding attack. Bell became satisfied that the contact of a sharp instrument with this tooth occasioned a return of the sensation in the arm. The tooth was extracted and a complete cure ensued, although not immediately. F. H. Thomson^ mentions three cases of facial neuralgia, consequent upon caries of the wall of the antrum. These cases are sufficient to show that facial neuralffias and * Guy's Hospital Reports, xiii, 1868. t Anat. Phys. and Path, of the Teeth, 2d ed. X Dental Review, 18G0. ANESTHESIA OF THE DENTAL NERVES. 443 various affections of the eye, ear, the cervical and brachial plexuses not infrequently have their origin in an irritation in the teeth, and that dentists, and surgeons, especially, should not neglect to make a careful examination of the teeth in connection with these aff'ections ; the experience and knoAvledge of an edu- cated dentist, of course, is requisite for this purpose ; the mere extraction of a tooth at random is of no avail. Anaesthesia of separate teeth occurs in connection with atrophy of the dental nerves, consequent upon previous inflam- mations, new-formations, within the pulp or outside of the same, folloAving chronic inflammation of the root-membrane, ab- scesses at the extremities of roots, &c. Anaesthesia of one or another side of a set of teeth has its origin in the trunks of the dental nerves or in more central localities. The possibility of the existence of new-formations ought to be taken into account as a cause of this affection. When apoplexy, tabes, hysteria, tumors of the pons Varolii and the posterior lobes of the cere- brum, which encroach upon the territory of the trigeminus (second and third divisions), give rise to anaesthesia of parts cor- responding to the anatomical distribution of the nerves, as shown by Ch. Voigt, then the teeth and the gums,* also, become de- prived of their sensibility. Rosenthalf cites a case, which came under his observation, where, in connection with anaesthesia of the second division of the trigeminus on the right side, the upper teeth and gums were entirely insensible, while the lower teeth and the floor of the oral cavity manifested the normal sensibility. At the autopsy, a new-formation, as large as a nut, was found in the left half of the pons Varolii. * Rosenthal, op. cit., p. 500. f Ibid., p. 77. ALPHABETICAL INDEX. PAGE Abscesses in the alveoli, 216 coronal dentine of human teeth, . 187 dentine of animals' teeth, . 187 gums, 198 jaws, 225 maxillary periosteum, . 222 P"lp, . 177, 179 186 root-membrane, .... 210 root, the cause of affections of the cil iary nerves. 438 tusks of elephants, new-formation of osseous substance with, 304 Absorbent organ, 79 Adenomata, 821 Adhesion of all the teeth impossible. 154 the pulp to the dentine, 241 Alveolar abscess, 216 arteries, injection of the, 60 process, affection of the ciliary nerves caused by exfoliations of the, 438 arch of the, .... 23 enostosis of the, .... 331 epulis of the, .... . 322 347 exostosis of the. . 228 327 hypertrophy of the, . 228 interstitial development of bone in exostoses of the. 329 necrosis of the, .... . 222 226 new-formations of the. 322 of the lower jaw. 25 of the upper jaw, 22 osteomata of the, . 228 327 purulent infiltration into the, . 217 results of fractures of the, . 223 senile resorption of the. . 266 Alveoli, abscesses in the, 216 cicatrization of the, ..... 258 description of the, ..... 22, 25 446 ALPHABETICAL INDEX. Alveoli, fracture of the, 223. 263 growth of the coronal, ........ 70 partial resorption of the, previous to the eruption of the teeth, 71 resorption of the, in connection with inflammation of the root- membrane, .......... 213 resorption of the, after extraction of teeth, .... 259 senile, ........... 2.3.5 septa of the, 23 Amaurosis consequent upon dental caries, ..... 439, 441 the impaction of foreign bodies in the teeth and jaws, 438 the malposition of teeth, .... 440 trifacialis, .......... 438 Anassthesia of the teeth, ......... 443 Anatomical changes in the nerves and ganglions in neuralgias, . . 426 Aneurism of the superior palatine artery, to be distinguished from an abscess, ............ 218 Angiomata of the gums, ......... 319 Angle of the lower jaw, peripheral and pericellular resorption of the, . 269 senile changes in the, ..... 269 Anomalies of the secretions, ......... 354 Antimony, effects upon the root-membrane, from the use of, . . 215 Antrum of Highmore, .......... 24 catarrhal inflammation of the, ...... 229 cj^sts of the, .......... 351 dropsy of the, . . . . ■ 229, 231 empyema of the, ......... 229 entozoa in the, .......... 3.53 facial neuralgia, caused by caries of the wall of the, . . 442 fistula of the, 219, 352 foreign bodies in the, ........ 280 inflammation of the membranes of the, a sequel of root-membrane, ...... polypi of the mucous membrane of the, . Appearances presented by carious cement, . dentine, . enamel. Arsenic, effects of, upon the root-membrane. Articular eminence of the temporal bone, senile flattening o Articulation of the lower jaw , Artificial caries. teeth, caries of, Atony of the gums, Atrophies, .... Atrophy, eccentric, of Rokitansky, net-like, of the pulp, of the maxilhe, maxillary periosteum, . f the, that of the 229 352 391 384 376 215 270 . 26 374, 375, 407 4, 376, 406, 414 255 232 2.58 238 257 257 ALPHABETICAL INDEX. 447 Ati'ophy of the pulp, ...... resulting from iiiflamniation, root-membrane, .... socket, ...... primary or senile, ..... secondary or consecutive, senile, of the gums, .... Axial torsions of the crowns, .... PAGE 232 191 2-55 2.58 232 232 2.:)4 132 Bacteria, 19.5, 211, 358, 407 Bicuspids, description of the, ......... 34 Blending of adjacent teeth, 147 distinguished from twin-formation, . . 149 milk teeth, 149 Bloodves.sels of the pulp in inflammation, changes in the, . . . 180 Bone, caries of, distinguished from that of teeth, . . 367, 370, 374, 4'Jl interstit'ial development of, . . . . . 78, 92. 276, 306, 329 growth of, in the jaws, ...... 92 resorption of, in the jaws, . Brachial plexus of nerves, affections of the, consequent upon of the dental nerves, ...... Buccal fistula, ........ BUhlmann's fibres, ....... Calcifications, combination of, with new-formations of dent of the pulp, ...... consequent upon inflammation, senile root-membrane, . Cancer, cystoid-gelatinous, of the upper jaw, epithelial, of the gums, jaws, fibrous, of the gums, .... jaws, .... gelatinous, of the jaws, medullary, of the gums, . jaws, . melanotic, of the dental sac, intermaxillary bone, of the root-membrane, Canine teeth, description of the, . Cantharides, effects of, upon the root-membrane, Carcinoma, see Cancer. Caries of the teeth, ..... acute or moist, . appearances presented by the cement in, dentine in, enamel in, . 92 ations . 442 . 219 3-57, 372 . 296 191, 233 . 191 . 2.5 . 351 . 320 . 349 . 3-51 . 351 . 351 . 321 . 350 . 350 . 350 . 317 . 34 . 215 . 367 7 et jmssim . 391 . 384 . 376 448 ALPHABETICAL INDEX. PAGE Caries, artificial, 374. 375, 407 carbonacea, .......... 416, 425 cartilaginous softening of dentine in, . . . . S87 et passim change in the color of the hair consequent upon, . . . 438 chronic, ......... 387 et passim of the dentine, ...... 389 et passim consolidation of the dentinal fibrils in, . . . 323,386,413 deposits of pigment in the enamel in, 378 diminished consistence of the enamel in, 379 transkicency of the dentine in, ....... 384 discoloration of the dentine in, ....... 384 extension of, to the root, ........ 392 frequency of, see Frequency of Caries, 397 historical sketch of, 368 increased transluceney of the surrounding dentine in, . . 386 increased transparency of the enamel in, ..... 378 interna, .... 191, 369, 371, 872, 374, 413, 421, 422 localities of, 393 neuralgic aflections consequent upon, . . . 438 ct passim of artificial teeth, 374,376,406,414 pivoted teeth, .......... 406 reinserted human teeth, ...... 404, 406, 414 teeth made from hippopotamus-ivorj-, ..... 406 signification of, ....... . 367 distinguished from that of bone, . . 367, 370, 374, 421 the different kinds of teeth, ....... 393 permanent teeth, ...... 394 milk teeth, ......... 396 roots of permanent teeth, ....... 396 teeth of animals, ........ 410 wall of the antrum, the cause of facial neuralgias, . . 442 sicca, 390, 423, 425 symmetrical afiection of corresponding teeth with, . . . 369 theories of, .......... . 411 undermining, of the dentine, ....... 389 enamel, ....... 382 white, 408 Carious teeth, amaurosis consequent upon, ..... 439, 441 deafness consequent upon, ...... 441 effects of, upon the rest of the body, . . 403 et passim neuralgic aflections of the ear consequent ujion, . . 441 ptosis consequent upon, ...... 437, 440 Cartilaginous softening of carious dentine, .... S87 ct passini Cases illustrating neuroses depending upon aflections of the teeth, . 435 Castor oil, eflects of, uj-on the root-membrane, ..... 215 Catarrhal inflammation of the antrum, ....... 229 ffums, ....... 192 ALPHABETICAL INDEX. 449 PAGE Cavity of the mouth, bony framework of the, ..... 21 Cement, 51 caries of the, 391, 421 changes in the, in connection with the process of shedding the teeth, 77 development of the, ......... 69 hypertrophy of the, ......... 271 in grooved teeth, ......... 149 interstitial hypertrophy of the, 276 resorption of hypertrophic, 274 junction of the, with the dentine, ...... 53 neuralgias consequent upon hypertrophy of the, . . . 272 new-formations of, ....... . 272, 312 perforating resorption of the, ....... 274 peripheral-concentric hypertrophy of the, .... 276 resorption of hypertrophic, ..... 278 progressive proliferation of the, ...... 437 resorption of senile, ......... 247 senile thickening of the, 244 Cervical plexus of nerves, affections of the, consequent upon irritations of the dental nerves, 442 Changes in the jaws during the second dentition, ..... 91 form of teeth, indicative of syphilis, .... 146 temporary and permanent dental arches compared, . 95 Chondromata of the jaws, . . . 839 Cicatrization of the socket, ......... 258 variation in the position of adjacent teeth during, . . 263 Ciliary nerves, affections of the, consequent upon abscesses of the root, 438 affections of the, consequent upon exfoliations of the alveolar process, ........ 438 affections of the, consequent upon irritation of the tri- facial nerve, ........ 438 affections of the, consequent upon the impaction of foreign bodies in the teeth and jaws, .... 438 Classification of malformations of the teeth, ...... 157 the teeth, 30 Cleavage of the teeth, 29, 376 Cleft-palate, 89 Coalition of the roots, ......... 147, 152 Coating upon the teeth; .......... 357 living organisms in the, ..... 357 Colloid deposits in the pulp, ......... 237 Concrescence of roots, ......... 147, 152 facial neuralgia consequent upon the, . . . 435 Condyle of the lower jaw, senile wasting of the, ..... 270 Condyloid or nodular enlargements upon the extremities of roots, 138, 139 Conical teeth, 100, 102 29 450 ALPHABETICAL INDEX. Consecutive atrophy, ..... Consolidation of the dentinal fibrils in caries, Convulsions during the first dentition, . in connection with anomalies in the Copper, efi'ects of, upon the root-membrane, . Coronoid process of the lower jaw, senile wasting Cracks in the enamel, ..... Cretefactions in the pulp, .... Croton oil, effects of, upon the root-membrane. Croupous inflammation of the gums, Crowns, axial torsions of the, flexions of the, . surfaces produced by friction upon the, and roots, dwarfish, . Cuticle of the enamel, . Cystoid-gelatinous cancer of the upper j Cysto-myxoma of the jaws, . Cysto-sarcoma adenoides, of the jaws, Cysts, dentigerous, of the antrum, jaws, ovarian, containing rudimentary teeth, Cytoblastions in the root-membrane of th Deafness consequent upon caries Deciduous teeth, see Temporary Teeth. Defective formation of the crowns and roots. Defectively developed enamel, histology of, . Defects in the enamel, causes of, ..... . 142 and wedge-shaped, upon the facial surface of the neck Deficiency of milk teeth, permanent teeth, Degeneration of the parenchyma of the embryonic pulp pulp into a soft, greasy mass Density of the teeth, Dental arches, comparison of the changes in the temporary and per- manent, . canal in old age, d den cap, .... cartilage, . groove, posterior, membrane, inflammation of the external, pulp, see Pulp. ridge, sac, development of the, . 373, tition. PAGE 232 413 434 435 215 270 0, 168, 376 . 234 . 215 . 196 . 132 . 130 . 247 . 157 51, 69 . 351 . 349 . 344 . 343 . 172 . 351 . 331 . 172 59, 317 45, 244, 441 139 143 Note 253 107 104 170 241 28 95 242 69 420 61 85 205 61 64 ALPHABETICAL INDEX 451 Dental sac, melanotic cancer of the, primary stage of the, . sarcomatous proliferation o DenticolsB, .... Dentinal canals or tubes, cells, inversion of the layer of. fibres, .... consolidation of the, in germ, development of the, primary stage of the, globules, .... sheaths, of E. Neumann, Dentigerous cysts, .... Dentine, ...... f the. canes, of. s portions of carioui abscesses in the, adhesion of the pulp to the, appearances presented by carious cartilaginous softening of the carious, chronic caries of the, combination of calcifications with new-formations concentrically laminated new-formation diminished translucency of carious, direction of the development of the, discoloration of carious, . duration of the development of the, growth of the radical portion of the, hardness of the, .... increased translucency of the contiguou in grooved teeth, interglobular spaces of the, interstitial development of, intertubular tissue of, junction of the cement with the, enamel with the, pulp with the, new-formations of, . of repair, .... of animals' teeth, abscesses in the, of the tusks of elephants, new-formation of osseous substance with abscesses in the, red color of the, with infiammation of the pulp, secondary, senile, .... sensitiveness of the, theories concerning the mode of development of the, undermining caries of the, ..... PAGE . 350 . 62 . 346 357, 358 . 43 . 54 . 295 . 44 373, 386, 413 . 65 . 61 . 45 44 . 172 . 43 187 241 384 387 et passim, 389 et passim of, . . 296 289 384 66 384 66 70 29 386 145 45 294 45 58 50 54 286 et passim 289 187 188, 304 183, 370 289 242 56 68 389 452 ALPHABETICAL INDEX. Dentition, see First, Second, and Third Dentition. Development of the cement, dentine, enamel, ..... germs of the first and second molars,, interstitial, of bone, dentine, . of malformations, mode of the, the teeth, ..... wisdom teeth, Digitalis, effects of, upon the root-membrane, Dilaceration, ........ Diminution in the size of the pulp-cavity and dental canal Diphtheritic inflammation of the gums, Diphtberitis, ........ Displacement, retention of teeth without, Distinctions between the milk and permanent teeth Double or twin-malformations, .... Dropsy of the antrum, Durability of the enamel, ..... Dwarfish malformations of the crowns and roots, Dyscrasic periostitis of the jaws, .... Ear, neuralgic aflTections of the, consequent upon carie Edentulous jaws, ...... Effects of carious teeth upon the rest of the body various substances upon the, . Elasticity of the teeth, .... Elephants' teeth, musket-balls in, . Empyema of the antrum. Enamel, ....... appearances presented by carious cap, appearances presented by the carious, detachment of the, . causes of defects in the, . cells, cracks or fissures in the, . deposits of pigment in carious, direction of the development of the, durability of the, . fibres, ..... germ, ..... germs of permanent teeth with a single root, the first and second permanent mol wisdom teeth, hardness of the, permanent 69 68 64 86 8, 92, 276, 306, 329 294 155 60 86 215 133 242 205 197 127 40 170 231 49 157 224 in old age 22 441 226 403 215 30 301 229 46 376 379 47 142 and Note 47, 63 30, 168, 370 378 66 49 47 61 66 86 86 29 ALPHABETICAL INDEX. 453 Enamel, histological appearances of defectively developed, irregular distribution of the, . junction of the, with the dentine, . membrane (Nasmyth's), . appearance of the cai'ious, in old age, new-formations of, . nodules, ...... of grooved teeth, .... organ, ...... prisms, ...... property of double refraction of the, senile, ...... striiB of the, ..... theories concerning the mode of development of the, thickness of the, .... undermining caries of the, Enchondromata of the jaws, .... Enostoses of the alveolar process, . jaws, Entozoa in the antrum, .... Epilepsy consequent upon exostosis of the roots. Epileptiform paroxysms in association with anomalies dentition, ....... Epileptiform paroxysms during the first dentition. Epithelial cancer of the gums, jaws, Epulis, . . .... fibromatosa, sarcomatosa, varieties of, . Erosion {Note), .... Eruption of the milk teeth, . intervals between the, first permanent molars, permanent teeth, . second permanent molars, wisdom teeth, Exanthemata, infiammation of the gums in Exanthematous periostitis of the jaws, . Excentric atrophy of Kokitansky, . Exostoses of the cement, cement, prosopalgia consequent upon, alveolar process, . interstitial developm roots, epilepsy consequent upon. Experiments with different substances upon the teeth, the, the second 51, 69 325 325 143 73 75 76 82 85 86 195 224 258 272, 312 . 315 228, 327 ent of bone in, 329 436 407 PAGE 143 141 50 , 165 381 247 296 134 144 62 47 50 246 48 64 47 382 339 331 337 353 436 435 434 320 349 322, 347 323 454 ALPHABETICAL INDEX. the opera- 30, 168, Extension of caries to the roots, ........ Extraction of teeth, a special cause of facial neuralgias. Facial neuralgia consequent upon caries of the wall of the antrum, . imbedded teeth, exostoses, . the concrescence of roots, Fatty degeneration of the pulp, resulting from inflammation of milk teeth, Fibro-chondroma of the jaws, ..... Fibromata of the gums, ....... jaws, Fibrous cancer of the gums, ...... jaws, Filling, importance of new-formations in connection with tion of, . . ... First dentition, ........ convulsions during the, . diseases occasioned by the, epileptiform paroxysms during the, reflex symptoms during the, . Fissures or cracks in the enamel, Fistula, buccal, in the gum, ....... of the antrum, ....... salivary, ........ Flexions and torsions of the crowns and roots, of the roots, ....... Foreign bodies in the antrum, ..... teeth, the cause of affections of the ciliary nerves, Formation, defective, of the crowns and roots, of the teeth, irregularities in the. Fractured teeth, ........ cases of, ..... . conditions necessary for the union of, union of, longitudinally. Fracture of the alveolus, ...... Fragilitas vitrea, Frequency of caries influence of age upon the, . diseases of the general sy; the, family upon the, food upon the, . locality upon the, occupations upon the, stem 219, 219, 223, upon 400, PAGE 392 432 442 435 315 435 232 191 233 339 319 340 351 351 300 73 434 199 435 434 876 219 198 352 221 130 132 230 438 139 98 307 307 309 311 253 258 397 399 413 400 402 400 402 ALPHABETICAL INDEX. 455 Frequency of caries, influence of popular customs upon the, race upon the, . sex upon the, the use of tobacco upon the, in the difl"erent kinds of teeth, Fusion of teeth, see Blending. Ganglions and nerves, anatomical changes in the, in neuralgias, Gangrene of the mouth (Noma), . pulp, moist and dry, Gangrenous degeneration of the root-membr Gelatinous cancer of the jaws, tumors of the jaws, Glands, mucous, salivary, secretion of the salivary, . Globular masses of the dentine. Globules, dentinal, .... Gold, eflfects of, upon the root-membrane. Groove, dental, ..... posterior dental. Grooved teeth, peculiarities of the tissues in Growth of the jaws, .... direction of the, . lower jaw, measurements of the. " Gumboil," .... Gums, abscesses in the, . action of lead upon the acute or inflammatory oedema of the, angiomata of the, atony of the, atrophy, senile, of the, bloodvessels of the, cancer of the, epithelial cancer of the, epithelium of the, fibromata of the, . fibrous cancer of the, fistulse in the, glands of the, hypertrophy of the, inflammations of the, see Inflammation. in mercurial salivation, lancing the, . medullary cancer of the, nerves of the, 456 ALPHABETICAL INDEX. Gums, new-formations of the, papillae of the, papilloma of the, sarcoma of the, . scorbutic, secretion of the, . senile atrophy of the, vascular tumors of the PAGE 319 57 281, 319 320 255 355 254 319 Hair, change in the color of the, resulting from caries, Hardness, Moh's scale of, of the dentine, enamel, Hard tissues of the teeth, Harelip, .... Hearing affected by diseased teeth. Herpetic (?) inflammation of the gums, History of caries, .... Horny character of senile dentine, Hydrargyriasis, .... Hydrocephalus, teeth in a case of congenital Hydrops antri, Hypertrophies, Hypertrophic cement, interstitial resorption of, perforating resorption of, peripheral resorption of, root-membrane, pigment deposits in the Hypertrophy of the alveolar process, . cement, .... neuralgias caused by, interstitial, peripheral concentric gums, .... root-membrane. Incisors, description of the, .... Inflammations, ...... Inflammation of the gums, .... during the first dentition, during the second dentition catarrhal, . causes of, croupous, diphtheritic, herpetic (?), in syphilis, . in the exanthemata, 488 •29 29 29 43 89 441 195 368 242 205 148 229, 231, 331 271 274 274 273 279 228 271 272 276 276 279 277 32 176 192 200 204 192 193 196 205 195 195 195 ALPHABETICAL INDEX. 457 Inflammation of the gums, modified by individual peculiarities, phlegmonous, .... rare sequels of, . suppurative, .... the origin of ulceration, mucous membrane and periosteum of the antrum consequent upon that of the root-membrane, nasal mucous membrane and periosteum, conse quent upon that of the root-membrane, pulp> acute, ..... changes in the bloodvessels in, nerves in, chronic, .... circumscribed, ...... terminating in acute or moist grangrene, . general, ....... leading to that of the root-membrane, . leads to atrophy, ...... calcifications, . . fatty degenerations, .... redness in, . suppurative, ..... 177, 179 the cause of the reddish color of dentine, increased volume in, . root-membrane, . . . changes in the hard tissues of the root in, . acute, . chronic, consequent upon that of the etiology of, . in animals, . resorption of the alveolus in resulting in gangrene, . stages of, . . . Inflammatory or acute oedema of the gums, .... Injection of the alveolar arteries, ...... Insanity, resulting from the diflicult eruption of a wisdom tooth Interalveolar bloodvessels, ....... nerves, ........ Interglobular spaces of the dentine, ..... Intermaxillary bone, melanotic cancer of the, Interstitial development of bone, . . . .78, 92, 2' dentine, ..... facets from the friction of contiguous crowns, . growth of bone in the jaws, .... PAGE 194 198 201 198 194 229 . 228 . 176 . 176, 179 . ISO . 181 176, 179, 186 . 178 182 178 192 191 191 191 178 186 183 178 204 . 212 205, 206 205, 208 pulp, 192 . 213 . 222 . 213 . 211 . 205 . 198 . 60 . 435 . 59 . 60 45 . 350 6, 306, 329 . 294 . 252 . 92 458 ALPHABETICAL INDEX. PAGE Interstitial hj-portrophy of cement, 276 resorption of bone in the jaws, ..... 92 hypertrophic cement, .... 274 Intertubular tissue of the dentine, 45 Intervals between the eruption of the milk teeth, . 75 Inversion of the layer of dentinal cells, 295 Iodine, effects of, upon the root-membrane, 215 Irregularities in the arrangement of entire sets of teeth, 108 distribution of the enamel, .... 141 formation of teeth, 98 number of permanent teeth, . 99 position of the milk teeth, .... 121 permanent teeth, . 112 separate permanent teeth imbedded within the jaw, 122 size of the milk teeth, ..... 99 permanent teeth, .... 98 structure of the teeth, 130 Jaw, see Upper and Lower Jaw, and Maxilla. Jaws, abscesses in the, .......... 226 atrophy of the, . 257 cancer of the, . 349 changes in the, during the second dentition ) . 91 arch of the. . 95 chondromata of the, .... . 339 cystoid-gelatinous cancer of the upper, . 351 cysto-myxoma of the, .... . 349 sarcoma of the, .... . 343 cysts of the, . .331 direction of the growth of the, . 89 edentulous, ..... . 266 enchondromata of the, . 339 enostoses in the, . 337 epithelial cancer of the. . 349 fibro-chondromata of the, . . 339 fibroma of the, . 340 fibrous cancer of the, .... . 351 gelatinous cancer of the. . 351 tumors of the, . 348 growth of the, . 88 interstitial growth of bone in the, . 92 medullary cancer of the. . 350 melanotic cancer of the, . 350 mj'^eloid sarcoma of the, . 347 myxomata of the, .... . 348 necrosis of the, during dentition. 223 ALPHABETICAL INDEX. 459 Jaws, osteoid-choudroma of the, . osteophytes upon the, . osteo-carcinoma of the, sarcoma of the, . periosteal sarcoma of the, . periostitis of the, see Periostitis. purulent infiltration of the, . relative growth of the, sarcomata of the, senile wasting of the, . wolf's, Juga alveolaria, .... Lancing the gums, Leptothrix buccalis, reaction of, with iodine and acids. Longitudinal fracture through the crown and root, union of a, Lower jaw, see Jaw. articulation of the, ...... description of the, ...... direction of the growth of the, .... measurements, showing the relative growth of the movements of the, ...... ossification of the, ...... periostitis of the, see Periostitis. senile changes in the, ...... 357 PAGE . 339 . 335 . 351 . 347 . 347 . 225 . 92 . 343 . 257 . 89 . 23 . 199 et passim . 358 . 311 . 26 . 24 . 89 . 92 . 26 . 89 . 269 Malformations of the teeth, . . 154 classification of the, ....... 157 dwarfish, of the crowns and roots, ..... 157 general, of the crown of a molar, with undeveloped roots, in connection with the deeply imbedded crown of a wisdom tooth, ....... 158 mode of the development of the, ..... 155 monstrous, of the coronal with a well-formed radical portion, ......... 158 of the teeth of animals, ....... 167 Malposition of the teeth, amaurosis consequent upon, .... 440 neuralgias consequent upon, . . . 435, 436 Masseter muscles, senile wasting of the, ...... 269 Mastication, actions of the muscles in, 27,270 movements in, . . . . . . . . 27, 270 muscles of, . . - . ■ • • • • .27 Maxillae, see Jaws. Maxillary periosteum, abscesses in the, 222 atrophy of the, 257 460 ALPHABETICAL INDEX. PAGE Maxillary periosteum, inflammatory afi'ections of the, from those of the pulp or root-membrane, ...... 222 sinus, ........... 24 Measurements showing the relative growth of the jaws, ... 93 Medullary cancer of the gums, ........ 321 jaws, 850 Melanotic cancer of the dental sac, ....... 350 intermaxillary bone, ..... 350 Membrane, Nasmyth's enamel, 51, 69, 165 of the root, see Koot-Membrane. Meningo-encephalitis, consequent upon the extraction of a tooth, . 223 Mental aberration, consequent upon the second dentition, . . . 435 foramen, ........... 24 Mercurial salivation, gums in, . . . . . . . . . 195 Mercury, effects of, upon the root-membrane, 215 Micrococcus, ............ 357 Milk teeth, see Temporary Teeth. Mixed saliva, see Saliva, ......... 355 Moh's scale of hardness, ......... 29 Molars, description of the, ......... 35 development of the enamel germs of the first and second per- manent, ........... 86 eruption of the first permanent, ...... 76 second permanent, 85 Monstrous malformation of the crown with well-formed roots, . .158 outgrowth of dentine and cement upon the root, . . . 169 Mouth, bony framework of the cavity of the, ..... 21 gangrene of the (Noma), 199, 201 the flat, 108 grinning (Fletschenmund), ...... 109 negro (os -^thiopum), ....... 108 senile (os senile), . . . . . . . .110 Movements of the lower jaw, ........ 26 Mucin, 354 Mucor, 194, 415 Mucous glands, 354 membrane of the antrum, inflammation of the, consequent upon that of the root-membrane, ...... 229 membrane of the antrum, polypi of the, ..... 352 mouth, new-formations of the, . . . 321 nasal cavitj'^, inflammation of the, consequent upon that of the root-membrane, . . 228 secretion of the, ....... 355 Mucus, 354 Multilocular ovarian cysts containing imperfectly developed teeth, . 172 Musket-balls in the teeth of elephants, 301 Myeloid sarcomata of the jaws, 347 ALPHABETICAL INDEX. 461 PAGE Myeloplaxes, 59, 317 Myxomata of the jaws, .......... 348 Nasal cavity, inflammation of the mucous membrane and periosteum of the, consequent upon that of the root-membrane, . . . 228 Nasmyth's membrane, ........ 51, 69, 165 Necrosis of the alveolar process, ....... 222, 226 cement, consequent upon inflammation of the root- membrane, 212 jaw, during dentition, 223 Nerves and ganglions in neuralgias, anatomical changes in the, . . 426 of the pulp in inflammation, changes in the, .... 181 resection of, for the relief of neuroses, ..... 430 Net-like atrophy of the pulp, ........ 238 Neuralgia in a molar, resulting in death, ...... 436 Neuralgias, anatomical changes in the nerves and ganglions in, . . 426 clinical phenomena of, ...... . 430 consequent upon caries, 438 ei jyassim Dobbelin's operation for the relief of, .... 434 exciting causes of, ....... . 427 extraction of teeth, a special cause of, .... 432 foci of irritation in, . . . . . . . . 427 irradiation of the pain in, ...... . 429 occasioned by anomalies in the second dentition, . . 435 impacted teeth, 435 painful points in, 431 reflex phenomena in, ....... . 431 resection of nerves in, ....... 430 Neuritic process [Neuritis], 427, 429 Neuroses, see Neuralgias, ......... 426 consequent upon afl'ections of the teeth, abstract of cases of, 435 New-formations, 284 importance of, in connection with the operation of till- ing, 300 in the teeth of animals, ...... 297 literature of, 286 of cement, ......... 312 dentine, 286 combination of, with calcifications, . . 296 concentrically laminated, .... 289 enamel, 296 osseous substance with abscess in elephants' ivory, 188, 804 the alveolar process, ...... 289 gums, ........ 319 hard dental tissues, ...... 286 oral mucous membrane, ..... 321 pulp, 191, 285 462 ALPHABETICAL INDEX. PAGE New-formations of the root-membrane, 316 osteo-dentinal, ...... 293 et passim physiological or pathological signification of, . . 299 progressive, ......... 434 dentinal, 300 Nitrous acid salt in the saliva, ........ 355 Nodules of enamel, .......... 134 Nodular or condyloid enlargements at the extremities of roots, . 138, 139 Noma, 199, 201 Oblique fractures of the crown, exposure of the pulp in, roots. Odontalgia nervosa ex carie, . Odontoblasts, ...... Odontolithus, ...... Odontomata (iVo^e), .... (Edema of the gums, acute or inflammatory, Oidium albicans, ..... Opium, eff"ects of, upon the root-membrane, Organ adamantiiic'e, \ . . . Os iEthiopum, . ... senile, ...... Ossification of the lower jaw, upper jaw, senile root-membrane, Osteoid chondromata of the jaws, . Osteo-carcinoma of the jaws, dentine, ..... in the teeth of animals, . odontomata, ..... sarcomata of the jaws, . Osteomata of the cement, prosopalgia consequent upon alveolar process, . interstitial Osteophytes upon the jaws, . Osteopsathyrosis of Lobstein, Ostitis, ....... Ovarian cysts, teeth in, . Papillte of the gums, Papilloma of the gums, . Parulis, .... Penicillium glaucum. Perforating caries, . resorption of hypertrophic cement, Pericellular resorption of the angle of the lower jaw, development of bone 20: 19 358, 311 309 177 54 361 155 198 406 215 163 108 110 89 255 339 351 46, 293 et passim . 297 169, 316 169, 343 . 312 . 315 228, 327 in, . 329 2, 228, 335 258 367 172 281, 57 319 198 357 176 et passi7)i 274 269 ALPHABETICAL INDEX. 463 chan Periodontitis, ........ Periosteal sarcoma of the jaws, ..... Periosteum of the root, see Root-Membrane. Periostitis of the alveoh\r process, consequent upon caries, jaw, during the first dentition, . second dentition, dyscrasic, exanthematous, rheumatic, . specific, traumatic, . lower jaw, symptoms of, upper jaw, symptoms of, Peripheral-concentric hypertrophy of the cement, resorption of hypertrophic cement, the angle of the lower jaw. Permanent and temporary dental arches, comparison of the the, teeth, arrangement of the, . caries of the diiFerent, carious roots of the, . deficiency of the, ♦ description of the, eruption of the, . imbedded within the jaw, irregular position of, irregularities in the arrangement of entire sets of, irregularities in the number of, position of separate, size of, Phlegmonous inflammation of the gums, Phosphornecrosis, ........ Phosphorus, effects of the fumes of, ujwn the teeth and adjacent tures, ..... Pigment deposits in atrophic pulps, carious enamel, the hypertrophic r Pivoted teeth, caries of, . Polypi of the mucous membrane of the pulp, root-membrane. Posterior dental groove. Primary atrophy, .... Progressive dentinal new-formation, new-formations, . proliferation of cement. Proliferation, sarcomatous, in the pulp, of the dental sac, oot-membrane, antrum, 205, struc- PAGE 205 347 464 ALPHABETICAL INDEX. Prosopalgia, see Facial Neuralgia. Protococcus dentalis, ........ Pterygoid muscles, senile wasting of the, .... Ptosis consequent upon dental caries, ..... Ptyaline, .......... Puccinia graminis, ......... Pulp, dental, abscesses in the, ........ adhesion of the, to the dentine, ..... atrophy of the, ........ resulting from inflammation, basis tissue of the, ....... bloodvessels of the, ....... calcifications of the, ....... resulting from inflammation, colloid deposits in the, ...... combination of difi'erent atrophic processes in the, cretefaction of the, degeneration of the, into a soft, greasy mass, parenchyma of the embryonic, . fatty degeneration of the, ...... resulting from inflammation, gangrene, moist and dry, of the, .... inflammation of the, see Inflammations. in transverse and oblique fractures, exposure of the, . junction of the, with the dentine, nerves of the, .... net-like atrophy of the, new-formations of the, of the milk teeth, fattj' degeneration of the, pigment deposits in atrophic, polypus of the, .... sarcoma of the, .... sarcomatous proliferation of the, sclerosis of the, .... cavity and dental canal, diminution in the Purulent infiltration of the alveolar process, jaws, . Pyorrhoea alveolaris, ..... size of, in old age Kedness of the pulp in inflammation, ..... Eeddish color of the dentine with inflammation of the pulp, teeth, occurs as an anomaly of formation, Keflex phenomena in connection with neuralgias, the first dentition, .... the second dentition, .... 372, 415 . 269 437, 440 354, 365 . 415 . 54 7, 179, 186 . 241 191, . 178 183, 370 . 186 . 431 . 434 . 435 Keinserted human teeth, caries of, 404, 406, 414 ALPHABETICAL INDEX. 465 Keplantation of teeth, ..... Eesection of nerves for the relief of neuroses, Resorption of bone in the jtiws, interstitial, . hypertrophic cement, interstitial, perforating, peripheral, senile dentine and cement, the angle of the lower jaw, peripheral and pericellular the alveolar process, senile, ..... the alveoli, after extraction of the teeth, consequent upon inflammation of the root- membrane, ...... previous to the eruption of the teeth, partial, the hard tissues of the root, consequent upon inflamma- tion of the root-membrane, . process in shedding the teeth, Retention of teeth without displacement. Rheumatic aflfection of the root-membrane, . periostitis of the jaws. Ridge, the dental, ...... Root-membrane, ...... abscesses of the, . affections of the, consequent upon the replantation and transplantation of teeth, affections of the, consequent upon the substances, atrophy of the, . bloodvessels of the, calcification of the, cancer of the, cytoblastions in the, gangrene of the, . hypertrophy of the, inflammation of the, see Inflammation myeloplaxes in the, nerves of the, new-formations of the, symptoms of the, ossiflcation of the, pigment deposits in the hypertrophic, polypi of the, .... rheumatic affection of the, . senile, ...... tumors of the, .... Root, periosteum of the, see Root-Membrane. Roots, abscesses of the, causing affections of the ciliary nerves, 30 PAGE 216 480 92 274 274 273 245 269 266 259 213 71 212 77 127 216 224 61 58 210 . 215 use of various . 214, 215 . 255 . 59 . 255 . 317 317 211 277 59, 59, 317 . 60 . 316 . 317 . 256 . 279 . 318 . 216 . 255 . 316 . 438 46G ALPHABETICAL INDEX. PAGE Eoots and crowns, dwarfish, 157 flexions and torsions of the, ..... 130 condyloid or nodular enlargements at the extremities of the, 138, 139 diminished number of, ........ 140 extension of caries to the, ........ 392 facial neuralgia, consequent upon the concrescence of, . . 435 flexions of the, .......... 132 formation of the, when completed, ...... 70 general monstrous malformation of the crown with well-formed, 158 general malformation of the crown of a molar with undeveloped growth of the, ....... of permanent teeth, caries of the, supernumerary, ....... union of the, ....... unusually long or thick, divergent and curved, . Saliva, acidity of the, . alkalinity of the, appearance and properties of the, the mixed, .... nitrous acid salt in, sugar in, . sulphocyanic acid in urea in, Salivarj' calculus, .... fistula, .... glands, .... secretion of the, . Sarcomata of the sums, jaws, pulp. Sarcomatous proliferations in the pulp, of the dental sac, Sclerosis of the pulp, Scorbutic gums, .... Scrofulous teeth [Note), . Second dentition, .... changes in the jaws during the, convulsions caused by anomalies in the, diseases caused by the, epilepsy caused by anomalies in the, . mental aberration caused bj' anomalies in neuralgias caused by anomalies in the. Secondary atrophy, ....... dentine, ....... osteoids, ....... 140, 14 the. 219 158 70 396 136 152 138 355 356 354 355 355 356 355 356 365 221 354 354 320 343 286 191 346 240 255 142 76 91 435 201 435 435 435 232 289 347 ALPHABETICAL INDEX. 467 the temp les o Secretion of the gums, .... mucous glands, . membrane, salivary glands, . Senile alveolus, atrophy, ..... of the gums, . cement, ..... calcification of the root-membrane, changes in the angle of the lower jaw dentine, ..... enamel, ..... membrane, flattening of the articular eminence of ossification of the root-membrane, resorption of the alveolar process, cement, dentine, . root-membrane, .... wasting of the coronoid processes and condy masseter and pterygoid muscles, maxilla, Sensations produced in the teeth by certain sound; Sensitiveness of the dentine, .... Shedding the teeth, process of, . . . Socket, atrophy of the, ..... cicatrization of the, .... Specific gravity of the teeth, periostitis of the jaws. Spirillum, ....... Stomatitis, hemorrhagica, .... ulcero-membranacea, . Structure of the teeth, irregularities in the, . Supernumerary roots, teeth, ..... Surfaces upon the crown, produced by friction, Sutura incisiva, ...... Syphilis, changes in the form of teeth indicative inflammation of the gums in, . f the Tartar, Teeth, see Temporary and Permanent Teeth, anesthesia of the, . . . , artificial caries of the, blending or fusion of adjacent, . f, oral bone, lower jaw, 100, 37 . 443 I, 375, 407 . 147 468 ALPHABETICAL INDEX. PAGE 374, 376, 406, 414 404, 406, 414 . 357 Teeth, caries of artificial, reinserted human teeth, the, different kinds of, . changes in the form of, indicative of syphilis, classification of the, ..... cleavage of the, ...... coalescence or concrescence of adjacent, . coating upon the, formation of the, . living organisms in the, conical, ....... deficiency of, ..... . density of, development of the, ..... distinctions between temporary and permanent effects upon the hearing caused by diseased, elasticity of the, ...... extraction of, a special cause of neuralgias, fractured, ....... cases of, .... . conditions necessary for the union of, general characters of the, . hard tissues of the, .... in a case of congenital hydrocephalus, in ovarian cysts, .... irregularities in the, see Irregularities. Magitot's experiments with various substances upon the, malformations of the, see Malformations. neuralgias consequent upon impacted, neuroses consequent upon affections of the, abstract of cases of, new-formations of the, see New-formations. of animals, caries of the, . malformations of the, new-formations of the, wear of the, . of elephants, musket-balls in the, peculiarities of the tissues in grooved, .... relation between affections of the uterus and those of the {Note) pivoted, caries of, . . . 29, 393 146 30 . 376 . 147 . 357 . 361 . 357 100, 102 104, 107 28 60 40 441 30 432 307 307 309 28 43 148 172 reinserted human, caries of, replantation of, . retention of, without displacement, shedding the, . . . • resorption in connection with, specific gravity of, ......... 28 407 435 435 410 167 297 253 301 44 432 . 406 374, 376, 406, 414 . 216 . 127 . ■ . .77 77 ALPHABETICAL INDEX. 469 facial Teeth, supernumerary, ........ transplantation of, trephining the, Dobbelin's operation for the relief of neuralgia, ........ Teething, see Dentition. inflammation of the gums attending, . rare sequelae of inflammation of the gums attending, Temporary and permanent dental arches, comparison of the eh in the, ..... Temporary teeth, arrangement of the, blending of the, caries of the, deficiency of the, description of the, distinction between permanent and, eruption of the, excessive number of the, . fatty degeneration of the pulps of, intervals between the eruption of th irregularities in the position of the, size of the. Tetanus following the extraction of a tooth. Theories of caries, .... Third dentition, .... Thrush, Tomes' processes of the dentinal cells. Torsions and flexions of the crowns and root axial, of the crowns, Transplantation of the teeth, Transverse fractures of the crowns, exposure of the pulp in root, . Traumatic periostitis of the jaws, . Trephining the teeth for the relief of neuralgias, Trifacial nerve, afi"ections of the ciliary nerves and apparatus of vision from irritation of the, .... Trismus cured by the extraction of a first molar, Tumors of the root-membrane, symptoms of the. Tusks of elephants, abscess in the. Twin-malformations, ..... distinguished from blended teeth. P.^GE 100, L35 216 434 199 201 95 43 149 396 107 38 40 73 102 233 75 121 99 436 411 87 194 64, 68 130 132 216 311 309 224 434 438 436 316 317 188, 304 140, 170 . 149 Ulceration of the gums consequent upon catarrhal inflammation, . 194 Undermining caries of the dentine, 389 enamel, ...... 382 Underhung, HO 470 ALPHABETICAL INDEX. Union of roots, 140, 147, 152 Upper jaw, see Jaw. cystoid-gelatinous cancer of the, 351 description of the, 22 ossification of the, ........ 88 periostitis of the, see Periostitis. Uterus, relation between afiectious of the teeth and those of the {Note)^ 432 Upright teeth, 110 Vascular tumors of the gums, Vaso-dentine, Yestibulum oris, ...... Volume of the pulp, increased in inflammation, . 320 46, 188 . 218 . 178 Wearing away of the teeth by attrition, forms in which and means by which it is effected [Note), . . . . . . . . 247 Wedge-shaped defects upon the facial surface of the dental neck, . 253 White caries, 408 Wisdom teeth, development of the, ....... 86 duplication of the, 140 eruption of the, ........ 86 Wolf's jaw, 89 THE END. CATALOGUE OF THE FTJBLIOATIONS OF Lindsay & Blakiston, INCLUDING WORKS ON The Practice of Medicine, Surgery, Anatomy, Physiology, Materia Medica, Ophthalmoscopy, Therapeutics, Diseases of Women, Diseases of Children, Obstetrics, Pathology, Chemistry, Pharmacy, Dentistry, AND THE COLLATERAL SCIENCES. ALSO, PHYSIOLOGICAL, ANATOMICAL, AND , OBSTETRICAL MAPS AND DIAGRAMS, THE SYDENHAM SOCIETY'S PUBLICATIONS, PHYSICIANS' VISITING LISTS, &c., &c. 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On some Affections of the Liver and Intestinal Canal. Legg, The Examination of the Urine. Third Edition. Mackenzie. On Laryngeal Growths. Colored Illustrations. *' Pharmacopoiia of the Hospital for Diseases of the Throat Beynold's Clinical Uses of Electricity. Bigby's Obstetric 3Iemoranda. Fourth Edition. Gant's Irritable Bladder. Third Edition. Habershon on Diseases of the Liver. NEARLY RKADY. Atthill's Clinical Lectures on the Diseases of Women. Second Editior Enlarged and Illustrated. Fothergill on Disettses of the Heart, and their Treatment. Trousseau's Clinical Lectures. Vol. 5, completing the worlc. 3Iacnamara on Diseases of the Eye. Second Edition. IN PREPARATION. Sanderson and Foster's Hand-book for the Laboratory, Stvevingen's Pharmaceutical Lexicon, Coles. Dental 3Iechanics. Illustrated. Brunton. Experimental Investigation into the Action of 3Iedicine€ Gant. The Science and Practice of Surgery. Second Edition. Allingham on tJte Rectum, tCv. Second Edition. Fuller on Rheu mutism , Sc. A New Edition. Fuller on the Heart, Lungs, tDc. Second Edition. Tomes' Dental Surgery. A New Enlarged Edition. Walton, on the Eye. From the Tliird London Edition. Hardwick's Photogruphic Chemistry. Eighth Edition. Martin's 3Iicroscopic 3Iounting. S^" For particulars, see under alphabetical arrangement, in Catalogue. LINDSAY AND BLAKISTON S PUBLICATIONS. " The Representative Book of Medical Science." — London Lancet. Aitken's Science and Practice of Medicine. THIRD AMERICAN, FROM THE SIXTH LONDON EDITION. rnOROUGHLY REVISED, REMODELLED, MANY PORTIONS REWRITTEN, AVITH ADDITIONS EQUAL ALMOST TO A THIRD VOLUME, AND NU- MEROUS ADDITIONAL ILLUSTRATIONS, WITHOUT ANY INCREASE IN BULK OR PRICE, The Science and Practice of Medicine. By William Aitken, M.D., Fro- fcHsor of Pathology in the Army Medical School, &c., &c. The Thir^d American, from the Sixth London Edition, edited with Additions De !'D, ^I.D., Fellow of the Royal College of Physician &c., d'C. Sixth American jrovi the Fourth London Edition. Revun and enlarged. One Volume, octavo. ..... 83/ Dr. Headland's work has been out of print in this country nearly two years, awi>i ing the revisions of the auihor, which now appear in this edition. It gives the ou scientific and satisfactory view of the action of medicine; and this not in the way t idle speculation, but by demonstration and experiments, and inferences almost as ii disputable as demonstrations. It is truly a great scientific work in a small conipas and deserves to be the handbook of every lover of the Profession. It has received il most unqualified approbation of the iledical Press, both in this country and in Europ and is pronounced by them to be the most original and practically useful work that ht been published for many years. Hille's Pocket Anatomist. Being a Complete Description of the Anatomy of the Human Body ; for th Use of Students. By M. W. Hilles, formerly Lecturer on Anatomy an Physiology at the Westminster Hospital School of Medicine. Price, in cloth, $1.0 " in Pocket-book form, ...... 1.2 Heath on the Injuries and Diseases of tlie Jn wj The Jacksonian Prize Es^^ay of the Royal College of Surgeons of En land, 1867. By Ciirtstopher Heath, F.R.C. S., Assistant Surgeon University College Rospiial, and Teacher of Operative Surgery in Un versify College. Containing over 150 Illustrations. Octavo. Price. .S<>.ii Hodge on Foeticide, or Criminal Abortio: By Hugh L. Hodge, M. D., Emeritus Professor in the Unvjcr.iiiy q Pennsylvania. A Small Pocket Volume. Price in papei- covovs, 3 " flexible cloth, 5 This little book is intcDded to place in the hands of professional men and others the lueans of ar.sweri latisfactoiily and intelliijently any inijiiiries that may be made of them in connect.ou wi.h this imjiortal nibject. Holmes' Surgical Diseases of Ipfancy an( L nilCinOOu. By J. holmes, M.A., S'Mgejn to the Hospital fo Si?.k Children, Sc. Second Edition. Revised and Enlarged. Oclav l^rice, ST. 5 Hufeland's Art of Prolonging Life. Edited b Erasmus Wilson, M.D., F R.S. Author of "^ System of Huma Anatomy;^ "Diseases of the Skin,^^ &c., &c. 12mo. Cloth. $1 1 LINDSAY AND BI.AKISTON S PUBLICATIONS. lewson's Earth in Surgery. EAETH AS A TOPICAL APPLICATION lU SUEGEET. Being a full Exj)osition of its use in all the Cases requiring Tojncal Ajypli- cations admitted in the Men's and Women's Surgical Wards of the Fenn- sijlvania Hosjntal during a period of Six Months in 1869. With Four full-page Fhoto-Eelief Blustrations. By Addinell Hewson, M.D,, one of the Attending Surgeons to the Fennsylvania Sospital. "What relates to Truth is greater than what relates to Opinion." — Baoon. CONTENTS. Preface; Introduction; Histories of Cases; Comments as to the Effects of the Contact 'the Earth; Its Effects on Fain; Its Power as a Deodorizer; Its Influence over Inflam- ation ; Its Influence over Putrefaction ; Its Influence over the Healing Processes ; lodus Operandi of the Earth; As a Deodorizer and over Putrefaction; In its Effects on jiving Parts. In One Volume. Price, $2.50. Tliis volume presents the results of researches by the author into the tions of Earth as a surgical dressing, and embraces the histories of over inety cases which occurred in the wards of the Pennsylvania Hospital some iree years since, but whose publication has been delayed until now, for the juble purpose of weighing them by subsequent experience, and of inter- retiug their meaning by a careful study of the various subjects which they »volve. The illustrations are introduced for the purpose of giving a demonstration as strong possible of the successes attending these experiments, and are from photographs produced by a method that would seem to leave nothing to be desired as to perma- ncy, as well as faithfulness and accuracy of representation. pinion of S. D. Gross, M.D., LL.D., Professor of Surgery iii the Jefferson Medical College, Philadelphia. II have perused with great interest and profit the work of Dr. Addinell Hewson, en- llled " Earth as a Topical Application in Surgei-y," and regard it as a highly valuable btribution to the literature of the profession, destined as it is from the novelty of the bject of which it treats to attract general attention, inquiry, and experiment. The ithor has shown himself to be an original thinker, and the treatment which he is boring to introduce is worthy, as I can testify from personal observation, of a fair id impartial trial. April 6, 1872. xtract of a Letter from Jos. Pancoast, jNI.D., Professor of Anatomy in Jefferson Medical College, Philadelphia. I am glad you have brought the subject so perfectly to the notice of the profession, Earih Treatment is destined hereafter to be one of the acknowledged resources of trgery. March 2, 1872. The cases conclusively show that, as a rule, the contact of the earth is cooling and easant to the wound, reduces the pain, deodorizes, prevents putrefaction, and hastens e lu'.iling process. These results are the highest possible testimonials in its favor. surgeon should neglect to read this evidence, the means being so simple and obtain- )le. — Medical and Surgical Reporter, March 23, 1872. Tlie subject is one of much practical importance, and the book will amply repay )th physician and surgeon for the time involved in its careful reading. — Chicago edical Ejcaminer, March 1, 1872. LINDSAY AND BLAKISTOK'S PUBLICATIONS. Kirkes' Hand-Book of Physiology. THE SEVENTH LONDON EDITION. HAND-BOOK OF PHYSIOLOGY, by William Senhouse Kirkes, M.D. Seventh Edition, edited by W. Morrant Baker, F.R.C.S., Lee turer on Physiology, <&c., &c. With 241 Illustrations. In one volume, demy-octavo, containing over 800 pages. Price, bound in cloth, $5.00. Tbis edition of Dr. Kirkes' Hand-Book of Physiology is fully brought up to the times, aud forms oue of the most complete and convenient Text-Books on the subject, for the Student of Medicine, now in print. Lewiii oil Syphilis. With Illustrations. THE TREATMENT OF SYPHILIS with Subcutaneous Sublimate Injections. With a Lithographic Plate illustrating the Mode and Proper Place of administering the Injections, and of the Syringe used for the purpose. By Dr. Georg Lewin, Professorat the Fr.-Wilh. University, and Surgeon-in- Chief of the Syphilitic Wards and Skin Diseases of the Charity Hospital, Berlin. Translated by Carl Prcegler, M.D., late Surgeon in the Prussian Service and in the United States Army, and E. H. Gale, M.D., late Surgeon in the United States Army. In One "Volume, small Octavo. Price, . . . $2.25 Lee's: on Urine, the third londox edition. A Guide to the E ramination of the Urine. For the Practitioner and Student. By J. Wickiia.m Legg, M.D., Member of the Royal College of Physicians, &c., &c. Third Edition. 16mo. Cloth. Price, 75 cts. "Dr. Legg's little manual has met with remarkable success, and the spppdy exhaustion of the first editioD has enabled the author to make certain emendations which have added greatly to its value. We can now confidently commend it to the student as a safe and reliable guide to sucli examinations of the urine as he may be called upon to make." — London Medical Times and Gazette. Lawson's Diseases and Injuries of the Eye^ their Medical and Surgical Treatment, with Illustrations. By George Lawson, F.R.C.S., Surgeon to the Royal London Ophthalmic Hospital, and Assistaiit Surgeon to the Middlesex Hospital. In one volume, royal 12mo. Price, . . . S2.50 This Manual comprises a brief account of all the Medical and Surgical Affections of the Eye, with the Treatment essential for their relief, each subject being discussed in a separate section under its own peculiar head- ing. The very favorable notices appended below attest its great value to the student. "We congratulate Mr. Lawson on the production of such an excellent work on ophthalmic diseases as this. Without depreciating the large aud valuable treatises on this subject that have recently appeared, we have long felt that a manual was wanted which would serve as a text-book for students, and also should form a trustworthy guide •for practitioners in dealing with diseases of the eye. Well has IMr. Lawson supplied this want. He has described the various afi'ections of the eye, briefly but yet clearly, and from the large experience he has acquired as surgeon to the Royal London Oph- thalmic Hospital, Moorfields, he has made his work thoroughly practical. The profession will find this niaiiual just the sort of work they want on eye diseases, vhile to the BLudeut it will be invaluable as a text-book." — British Medical Journal, July 24, 1801' Meigs and Pepper on Children. rOUETH EDITION, ENLAEGED AO IMPROVED. The pulilishers have selected the following notice, from a late number of the London Lancet, of the New Edition of this work, as indicating, per- haps, more fully than any other of the numerous favorable criticisms that have appeared of it elsewhere, its great value to the Practitioner and Student of 3Iedicme. "It is not necessary to say much, in the way of criticism, of a work so well known as Meigs on Diseases of Children,' especially when it has reached a fourth edition. Our duty is wellnigh restricted to the point of ascertaining how far, under an old color, it preserves the freshness and the value of a new book — how far it incorpo- rates what is new with what is old without unseemly marks of mere joining. There is some advantage in starting entirely afresh, in being merely clinical, or in being very short, and limiting one's self to the expression of one's own views and experience. But sucli is not the nature of this book, and the advantages of it are different. It is a work of more than 900 good American pages,, and is more encyclopajdial than clinical. But it is clinical, and withal most effectually brought up to the light, pathological and therapeutical, of the present day. "The book is like so many other good American medical books which we have lately fiad occasion to notice ; it marvellously combines a resume of all the best European literature and practice with evidence throughout of good personal judgment, knowl- edge, and experience. It is gratifying to see how our English authors are quoted, and especially how the labors of Hillier, who died so prematurely, are recognized. But the book abounds in exposition of American experience and observation in all that relates to the diseases of children. Not the least interesting additions to the volume are sevei'al extensive tables, exhibiting the mortality in Philadelphia of some of the most common and fatal diseases in connection M'ith the variations of the temperature. And prepared with great care from the records of the Board of Health. "The thoroughly fresh nature of the book is especially seen in the care with which certain articles have been written. Such are those on Rickets and Tuberculosis, Infan- tile Atrophic Paralysis, and Progressive Paralysis. No book now on diseases of chil- dren is Complete which does not treat specially of constitutional or diathetic diseases, Buch as rickets and tuberculosis, syphilis, &c. "Among other articles of great interest and value we would mention those on Dis- eases of the Ctccum and Appendix Vermiformis, on Indigestion in Children, on Diar- rhoea, on Entero-Colitis, on Intussusception, on Chronic Hydrocephalus, and on Croup and the value of Tracheotomy. "The difficulties of editing a new edition of a medical book of some standing are not more fell in tlie region of pathology and the classification of disease than in that of therapeutics. In this work this difficulty has been fairly faced by the authors. They liave to confess to having changed their practice very materially in the treatment of acute diseases, to having given up mercury in most inftammatory diseases, and almost given \ip bloodletting. We recommend the views of these authors as to the injurious Bffects of calomel and antimony to careful consideration. They do not entirely abjure the use of bloodletting in certain cases of pneumonia and meningitis. Indeed, we think they will find reason in future editions to talk a little less freely than they do about bleeding and cupping very young children in certain circumstances of pneumonia, and in certain cases of simple meningitis. With a few exceptions of this kind, the therapeutics are sound and commendable, great importance being given to proper feeding and the general management of infancy and childhood. It is due to authors of so much fairness and experience to publish widely their opinion of the injurious nnd depressing effects of antimony in the inflammations of children. To infants under two years of age they think it best to give no antimony even in pneumonia. They do lot use tartar emetic at all in the cases of children, but small doses, such as the twelfih of a grain, of the precipitated sulphuret of antimony, every two, three, or four hours, watching its effects, and withdrawing it quickly if symptoms of prostration appear, perhaps without any vomiting. "We are glad to add this work to our library. There are few diseases of children which it does not treat of fully and wisely in the light of the latest physiological, pathological, and therapeutical science." — London Lancet, July 23, 1870, Frice, handsomely bound in Cloth . . . . . . . $6 00 " " " Leather 7 00 LINDSAY & BLAKISTON, PUBLISHERS, rUIL A DELPHI A. Mackenzie on Growths in the Larynx. With Numerous Colored and other Illustrations. Their History, Causes, Symptoms, Diagnosis, Pathology, Prognosis, AND Treatment. With Reports and Analysis of One Hundred Con- seciUive Gases treated by the Author ; and a Tabular Statement of every published case treated since the invention of the Laryngoscope. By MoRELL Mackenzie, M.D., Physician to the Hospital for Diseases of the Throat, author of " The Laryngoscope,^' &c. Octavo, Price $3.00 "Dr. Mackenzie stiows possession of what has been well called ' the complete professional mind.' " — The Lancet. " The most complete and original essay on new formations in the larynx." — Medical Times and Gazette. "A model of honest and complete work, and honorable to British medicine, as it is useful to practitioners of every country." — British Medical Journal. "This work will certainly at once take its place as the author's chief one, and on it alone he may be content to let his reputation rest The book is as complete as it is possible to make it." — Medical Press. "A storehouse of sound knowledge on the subject it treats." — Practitioner. "The entire profession is under a deep obligation to Dr. Mackenzie for his really interesting, instructive, and opportune essay." — Edinburgh Medical Journal. "Contains a large amount of information which is of the very greatest value." — Glasgow Med. Journal. " Of extreme interest and value, and reflects the greatest credit on Dr. Mackenzie." — Birmingham Med. Rev. "The essay can hardly fail to increase Dr. Mackenzie's already honorable position as an accomplished laryngologist and instructor. We trust that the work will find readers, not only among physicians espe- cially interested in the subject of which it treats, but among general practitioners as well. They will find it particularly free from the technicalities which often make works on special subjects dull reading." — Anier. Journal of Medical Science. " As a work which contains much that is new and cannot be found elsewhere, we bespeak for it a welcome in America. It contains the most perfect and satisfiictorj' tabular record that any laryngoscopist has ever presented to the profession." — iVew) Tbi-li Medical Journal. " It is not in mere compliment that we say that no practitioner engaged in the surgical treatment of laryn- geal tumors can afford to forego the study of Dr. Mackenzie's volume." — New York Medical Becord. "This is certainly the chefd'ceuvre of Dr. Mackenzie's productions The last and decidedly the best section of the book is upon treatment. It is esjiecially commendable for the perspicuity and fairness with which it discusses the comparative merits of the different operations and instruments." — Phila. Med. Times. Mackenzie on the Laryngoscope in Diseases Of the Throat, with an Appendix on Bhinoscopy, and an Essay on Hoarseness, and Loss of Voice. With additions, by J. SoLis Cohen, M.D., Author of " Lihalation, Its Therapeutics and Practice,'" &c. Il- lustrated by two Lithographic Plates, and 51 Engravings on Wood. Price, $3.00 " The Use of the Laryngoscope in Diseases of the Throat, and Essays on Hoarseness, &c., are two monographs of first-rate merit. Dr. Mackenzie's Essays wouM do honor to any place ; and he has used the opportunities afforded to diligence and skill to make solid and enduring contributions to sciencfe and practice. Both works are, througliout, models of honest and complete work, and are honorable to medicine, as they are useful to practitiresent Members of the Staff, now eminent in the Profession, with Litho- graphic and other Illustrations. Price per volume, . . $4.00 At last, however, the work has been commenced, the Philadelphia Physicians being llio first to occupj' this field of usefulness. The first Picports were so favorably re- ceived, on both sides of the Atlantic, that it is hardly necessary to speak for them the universal welcome of which they are deserving. The papers are all valuable contri butions to the literature of medicine, reflecting great credit upon their authors. The work is one of which the Pennsylvania Hospital may well be proud. It will do much icward elevating the profession of this country. — American Journal of Obstetrics. No. 5. The Lymphatics or Absorbents. No. 6. The Digestive Organs. No. 7. The Brain and Nerves. No. 8. The Organs of Sense and Voice. No. 9. The Textures. — Microscopic Struc- tures. Marshall's Physiological Dijigranis. LIFE-SIZE, AND BEAUTIFULLY COLORED, On account of their large size and the great distinctness of the figures on them, there has been a growing demand in this country for these Maps for the Lkciure Room and for lecturing from in Medical as well as other Schools. In order to supply this demand on more favorable terms, we have recently completed an arrangement with the publishers in London, by which we can sell them to the trade and others at a reduced price and on better terms than heretofore. The series, illustrating the whole Human Body, are life-size, each map printed on a single sheet of paper, made specially for the purpose, 1 feet long and Z feet 9 inches broad^ colored in fac-simile of the Original Drawings. There are nine diagrams, as follows* No. I. The Skeleton and Ligaments. No. 2. The Muscles and Joints, with Ani- mal Mechanics. No. 3. The Viscera in Position. — The Structure of the Lungs. No. 4. The Heart and principal Blood- vessels. Prepared under the direction of John Marshall, F.R.S., F.E.C.S., Pro- fessor of Surgery, University College, and Surgeon to University College Hospital. Price of the Set, Nine Maps, in Sheets, .... $50.00 " " " " handsomely Mounted on Canvas, with Rollers, and Varnished, $80.00 Though designed more especially for purposes of general education, supplying an acknowledged necessity of modern teaching, these diagrams will be found not inappli- cable to the requirements of professed Medical Schools, affording, as they do, a correct preliminary view of the various systems and organs in the human body. For Public School Purposes, for Lectures at Literary, Scientific, and other Institutes, they will be found invaluable; and also to students of Artistic Anatomy, imparting, as they do, when suspended on the walls of the Lecture-hall, School-room, or Studio, a familiar acquaintance with the whole human system. An Explanatory Key to the Physiological Diagrams. By John Marshall, F.R.S., F.R.C.S., &c. Octavo. Paper covers 50 cts. Description of the Human Body. Its Structure and Functions. Illustrated by Physiological Diagrams, Designed for the Use of Teachers in Schools and Young Men destined for the Medical Profession, and for popular Instruction generally. New Edition. By John Marshall, F.R.S., F.R.C.S., Professor of Surgery University College, and Surgeon to the University College Hospital. The work contains 260 quarto pages of Text, bound in cloth, and 193 Colored Illustrations, arranged in Nine Folio Diagrams, carefully colored and reduced from Prof. Marshall's large tvork. 2 vols. Cloth. . SIO.OO Murpliy's Review of Chemistry for Students. Adapted to the Courses as Taught in the Principal Medical Schools in the United States. By John G. Murphy, M.D. . . . $1 .25 LINDSAY AND BLAKISTON S PUBLICATIONS. I Martin's Manual of Microscopic Mounting. Wilh Illiistralions on Stone and Wood. 8vo. Preparing. Macnamara's Manual of the Diseases of the iliye. With Colored Plates. Second Edition, carefully Revised, with Additions, &g., &c. Octavo. Preparing. Morfit's Chemical and Pharmaceutical Man- ipulations. A Manual of the Chemical and Chemico- Mechani- cal Operations of the Laboratory. By Campbell Morpit, Professor of Analytic and Applied Chemistry in the University of Maryland. New Edition, with over 500 Illustrations. Preparing. Miller on Alcohol, and Lizars on Tobacco. Alcohol: Its Place and Power. B}" James Miller, F.R S.E., Professor of Surgery in the University of Edinburgh, President of the Medico- Chiru7-gical Society, Author 0/ Miller's Principles and Practice of Surgery, &c., &c. — The Use and Abuse of Tobacco. By John Lizars, late Professor of Sm'gery to the Moyal College of Surgeons, &c., (f;c. The Two Essays in One Volume. 12mo. .... $1.00 Ott on Soaps and Candles. Including the Most Recent Discoveries in the Manufactxire of all kinds of Ordinary Hard, Soft, and Toilet Soajys, and of Tallow and Com- fjosiie Candles. By Adolph Ott, Practical and Analytical Chemist. 12mo. With Illustrations $2.50 Overman's Practical Mineralogy, Assaying and Mining. WUh a Description of the Useful Minerals, and Instructions^ for Assaying, according to the Simplest Methods. By Frederick Overman, Mining Engineer, &c. 12mo. . $1.25- Piesse's Whole Art of Perfumery. And the Methods of Obtaining the Odors of Plants; the Manufacture tf Perfumes for the Handkerchief, Scented Powders, Odorous Vinegars, Dentifrices, Pomatums, Cosmetics, Perfumed Soaps, &c.; the Prepa- ration of Artificial Fruit Essences, &c. By G. W. Septimus Piesse,. Analytical Chemist. Second American, from the Third London Edition. 12mo. With Illustrations $3.00 Piggott on Copper Mining and Copper Ore. Containing a full Description of some of the Principal Copper Mines- of the United States, the Art of Mining, the Mode of Preparing the Ore for Market, &c., &c. By A. Snowden Piggott, M.D., Practical Chemist. 12nio $1.50^ LINDSAY AND BLAKISTON'S PUBLICATIONS. Pereira's Physician's Prescription Book. Cohtaining Lists of Terms, Phrases, Contractions, and Abbreviations, used in Prescriptions, with Explanatory Notes, the Grammatical Constructicna of Prescriptions, Pules for the Pronunciation of Pharmaceutical Terms, A Prosodiacal Vocabulary of the Names of Drugs, etc., and a scries of Abbreviated Prescriptions illustrating the use of the preceding terms, etc. ; to tvJiich is added a Key, containing the Prescriptions in an unabbreviated Form, tvith a Literal Translation, intended for the uxe of Medical and Pharmaceutical Students. By Jonathan Pereira, M.D., F.R.S., etc. From the Fifteenth London Edition. Price, in cloth, $1.25 " in leather, with Tucks and Pocket, . . . 1.50 This lit'le work has passed through fifteen editions in London and several in this country. The present edition of which this is a reprint has been carefully revised and many additions made to it. Its great value is proven both by its large sale and the many favorable notices of it in the Medical Press. Paget's Surgical Pathology. Third London Edition. Lectures delivered at the Royal College of Surgeons of England, by James Paget, F.R.S., Surgeon to St. Bartliolomeio''s Hospital, rfec, &c. Third London Edition, edited and Revised by William Turner, M.D., Lond. Professor of Anatomy in the University of Edinburgh, &c. One volume. Octavo, with numerous Illustrations. Price, .... $7.50 A new and revised edition of Mr. Paget's Classical Lectures on Surgical Pathology needs no introduction to our readers. Commendation of it would be as superiiuous as criticism would be out of place. Suffice it to say that almost every page bears evidence that the present edition has been, as the author mentions in his preface, " carefully re- vised," from a clinical point of view by himself, and from the pathological by his only less distinguished editor, Professor Turner. The latest observations of pathologists in all parts of the world have received due attention, and, as a consequence, the lectures in their present shape are not only, as Mr. Paget modestly hopes they may be «on- sidered, "better than they were," but probably the very best to which the student of pathology can resort. — American Medical Journal. Prince's Plastic and Orthopedic Surgery. Containing, 1. A Report on the Condition of and Advances made in, Plastic and Orthopedic Surgery up to the Year 1871. 2. A Neu) Classification and Brief Exposition of Plastic Surgery. With numerous Illusti-ations. 3. ORTHorEDics: A Syxtematio Work upon the Prevention and Cure of Deformities. With numerous Illustrations. In one volume, Octavo. Price, ...... $4.50 •'This is a good book, upon an important practical subject; carefully written, ubuudiintly ilULSirated, and well printed. It goes over the whole ground of deformi- ties of all degrees — from cleft-palate and club-foot, to spinal curvatures and ununited fractures. It appears, moreover, to be an original book, so far as one chiefly of com- pilation can be so. Such a book was wanted, and it deserves success." — Mtd. and Su-; Cerebrospinal Meningitis. By Alfred Stille, M.D., Professorof the Theory and Practice of Medicine in the University of Pennsylvo/- nia, &c., &c. In one volume, Octavo, .... $2.00 "This monograph is a timely publication, comprehensive in its scope, and present- ing within a small compass a fair digest of our existing knowledge of the disease, par- ticularly acceptable at the present time. It is just such a one as is needed, and may be taken as a model for similar works." — Am. Journal Med. Sciences. Stille's Elements of General Pathology. A Practical Treatise on the Causes, Forms, Symptoms, and Results of Disease. Second Edition preparing. Sweringen's Pharmaceutical Dictionary. A Lexicon of Pharmaceutical Science. In preparation. Schultze's Lecture Diagrams for Instruction in Pregnancy and Midwifery. 20 piates of the largest Imperial size, p)rinted in colors. Drawn and Edited with Explanatory Notes by Dr. B. S. Schultze, Professor of Midicifery at the University of Jena. With 4to volume of letter-press. $15.00 Sansom on Chloroform. Its Action and Administration. By Arthur Ernest Sansom, M.B., Physician to King^s College Hospital, &c , &c. 12mo. . $2.00 " The work of Dr. Sansom may be characterized as most excellent. Written not alone from a theoretical point of view, but showing very considerable experimental study, and an intimate clinical acquaintance with the administration of these remedies, — passing concisely over the whole ground, giving the latest information upon every point, — it is just the work for the student and practitioner." — Amer. Medical Journal. Scanzoni on Women. A Practical Treatise on the Diseases of the Sexual Organs of Women. Translated from the French. By A. K. Gardner, A.M., M.D., &c. With Illustrations. Octavo, $5.00 Stokes on the Diseases of the Heart And the Aorta. By William Stokes, Regius Professor of Physic in the University if Dublin ; Author of the Diseases of the Chest, &c., &c. Seco id American Edition. Octavo, .... $3.00 LINDSAY AND BLAKISTON's PUBLICATIONS. THOMAS HAWXES TANNER'S WORKS. " The leading feature of Dr. Tanner'' s hooks is their essential li/ practical character." London Lancet. Tanner's Practice of Medicine. FIFTH AMERICAN, FROM THE SIXTH LONDON EDITION. lietmed, much Enlarged, and thoroughly brought up to the present time. With a complete Section on the Diseanes Peculiar to Women, an exten- sive Appendix of Formidse for Medicines, Baths, &c., &c. By Thomas Hawkes Tanner, M.D., Fellow of the Royal College of Physicians, &c. Royal Octavo, over 1100 pages. Price, bound in Cloth, $6.00 " Leather, 7-00 Thero is a common character about the writings of Dr. Tanner — a character which constitutes one of their chief values: they are all esseatially and thoi-oughly practical. Dr. Tanner never, for one moment, allows this utilitarian end to escape his mental view. He aims at teaching how to recognize and how to cure dis- ease, and in this he is thoroughly successful. . . . It is. Indeed, a wonderful mine of knowledge. — Midicnl Tiiin's. Tanner's Practical Treatise on the Diseases of Infiincy and Childhood, price, ss.so. THIRD AMERICAN EDITION, REVISED AND ENLARGED. By Alfred Meadows, M.D., London, M.R.C.P., Physician to the Eos- pital for Womeri and to the Gener'al Lying-in Hospital, &c., (&c. This book of Dr. Tanner's has been much enlarged and the plan altered by Dr. Meadows. As it now stands it is probably one of the most complete in our language. It no longer deals with children's diseases only, but includes the peculiar conditions of childhood, both normal and abnormal, as well as the therapeutics specially applicable to that class of patients. The articles on Skin Diseases have been revised by Dr. Tilbury Fox, and those on Diseases of the Eye by Dr. Brudenell Carter, both gentlemen distinguished in these spe- cialties.— ^/cdicai 'rimes and Gazette. Tanner's Index of Diseases and their Ireatnient. WUh upwards 0/500 Formulse for Medicines, Baths, Mineral Waters, Climates for Livalids, &c., &c. 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Leather, 3-1.50 Professor Taft has done good service in thus embodying, in a separate volume, a comprehensive view of Operative Dentistry. This gentleman's position as a teacher must have rendered him fomiliar with the most recent views which are entertained in America on this matter, while his extensive experience and well-earned reputation in practice must have rendered him a competent judge of their merits. We willingly commeud Prcf. Taft's able and useful work to the profession. — London Dental Jieviete. LINDSAY AND BLAKISTON's PUBLICATIONS. Tilt's Change of Life In Health and Disease. A Practical Treatise on the Nei-vous and other Affections incidental to Women at the Decline of Life. By Edward John Tilt, M.D. From the Third London Edition. In one volume. Octavo, $3.00 The work is rich in personal experience and observation, as well as in ready and sensible reflection on the experience and observation of others. 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By Frank Chance, B.A., M.A., &c With Notes and Emendations, and 144 Engravings. 8vo. $5.00 Ty t- lu LINDSAY AND BLAKISTON S PUBLICATIONS. Trousseau's Clinical Lectures. VOL. v., COMPLETING THE WORK, NEARLY READY. Lectures on Clinical Medicine, delivered at the Hotel-dieu, Paris. By A. Trousseau, Professor of Clinical Medicine in the Faculty of Medv cine, Paris, &c., &c. Trousseau's Lectures on Clinical Medicine, so fayorably received, as well by the profession of the United States as abroad, are published in this country in conneotioy with the New Sydenham Society, under whose auspices the translation of Vols. XL and III. have been made. Either of these volumes can be furnished separately, and in order to still further extend the circulation of so valuable a work, the Publishers have now reduced the price to Five Dollars per volume. Contents of Volume I. — Translated and Edited by P. Victor Bazire, M. D., 3fc. — Lecture 1. On Venesection in Cerebral Haemorrhage and Apoplexy. 2. On Apoplec- tiform Cerebral Congestion, and its Relations to Epilepsy and Eclampsia. 3. On Epilepsy. 4. On Epileptiform Neuralgia. 5. On Glosso-laryngeal Paralysis. 6. Pro- gressive Locomotor Ataxy. 7. On Aphasia. 8. Progressive Muscular Atrophy. 9. Facial Paralysis, or Bell's Paralysis. 10. Cross-paralysis, or Alternate Hemiplegia. 11. Infantile Convulsions. 12. Eclampsia of Pregnant and Parturient Women. 13. On Tetany. 14. On Chorea. 15. Senile Trembling and Paralysis Agitans. 16. Ce- rebral Fever. 17. On Neuralgia. 18. Cerebral Rheumatism. 19. Exophthalmic Goitre, or Graves' Disease. 20. Angina Pectoris. 21. Asthma. 22. Hjoping Cough. 23. On Hydrophobia. Contents of Volume II. — Translated from the Edition of 1868 [being the last revised and enlarged edition), by John Rose Cormack, M. D., Edin., F.R.S.E ,^Sfc. — Lecture 1. Small-pox. 2. Variolous Inoculation. 3. Cow-pox. 4. Chicken-pox. 5. Scarlatina. B. Measles, and in particular its unfavorable Symptoms and Complications. 7. 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Pulmonary Abscesses and Peripneumonic Vomicoe. 36. Treatment of Pneumonia. 37. Paracen- tesis of the Pericardium. 38. Organic AflFections of the Heart. 52. Alcoholism. 62. Spermatorrhoea. 63. Nocturnal Incontinence of Urine. 64. Glucosuria: Saccharine Diabetes. 65. Polydipsia. 67. Vertigo a Stomacho Lteso. 4 Volumes Octavo. Vols. 1, 2, and 3, Price $5.00 each ; Vol. 4, Price $4.00 OPINIONS OF THE PRESS. "Trousseau furnishes us with an example of the best kind of Clinical teaching. It is a book that deserves to be popularized. The translation is perfect." — Medical Tima and Gazette. "The great reputation of Prof. Trousseau as a practitioner and teacher of Medicine in all its branches, renders the present appearance of his Clinical Lectures particularly welcome." — Medical Press and Circular. "The publication of Trousseau's Lectures will furnish us with one cf the very best practical treatises on disease as seen at the bedside." — British and Foreign Medieo- Chirurgical Review. "A clever translation of Prof. Trousseau's admirable and exhaustive work, the best bock of reference upon the Practice of Medicine." — Indiaii Medical Gazette. 'The Lectures of Trousseau, in attractiveness of manner and richness of thoroughly practical matter, worthily takes a place beside the classical lectures of Wat.ion and firiive'j." — British Medical Journal. • I'roussoau is essentially the French Graves, and his lectures should sooEer that ihis Uisve been nanalaied into English." — Lancet. LINDSAY AND BLAKISTON'S PlTBLICATloyS. Wythes' Physician's Pocket, Dose, and Symp- tom Book. THE TENTH EDITION. Containing the Doses and Uses of all the PHncipal Articles of the Materia Medica, and Original Preparations ; A Table of Weights and Mea- sures, Rules to Proportion the Doses of Medicines, Common Ahbre motions used in Writing Prescriptions, Table of Poisons and Antidotes, Classification of the Materia Medica, Dietetic Preparations, Table of Symptomatology, Outlines of General Pathology and Therapeutics, &c. ByJosEPHH. Wythes, A.M., M-D-,&c. The Tenth Revised Edition. Price, in cloth, 81.25 " leather, tucks, with pockets, . . . 1.50 This little manual has been received with much favor, and a large number of copiea gold. It was compiled for the assistance of students, and to furnish a vade mecum for the general practitioner, which would save the trouble of reference to larger and more elaborate works. The present edition has undergone a careful revision. The thera- peutical arrangement of the Materia Jlcdica has been added to it, together with such other improvements as it was thought might prove of value to the woi-«. Williams on Consumption, london edition. Pulmonary Consumption; Its Nature, Varieties, and Treatment. With an Analysis of One Thousand Cases to exemplify its duration. By C. J. B. Williams, M.D., F.R.S., author of Williams' Principles of Medicine, Senior Consulting Physician to the Hospital for Con- sumption, &c. &c., and Charles Theodore Williams, M.D., Physi- cian to the Hospital for Consumption. Brompton. Demy Octavo. Price, $3.00 This edition of Williams on Consumption is issued in the United States by special arrangement with the London publishers. It is the Author's Edition, printed in London under his supervision, on fine paper and large clear type, and is offered at a much less rate than under ordinary circumstances it could be imported and sold at. "For the last forty years, Dr. Williams has been studying and treating Tubercular Diseases, and if he has had to modify much of his teaching, and more of his treatment, he can still speak from a more enormous experience, and a closer study of the morbid processes involved in tuberculosis, than most living men, and he can look backwards and forwards with as much satisfaction as most of his contemporaries." — London Lancet. Walker on Intermarriage. Or, the Mode in which, and the Causes why, Beauty, Health, and Intellect result from certain Unions, and Deformity, Disease, and Insanity from others. With Illustrations. By Alexander Walker, Author of *' Woman, ^^ " Beauty," Sc, &c. 12mo. . . . S1.50 LINDSAY AND BLAKISTON S PUBLICATIOXS. Waring s Practical Therapeutics, a new edition. Considered chiefly with reference to Articles of the Materia Medica. By Edward John Waring, F.R.C.S., F.L.S., &c.,&c. Second American, from the Third London Edition. Royal Octavo. Price in Cloth, 85. oo; Leather, 6.00. There are many features in Dr Waring's Therapeutics which render it especially vjihuible to the Practitioner and Student of Medicine, much important and reliable information being found in it not contained in similar works; it also differs from them in its completeness, the convenience of its arrangement, and the greater promi- nence given to the medicinal application of the various articles of the Materia Modica in the treatment of morbid conditions of the Human Body, &c. It is divided into two parts, the alphahetical arrangement being adojjted throughout; there is also added an excellent Index of Diskases, with a list of the medicines applicable as remedies, and a full Ixdex of the medicines and preparations noticed in the work. " This new edition of Waring's Practical Therapeutics has been altered and improved with great judgment. A satisfactory account of new agents — chloral, apomorphia, nitrous oxide, carbolic acid, &c., is introduced without adding to its bulli. The additions are made with remarkable skill in con- densation. It is one of the best manuals of therapeutics yet in existence." — Brit. Med. Journal. "There has been no scarcity, latterly, of works of this class, several of them we regard as having great professional value ; but, it must bo allowed, we think, that this holds no inferior place among them. Stillj's is a national book, but much more voluminous : and, therefore, while it is high author- ity. It is less convenient for office use. Furthermore, we prefer the literary arrangement and execu- tion of Wariyig. It can be used with more readiness and always relied on for the correctness of ita facts. In the daily treatment of diseases, it seems to supply everything that can be desired. 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" Our admiration, not only for the immense industry of the author, but also of the great practical value of the volume, increases with every reading or consultation of it. We wish a copy could be put in the hands of every student or practitioner in the country. In our estimation it is the best book of the kind ever written." — A'. Y. Medical Journal. Ward on Some Affections of the Liver And Intestinal Canal, with Remarks on Ague and its Sequelce, Scui^vy, Purpura, Sc. By Stephen H. Ward, M.D., F.R.C.P., Physician to the Seamanh Hospital, &c., &c. Octavo. Price, . . S3. 00 Wedl's Dental Pathology. The Pathology of the Teeth. With Special Reference to their Anatomy and Physiology. By Prof. Wedl, of the ilniversity of Vienna. Fir.st American Edition, Trans- lated by W. E. BoARDMAN, M.D., with Notes by Thos. B. Hitchcock, M.D., Professor of Dental Pathology and Therapeutics in the Dental School of Harvard University, Cambridge. With 105 Illustrations. 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A neat Locket Volume bound in cloth flexible. . . . $2.00 Wells' Treatise on the Diseases of the Eye, illustrated by Ophthalmoscopic Plates and Numerous Engravings on Wuod. By J. ScELBERU vVklls, Ophthalmic Surgeon to King^s College Hospital, Sc. Second London Edition, cloth, $6.50; leather, $7 50. This is the author's own edition, printed in London under his supervision, and issued in this country by special arrangement with him. Wright on Headaches. Their Causes and their Cure. By Henry G. Wright, M.D., Membet of the Royal College of Physicians, &C. &e. From the Fourth London Edition. 12mo. Cloth S1.25 " Few afiFections are more unmanageable and more troublesome than those of which this essay treats; and we doubt not that any suggestions by which we can relie-ve them will be gladly received by physicians. The author's plan is simple and practical. 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Spencer Wells' Note Book, for Cases of Ovarian and other Abdominal Tiunors. Tiiird Edition. .... ...... 50 Pergusson's System of Practical Surgery. Fifth Edition, much enlarge 1. 463 Illustrations, 9 00 Dennett on Cancerous and other Intrathoracic Growths. With Illustra tion^, .............. 3.25 Marsolen's New and Successful Mode of Treating Certain Forms of Cancer. Witii Colored Phites, . . . . . . . .2.75 Hood on Gout, Rheumatism, and the Allied Affections, . . . 4.50 Jg^* Any of Messrs. Cliiuchiirs publications not in stock, will be supplied to order. NEW SYDENHAM SOCIETY'S PUBLICATIONS. VOLUMKS TO BE ISSUED IN 1872. I. STRICKER'S MANUAL OF HISTOLOGY. Tiansluted by Mr. Power. Vol. II. TROUSSEAU'S LECTURES ON CLINICAL MEDICINE. Fifth and II. in. IV. Vol. ?0L. 1859. (First Tear.) 1. DiDAT on Infantile Syphilis. 2. GOOCH on Diseases of Women. 3. Memoirs on Diphtheria. 4. Van der Kolk on the Spinal Cord, &c. 6. 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The Publishers, in order to still further extend its circulation and useful- ness, and to keep up the reputation which it has so long retained, of being THE CHEAPEST AND BEST, as well as the Oldest Visiting List published, have now made a very considerable r'educlion in the price. It can be procured from the principal booksellers in any of the large cities of the United Stales and Canada, or copies will be forwarded by mail, free of postage, by the Publishers, upon receipt by them of the retail price as annexed. In ordering the work from other booksellers, order Liiidsatj & lUdkiston^s Phi/siclan's Visiting List. And la all cases, whether ordering from the Publishers or otherwise, specify the size, style, &c., wanted. It is, beyond all doubt, the most complete and yet the simplest Visiting List which is published. 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HEWITT'S Diagnosis and Treatment of the Diseases of Women.-Third Edition. - HEADLAND on the Action of Medicines.— Sixth American Edition. BE.\EE*S How to Work with the Microscope. — Fourth Edition. HARIiElT on the Urine and its Derangeniont««. 'With Illustrations. MANUALS FOR STUDENTS. ME.\DOW'S Mannal of Midwifery.— Second Edition Illustrated. ATTHIIili'S Manual of the Diseases of Women.— With Illustrations. EAWSON'S Diseases and Injuries of the Eye, their Medical and Surgical Treatment. CHEW'S Eectures on Medical Education. MENDENHAIilj'S Medical Student's Vadc Mecum.— The Tenth Edition. 224 ninstratione, ROBERTSON'S Manual for Extracting Teeth.— Second Edition. Kevlsed. DIXON'S Practical Study of the Diseases of the Eye.— Third Edition. PEREIRA'S Physician's Prescription Book.— The Fifteenth Eevised Edition. REESE'S Analysis of Physiology.— Second Edition. WYTHES' Pocket Dose and Symptom Book.— Tenth Edition, with Additions. BARTH & ROGER'S Mannal of Auscultation and Percussion.— Sixth Edition. CXEAVEEAND'.S Pronouncing Medical LiCxlcon.— Thirteenth Edition. L.EGG'S Guide to the Examination of the Urine.— Third London Edition. HIEli's Pocket Anatomist, for the use of Students. TANNER'S Meiiioran«la of Poisons. — From the Third London Edition. RIGBY'S Obstetric Meuiornnda. Fourth Edition. yf complete 'Descriptive Catalogue of their Publications .^ together with a classified and priced list of all recent Medical Books .^ American and Englishy furnished or mailed free on application, ^a V" '&A vdni tvdAl i'^-L/f s ^JITVDJO'^ ^s:lOSWJCF o mi m lOM i^j 1^1 1©\ '^jo^ ^OfCAllFO/?/^, ^(?AavaaiH^ -\V\tUKIV CO =3 CAllFO/?/<;J NOJkW ^^AavaaiH^'^ ^4- o DNVSQ\^ o ^^lllBRAHY6// -^^tLlBRAftYd?/ %ii3AINn-3^V^ ^(!/0JllVJJO-^ ^.^OillVJJO-^ AWEUNIVERS// o O >;^OFCAIIFO% ^ ^OF-CALIFO/?^ £? :5 %a3MNa-3WV^ ^^ ^>&Aaviian-# AWEUNIVERS// '^J'iUONVSOV'^' % ^UIBRARYQ^ '^(!/0JllV3JO>' < " ' ' O ^lOS-ANCElfX^ ■^/sajAiNajiW ^lUBRARY^/ ^:VOSANGEl% o JGElfx>^ '^''/5d3AINil-3Wv 5^tUBRARY£?/ ^tllBRARYO/^ ^(!/0JllVJ3O^^ '^«!/0illV3 J0>- J^ £-? "^XiUDNVSOV^ ;j;OF-CAll FOff^^ ^.OF-CAll FOfi>^ ^^ME L'Nl VERJ/, '^i'iUONVSOl^