THE LIBRARY 
 
 OF 
 
 THE UNIVERSITY 
 
 OF CALIFORNIA 
 
 PRESENTED BY 
 
 PROF. CHARLES A. KOFOID AND 
 
 MRS. PRUDENCE W. KOFOID 
 
DENTAL CAEIES 
 
 ITS CAUSES. 
 
 AN INVESTIGATION INTO THE INFLUENCE OF FUNGI 
 IN THE DESTRUCTION OF THE TEETH. 
 
 Drs. LEBER AND HOTTENSTEIN. 
 
 TUANSLATED 15Y 
 
 H. CHANDLER, D.M.D. 
 
 PB0FBS80B IN THK DENTAL SCHOOL OF HAUVAKD UXIVBIiSITT. 
 
 WITH ILLUSTRATIONS. 
 
 LONDON : 
 J. & A. CHURCHILL, NEW BURLINGTON STREET. 
 
 187H. 
 
BiO(o6Jy 
 
 P R E F A C E. 
 
 We submit to the English Medical and Dental Pin- 
 fessions the translation of a work pnblislied simnl- 
 taneously in Germany and France, which contains the 
 exposition of a tlieory of the process of Dental Carie.s. 
 This question })ears so much the greater interest as the 
 parasitic theories become more and more the (piestion ot 
 the day, and have gained considerable ground witliin 
 the last few years. They ofter, in fact, to Patliology 
 the most satisfactory solutions, and furnish us ^^•ith 
 the most rational means of combating a i nun he)' of 
 affections wliich up to the present day liave l)een 
 ineffectually treated by therapeutic agents. 
 
 The theories whicli are here expounded are founded 
 on research, and on facts so numerous that tliey are 
 almost beyond any serious question. They have now 
 the sanction of experience and of competent autliors 
 and investigators. In Dental Pathology they oti'ei- new 
 resources of prophylactic treatment. We therefore 
 believe that in submitting to the i)rofession in England 
 this work, we contribute to the progress of science : 
 and we hope that it will receive the same fax'oni- as in 
 Germany and France. 
 
 MM 9944 
 
 / 
 
 /' 
 / 
 
INQUIRIES 
 
 DENTAL CARIES. 
 
 I. 
 
 liESUME OF THE INQUIRIES MADE, UP TO THE 
 
 PRESENT DAY, INTO THE NATURE OF 
 
 DENTAL CARIES 
 
 Under the name of Dental Caries is comprehended a path- 
 ologic process which, after having more or less softened and 
 destroyed the tissues, occasions a loss of substance, and ends, 
 after the destruction of the pulp, in the entire loss of the 
 dental organ. This process has nothing in common with 
 caries of the bones but the name. It differs from it entirely 
 in its nature. Nevertheless, the name of caries has come 
 into so common use that it would be difficult to replace it 
 by another, and as for the rest, no one will ever confound 
 dental caries with the aftection of the bones which passes 
 by the same name. 
 
 The nature of dental caries has for ages been the subject 
 of investigation. The ancient physicians, the dentists of 
 their times, who engaged in this inquiry, coniined them- 
 selves to making hypotheses more or less ingenious, and 
 founded them upon experience and clinical observation. In- 
 vestigation, in its proper sense, was only possible when the 
 histoloo-ie structure of the dental tissues was known. 
 
 For a long period two hypotheses held a balanced sway : 
 
 2 
 
10 INQUIRIES INTO DENTAL CARIES. 
 
 one, chemioal^ explained caries by the action of clieniical 
 agents, acids in particular; the other, vital^ considered dental 
 caries as a veritable malady, caused by an organic change, 
 and tlie reaction of the dental tissues against an external 
 irritation. 
 
 The defenders of the chemical theory did not trouble 
 themselves about the vital properties of the dental tissues. 
 Some denied tliat the developed organs had an'y such prop- 
 erties ; others thought they [lossessed so little energy that 
 they must always yield under the action of injurious agents, 
 without being able to react in any manner against this irri- 
 tation. 
 
 For them the process followed its course just as though 
 the vital properties h^d never existed. 
 
 These ditlerent opinions remain to-day unsolved in spite 
 of the researches which have been made upon this subject. 
 It is true, tliat in these later days, the chemical theory has 
 seemed to have the upper hand, although quite recently an 
 attempt has been made to reinstate the vitalist theory by 
 the aid of histologic investigations. But by the side of these 
 two hypotheses, other observers, particularly in Germany, 
 assert the parasitic character of caries, attributing it step by 
 step to the action of animal or vegetable parasites. 
 
 The results published by these latter authors have not as 
 3'et been criticized very vigorously ; for, accepted too hastily, 
 in Germany especially, they seem completely ignored in other 
 countries. Messieurs Klencke and Ficinus were among the 
 first to occupy themselves with the histologic alterations of 
 the teeth, and, although their labors have no longer any 
 more than a purely historic interest, we will yet give a short 
 resume of them. 
 
 Ficinus attributed dental caries to a putrefaction [)ro- 
 duced by the minute infusorial animalcules which live in 
 the mouth and to which he has given the name of Dentieola. 
 These infusoriixi are found in great numbers in the mucus 
 which covers the teeth, as well as in the carious cavities. 
 They produce, according to him, a kind of putrefaction 
 which, after having first attacked the enamel cuticle, pro- 
 
INQUIRIES INTO THE NATURE OF DENTAL CARIES. 11 
 
 ceecls to coiismne the enamel itself and al'terwards the den- 
 tine, lie thinks that the fibres described by Biihhnann, and 
 which are no other than the filaments of the Leptothrix bac- 
 calis^ derive their origin from the infusoripe which he calls 
 deniicola, and that the former are formed by contact with 
 the latter. 
 
 But this theory does not explain the disappearance of the 
 calcareous salts, wdiicli are soluble oidy in acids, while the 
 process of putrefaction supposes an alkaline reaction. 
 
 The investigations of AI. Ivlencke were published a little 
 later. This author adopts several opinions offered by M. 
 Ficinus, but he admits, besides the process of putrefaction, 
 several species of caries. 
 
 And tirst he distinguishes central caries from the common 
 peripheric caries. The former commences in the cavity of 
 the pulp, the latter in the external portions of the teeth. 
 
 He also subdivides this latter into three different kinds. 
 
 1st. A soft caries, caused by putrefaction. 
 
 2d. A soft caries, due to the proliferation of a vegetable 
 parasite called protococcus dentalis. 
 
 We must remark here that the existence of this epiphyte 
 has not been confirmed by later observers, and that, in spite 
 of all the pains which we have taken in the search for it, we 
 have not been able to find it. 
 
 3d. The so-called dry caries, with wliicli the parasites have 
 nothing to do. It is caused by the chemical action of acids 
 upon the dental tissues. 
 
 The histologic alterations of which the dental tissues are 
 the seat in caries, were described for the first time with ac- 
 curacy by Mr. J. Tomes. According to this author, the 
 changes of the enamel are caused, in the majority of cases, 
 by an imperfect development, with a greater porosity of the 
 tissues ; a porosity which increases with the progress of the 
 caries. 
 
 The canaliculi of the dentine present remarkable altera- 
 tions during caries. In a cross-section we see them sur- 
 rounded by a thickish sheatl^. One might say that the con- 
 tours of the old cells of the dentine are re-established, and 
 
12 INQUIRIES INTO DENTAL CARIES. 
 
 tliat tlio tissue is resolved into its primitive elements of for- 
 mation. AVe know, in fact, that the dentine is formed at 
 the expense of cylindrical juxtaposed cells which unite dur- 
 ing the ossification of the dentine and become impregnated 
 with calcareous salts. The dental canaliculi alone remain 
 free in the mass with the soft fibrils, discovered b}^ Mr. 
 Tomes, in the very centre of these canaliculi. 
 
 In a more advanced stage the elements lose the sharpness 
 of their contours and the entire tissue takes a finely granular 
 aspect. If the destruction is rapid, we find, on the contrary, 
 the canaliculi expanded and with badl^- defined contours. 
 
 The pathologic alteration proceeds along the canaliculi 
 towards the cavity of the pulp, giving, in most cases, to the 
 carious portion of the dentine the form of a brownish cone, 
 with the base turned outwards. In cases where a more ex- 
 tended surface of the enamel has been attacked at once by 
 caries, and where the destruction proceeds rapidly, the cone 
 may exist incompletely, or be entirely wanting. 
 
 Around the cone is found a zone relatively transparent, in 
 which the canaliculi contain dental fibrils calcified, which 
 are often separated into portions more or less long, and in 
 some preparations extend beyond the extremities of the ca- 
 naliculi. 
 
 Mr. Tomes attributes this calcification of the canaliculi to 
 an organic reaction of the dentine against the pathologic 
 irritation, and he believes that it retards or arrests the prog- 
 ress of the caries. 
 
 Another manifestation of the vital ja-operties of the dentine 
 consists, according to him, in the augmentation of sensibility 
 in this tissue which is observed in some cases of caries. lie 
 concludes from this that the dentine is sensitive of itself, 
 and not through its neighborhood to the pulp. 
 
 According to Mr. Tomes, acids Jirc the principal cause of 
 dental caries. After luiving first destroyed the vitality of 
 the parts the acids deconq»ose them little by little. But we 
 do not succeed in producing artificially, by the action of 
 acids upon the dentine, histologic changes like those which 
 Ave ol.»serve in carious teeth. Nevertheless, the decalcification. 
 
INQUIRIES INTO TUE NATURE OF DENTAL CARIES. 13 
 
 the softening, the destruction of the teeth are till jjlicuoinena 
 due to the chemical nature of the process. But the dental 
 tissues, while undergoing destruction, react against the ac- 
 tion of the destroying agents, and this reaction is made 
 manifest by the calcification of the dentinal fibrils in the parts 
 which surround the carious dentine, and also by increased 
 sensibility. 
 
 The observations of Mr. Tomes upon the histologic struc- 
 ture of the dentine have been confirmed and in part com- 
 pleted by a more recent work of M. E, JSTeumann."-^' Mr. 
 Neumanu endeavors to prove by his observations, which 
 bear almost exclusively upon the caries of the dentine, that 
 this aticctiou has, in part at least, an inflammatory nature. 
 According to this author, the injurious agents irritate the 
 dentine and produce phenomena of organic irritation which 
 end by causing the destruction of the tissue. lie distin- 
 guishes two series of alterations, viz. : 1st, those of the sheaths 
 of the dental canaliculi and of the intertubular substance, 
 which have the character of simple degeneration, and are 
 found in all cases of caries ; 2d, those of the fibrils contained 
 in the canaliculi, produced by an inflammatory process. 
 
 The alterations of the first series, identical with those of 
 which Mr. Tomes has given the description, are characterized 
 by a thickening of the walls of the canaliculi. Nevertheless, 
 M. Neumann does not believe, with the English author, that 
 the dentine is formed directly by the calcification of the cells 
 of the dentine. According; to him the intertubular substance 
 is formed at the expense of an exudation, and the cells of 
 the dentine furnish only prolongations which are transformed 
 into the fibrils contained in the interior of the canaliculi. 
 According to Mr. Tomes, the thickened walls of the ca- 
 naliculi are formed by the old cells of the dentine which 
 have acquired new contours. M. Neumann sees in this only 
 a thickening of the normal walls of the canaliculi or dental 
 sheaths, at the expense of the intertubular substance, with 
 consequent obliteration of the canaliculi. 
 
 * Sur la nature de la curie dentaire (Archiv. f'iir Klin. Chir., torn, v, fasc. 
 1, p. 117). 
 
14 INQUIRIES INTO DENTAL CARTES. 
 
 The second series of alterations consists, accordino; to >[. 
 Neumann, in a thickening of the dental tihrils in the interior 
 of the canalicnli. These fibrils have considerably increased 
 in diameter and are divided into little l)undles slio-htly sepa- 
 rated from each other. He considers them as cells produced 
 by division of the fibrils. If this explanation is correc-t we 
 should not find in teeth of substitution, whether obtained 
 from man or animals, alterations analogous to those of living 
 teeth. AI. Xeumann had had occasion to examine a peg of 
 ivory which, inserted into a bone for the purpose of effecting 
 the cure of a pseudarthrosis, had been attacked by the caries 
 of the bone. ISTone of the changes observed in carious teeth 
 were found. M. ISTeumann conelndes from this that ex[)eri- 
 ments made upon substituted teeth would probabl\' lead to 
 the same negative result, and that their caries is essentially 
 different from that of living teeth. 
 
 At the beginning of this year (1868) appeared the " Trea- 
 tise ujion Dental Caries" by M. E. Magitot. Some chajtters 
 of this work had been published separately the 3'ear preced- 
 ing. The author wishes to prove that the acids contained 
 in the saliva, or mixed with it, are the cause of dental caries, 
 and that the nature of this affection is consequently purely 
 chemical. He has made experiments Avith the object of arti- 
 ficially producing caries, hy the action, during a sufficiently 
 long jieriod, of diluted acids upon teeth. The teeth were, in 
 fact, destroyed, and the author observed curious differences 
 in the action of the various acids u})on each of the dental 
 tissues. The teeth destroyed were not submitted to micro- 
 scopical examination. 
 
 The book of M. Magitot contains no new facts npon the 
 subject of the pathologic alterations of the dental tissues. 
 He does not even mention the alterations describnl by 
 Messrs. Tomes and Neumann, and contents himself with 
 saying that the canalicnli contain sometimes a finely granu- 
 lated substance. 
 
 He attaches great importance to the calcareous deposits 
 in tlie interior of the canalicnli. a!id considers tliem as tlie 
 result of a secretion from the irritated }ml}t. While the 
 
INQUIRIES INTO THE NATURE OF DENTAL CARIES. 15 
 
 enamel is disappearing nnder the action of acids, tlic irrita- 
 tion is conveyed across the dentine even to the pulp, whicli, 
 reacting, throws out a calcareous exudation. This exuda- 
 tion fills the canaliculi from without inwards, towards the 
 cavity of the pulp, and, when they are entirely filled, it is 
 deposited at times on the internal wall of the pulp-cavity 
 nnder the form of dentine of new formation. The deposition 
 of calcareous salts in the interior of the canaliculi, and the 
 production of true dentine in the pulp-cavity, are, according 
 to M. Magitot, two analogous phenomena. 
 
 The portions of the dentine containing these canaliculi ob- 
 literated hy calcareous deposits, form a cone or zone of trans- 
 parent substance, which must be destined to arrest or retard 
 the march of the malady. M. Magitot does not, therefore, 
 attribute caries exclusively to chemical destruction. He ad- 
 mits at the same time the irritation of the pulp which, by a 
 cahtareous exudation, can arrest the destructive progress. 
 The cavity of the pulp once opened, inflammatory symptoms 
 manifest themselves, after which the rest of the tooth, no 
 longer protected by the pulp, undergoes decomposition by 
 the acids. 
 
 Before concluding our resume let us remark upon a strange 
 idea, started a little while ago in England. It would explain 
 not only the destruction but also the formation of the teeth 
 by electricitj'. This publication, coming from Mr. K. Bridg- 
 man, has been indorsed by the Odontological Society of Lon- 
 don. The author has demonstrated by his experiments that 
 teeth can be destroyed by electrolysis. But his whole sys- 
 tem is based upon a series of hypotheses ; he attributes en- 
 tirely arbitrarily, different electric properties to different 
 parts of the teeth. The pulp vessels should be charged with 
 negative electricity, the normal pulp with positive elec- 
 tricity ; but, in a pathologic state, the surface of the dentine 
 as well as the roots would be charged with negative elec- 
 tricity. It is useless to dwell upon this work, inasmuch as 
 no direct proofs are offered of the existence of these positive 
 or negative qualities, nor of the currents which result there- 
 from. 
 
16 INQUIRIES INTO DENTAL CARIES. 
 
 If we review tlie numerous and diverse opinions wliieh we 
 have just passed in review, we see that their authors difter 
 in points the most essential. We have said above that the 
 difterent theories can be ranged in three categories — chem- 
 ical, vital, and parasitic — which can in their turn be sub- 
 divided. 
 
 In general, we can say that the chemical process plays an 
 essential part in the production of caries ; but it is a question 
 if the organic processes enter equally for a certain share. 
 We shall show in the course of this work, that the organic 
 process is nothing, or nearly so, and that a parasitic element 
 plan's an important part in the production of caries, but in a 
 wholly dilferent way Irom what has been described up to 
 the present time. 
 
IT. 
 
 ANA7V3IICAL ALTERATIONS OF THE TEETH 
 DURING CARIES. 
 
 Caries, at least in a majority of cases, commences at the 
 surface of the teeth ; it attacks first the enamel, which alone 
 is exposed, while the dentine is covered entirely, either by 
 the enamel itself or by the cementum ; this last is moreover 
 protected by the gums. 
 
 Caries rarely attacks the exposed portions of the necks 
 of teeth, and, when it does, naturally has its origin in the 
 cementum. We shall dwell particularly upon the alterations 
 undergone by the enamel and dentine when attacked by ca- 
 ries, as these are the most important tissues "of the teeth, 
 and shall speak of its eflfects upon the cementum only as 
 connected with these tissues. 
 
 Of Central Caries. 
 
 Many authors, Klencke among others, have asserted the 
 existence of a caries which originates in the interior of the 
 tooth and in the cavity of the pulp. Nowadays most den- 
 tists pronounce against the existence of a central caries. It 
 is true that the process of destruction often begins in a mi- 
 nute crevice or furrow in the surface, and so penetrates the 
 dentine even to the pulp-cavity, where it performs its rav- 
 ages, while the enamel of the surface seems intact, at least 
 to a superficial examination. This caries, although central, 
 has yet its origin at the surface of the tooth. Therefore, in 
 these latter days, the existence of a true central caries has 
 been generally denied. 
 
 Although in most cases the caries called central is so only 
 in appearance, there are cases, very rare it is true, where the 
 
18 INQUIRIES INTO DENTAL CARIES. 
 
 destructive process has commenced in tlie dental pulp itself. 
 In support of this opinion we will cite the following obser- 
 vation, the sole case which has presented itself during the 
 long practice of one of us. Therefore it must be concluded 
 that such cases are extremely rare. 
 
 A lady of 21 years of age presented herself and complained 
 of three teeth, one inferior and two superior incisors which 
 had an extraordinary bluish tinge. They were not painful, 
 and one only caused any disagreeable sensation to the pa- 
 tient. She had consulted several dentists, who had told her 
 that her teeth were dead, and there was no remed\'. At the 
 surface of these teeth no trace of caries was to be found. 
 The blue color alone met the view and jjroved their death. 
 
 In piercing the posterior face of one of these teeth it was 
 found completelj^ softened, even to the enamel, and the tis- 
 sues had a brownish color. The root itself was hollowed to 
 a considerable extent. The same Avas found to be the case 
 with one of the other teeth. The third, whose color was not 
 so marked and which caused no unpleasant sensation, was 
 let alone. As the cause, the patient referred to a blow from 
 a fall which she had had in childhood, and which was fol- 
 lowed by a swelling of the face. The pierced teeth were 
 filled with gold. As for the inferior, there subsequently de- 
 veloped an abscess which was treated by puncturing the root. 
 
 It follows, from these observations, that the vessels and 
 nerves of the pulp had been lacerated at the time of the fall 
 of the patient, which lesion was followed by the death of the 
 pulp. T>ut this might have taken place without the destruc- 
 tion of the dentine following. AVe cannot explain in this 
 case the cause of the destruction of the dentine, for the teeth 
 could not be examined by the microscope. Facts of this 
 kind must never be confounded witli those of ordinary den- 
 tal caries, which is due essentially to the action of destruc- 
 tive agencies acting from the exterior. 
 
 We believe then that there exist cases where the dental tis- 
 sues are attacked and destroyed from the cavity of the pulp ; 
 but these cases are extremely rare, and the conditions of their 
 
CARIES OF THE ENAMEL. 19 
 
 production are not yet well nmlerstood, except perhaps the 
 previously necessary- death of the tootli. 
 
 Caries of the Enamel. 
 
 Since caries begins ordinarily at the crown of the teeth, 
 the caries of the enamel constitutes the first stage of the 
 process. The destruction reaches the dentine hiter, but the 
 first pathological phenomena make their appearance in it, 
 even before the enamel is destroyed in its wliole thickness. 
 Most frequently there is seen a black or brownish point in 
 one of the furrows or folds of the crown. On examining a 
 section of the diseased portion the dark color is seen to have 
 its seat in the superficial layers of the enamel, and pene- 
 trates clear to the bottom of the furrow-, where the thickness 
 of the enamel is, in general, less than at other points. 
 
 If, on the contrary-, the caries begins on a smooth surface, 
 the approximal face of the tooth, for example, there appears 
 an opaque spot of a yellowish or brownish shade. The points 
 where anomalies of form, of thickness, of quality of dentine 
 exist, are the preferred seats of caries. The dark color of 
 the spots increases with the progress of the disease ; some- 
 times the centre is of a dark brown while the periphery has 
 a yellowisli or wdiitish tinge. The harder the enamel the 
 darker is the color, for in a dense enamel the progress of the 
 caries is slower and the intensity of the color increases more 
 rapidlj' than the process, which is a long time in extending 
 itself to the periphery, and to any depth. 
 
 The carious spots are easil}' distinguished, for in them the 
 enamel has utterly lost its normal appearance; it is trans- 
 formed into a chalky mass, analogous to that which forms 
 the congenital wdiite spots of the enamel, which are also a 
 frequent seat of dental caries At the carious points the 
 enamel also possesses less hardness than in the normal con- 
 dition ; but it is sometimes so resistant that it is almost im- 
 possible to detach fragments at the surface. Often the super- 
 ficial seats seem to ofi^'er greater resistance than those which 
 are deeper, which, the former once removed, permit them- 
 selves to be more easily excavated. 
 
20 INQUIRIES INTO DENTAL CARIES. 
 
 In other cases the consistency of the enamel is much fee- 
 bler ; it is no more than a chalky mass, or even of no greater 
 consistency than paper-pulp. These differences are explained 
 partly by the stage of destruction, the density of the enamel 
 diminishing with its progress ; but the pre-existing differ- 
 ences of the chemical composition, or consistencj' of the 
 , tooth, take an equal part, for the enamel is softened much 
 more rapidly in some teeth than in others. At the begin- 
 ning, the surface of the enamel is smooth and uniform ; the 
 fine and parallel striae which are ordinarily noticed on its 
 surface, are w^ell defined ; there is, as yet, no loss of sub- 
 stance. This stage, in which the alterations may reach even 
 to a considerable depth in the dentine, is generally' described 
 under the name of dry caries. The more the tooth resists 
 the longer is the duration of this stage; but, in many cases, 
 this stage has but a short life, and the disease rapidly passes 
 on to the humid form. 
 
 Soon the portions of the enamel transformed by the caries 
 are destroyed ; there is a loss of substance sometimes spread 
 over the surface, or forming a carious cavity, but, generally, 
 this destruction has little extent before the dentine has been 
 attacked in its turn. In this latter case the caries progresses 
 rapidly, and extends itself in depth and laterally. The por- 
 tions of the enamel situated at the borders of the cavity are 
 undermined at their base, or greatly softened on their in- 
 ternal surface, and break in because they have no longer the 
 natural support, the dentine. 
 
 We may distinguish two forms in the destruction of the 
 ena)uel ; one progressive, extending itself over the surface, the 
 other penetrating. The former shows itself especially in cases 
 where the caries has attacked a smooth surface of the enamel, 
 the latter is found where the caries has commenced in a 
 furrow. In the former case the caries has attacked, at the 
 bcgiiming, a considerable part of the surface, and the de- 
 struction will be quite extensive before it has [lenetrated as 
 far as the dentine. In the latter case, on the contrary, the 
 alteration of the enamel is limited by the sides of the 
 furi'ow. '{'he enamel is generally thin at Ibis point, so that 
 
HISTOLOGIC CHANGES IN CARIES OF THE ENAMEL. 21 
 
 the dentine rujiidly becomes exposed, and its qnick destruc- 
 tion causes the phenomena of tlie caries of the enamel to pass 
 to the second form. 
 
 When a carious cavity is formed in the enamel, it is not 
 unusual to see this tissue become carious, sooner or later in 
 one or several other points ; these new points of disease pro- 
 gress by themselves, or add their forces to those already in 
 existence. It is more rare to see the caries spread itself at 
 once over a large surface ; there are, nevertheless, cases 
 where the greater part of the enamel is attacked or de- 
 stroyed by caries, and, at the same time, one or several 
 carious cavities formed. In such cases there are generally 
 faults of formation of the enamel, which presents, at several 
 points, depressions, hollows, &c., or anomalies of structure. 
 Each one of these points may then originate, either simul- 
 taneously or successively, the production of caries. 
 
 IIiSTOLOGic Changes in Caries of the Enamel. 
 
 Great importance has generally been attributed to the 
 enamel cuticle, discovered by jSTasmyth, in the production of 
 caries, some regarding it as a protecting covering, others as 
 the seat of the disease. 
 
 The cuticle of the enamel is, as is known, a very thin 
 mendjrane, whose existence is easily shown by immersing a 
 tooth for a short time in a weak solution of hydrochloric 
 acid. We can thus readily detach the cuticle from the 
 tooth's surface. This membrane, according to the investi- 
 gations of M. Waldeyer, must be the vestige of the first 
 formative strata of the enamel, and particularly of the in- 
 termediate layer and the external epithelium. After the 
 development of the enamel has been completed the elements 
 of these strata are transformed into a pavement-epithelium 
 composed of two or three layers of large polygonal cells, 
 which cover the surface of the enamel. These cells l)ecome 
 smooth, little by little, till their nuclei are difficult to be 
 seen; and, during the dental evolution, they unite into a 
 membrane of homogeneous appearance, in which is to be 
 
22 INQUIRIES INTO DENTAL CARIES. 
 
 seen neither nucleus nor cell, and in which Mr. Waldej-er, 
 by means of a solution of silver, has been able to i-ender 
 again visible the cell contours. 
 
 It is generally thought that the cuticle, on account of its 
 great resistance to chemical agents, must protect the teeth. 
 In fact, according to Ficinus, neither maceration nor boiling 
 in water atl'ected it, and concentrated mineral acids did not 
 dissolve it. Potassa and soda gave it a whitish appearance, 
 and caused it to swell, but without making it lose its con- 
 sistency. But it must be remembered that if this mend)rane 
 cannot be attacked by acids, it permits itself to be joene- 
 trated by dilfusiou ; we must not tlieu laj' too much stress 
 upon its I'ole of protection. If the acids can reach the 
 enamel by passing through it, as the method for the isolation 
 of the membrane has already proved, it can at the most re- 
 tard their action, but cannot hinder it completely. It may 
 then be useful in cases where the acids act only in a transi- 
 tory manner ; as, for example, when they have been intro- 
 duced into the mouth with the food, or where they have 
 come from the stomach, as happens in certain diseases, and 
 are immediatelj' removed from the mouth. But if a con- 
 tinuous acid reaction takes place in the mouth, as happens 
 in the case of fermentation, then the protective office of the 
 cuticle is nil. 
 
 In many cases we cannot even invoke the protective office 
 of the cuticle, for it is often worn away on the masticating 
 surface of the teeth, and may be wanting entirely to a 
 greater or less extent. This cuticle is frequently wanting in 
 the furrows or chinks of the masticating surface, which arc 
 also the favorite seats of caries. It has been deduced from 
 this fact that caries is developed on account of the absence 
 of the cuticle, but this chosen seat is explained as well by 
 the presence of the furrows which favor the development of 
 fermentations and chemical decompositions. 
 
 It is astonishing to see authors defending the jirotective 
 role of the cuticle, and at the same time admitting that it 
 is the seat, the abiding-place of caries. Messrs. Ficinus and 
 Klencke share this opinion. They admit with Erdl, that at 
 
LEPTOTHRIX BUCCALIS. 23 
 
 the beginning of caries, the cuticle, at the surface of the 
 brown spots, is covered with a deposit whose nature they do 
 not agree upon. Ficinus says this deposit is formed of 
 vibrios, and of the fibres called by Bulihnann filaments of 
 the leptothrix. According to Klencke it consists of these ele- 
 ments sometimes, but, in other cases, there are found the 
 cells of his pretended yrotococcus dcntalis. 
 
 It is in fact easy to show that, at the point of the carious 
 spots, the cuticle is almost always covered with the accumu- 
 lated deposits of leptothrix buccalis ; there is found there a 
 substance finely granular, or bed of fungi, which is composed 
 of very minute sporules. At the surface of this granular 
 substance there are also to be found at times very delicate 
 filaments which spring from it, and which are identical with 
 the fibres of Biihlmann. As this fungus* plays a very im- 
 portant part in the production of caries, w^e will proceed to 
 study it more in detail. 
 
 Leptothrix Buccalis. 
 
 There is almost always found in the mucus of the mouth, 
 at the surface of the tongue, and in the interstices of the 
 teeth, a whitish, cheesy substance, formed in great part by 
 the leptothrix buccalis. Under the microscope we see a gray, 
 finely granular mass, gangue or matrix, then filaments deli- 
 cate and stiff", of various lengths, which erect themselves 
 above the surface of this granular sul)stance, so as to resemble 
 an uneven turf. It is in the interstices of the teeth that 
 this fungus attains its greatest size, when we do nothing to 
 check its development ; its filaments there attain consider- 
 able length, and form bundles, sometimes parallel and undu- 
 
 * It may astonish some to see us designate the lepiothrix buccalis by the 
 name of fungus, and not by that of alga. Opinions are divided on this 
 question which, for the rest, seems to have no great importance for our sub- 
 ject. We have simply used the name most common in Germany, without 
 permitting ourselves to judge a question purely botanic. Yet, if it should 
 come to be shown that the opinion of M. Hallier is correct, which is that the 
 leptothrix is only a form of development of the funt^us penicilliiim (jlaucwm, 
 it must be admitted as without doubl that the leptothrix is a fungus. 
 
24 INQUIRIES INTO DENTAL CARIES. 
 
 lous, at others firmly interlaced among one another. On the 
 surface of the tongue we see cylindrical or club-shaped ele- 
 ments, which are epithelial prolongations of the filiform 
 papilLie of the tongue, as Kolliker has proved. 
 
 These prolongations are covered by a rather thick mass of 
 granular substance of leptothrix^ bristling at times with short 
 filaments. In the fluids of the mouth, detached filaments 
 are often met. The epithelial cells of the mouth are also 
 frequently covered with numerous fine, oblong granulations, 
 identical with those which compose the bed of the fungus. 
 If we closely examine the grayish masses which the granu- 
 lations form at the surface of the filiform papillfe, we see 
 that they are composed of epithelial cells, detached in part, 
 and dissociated, covered with thick masses of granulations 
 which unite and make of them a compact mass. The club,, 
 shaped prolongations which result have often very well- 
 marked contours, and the granulations are so intimately in- 
 terwoven that the substance often appears homogeneous, but 
 the addition of a little acidulated liquid permits the granular 
 elements to be readily isolated. The cheesy matter which 
 collects in the interstices of the teeth has an analogous 
 structure, except that the granulations, instead of attaching 
 themselves to the epithelial cells, are joined to the filaments 
 of the fungus, cover and unite them. 
 
 It is easy to follow the formation of this substance. "We 
 observe, under the microscope, filaments upon which granu- 
 lations have fixed themselves ; some enveloped by a sheath 
 of granulations, some united and intermingled with them. 
 Frequently a great portion of the cheesy substance is exclu- 
 sively composed of the granulations, fine, and generally a 
 little drawn out, of which we have spoken. 
 
 These granulations are, according to M. Ilallier,* only 
 movable spores in repose, which wander during a certain 
 period in the liquid, but finally attach themselves some- 
 where and increase by forming new articulations. If these 
 observations are exact, as we are inclined to think, the 
 
 * Dii' idliinzlicln'ii r;ir:i>iti'n dcs incnsclilirlirii Kotihts. Lcip/.i<jj, ISdC) 
 p. GO. 
 
LEPTOTIIRIX BUCCALIS. 25 
 
 nioval)le spores resemble vibrios whicli are found in the 
 nuicns of the niontli, and possess the power of rapid move- 
 ment. These organisms, called denticoke by M. Ficinus, be- 
 long then not to the animal but rather to the vegetable 
 kingdom. Moreover, M. Ficinus compared them with the 
 so called filaments of Buhlmann, or filaments of leptothrix. 
 He had seen spores, which he considered infusoria, move for 
 a time in the liquid among the filaments of the leptothrix 
 and epithelial cells, and afterwards attach and fasten them- 
 selves to one of the filaments. Soon others were added, and 
 thus was explained the formation of the filaments and epi- 
 thelial cells covered with granulations of which we have 
 just spoken M. Ficinus also believes that the filaments are 
 due to the juxtaposition of the granulations, which is not 
 correct. It appears, on the contrary, that the granulations 
 push out prolongations, and that thus is formed successively 
 an articulated chain. As M. Ficinus took the denticolce for 
 infusoria, he could not have had a just idea of the nature of 
 the fibres of Biihlmann. Later the vegetable nature of the 
 filaments was recognized, but that of the granular substance 
 could not be explained. M. Robin among others thought 
 it was formed b}^ the debris of alimentary substances. This 
 supposition is false ; for, if this were so, the granular sub- 
 stance would not alwa\"s present the same characteristic 
 aspect. Composed, in fact, of granulations, fine, elongated, 
 and shining, it has a peculiar matted appearance, by which 
 it is easily recognizable. 
 
 According to M. Ilallier, to whom we owe the opinions 
 just given upon the spores of leptothrix^ this fungus may be 
 only a form of development of the i')enicillium. glaucum. [f 
 so this fungus should always be produced wdien the spores 
 of penicillituii are kept in a watery liquid. We have not 
 verified the truth of this opinioil. However this may be, 
 M. Hallier explains by his theory the formation of the 
 granular substance, and teaches us the nature of the denticolce 
 of M. Ficinus. 
 
 It remains to explain uhy, in the mouth, the spores so 
 quickly lose their movements ; in the cheesy substance, 
 
 3 
 
26 INQUIRIES INTO DENTAL CARIES. 
 
 where the granulations are found closely packed, no move- 
 ments are perceived. A portion of the elements which move 
 about in the saliva as vibrios are larger than the little granu- 
 lations of the lepfothrix, which can nevertheless change both 
 form and volume. 
 
 In cultivating the leptothrix in the saliva with the addition 
 of sugar, or an}' other appropriate liquid, Ave ordinarily see 
 developed movable spores in numberless quantities, and en- 
 dowed with a power of very rapid motion. If the move- 
 ments cease, which is observed on the edges of the prepara- 
 tion where it begins to dry, the spores resemble exactly the 
 granular masses of the leptothrix which are met with in the 
 mouth. The cessation of movement in the mouth can be 
 explained by the viscosity of the medium, and by the pres- 
 ence of the buccal mucus.* 
 
 We have already observed that it is always very easy to 
 recognize the elements of the leptothrix by their characteristic 
 aspect ; but it is always desirable to have at hand a chemical 
 reagent which will enable us to perceive the existence of the 
 fungus when its external aspect is deceptive. This reagent 
 we have found in iodine and the acids, which give to the 
 
 * The details which we have ju,st given exphiin equally well the various 
 opinions which have been expressed upon the composition of the tartar of 
 the teeth, and upon the inferior orders of being which it contains. Accord- 
 ing to.M. Mandl, the tartar may be composed of the calcareous carapaces of 
 infusoria which live by millions in the mucus of the mouth. M. Ficinus 
 had the same opinion, as his deniicolce are evidently the equivalent of the ui- 
 fuHoria of M. Mandl. Formerly the tartar was regarded as a deposit of salts 
 dissolved in the saliva ; its chemical composition, analogous to tliat of the 
 inorganic products of the salivary liquids, still pleads in favor of this ojiinion. 
 M. Kobin found in the tartar filaments of leptothrix, and doubted the indi- 
 cations of M. Mandl. According to our researches there do exist in the 
 tartar filaments and granulations of leptotlirix. They are easilj' recognized 
 after treating the tartar with dijuted acids. It is probable that it may con- 
 tain at times more filaments, at others more granulations of leptotlirix, so 
 that there may occur cases where there can be found only granular masses, 
 which would very closely resemble the indications of M. Mandl. The infu- 
 soria with calcareous shells must be rejected. As for the salts of the tartar, 
 they are precipitated very jjrobably in the saliva, mixed with viscous mucus 
 which incloses the filaments of leptothrix, and dejiosited gradually upon the 
 .'■urface of the teeth. 
 
LEPTOTHRIX BUCCALIS. 27 
 
 elements of Icptothri.r a beautiful violet tinge. We obtained 
 this reaction in trying the effect of that for cellulose (colored 
 blue by iodine and sulphuric acid) upon our fungus, and we 
 have noticed that MM. Leydcn and Jaffe had already recom- 
 mended tlie same reagent for the leptothrix which is found 
 in putrid sputa, and in the lungs.* They are treating of 
 fungi which are discovered in s[)uta which have become 
 putrid in cases of gangrene of the lungs. 'J"he sputa had a 
 very acid reaction. The fungi Avere colored a beautiful 
 violet by the simple addition of iodine. The fungi of the 
 mouth which have undergone no change are colored, for the 
 most part, 3'ellow by iodine; generally we notice a violet 
 color only after adding an acid. Sometimes we obtain a 
 violet reaction by the aid of iodine alone, a fact which we 
 must attribute to acidity of the buccal mucus. It is not 
 necessary to make use of sulphuric acid, as in the case of the 
 reaction of cellulose ; but any acid whose action is not too 
 violent will render the same service. "VYe have obtained ex- 
 cellent effects by the use of weak hydrochloric acid, by 
 acetic, and by lactic acid. Sulphuric acid has with us less 
 generally succeeded, because it occasions so rapidly other 
 decompositions. Tlie reaction which we have obtained is 
 identical with that which MM. Leyden and Jafte have de- 
 scribed, for the color is likewise that of a beautiful violet 
 (not blue as in the action with cellulose), and it is the con- 
 tents of the filaments and not their envelope which is colored. 
 We know this by the circumstance that the septa of the fila- 
 ments remain inaccessible to all coloration. It results from 
 this that the presence of an acid is indispensable to obtain 
 the reaction. Nevertheless it will be useless to have recourse 
 to any acid when the liquid which contains these fungi is 
 acid enough, as is the case in putrid sjuita, and even, at 
 times, in the mucus of the mouth. 
 
 We almost always find, as we have already observed, at 
 the surface of the carious points of the enamel, a coating of 
 
 * Vide Lej'den and Jaflo. Sur les crachats putrides, la gangrene pulmo- 
 naire et la bronchite putride. (Ai'chives alleniandes de clinique medicale. 
 Tomes ii, iv, and v, 1866, p. 488.) 
 
28 INQUIRIES INTO DENTAL CARTES. 
 
 Icptothrix, even when this surface seems still pohshed and 
 intact. This coating adheres strongly, and is not so easily 
 removed as the cheesy masses of leptothrix which cover other 
 parts of the surface. When, by the aid of a weak acid, the 
 enamel cuticle is removed, we find this coating thickened, 
 composed most frequently of the accumulations of grauular 
 matters, and there is rarely to be recognized the presence of 
 filaments of leptothrix. The fungi seem to have penetrated 
 through the enamel cuticle, as they adhere to it strongly ; 
 but, at this stage, it is not possible to prove their presence 
 in the enamel itself. 
 
 'J'he filamentous and granular matters of leptothrix which 
 are found accumulated on the cuticle of the tooth are not 
 arranged in any regular manner ; we often see them under 
 the form of rounded and irregularly disposed masses. 
 Neither are these masses well defined, but are joined one to 
 another by delicate beds of granular matter. It is prol.)able 
 that these appearances have formed the base of the observa- 
 tions of MM. Erdl, Ficinus, and Ivlencke : but they have not 
 given us exact descriptions of them. We have never been 
 able to perceive the presence of the cells described and pic- 
 tured by M. Klencke in his Protoeoccus dcntalis, and we think, 
 after investigations made upon a great number of teeth which 
 have all yielded us identical results, that his conclusions are 
 founded in error. We are the more convinced of the cor- 
 rectness of our own results, in that no observer has succeeded 
 in confirming the facts as stated by M. Klencke. Yet it is 
 hard to say what could have given rise to this error, inas- 
 much as there exists absolutely nothing which otters any 
 analogy to the facts as stated. M. Ivlencke describes cells 
 of from jlji to sio'" i^^ diameter, which would be collected, 
 at the beginning of the caries, in simple beds crowded to- 
 gether upon the enamel cuticle, and, later, these same cells 
 would form layers superposed, and capable of multiplying 
 by division or by endogenous proliferation. The mode of 
 propagation of these cells penetrating tlie dental substance 
 is described and pictured with so great exactness that we 
 
LEPTOTHRIX BUCCALIS. 29 
 
 may be pennittcd to wait, at least until the discovery again 
 of some analogous elements. 
 
 We iind, occasionally, after having removed, by the aid of 
 a weak acid, the cuticle which covers the tooth, minute ele- 
 ments, crowded against each other u[ion the denuded surface, 
 wliich might he confounded with a sort of granular epithelium 
 with ill-detined contours. These are nothing but the extremi- 
 ties of the enamel prisms left adhering to the cuticle. It is 
 impossible to confound them with the cells of the fungus. 
 It might with equal probability l)e supposed that such an 
 error could spring from portions of vegetable or other ali- 
 mentary substances which are found adhering to the teeth. 
 It seems to us, from certain indications, that the round, 
 granular masses of leptothrix which form upon the surface of 
 the cuticle have given rise to this error, although a certain 
 power of imagination is necessary to consider these irregular 
 and badl}' defined masses as cells. In caries of the enamel 
 these fungi, as we shall show, appear not to play a part as 
 important as in that of the dentine. The action of acids and 
 the decomposition of organic substances, which is its conse- 
 quence, and which is recognized by a brown color, seem to 
 us to demand more attention. Yet equal account should be 
 made of the effect produced by the fungi. 
 
 The seat of leptothrix seems generally to be confined to the 
 surface of the tooth as long as the dental substance remains 
 intact. It may be otherwise when the teeth are covered with 
 a greenish coating, and the lesion seems to have its seat in 
 the verj^ substance of the enamel. 
 
 We meet with this greenish coating in young people and 
 upon the front teeth. It is generally attributed to the alter- 
 ation of the enamel cuticle. The action is not bounded by 
 the surface of the tooth, but penetrates even into the sub- 
 stance of the enamel. AVe have examined but a single case 
 of this kind. AVe removed from the surface of the tooth 
 small green and rather hard portions which resembled tar- 
 tar, but which appeared to be rather minute fragments of 
 enamel. Xevertheless it was impossible, after examining 
 them under the microscope, to decide whether it was enamel 
 
30 INQUIRIES INTO DENTAL CARIES. 
 
 or Dot. After liaving dissolved out the calcareous portions, 
 we were convinced that the whole substance was strewn with 
 granular matter of ieptothrix. The greenish tinge was found 
 only at the surface of the pieces; the acids could not destroy 
 it ; it had an appearance of shreds, delicate and plicated, or 
 perhaps granular, and without other structure. It is im- 
 portant, therefore, to make new experiments to ascertain if, 
 at the place of this green color, the fungi penetrate the sub- 
 stance of the enamel, or if we must attribute it to a particular 
 kind of tartar, as appears much less probable. If the first 
 supposition should be confirmed, we must seek to find why 
 and how the fungi succeed in penetrating the enamel. It 
 will not be less interesting to know the origin and the cause 
 of this greenish color. 
 
 As regards the elements of the enamel, no particular change 
 seems to precede its alteration. It can only be shown by the 
 aid of the microscope that it is easier to recognize in minute 
 fragments of diseased enamel the structure of this tissue, than 
 in its fragments in a state of health, when the union of the 
 prisms can with difliculty be perceived. This phenomenon 
 can be explained by the disappearance of the calcareous salts 
 consequent upon the work of caries. Carious enamel ai)pears 
 under the microscope like that which has been submitted to 
 the action of acids, and differs only by a little more or less 
 brownish color. The farther the work of caries has pro- 
 ceeded, the easier it is to prove this difference. There are 
 found in minute cavities of the enamel delicate debris of this 
 tissue. The extremities of the enamel prisms and their ob- 
 lique strire have contours so fine that it is only by the shade 
 of brown that we can recognize them. This occurs likewise 
 when we employ acids. We find no more ^han a residue, 
 very delicate and of a membranous nature, which reveals 
 the composition of the enamel, whose total destruction is 
 not slow in taking place. 
 
 The porosity of the carious enamel, which makes this 
 tissue lose its normal transparency and its hardness, is the 
 same as in enamel exposed to weak acids. It is (piite easy 
 to detach from it portions which, under a moderate pressure, 
 
LEPTOTIIRIX BUCOALIS. 31 
 
 are reduced to niiimtc debris. By these processes the enamel 
 prisms separate only exceptionallj^ ; the frag-ments have, for 
 the most part, a direction inclined and oblique, and the 
 isolated prisms appear only under the form of very short 
 i'ragments. The porosity cannot then be attributed to a 
 diminution of cohesion between the enamel prisms, but we 
 may admit, as very probable, that fissures or meshes of a 
 very great delicacy traverse the enamel in directions the 
 most varied, and completely independent of its histological 
 composition. The porosity is equally due to the action of 
 acids. It is produced by the dissolution of tlie calcareous salts, 
 and [lei'haps by the production of carbonic acid, which may 
 cause the dissociation of the smaller particles of the enamel. 
 The brownish color of carious enamel, which exists also in 
 carious dentine, arises probably from the change of the 
 organic portion of these tissues. ]n no case is this color 
 caused by the leptothrix, which remains colorless, or causes a 
 slightly yellowish shade only when in beds of great thick- 
 ness. In a good number of cases, and notably in carious 
 cavities, the leptotJwix appears to produce a yellow color, but, 
 on attentively examining, we shall be convinced that this 
 color proceeds from the surrounding diseased materials. 
 We can, on the other hand, in microscopic preparations, 
 easily distinguish by their brown color the residues of dental 
 tissues, which are covered with masses of /cpto^/;?-?^, while the 
 leptothrix alone will have a grayish appearance. The color 
 will vary in intensity, as we have alreadj' shown, and, in 
 general, it will be dark in proportion to the hardness of the 
 tooth, the age of the caries, and the time the color has had 
 to develop itself. When the enamel has not yet undergone 
 decomposition, we ordinarily observe this color only upon the 
 upper layers, without doubt because the cuticle contains a 
 greater proportion of organic elements subject to change. 
 We might think that this was caused also by the easy access 
 of the air to the parts ; nevertheless, and contrary to this 
 opinion, we can say that this color is formed anew in the 
 dentine after having disappeared from the deeper parts of 
 the enamel, and that it gradually lessens as it extends to the 
 
32 INQUIRIES INTO DENTAL CARIES. 
 
 cavity of the dental pulp (Plate I, Fig. 2\ where, upon a 
 point of the left side of the crown, the brown color of the 
 enamel diminishes little by little from the surface to the deep 
 parts, and becomes again more intense at the surface of the 
 dentine. 
 
 When the caries has occasioned a loss of substance at the 
 surface of the enamel, the bottom of the cavity is always 
 covered bj' the granular masses, and by filaments of lepiothrix, 
 which penetrate the inequalities and excavations of the sur- 
 face. The minute cavities frequently found in the depths of 
 the enamel are filled with Icptothiix, and with debris of 
 enamel mixed with. it. It is in general very diificult to 
 recognize b}' the aid of the microscope the elements of the 
 enamel when they have become greatly softened. Yet, in 
 cases where the oblique striation is well pronounced, w^e 
 sometimes find fragments of enamel colored brown, and 
 almost entirely deprived of calcareous matters. Masses of 
 leptothrix envelop them, and contribute, by their prodigious 
 proliferation, to their destruction. 
 
 In our opinion the progress of caries of the enamel is this: 
 By the action of an acid the enamel becomes porous at some 
 point, and loses its normal consistence. At the same time 
 there is seen to appear a brown color, in consequence of the 
 change which has taken place in its organic structure. 
 There is formed at the surface a bed of leptothrix^ wliich 
 probably penetrates the dental cuticle, if it still exists, and 
 destroys it. Chinks and fissures are opened in the enamel, 
 which has become less consistent. Acid liquids and granu- 
 lations of leptothrix penetrate there, while minute fragments 
 become detached, and are promptly enveloped hy the elements 
 of leptothrix, which, joined to the continued action of the 
 acids, hasten the dissolution. There are many cases where 
 the work may be stationary for a long time, and perhaps for 
 always, corresponding to that of the caries calk'd dry, char- 
 acterized onl}' by the 1)rown color of the surface, and a little 
 more porosity, which should ])c attributed to the more decided 
 action of acids. In answer to what we have just said may 
 be cited the alterations of the enamel which appeal* almost 
 
CARIES OF THE DENTINE. 33 
 
 immediately after the commencement of tlie diseased action, 
 when the hrown color has hardly had time to hecome formed. 
 We can attrihute these diiferences in the progress of the dis- 
 ease only to particular predispositions, due, it may he, to 
 vicious structure, or to differing consistency, or resistance of 
 the enamel. 
 
 Caries of the Dentine. 
 
 In the dentine the work of caries hegins general!}' as soon 
 as that of the enamel has pentrated to its surface. Particular 
 circumstances enable us to ascertain whether any alteration, 
 properly so called, and loss of substance at the surface of the 
 enamel, have or have not preceded this morbid action. We 
 can also divide into two periods the action of caries in the 
 dentine, viz., that of the 'pre-paratory work of the caries^ and the 
 period, of destruction. Before decaying the dentine also under- 
 goes certain transformations which can be recognized, as in 
 the alterations of the enamel, by a brownish color more or 
 less marked, and by a lessening of consistency, due to the 
 loss of a portion of the calcareous salts. We observe, more- 
 over, when the disease has progressed to a certain degree, 
 certain histologic changes which were thought to be the 
 result of an active, vital action, and which can only be 
 attributed to the proliferation of the lepfothri.r. 
 
 These same vegetations play also a very important part in 
 the definitive alteration which takes place in caries of the 
 dentine. The caries ordinarily proceeds from the enamel to 
 the dentine; more rarely it has its point of departure in the 
 cement, when this has become exposed, or is defective. 
 Caries may also commence directly in the dentine when it is 
 denuded, whether by a vice of conformation, or by an external 
 lesion. The march of caries is still more rapid in the dentine 
 than in the enamel. Starting from a minute point upon the 
 surface, the caries may promptly extend through a great 
 part of the dentine; that of the enamel cannot make such 
 rapid progress. The more rapid march of the caries in the 
 dentine is occasioned by its structure. The minute dentinal 
 
34 INQUIRIES INTO DENTAL CARIES. 
 
 canaliculi, so accessible to liquids, olier to tlie action of 
 destructive agents a much more extended surface, and per- 
 mit them to penetrate to the depths of the dentine, an action 
 not possible in the enamel wliich has not these canals. 
 
 Another cause, which, in the majority of cases, explains 
 the more rapid march of caries of the dentine, is this, viz., 
 the carious cavity once formed, the destructive process can 
 dev^elop itself freely without hindrance from the friction of 
 the teeth during mastication, or from the cleansing of the 
 mouth. While at the surface of the teeth the injurious sub- 
 stances are continuallj' removed, and the enamel forms upon 
 the borders of the cavity a protecting wall, favorable to the 
 development of caries behind it. Its canaliculous structure 
 appears, however, to be the main cause of the more rapid 
 progress of caries in the dentine, and the observation of the 
 facts leaves no doubt upon this subject. The caries follows 
 chiefly the direction of the dentinal camdiculi, and extends itself 
 less easily and with less rapidity in the direction of the width 
 of the tooth than in that of its depth, that is to say, towards 
 the cavity of the pulp. 
 
 If we divide a carious tooth in the direction of its length, 
 we find, as Tomes has first remarked, that the dentine altered 
 by caries, when no destruction has as yet taken place, [)re- 
 sents the form of a cone with its base turned outwards, and 
 of a brownish color, which owes its origin to that which the 
 caries follows in its progressive march, viz., the direction of 
 the canals towards the pulp ; the conical form is determined 
 by the convergent direction of the dentinal canaliculi. (Plate 
 I, Figs. 1 and 2, shows, three times magnitied, cones of den- 
 tal caries upon a tooth divided lengthwise, with and without 
 alteration at the surface.) 
 
 When a portion of the dentine has been destroyed by 
 caries, it can no longer have the form of a perfect cone ; but 
 there is alwaj-s found, at the circumference of the carious 
 cavity, a zone of altered substance which goes on diminishing 
 in thickness in the direction of the pulp. We find these 
 cones in teeth altered hy caries at a period when the exterior 
 surface of the enamel has still all its polish, and, consequently, 
 
CARIES OF THE DENTINE, 35 
 
 lias lost no purt of its substance.* But, at this ej)oeli, the 
 wliole thickness of the enamel is already changed, and there 
 exists no covering of normal enamel at the surface of tlie 
 dentine. M. Magitot says that the cone commences some- 
 times at a point at a distance from the surface of the tooth. 
 AVe believe that the tooth pictured by this author can be ex- 
 plained by supposing that the section, in the direction of its' 
 length, has not been made across the centre of the caries, and, 
 consequently, has not touched the point whence the morbid 
 action has been propagated from the enamel to the dentine. 
 The alterations etfected by the caries in the dentine may 
 have extended themseh^es laterally to a slight depth, and 
 have left untouched the more superficial portions. Wheu 
 we have made sections -of teeth across the centre of the caries, 
 we have constantly observed that the alteration had its be- 
 ginning at the surface of the dentine. The cones which we 
 have mentioned have also been spoken of and described bj- 
 various authors, and especially by MM. Tomes and Magitot. 
 I^v^evertheless we have reason for surprise that these cones 
 have not been considered as the point of departure of the 
 caries itself, but rather as the result of an organic reaction 
 whicji preceded the caries, and opposed itself as much as 
 possible to its progress. After our experiments made upon 
 a great number of teeth cut across in every direction, we 
 cannot share this opinion. We think, as does also Mr. 
 Spence Bate,! the cones are only the tirst degree of the work 
 of caries in the dentine This results from their physical 
 properties ; the color is brownish ; the consistence lessened ; 
 and the transparency greater. 
 
 We have found the brownhh color in all the cones, whether 
 there has or not been loss of substance at the surface of the 
 tooth. In speaking of the enamel, we have already expressed 
 the opinion that the brownish color is due to a decomposition 
 of the organic portions of the tooth. TJie intensity of this 
 color ditfers in the dentine as in the enamel. It is darker as 
 
 * Traite do lii'carie dcntaire, 8, 26. 
 
 t Report of tlic Sittintrs of tlie Odontologic Society of London. March 7, 
 1804. Brit. Journal of Dciitai Science. 
 
36 INQUIRIES INTO DENTAL CARIES. 
 
 the progress of the caries is slower and the density of the tooth 
 greater. As a general rule we may say that the color is 
 diffused ; from time to time we find in the dental canaliculi 
 minute granulations of pigment which are deposited there in 
 greater or less quantity. The hardness of the substance which 
 has acquired the conical forin also varies greatly. When there 
 has not wQt occurred any destruction of substance, nor any 
 carious cavity, this hardness may, in certain circumstances, 
 be quite marked, above all in the deeper seats, and in teeth 
 which are naturally very hard, and consequentl}' in the cases 
 of caries called dry. ISTotwithstanding, it is easy to convince 
 oneself that, even in this form of caries, the consistence of 
 the cone, however hard it may be, is always less than that 
 of the sound portion of the same tooth. lu other cases, on 
 the contrary, all the substance which constitutes the cone is 
 manifestly more softened than the dentine in its normal 
 state. It is to be remarked that the deeper seats of the dis- 
 ease are always less softened than those at the surface. This 
 is markedly the case when the caries has hollowed out a 
 cavity. We tind then, among the most superticial layers, 
 always a softened layer of dentine which is on the way to 
 complete dissolution. The thickness of this layer varies 
 greatly ; in moist caries it is quite thick, and insensibly ex- 
 tends itself to the deeper parts of the con^. 
 
 In the drier caries, the softened layer of the surface has a 
 much less thickness, and at times is wanting altogether. 
 These differences evidently depend upon the rapidity of the 
 evolution of the caries of the dentine. If the pathologic 
 alteration of the dentine which has preceded its decomposi- 
 tion has occasioned a considerable softening of the substance, 
 the caries will naturally make more rapid strides, and a 
 thick layer of substance undergoing decomposition is upon 
 the point of detaching itself at the surface. r>ut, if the den- 
 tine is very hard and little softened by the work of the caries, 
 the decomposition extends itself but slowly, and the destroyed 
 substance at the surface forms but a thin layer, and some- 
 times seems not to exist at all. 
 
 The transjiarent appearance of the conical, substance oipially 
 
CARIES OF THE DENTINE. 37 
 
 proves tluit it is tlie coiiinicncenient of the work of caries. 
 It is especially easy to recognize it in thin portions which 
 are detached without difHculty from the softened carious 
 substance ; or, if this is too hard, we can always perceive it 
 in sections rubbed dowu with pumice. The brownish color 
 is scarcely seen iu such thin })rcpa rations; we see it well only 
 when it is very intense ; therefore MM. Tomes and Magitot 
 have not attached a sufficient importance to it. 
 
 The dentine, as regards transparency, has properties the 
 very opposite of those of the enamel. While the enamel is 
 translucent in its normal state, the dentine presents an opaque 
 whitish or yellowish shade; the enamel loses its translucence 
 by caries, while the dentine becomes more translucent and 
 almost cartilaginous. A\"e have already remarked, in treat- 
 ing of caries of the enamel, that we must attribute its loss of 
 transparency to the action of acids. We shall take occasion 
 to show further on that acids produce the same effect out of 
 the mouth as in it. 
 
 Experiments also lead us to the same results with the den- 
 tine. If, by the aid of an acid, we decalcify the dentine, it 
 becomes transparent and acquires the aspect and consistence 
 of cartilage. When the dentine is incompletely decalcified, 
 it resembles, minus the brown tinge, certain kinds of dentine 
 altered b}^ caries. Yet, at a more advanced stage of the dis- 
 ease, carious dentine is distinguished by less consistence, and, 
 moreover, by peculiarities of structure, inasmuch as the action 
 of acids alone is not enough to produce caries. It ought not, 
 tlierefore, to be any longer doubted that the transparency of 
 carious teeth should be attributed to the loss of their calca- 
 reous salts. 
 
 Mr. Tomes and, after him, M. Magitot have endeavored to 
 explain this transparency otherwise. Mr. Tomes attributes 
 it to the calcification of the fibrilhxi which he discovered in 
 the interior of the dentinal canaliculi. In fact, we also have 
 been able to verify very often, and notably at the borders of 
 the diaphanous zone, in the direction of the still sound den- 
 tine, the existence of a considerable number of minute cavi- 
 ties and of granulations ranged side by side, formed by cal- 
 
38 INQUIRIES INTO DKNTAL CARIES. 
 
 careons salts and siluatod in the interior of tlie dentinal 
 caiialicnli. 
 
 Xevertheless it is impossible that the transparenc}' shonld 
 be due to the presence of these concretions, for we do not 
 always meet with them, and when they do exist they are 
 not found in every part of the transparent substance. They 
 fjenerally show themselves onl}^ in the form of a very slender 
 zone at the limits of the portion of the dentine altered In- tlie 
 malady. It is easy to recognize in sections for the microscope 
 that the transparency does not exist except where these con- 
 cretions are seen, and that these same concretions form no 
 part of the appearance which the tissue presents to the naked 
 eye. Finally, it is eas}^ to demonstrate a priori that these 
 concretions cannot in any manner cause the transparency of 
 these tissues. They could do so only by rendering them 
 more homogeneous ; that is to sa}-, the matters deposited in 
 the canaliculi ought to have the same index of refraction as 
 the intercellular substance; the boundaries of the canaliculi 
 would thus become, in the sections, [)aler and less obscure. 
 The opaque aspect of the dentine in its normal state depends, 
 at least in part, upon its structure. It is composed of parts 
 which have different indices of refraction (the canaliculi and 
 the intercellular substance^ and which alternate regularly in 
 position. But the concretions contained in the dentinal ca- 
 naliculi ought rather to produce an opposite effect. In fact 
 they are distinguished under the microscope by their dark 
 margins, which proves that their index of refraction is dif- 
 ferent from that of the surrounding substance. They are, 
 moreover, dispersed in little i)arcels, which increase the ine- 
 qualities of the structure and lessen the transparency. In 
 this connection we here remark the opacity which is pro- 
 duced in the tissues by minute globules of fat, ranged side 
 by side, whose power of refraction is well known. If, in spite 
 of this, the tissue remains transparent, we can explain the 
 fact only hy admitting that the disappearance of the calca- 
 reous salts has much to do with it, and it cannot be sensibly 
 affected by slight inequalities of tissue. 
 
 We shall recur, in the course of this treatise, to the oriijin 
 
MICROSCOPIC CHANGES. 39 
 
 of these cnlcarcons concretions in tlie canaliculi, and u[ion 
 the effects wliich MM. Tomes and Mas-itot have sona;ht to 
 attribute to their presence. We confine ourselves, for tlie 
 moment, to asserting that tlie transparency of the carious 
 dentine cannot at all be attributed to them. 
 
 It results, from what we have just said, that the cones, 
 formed of a brownish and more diaphanous substance, make 
 an integral part of the commencemont of the work of decay, 
 and should not be considered as a peculiar morbid condition 
 preceding the caries properly so called. All can easily verify 
 this for themselves by exaniining a great number of sections 
 of carious teeth, for thus the diflerent forms and periods can 
 be followed and compared, from teeth where the cones are 
 hard and where doubts may exist, to those whose cones are 
 formed of a substance very distinctly softened and on the 
 road to decomposition. 
 
 MiCKOSCopic Changes of the Dentine in a Carious State. 
 
 The microscopic changes which are undergone by dentine 
 during the work of caries are of great im[)ortance in resolv- 
 ing the doubts which exist npon the natnre of this malady, 
 and especially in ascertaining whether or not organic action 
 is to be regarded as among its causes. 
 
 We have estal)lished hereinbefore (in our review of what 
 we actually know), that diflerent authors have ascertained 
 the existence in the dentine of histologic changes, upon the 
 nature of which, nevertheless, they are far from agreement. 
 Perhaps their differences would have disappeared if more 
 importance had been attached to the manner in which the 
 tissue was destroyed. We distinguish in dentinal caries two 
 periods which cannot be rigorously defined ; the preparatory 
 period of decalrijica Hon and softening ^duv'u^g which the micro- 
 scopic changes in question are to be observed ; and the period 
 of direct decomposi ion. Up to the present time it has been 
 the custom to admit in general that the dentine, deprived of 
 its calcareous salts, is dissolved by a sort of putrefaction. 
 I)Ut it is not difficult to demonstrate that the infiuence of 
 
40 INQUIRIES INTO DENTAL CARIES. 
 
 leptotlirix is very great in this work of destruction, inasmuch 
 as it penetrates very deeply into the clefts and interstices of 
 the decalcified dentine, which it reduces into small fragments- 
 It is equally prohahle that this same leptothrix plays, by its 
 extension, an active and direct part in the absorption of the 
 carious tissue. 
 
 We shall demonstrate farther on that a great part, if not 
 the whole, of the microscopic changes observed in carious 
 dentine should be attrib.uted to the introduction of the ele- 
 ments of leptot/o'ix into the dentinal canaliculi, and in part 
 into the intertubular substance. AVe will first examine the 
 ■phenomena which characterize the direct (lecontposiiion of the 
 tissue. We follow, it is true, a method just the opposite of 
 that Avhich the changes themselves have taken. Yet this 
 ofiers no inconvenience, for the knowledge of these phenom- 
 ena is indispensable in order to comprehend the changes 
 which i^recede the caries. 
 
 If we examine the disorganized substance which covers 
 the superficies of a carious cavity, and which, moreover, 
 presents an acid reaction, we are truly astonished at the 
 quantity of elements of lepiothrix which are found there. 
 The su[)erficial layers, with the exception of some particles 
 of food, are formed exclusively by the granular masses, and 
 by the filaments of lepiothrix. On removing these we come 
 upon layers which pwssess sufficient consistency to permit us 
 to make sections. These latter, as is shown in i'late II, 
 Fig. 2, consist of irregular minute fragments of carious den- 
 tine of a brown color. They are enveloped and united by 
 masses o{ leptothrix ; above all, granular leptothiix. In the 
 layers which lie still deeper the volume of tlie dentine in- 
 creases ; the leptothrix dinunishes in such a proportion that 
 the dentine here forms the principal part. We see, then, in 
 the carious portions, colored brown, irregular chinks and 
 interstices filled with Irptot/irix and its elements (Plate II, 
 Fig. 1). This arrangement may well be compared to the 
 canals and veins which arc exhibited by certain stones. The 
 leptothrix always dimiuishos in proportion lo the depth; yet 
 sometimes it is found at a remarkable depth, where it takes 
 
MICROSCOPIC CHANGES. 41 
 
 a direction parallel to the dentinal canaliculi. We recognize 
 very clearly this arrangement in sections of decalcified teeth, 
 or in those ground thin with pumice. The images ohtained 
 in this manner do not permit us to doul)t that these fungi 
 hy their extension have deeply penetrated the dentine, and 
 have not confined themselves to simjily filling pre-existent 
 cavities. AVe find these latter nowhere, and we shall prove 
 by and hy that the minute dentinal canaliculi constitute the 
 principal roads by which the leptothrix penetrates the dental 
 tissues. 
 
 AVe often observe in sections islets which are filled with 
 the finely granular matter of the fungus (Plate II, Fig. 6). 
 The origin of these islets is easily explained hy the direction 
 of the sections which cross a conduit filled with leptothrix^ 
 and which, in consequence, offer the image of an isolated 
 islet. AVe see there, moreover, other conduits which corre- 
 spond with the surface. Up to the present time observers 
 have confined themselves to proving the presence of the 
 leptothrix in the carious cavities of the tooth, but without 
 assigning it any influence in the work of decomposition. 
 They have not noticed the introduction of the leptothrix into 
 the softened substance of the dentine; and its presence in 
 the carious cavities has consequently been considered as 
 accidental and without importance. According to our ob- 
 servations we cannot refuse to admit that the proliferation 
 of the fungus plays an important part in the decomposition 
 of the dental tissue. What explains the ignorance of authors 
 upon this point is that they confounded the vegetable granu- 
 lations with the organic matters in decomposition, and that 
 the elements proper to leptothrix passed unperceived. The 
 reaction with iodine and the acids, which produces a beauti- 
 ful violet color, as well with the granular masses as with the 
 filaments, leaves no doubt about the nature of the sranular 
 lejjtothrix. 
 
 The figures and their explanations of Ivlencke, upon the 
 penetration of the protocorrits dentalis into the dentine, have 
 a certain analogy with the images which we have just de- 
 scribed above. The analogy, nevertheless, holds only as to 
 
 4 
 
42 INQUIRIES INTO DENTAL CARIES. 
 
 the mode of penetration of the cells, as he calls them, into 
 the interior of the dentine. His Figure 15- (loc. cit., S. 57), 
 might cause it to be thought that he had under his eyes the 
 same image as we. Yet all that concerns, in these consid- 
 erations and in these sketches, the form, &c., of the extension 
 of these parasitic plants is, as we have already remarked, hut 
 the work of the imagination. The opinion of Ficinus, who 
 figured at the surface of the carious dentine a considerable 
 number of vibrios, called by him dcnticokr, is explained in the 
 simplest manner by the theory of M. Hallier, if he is correct. 
 According to this author the granulations of the leptothrix 
 are spores which have come to a state of repose. 
 
 In our researches upon carious teeth we have, it is true, 
 seen the granular masses of the leptothrix stationary, and in 
 proportion but a small quantity of granulations in movement. 
 ISTevertheless we believe that there may be great variety in 
 the cases, and that, in given circumstances, we may come 
 across considerable masses of spores dispersed and moving. 
 The observations of Ficinus will thus become conformed to 
 ours, when it Avill be necessary to consider the presumed 
 infusoria as scattered spores of leptothrix. 
 
 Let us pass now to the examination of the changes which 
 take place in the dentine before direct decomposition of the tissue. 
 The softened dentine of a brownish color and of a feeble con- 
 sistence, situated under a carious surface, presents, after re- 
 moval of the masses of le/ptothrix which penetrate there, pecu- 
 liar changes in the dentinal canaliculi. These changes become 
 in general more and more perceptible as we proceed from the 
 depths of the dentine to its surface. It is easy to see in cross- 
 
 * Wo have just learned that M. Georges Pouchet liad exj.ressed a similar 
 opinion to ours upon tlie nature of the granuhitions of lepiotlirir. He con- 
 sidered them as one of the phases of development of the plant. This author 
 has not noticed movements in the granulations which compose the granular 
 masses, and he has concluded from this that they are always immovable. 
 The movements which others have observed may be caused by vibrios which 
 have penetrated the granular ma.ss. New observations will show if we must 
 receive the opinion of M. Pouchet, or that of M. Hallier, who thinks that 
 the granulations of /e/}te//i7"ia; before coming to a state of repose, move through 
 tlie liquids in every direction, under the form of movable spores. 
 
MICROSCOPIC CHANGES. 43 
 
 sections of teeth that the canaliculi become vet y gradually larger^ 
 till tliey reach a considerable size, by the accumidation in their in- 
 terior of a finely grarndar substance. The canals so enlarged 
 present for the most part a double contour, invisible in the 
 normal state, a fact which indicates that the bore is bounded 
 by thick walls. The thickness of the walls varies, but less 
 than the calibre of tlie canals. Taking for our point of de- 
 parture the portions which remain sound, we can observe in 
 the sections the passage of the dentinal canaliculi from those 
 without distinct walls to those whose walls are thickened, 
 and whose dilatation goes on increasing by means of the ac- 
 cumulation of foreign substances (see Plate II, Fig. 2). In 
 the latter case, there may still exist a wall distinct from the 
 material contained in the canals ; nevertheless, when the di- 
 latation is very great, it may happen that this wall entirely 
 ceases to be visible. Finally, if, in other cases, the canaliculi 
 are but little dilated, while the walls are much thickened, 
 we observe rings quite large, brilliant, and crowded upon 
 each other, which have a brownish-yellow color, like the in- 
 terposed substance. Close observation is necessary to distin- 
 guish the granular contents from the wall, which presents a 
 brilliant aspect (see by the aid of a feeble magnifier Plate II, 
 Fig. 3, where the walls are not at all visible^ 
 
 At times the dilatation is carried so far that the canals, 
 crowded together, not only touch at their circumferences, 
 but become reciprocally flattened. We then observe in trans- 
 verse sections polygonal instead of circular figures. At first 
 sight, we might be disposed to think that the canaliculi be- 
 come gradually obliterated by the successive thickening of 
 the walls, according to the opinion of M. ISTeumann,* while 
 Mr. Tomes compares the dentinal canaliculi with thickened 
 walls to pipe-stems, and does not admit of complete oblitera- 
 tion. Xevertheless, we have come to be convinced that in 
 all cases the tubes of the canaliculi are increased and filled 
 with a mass which ordinarily will be finely granular and 
 sometimes homogeneous, surrounded with more or less thick- 
 ened walls. 
 
 * See loc. cit. Archives de Clinique Chirurgicale, t. vi, p. 1. 
 
44 INQUIRIES INTO DENTAL CARIES. 
 
 The principal reason which has caused M. Xeumanu to 
 believe in the obliteration of the canaliculi by the successive 
 thickening of the walls, is the images which are obtained 
 after impregnating the preparation with carmine. The 
 thickened walls do not take the color from carmine, while 
 the matter contained in their interior is sometimes very 
 strongly colored by it, and is thus very clearly distinguished 
 from the walls. Sometimes, nevertheless, the contents are 
 but slightly colored ; it is then difficult to distinguish it 
 from the thickened and brilliant wall, which gives rise to 
 the belief that the canal is completely obliterated ; but an 
 attentive examination will always reveal the true state of 
 things. The most remarkable varieties of coloration by car- 
 mine manifest themselves in the iutertubular substance. In 
 the normal state this substance is colored, feebly it is true, 
 by the carmine ; in the carious portions, on the contrary, 
 and particularly when the brown color is strongly marked, 
 this substance entirely resists coloring, so that these parts, 
 including the dilated canaliculi whose contents remain 
 equally inaccessible to coloration, contrast by their yellow 
 hue with the surrounding parts colored red. On the con- 
 trary, in other circumstances, this same substance will take 
 the color. This is the case with preparations made from the 
 superficial layers, where the iutertubular substance shows 
 itself spotted throughout with very fine granulations. It 
 may be said that the brown color is opposed to the red of 
 the carmine, for this latter is perceived nowhere where the 
 brown is strongly marked. We must not, therefore, place 
 any great importance upon the coloration with carmine. 
 We cannot share the opinion of M. Neumann who distin- 
 guishes two kinds of changes: 1st, obliteration of the canal- 
 iculi by successive thickening of the walls ; and 2d, thicken- 
 ing of the fibrils contained in the dentinal canaliculi, and 
 their division into successive cellular elements. 
 
 As for us, we altribalc all the changes to a gradually increas- 
 ing dilatation of the canaliadi by the formation of afmiy gran- 
 ■ular substance which is more or less strongly colored by 
 carmine, and to a thickening of the walls of these same canals. 
 
MICROSCOPIC CHANGES. 45 
 
 111 longitudinal sections, which rarely furnish images as 
 distinct as oblique ones, we often see the contents of these 
 dilated canalieuli redneed to the condition of small threads 
 which at times become sejiarated b}- minute intervals. Thus 
 the dilatation of the canalieuli may become very consider- 
 able ; but we iind the threads in the canals already slightly 
 dilated, and, in this case, carmine colors them a bright red 
 (they correspond to the cellular elements which, according 
 to M. Xeumann, come from the thickening and division ot 
 the dentinal fibrils). In cases where the contents of the 
 canalieuli does not take the carmine and, as well as the in- 
 termediary substance, presents a yellowish-brown shade, we 
 perceive, in general, the canalieuli thickened only in a con- 
 fused manner in the longitudinal sections; we can prove 
 only that the dentinal canalieuli are badly detined, and that 
 their contours are replaced by longitudinal strijc but little 
 marked. 
 
 Analogous images under the form of bundles of rods, but 
 in general of a smaller diameter and rebellious to the action 
 of carmine, arise from deposits of calcareous salts in the 
 canalieuli. We shall recur again to this subject farther on. 
 
 As M. Neumann has already observed, we can easily 
 isolate the thickened dentinal canalieuli by macerating them 
 in nitric or hydrochloric acid, just as is done for the normal 
 ones (Plate II, Fig. 5). It is not rare to observe in the same 
 canal the passage from the minute dimensions of the normal 
 state to a pathologic thickening (Fig. 5, b). The isolated 
 canals also present differences in the degree of coloration by 
 carmine, and very often the division of their contents into 
 threads can be recognized. The contents of the canalieuli 
 often projects beyond their ends, and is seen under the form 
 of a prominence with fine granulations, or else as a brilliant 
 and viscous drop ; in general the extremity of the canalieuli 
 is then contracted. Sometimes, also, there can be distin- 
 guished through the walls in isolated canalieuli the contents 
 composed of fine granulations. 
 
 Another peculiarity belonging to the thickened canalieuli 
 consists of partial varicose dilatations and the sinuosities 
 
46 INQUIRIES INTO DENTAL CARIES. 
 
 wliicli they present ; this contrihutes towards rendering 
 them susceptible of acquiring at these points a rehitively 
 considerable thickness. 
 
 The mean diameter of the thickened canalicule of a tooth 
 was from .003 to .006 of a millimetre; some presented a 
 much greater diameter, notably at the thickened and vari- 
 cose [loints; the normal canalicule of the same tooth showed 
 a diameter of only from .001 to .0015 of a millimetre. To 
 form an opinion upon the nature of the changes just men- 
 tioned, it is of the highest importance to well consider the 
 condition of the dentine in the caries of natural teeth of implan- 
 tation. 
 
 The solution of this question will lead us to know if the 
 changes are in part or wholly of a vital nature, or not. M. 
 iSTeumann has expressed the same opinion, for he has declared 
 that his conclusions would cease to be true if it should come 
 to be proved that, in the caries of natural implanted teeth, 
 the same changes take place as in living teeth. It is a well- 
 known fact, long since observed, that false teeth, whether 
 procured from man or made from the ivory of the elephant 
 or hippopotamus, decay in the mouth as well as the natural 
 teeth. Caries, indeed, establishes itself very quickly in these 
 false teeth, and begins ordinarily in the points where the 
 teeth are fastened upon the plates, or kept in place by the 
 aid of wires. These places constitute, for the development 
 of morbid phenomena, points of departure as favorable as 
 the clefts in the enamel, or interstices in the teeth. 
 
 The partisans of the chemical theory of caries of teeth 
 have always cited, as proof of their opinion, the caries of 
 natural teeth of substitution. Nevertheless it could be ob- 
 jected that there is but an external analogy between the 
 caries of these teeth and that of living ones, and that there 
 may exist between the two essential histologic ditferenccs. 
 This is the o])inion of M. Xeumaun. Ho found, especially 
 in examining a piece of ivory inserted in a l)one and attacked 
 by caries, that the characteristic changes of tlie dentine, as 
 they have been described, were wholly wanting. He con- 
 cluded from this that the caries of artiiicial teeth of ivory 
 
MICROSCOPIC CHANGES. 47 
 
 may, in all probability, also not reseniMo that of the natural 
 ones. On the contrary, we have remarked, in examining 
 several teeth made of hippopotamus ivory, as well as three 
 human teeth of substitution which had all decayed in the 
 mouth, that the microscopic changes of the dentine, as they 
 have been described, take place equally in these artiticial 
 teeth. In every case the canaliculi were more or less dilated, 
 sometimes even extraordinarily so, and their contents were 
 generally susceptible of being colored by carmine. Above 
 all, in [)reparations made from hippopotamus ivory, we were 
 able to observe these changes in the most marked manner 
 (IMate II, Fig. 6). The isolated canals were in part very 
 much thickened and presented the varicosities which we 
 have spoken of. At the greatly dilated points these canals 
 attained a diameter of .009 of a millimetre. There were even 
 some of them which measured as much as .015 ; their con- 
 tents were finely granular and were easily colored by carmine 
 (Plate II, Fig. 7). It is true, we did not find in these the 
 elements in the form of threads, but it is equally true that 
 they are not alwa^^s found thus in caries of the living teeth. 
 Nevertheless, we have observed these same thread-like ob- 
 jects in the canaliculi of carious pivoted human teeth. The 
 threads then do not form special elements, and the mass 
 which fills the dilated canaliculi, and which is susceptible of 
 coloration by carmine, ought not to be considered a substance 
 of a different nature. In teeth made from hippopotamus 
 ivory we do not see the walls of the canals thickened as in 
 human teeth of substitution. In fact, the pieces made with 
 human teeth of substitution,present no difference from the 
 preparations made from natural teeth. 
 
 Aside from these considerations there exist still other 
 reasons for combating the opinion of JNI. jSTeumann, who 
 admits a vital action in the changes we have just mentioned. 
 
 M. iSeumann himself declares that the transformation of 
 the dentinal fil)rils, deprived of nadei^ into cellular elements 
 ranged one after the other, appeared extraordinary. Farther, 
 as to the cells, we cannot reasonably expect to see their di- 
 mensions vary within too narrow limits. But, indeed, the 
 
48 INQUIRIES INTO DENTAL CARIES. 
 
 threads are already seen in canaliculi which exceed hut- 
 slightly their normal thickness, as well as in those which 
 have acquired a considerahle dilatation, and the volume of 
 the threads corresponds to the dilatation of the canaliculi. 
 From time to time we see the contents of the canaliculi 
 divided into minute and rather short fragments ; in other 
 cases divisions are noticed only here and there at great dis- 
 tances, and often the}' are entirely wanting for a large extent. 
 
 It would as well be permitted to suppose that, by the fact 
 of maceration in mineral acids, the cells are completely de- 
 stroyed, and that the threads no longer exist. But it is by 
 no means so ; the threads are excellently preserved, a fact 
 which proves that they are composed of a material more re- 
 sistant than the substance of which the animal cells are 
 formed. 
 
 We profit by this circumstance to call attention to the fact 
 that in artificial teeth caries extends equally and by prefer- 
 ence along the dentinal canaliculi. 
 
 In the human teeth of substitution which we have had 
 the opportunity of examining, the caries did not commence 
 on the natural surface, but rather on one which had been cut 
 away; thus the formation of a cone became impossible, inas- 
 much as this can be produced only by the convergence of the 
 dentinal canaliculi which proceed from the surface into the 
 central portion of the tooth. In spite of this we could per- 
 ceive clearly that, at the points where the dentinal canaliculi 
 were perpendicular to the surface, the changes had penetrated 
 much more deeply than there where the canaliculi presented 
 a direction parallel to the surfa^ce. 
 
 If, in accordance with what has just been said, the changes 
 mentioned do not owe their origin to a vital action, it be- 
 hooves us now to inquire into their true nature. 
 
 One might think, a j^riori, that they had been occasioned 
 by the action of acids. Nevertheless, this cannot be proved 
 experimentally, and as ^(r. Tomes has well said, we do not 
 succeed in any manner in imitating artificially the caries of 
 the teeth. The experiments of M. Magitot, in which he has 
 succeeded in producing profound changes in teeth submitted 
 
MICROSCOPIC CHANGES. 49 
 
 for a very long time to tlie action of diluted acids, are not at 
 all conclusive, inasniucli as tliey are not supported by any 
 microscopic examination. In fact, examination under the 
 microscope is indispensable, because by this alone can we 
 verify tlie changes characteristic of caries. In the second 
 place, it is possible that the elements of leptothrix, which 
 take an essential [)art in the final destruction of carious den- 
 tine, occasion as well the changes of the canaliculi which 
 precede this destruction. This opinion alone is capable of 
 explaining the changes undergone by artificial teeth, and is 
 completely confirmed by the facts ; for the contents of the 
 dilated canals |)resents the same violet reaction as the lep- 
 tothrix. In preparations in which are found together elements 
 of leptothrix and thickened canals, we obtain in a like manner 
 the violet coloration, which gives us beautiful images of the 
 contents of the dilated canals. 
 
 It is useless to remark that we have satisfied ourselves 
 that with the normal dentine such a reaction never takes 
 place. Iodine and the acids color it nothing but yellow. 
 The reaction is independent of the coloration of the contents 
 of the dentinal canaliculi by the carmine. In transverse sec- 
 tions of the canals the rounded and brilliant disks, which are 
 rebellious to the coloration by carmine, give the reaction, as 
 w^ell as the dilated canals which contain a finely granular 
 matter susceptible of taking a vivid color from carmine. 
 
 We easily distinguish, in the first, the contents from the 
 walls, and these contents have also taken a finely granular 
 appearance. 
 
 The difiference of coloration by the carmine does not then 
 establish any essential difi'erence between the minute canals. 
 It, perhaps, has for its cause, in part at least, a dittering state 
 of development in the spores of the lepiothri.r. Wo. have at 
 least noticed that the masses of kptothri:r taken from the sur- 
 face of the tongue, and older, to judge from the strong adhe- 
 sion of their elements, are less strongly colored b}' carmine 
 than the more recent masses whose elements are more easily 
 isolated. Iodine alone colors the canals yellow. There are, 
 nevertheless, cases where the violet reaction has taken place 
 
50 INQUIRIES INTO DENTAL CARIES, 
 
 by the simple addition of iodine. The fungi situated at the 
 surface are generally colored more strongly. The concen- 
 trated acids, in which teeth are placed for the purpose of de- 
 calcification, appear to render the reaction impossible. This 
 is the reason, without doubt, that M. Neumann obtained no 
 violet reaction upon prepared portions of decalcified teeth. 
 
 There is, then, no manner of doubt that the elementary 
 parts of the fungus penetrate into the interior of the canals, 
 and there develop in a manner to acquire a relatively con- 
 siderable diameter. It also results, from the very fact of the 
 dilatation of the canals, that tlie appearance of the fungus is 
 not accidental, and that it is not by a purely passive action 
 that it invades the canals. It is necessary that there be a 
 proliferation of spores infinitely minute and innumerabl<3 of 
 the fungus to effect the dilatation of the dentinal canals. It 
 is, moreover, very important that the elements of the lej)- 
 toihrix should have, at a certain stage, a mobility of their 
 own, in virtue of which they easily penetrate the interior of 
 the canals. As for the rest, we have met in the canals with 
 only the granular masses of the /eptothrix, and never the fila- 
 ments which appear to show themselves only at the surface.* 
 
 According to experiments actually made are also explained 
 the formation of eondnils and clefts filled, ivlth granular masses 
 ofleptothrix^ u'hich are found in the superficial layers of carious 
 dentine. 
 
 They spring from the dilatation, gradually increasing, of 
 
 * The fungi described by MM. Wedl and Hcide-r (see Wodl "upon a 
 fungus developed in tlie dentine ") (Comptes rendus de racadeniie de Vienne, 
 18f)4, t. 1, ]). 173-193) have, according to 'the descrij)tion of these authors, 
 nothing in coininon with the Icptothrix. These develop, after some days, in 
 the cement and dentine of sound teeth which have been extracted and placed 
 in water. The fungi from the cement penetrate the dentine, after ten days, 
 to a depth of from .2 to .2-5 of a millimetre. Portions of dentine which were 
 exposed to their invasions were, after three or four weeks, pierced like a 
 sieve. These experiments come to the aid of ours, inasmuch as they prove 
 that fungi can develop in the cement and dentine, even wlicn these tissues 
 still j)osse.«s all their calcareous salts. 
 
 The soft filaments whicli ^Ir. Tomes has found in the interior of the canals 
 are prohahly too tender to resist the invasion of the elements of leptothrix, 
 and ajipcar therefiH'e to be promptly destro3'cd. 
 
 ( 
 
MICROSCOPIC CHANGES. 51 
 
 certain niimito canals. Under the influence of this morbid 
 action, the walls and a part of the surrounding tissue com- 
 pletely disappear. It will, then, be wrong to conclude from 
 this the introduction of the fungus into pre-existing tissures. 
 AVe can, in fact, observe all the transitions between tlie den- 
 tinal canals greatly dilated and the conduits tilled with lep- 
 tothrix, and thus assist at the development of these conduits. 
 At the outset these latter always follow a direction parallel 
 to the dentinal canals; in consequence, at certain points, 
 more marked dilatations are found corresponding to the 
 varicosities of the dilated canals. Xeighboring conduits 
 may meet at these points and anastomose with each other. 
 Viv the incessant development oi leptothrix the softened den- 
 tine becomes decom[)Osed into irregular parcels, which, 
 towards the surface, become more and more minute and 
 tinally separate, completing the destruction of the tissue. 
 
 We, conceive that the dilatation of the dentinal canals, 
 found in the tissue situated immediately below the carious 
 surface, may be more or less pronounced and not always 
 reach the highest degree of development. If, in certain 
 canals, the extension of the leptothrix is more considerable, 
 the intermediate parts may be isolated and undergo decom- 
 position, even when the canals have undergone but a mode- 
 rate extension. The decomposition of the substance may, it 
 is true, likewise commence at the very beginning of the 
 carious surface, which is constantly covered with a prodigious 
 quantity of leptothrir. It frequently happens that, in the 
 layers of the surface, the leptothrix also intilfrates the whole 
 intertubular substance, which then presents a granular ap- 
 pearance, and the contours of the canals thus become very 
 confused. In these cases iodine and the acids produce upon 
 the whole tissue a violet reaction. 
 
 The thickening of the walls can, it is true, have for its 
 cause an action purely mechanical following upon the dis- 
 tension of the canals and the consequent thickening of the 
 environing substance. Yet, we must remark, that we have 
 observed similar walls where the canals have not been at all 
 dilated. In cases where the action of caries has just com- 
 
52 INQUIRIES INTO DENTAL CARIES. 
 
 menced, we have seen a portion of the canalieuli moderately 
 dilated and filled as usual with leptotlirix. Other canals, on 
 the contrary, had a normal calibre ; they may even have 
 been a little narrow, very pale, and surrounded with glisten- 
 ing walls ; whilst the walls of the dilated canals were dif- 
 ficult to distinguish. JSTevertheless, we are not quite sure 
 that the phenomenon is analogous to that which presides 
 over the dilatation of the canals. By the aid of maceration 
 in hydrochloric acid the canals are easily isolated; they pre- 
 sent their normal delicacy ; whilst there, where the canals 
 are dilated, the walls are isolated at the same time with 
 the canals ; in the former case the wall evidently oft'ers less 
 resistance to the action of the acid than in the latter. 
 
 According to Mr. Tomes the thickening of the walls in 
 caries is the result of the regeneration of the contours of the 
 organic cellules of the dentine. 
 
 M. ]Sreumann declares, on the other hand, that the dentinal 
 walls are thickened at the expense of the intercellular sub- 
 stance. These authors explain ditl'erently tile manner in 
 which dentine is formed by the aid of dentinal cells, and it 
 is very difiicult to say what is or is not the truth among such 
 difterent statements. The opinion of Mr. Tomes is based 
 upon the following supposition: According to him the den- 
 tinal cells are penetrated with calcareous salts, except an in- 
 terior portion which is left free, and which forms the dentinal 
 canalieuli with the fibrils which are found there. At the 
 same time there is seen to form a certain quantity of inter- 
 cellular suljstan*ce Avhich is impregnated, as well as the cells, 
 with calcareous salts, and becomes so fused together with 
 them that their proper contours disappear. 
 
 M. JSTeumann, on the contrary, considers all the intercellu- 
 lar substance as the product of a secretion: as for the cells 
 of the dentine they send out very delicate prolongations 
 which go to form the fibrils found in the canalieuli. How- 
 ever this may be the question still remains how the connec- 
 tion of the fused cells comes to be dissolved ; or, if the opinion 
 of M. Neumann is preferred, from whence springs the thick- 
 ening of the dentinal wnlls? AVe have already reiiiarked 
 
MICROSCOPIC CHANGES. 53 
 
 tliat acids give rise to no such alterations. To recapitulate, 
 it appears to us very prohable that the thickening of the 
 walls of the dilated canals is produced mechanically, on ac- 
 count of the pressure of the surrounding substance. Here, 
 nevertlieless, we are oljliged to acknowledge that in sonie 
 rare cases there are found walls thickened without the canals 
 being dilated, and we confess our ignorance of the cause. 
 Perhaps we may be permitted to suppose a chemical action 
 by the elements of the leptothrix upon the environing tissue. 
 
 We have already remarked that during the action of caries 
 there are often formed calcareous deposits in the interior 
 of the dentinal tubes, deposits which Mr. Tomes and M. 
 Magitot have regarded as of great importance. They are 
 seen ranged singly, or in groups, under the form of minute 
 threads, or bundles of them, more or less long ; or else under 
 the form of separate cylindrical granulations. On submitting 
 them to the action of acids they dissolve, and leave, most 
 frequently, an organic residue, which preserves the same 
 form. 
 
 At times the masses of leptothrix contained in the dilated 
 canals are also impregnated with calcareous salts ; but oftener 
 w^e meet these deposits in the undilated canals of the deep 
 layers of dentine changed by caries. We likewise iind from 
 time to time minute calcareous granulations in the inter- 
 globular spaces of the dentine. They are observed most fre- 
 quently in sections of carious teeth in which the changes are 
 not far advanced. In these cases they are always found in 
 a zone which surrounds this altered portion of the dentine 
 whose canaliculi are dilated, and show a very intense brown 
 color (see Plate I, Fig. 4, which represents a portion of the 
 dental section pictured in Fig. 3; we see here that the cal- 
 careous deposits do not begin to appear until at a certain 
 depth from the surface). If the change of the dentine has 
 but just begun we sometimes meet the calcareous deposits 
 throughout the greater part of the cone. We have already 
 demonstrated that the transparency of carious dentine cannot 
 be attributed to the presence of calcareous salts in tbe inte- 
 rior of the canals. These deposits should rather diuiinish 
 
5-i INQUIRIES INTO DENTAL CARIES. 
 
 tLe ti-anspareney ; and yet the zone which contains them is 
 more transparent than in the normal state. We can tliere- 
 fore attribute it only to the ai>straction of a portion of the 
 calcareous salts. These deposits of calcareous salts in the 
 interior of the dentinal canaliculi are considered by Mr. 
 Tomes, and after him by M. Macjitot, as the product of a 
 vital action. But inasmuch as these same calcareous salts 
 are likewise found in carious artificial teeth, we can also 
 adduce here all the objections already made against the vital 
 character of the other changes which we have described. 
 
 We are still more inclined to believe that these calcareous 
 deposits are formed by a purely chemical process; that is to 
 say, by the residue resulting from the solution ot the calca- 
 reous salts by contact with acids. 
 
 In the work of caries a portion of the calcareous salts of 
 the teeth is always dissolved out ; these same salts, so dis- 
 solved, must by diffusion penetrate the canals towards the 
 cavity of the pulp; there in contact with the neutral or alka- 
 line liquid which fills the interior of the canals, or which 
 penetrates the dentinal fibrils, a precipitate is formed. If we 
 drop upon the section of a sound tooth, placed under the 
 microscope, a little concentrated acid, then, shortly after, 
 some drops of water, we see a great number of needle-shaped 
 crystals immediately form, which arrange themselves in the 
 form of rosettes. 
 
 These crystals must be composed of phosphate of lime. In 
 glasses, in which we have for some time preserved carious 
 teetli in water slight]}' acidulated, we have seen an abundance 
 of these same crystals precipitate themselves upon still farther 
 weakening the solution by the addition of water. The cal- 
 careous salts which have been dissolved by the acids are pre- 
 cipitated by the simple addition of a neutral liquid, and still 
 more by the mixture of a liquid slightly alkaline. From 
 this it is easy to understand why the calcareous deposits are 
 always found at the extremity of that part of the dentine 
 which is altered by cai'ies ; and it is not necessary to admit 
 that they are formed in the pulp-cavity. 
 
 Mr. Tomes compares the calcareous deposits which form 
 
MICROSCOPIC CHANGES. 5o 
 
 at the extreniit}- of the diseased dentine to tlie work of 
 exfoliation in the parts bordering upon a portion of necrosed 
 bone or gangrened tissue. In the two cases the reaction 
 takes place in the surrounding sound parts, with this ditl'er- 
 ence, nevertheless, that in dental caries there is no elimina- 
 tion of the diseased tissues 
 
 M. Magitot, on the contrary, believes that the calcareous 
 deposits spring from the pulp; tliis being irritated gives out 
 a calcareous exudation which at first tills the canals, from 
 without inwards, and which, in tine, according to circum- 
 stances, is deposited as dentine of new formation upon the 
 interior surface of the pulp-cavity. It is, nevertheless, abso- 
 lutely proved that the calcareous deposits in the interior of 
 the canals cannot be identified with the new laj-ers of dentine 
 which are formed at the surface of the pnlp-cavity. These 
 formations, in fact, as well as the normal dentine, take their 
 origin from the dentinal cells of the pulji. If the calcareous 
 deposits arise from the pulp, why are they at first so for from 
 it? and why are tliey not always found in its immediate 
 vicinity? As for the rest, all explanations of this class are 
 formally refuted by the formation of calcareous salts in the 
 caries of artificial teeth, and it is therefore useless to seek 
 for other explanations. Calcareous deposits are more abun- 
 dant in proportion as the progress of the caries is slower, and 
 they develop themselves in an especial manner when the 
 caries remains at rest during a certain time. 
 
 The protection which these calcareous deposits seem to 
 furnish to the dentine can, consequently, be of no great ac- 
 count. As soon as the caries makes new^ progress, they are 
 dissolved, and probably with more facility than the normal 
 calcareous salts of the dentine. From tlie fact that these 
 deposits manifest themselves more particularly when the 
 march of the caries is slow, it has been concluded that they 
 oppose the morbid action ; wdiile according to our views the 
 slow march of the caries has, on the contrary, for its efi'ect, 
 the formation of the calcareous deposits. 
 
 It remains now^ to examine if the phenomena whirh ice have 
 just described ., and which relate to the action of acids and of the 
 
56 INQUIRIES INTO DENTAL CARIES. 
 
 Icpiothrix^ are the only ones v:hicJi. are to he observed in caries of 
 the dentine^ and if, hereafter, ice are authorized to deny all inter- 
 vention of vital action. Although we have demonstrated that 
 all the changes described heretofore do not have for their 
 base an}" vital action whatsoever, we are not permitted, « 
 priori, to reject it as impossible. 
 
 We can have no doubt of a certain vital action in an or- 
 ganic tissue like the dentine, even when it has reached its 
 complete development, even if these vital properties are l)ut 
 little marked. We can very well conceive that the delicate 
 fibrils which, according to Mr, Tomes's discovery, till the 
 interior of the canals, and preside, in all probability, over the 
 phenomena of nutrition in the dentine, may become changed 
 by an abnormal excitation and tliicken like cellular elements 
 irritated or inflamed, and produce by division new elements, 
 as M. ISTeumann has established. It is evident that we must 
 admit chano;es of this nature at the outset of the diseased 
 action, and before the elements of the leptothrix have pene- 
 trated into the dentinal canals and destroj^ed the fibrils 
 which they find there. 
 
 We have already established that the first changes 'mani- 
 fest themselves in the dentine, when the enamel is carious 
 throughout its thickness, though there ma}" not be even the 
 slightest loss of substance at the surface of the tooth. As 
 the hptothrix is obliged to traverse the enamel to reach the 
 dentine, and as, in our researches, we have found no element 
 of leptoi/irix in carious enamel, as long as the caries has not 
 attacked the surface of the dentine, we should expect to ob- 
 serve, at this first degree of the malady, isolated changes of 
 the dentine completely foreign to the action of the leptothrix. 
 To the naked eye, the dentine ofi'ers, at this period of the 
 malady, the same In-ownish appearance as later ; we remark 
 also that its consistency is not sensibly diminished, excei)t at 
 the surface, in the vicinity of the enamel, and then only in a 
 very thin layer; its hardness increasing ra[)idly as we go 
 towards the deeper portions. In most cases we have found, 
 at this stage of caries, no alteration of the canals; their dila- • 
 tation is normal, and they are but rarely to be distinguished 
 
MICROSCOPIC CHANGES. 57 
 
 from the intertubular substance l)y less marked contours. 
 Inconsequence, this dentine gives no reaction which indicates 
 the presence of (cptot/tri.c. Yet, exceptionally, we have found 
 in the superficial layers changes resembling those which we 
 have heretofore described, but they have been very much 
 less developed. Sometimes' the canals were little dilated, 
 and their walls were thickened at certain points. In the 
 small number of cases, where we have had the opportunity 
 of verifying this result, we have not been able to obtain any 
 reaction capable of indicating the presence of the fungus ; 
 nevertheless this does not prove the absence of the leptothix, 
 inasmuch as at that time we hapj)ened to use too strong acids, 
 and so failed of the reaction, even when the presence of the 
 fungus was certain. As the changes existed only in an ex- 
 ceedingly thin layer under the surface of the dentine, the 
 substance capable of giving the reaction was present in but 
 a very minute quantity. We think, nevertheless, from the 
 identity of the phenomena which were present in this case 
 with those which determine the introduction of the leptothnx 
 into the canals, that they depend upon the same cause. It 
 is true that we have not succeeded in proving the presence 
 of the leptothrix in the substance of the enamel, but its sur- 
 face was usually covered with a granular mass of leptothrix. 
 Yet it is possible that, on account of the extreme minuteness 
 of tlie elements of the fungus, w^e have not been able to see 
 in the enamel the very delicate chinks through which the 
 fungus would have to travel to reach the dentine, and there 
 develop in a more favorable soil. This point, nevertheless, 
 will agree with still other observations. 
 
 In all cases it results from this that the introduction of 
 the fungus into the dentine does not take place during the 
 first evolution of the caries ; at this epoch of the malady, we 
 remark only the loss of calcareous salts, and the decomposi- 
 tion of organic substances, then diminution of consistency, 
 transparent appearance, and brownish color. 
 
 At this stage the histologic examination permits us to 
 view, in the structure of the dentine, no marked change. 
 ^Ve cannot say that there are already calcareous deposits in 
 
58 INQUIRIES INTO DENTAL CARIES. 
 
 the canals, inasmuch as we have not given sufficient attention 
 to that point ; nevertheless these deposits may be early 
 formed, even at a time when no marked, change of the tooth 
 is yet perceptible. 
 
 From what has just been said we conclude that there exists, 
 up to the present time, no observation which authorizes us 
 in admitting in caries of the teeth an active reaction on the 
 part of the dentine — an inflammation, for example. AYe as- 
 sert that this caries comes not from such causes, although it 
 is impossible to deny with certainty that there exist slight 
 histologic changes of the dentine, observed at the beginning 
 of the malady, which are not clue to the action oileptothrix. 
 AVe ought to add here that the leptothrix acts in like manner 
 in the destruction of the cement by caries, when it has its seat 
 at the neck of the tooth. 
 
 We have seen, in cases of this kind, the granular masses 
 of the fungus buried in the chinks and excavations of the 
 cement, just as we see them at the surface of the dentine. 
 We have not been able to prove a particular change in the 
 bony corpuscles ; and, further, there is wanting every indi- 
 cation which can cause a suspicion of an inflammatory state 
 of these elements. As the number of cases in which we have 
 had. an opportunity of examining caries of the cement is but 
 small, we cannot draw from them general conclusions as to 
 the absence of inflammatory changes. Such changes would 
 not, however, be surprising, inasmuch as the causes of irrita- 
 tion of the periosteum of the root of the tooth, as well as the 
 production of cementous substance of new formation, can* be 
 considered as ordinary consequences of dental caries. 
 
IIT. 
 
 CONSIDERATIONS UPON THE PROGRESS AND 
 SY3IPT031S OF CARIES OF THE TEETH 
 
 Haying described the anatonio-pathologic changes which 
 take phice in caries of the enamel, and of the dentine, we 
 will now proceed to define in a few words the variations of 
 the progress, symptoms, &c., of this atlection, and to show 
 that these variations are perfectly explained by the results 
 of our researches. 
 
 First, the different varieties of the beginning of caries have 
 received a considerable number of denominations, but we are 
 obliged to confess that we have not found essential ditierences, 
 and we think they can all be explained by a greater or less 
 duration, by the variable resistance of the dental tissue, and 
 by the lesions, more or less extensive, which exist from the 
 first in the enamel. We have already remarked that there 
 can be distinguished a form of caries which is propagated more 
 towards the surface^ and another whose character is to burrow 
 into the deeper portions ; these two forms do not ofter any 
 other essential difi'erence. The caries called dry is, properly 
 speaking, only tlie first degree of the work of the malady, 
 when the dentine is as yet but incompletely decalcified, 
 when no element of leptot/irix has yet penetrated there, and 
 no change has manifested itself at its surfiice. Then the 
 enamel as well as the dentine is transformed by mechanical 
 action into a rather fine, hard, pulverulent mass : while in 
 the so-called fibrillary caries, the substance of the dentine, 
 much softer, and as it were cartilaginous, appears to be com- 
 j.)Osed of very fine filaments. This filamentous texture de- 
 pends upon the great dilatation of the dentinal canals. 
 
 The tooth will remain in the state of dry caries the longer 
 
60 INQUIRIES INTO DENTAL CARIES. 
 
 ill proportion as it shall ofi'er by its density greater resistance 
 to the invasion of the malady, so that the fibrillary or humid 
 caries may perhaps at times never become established there. 
 The carious substance is at such times marked by a very 
 dark color. 
 
 When the caries, on the other hand, makes rapid progress 
 in a tooth of little resistance, it may happen that the destruc- 
 tion follows promptly the preparatory changes. In this case 
 the dry caries may pass wholly unperceived, or be observed 
 but a short time ; the brown discoloration will also be but 
 slio-ht. The enamel and the dentine are in such cases chano-ed 
 into a soft, whitish, pulpy mass, and the tooth promptly 
 reaches its total destruction. 
 
 There is distinguished a form of caries which attacks the 
 necks of the teeth. It attacks almost always, and at the 
 same time, all the teeth in front, and more particularly those 
 of the lower jaw. It forms at the necks of the teeth a smooth, 
 gutter-like furrow. This is often so marked and so polished 
 that one might say it had been made wdth a file. Generally 
 it is only the incisors and canines which are attacked ; yet, 
 sometimes, this caries extends to all the teeth of a jaw, but 
 the incisors and canines are always more strongly attacked 
 than the molars. 
 
 Very often the gutters which exist across the necks of the 
 teeth are of a normal white color, and wholly smooth, as if 
 they had been polished. In other cases the surface of the 
 gutters is smooth, it is true, but has the brownish coloring 
 of caries. We have had opportunities of examining anatomi- 
 cally two teeth of this kind. Upon a section made longitu- 
 dinally we have observed that, proceeding from the gutter, 
 there was only a feeble trace of a brownish cone looking 
 towards the pulp- cavity, for this reason, the changes which 
 precede the caries of the dentine extended to but a slight 
 depth, and were not marked. The density of the dentine 
 was but little less than normal; there was, just below the 
 surface, a slightly marked brownish shade. Under the 
 microscope we observed in this superficial layer, as usual, 
 the dentinal canals filled with leptotlwix. The surface was 
 
PROGRESS AND SYMPTOMS OF CARIES. 61 
 
 smooth, and it was impossible to find there a layer evidently 
 softened. The enamel had been wanting for a lono- time in 
 the greater part of the gutter; but, on the side of one tooth, 
 we observed that the gutter, in becoming of less and less 
 depth, extended for a short space across a bit of carious 
 enamel of a brownish color. Upon the otlier tooth the gutter 
 stopped suddenly with well-defined outlines on every side. 
 In a vertical section it presented the form of a triangle 
 with its base turned outwards, and its vertex towards the 
 cavity of the pulp. On the lower side of this triangle there 
 appeared a brownish cone directed towards the pulp-cavity. 
 Upon the interior surface of the pulp-cavity, at the place 
 corresponding to the gutter without, there was found at the 
 extremity of the brownish cone a projection formed of den- 
 tinal substance, of new formation, which had penetrated the 
 pulp-cavity to a considerable depth. 
 
 In this observation it was evident that the caries was of a 
 very slow progress, but had, notwithstanding, all the essen- 
 tial characters of this affection. The surface changes took 
 place slowly, and the affected portions were with proportion- 
 ate slowness involved, while the surface was kept constantly 
 smooth by friction with the brush. The polish of the surface 
 is sometimes so great that it might be supposed to be effected 
 by friction against a tooth ; yet this is impossible for the 
 neck, in consequence of the position of the teeth. To explain, 
 therefore, the polish of the surface, we can invoke only the 
 action of the brush, and the friction of the lips and of the 
 tongue. It remains, nevertheless, to inquire if these gutters, 
 wnth so highly polished surfaces, must be considered as sta- 
 tionary, as most authors think. There are cases where the 
 teeth always preserve a white and polished surface, and in 
 which, nevertheless, the affection makes incessant progress, 
 but in a manner so slow that 3'ears often roll by before only 
 a thin wall separates the caries from the pulp-cavity. The 
 affection, arrived at this stage, ends by exposing the dental 
 pulp, and the tooth is often broken at this point. Doubtless 
 the progress of the caries can be retarded l)y dentine of new 
 formatiou deposited upon the interior surface of the dental 
 
62 INQUIRIES INTO DENTAL CARIES. 
 
 canal, otherwise we should see, particularly in the incisors, 
 this thin wall of dentine much sooner destroyed, and the 
 canal opened. If we consider isolated facts of this kind, we 
 feel little disposed to take these phenomena for symptoms of 
 veritable caries ; but by analogy with other facts, where the 
 nature of the caries is shown, we are compelled to admit 
 equally for these exceptional cases that we have to do with 
 a caries whose progress is very slow, which, for a time, may 
 be really stationar}^, and afterwards take on new life under 
 the influence of a favorable cause. 
 
 Nevertheless, it should not be asserted that all cases of 
 caries of the neck have this slow evolution. There are cases 
 where its march is absolutely the same as in ordinary caries. 
 It would appear that the cause of this caries is the denuda- 
 tion of the neck by the absence of the gum. Upon the 
 slightly rough surface of the cement fermenting mucus and 
 fragments of food are more easily deposited, and these same 
 agents fixed between the gums and the neck of the tooth are 
 less easily removed. It may then happen in cases where the 
 injurious causes are weak, or the teeth of a special hardness, 
 that it is just the necks of the teeth which are more likely 
 to be affected. 
 
 In some very rare cases we notice a peculiar wasting of 
 the incisor and canine teeth, attacking as well the enamel 
 as the dentine, and which shows its greatest intensity upon 
 the centrals. There, when the mouth is closed, the cutting 
 edges of the teeth form arcs of opposite concavity, and show 
 a longitudinal interval between them. For want of sufficient 
 observations it is not possible for us to say if these morbid 
 phenomena belong or not to caries. The form of the wasting 
 docs not permit us to attribute it to mechanical action. 
 
 Stationary Caries. 
 
 In what is called stationary caries reference is often had 
 to dry caries only whose progress is very slow, or is distin- 
 guished l)y longer or shorter times of rest. There arc, never- 
 theless, cases where the disease is really stationary, but this 
 
STATIONARY CARIES. 63 
 
 can be only where the teeth possess great power of resistance, 
 and Avhen the caries has a very slow progress. It is, not- 
 withstanding, necessary to distinguish the ditterent stages of 
 caries in which it becomes stationary. 
 
 In the dry caries, when there does not yet exist any change 
 at the surface, it seems that the caries may easily become 
 stationary. This is readily understood, inasmuch as it is 
 enough to suppress the action of acids, the tooth having still 
 sufHcieut hardness, and being still free from all attack of 
 leptothrix. Yet it may sometimes happen, when the caries 
 has reached a stage where the greater part of the enamel and 
 a superficial layer of dentine are destroyed, that the malady 
 is stopped. This is seen in molar teeth whose depressions 
 are incompletely provided with enamel, and which show 
 defects upon their surfaces. In these cases we see ordinarily, 
 from the beginning of the malad}", a great part of the surface 
 of the enamel attacked by caries ; the dentine may be still 
 sound, and offer great resistance. While the enamel is so 
 rapidly destroyed, as far as the surface of the dentine, the 
 softening of this latter, and the loss of its calcareous salts, 
 are carried to but a slight depth. The relation between the 
 rapiditj' of the destruction of the enamel and that of the 
 dentine is then, in such cases, the inverse of that which 
 exists in the normal state. When the caries has attacked 
 the surface of the dentine, which, in consequence of the 
 defective structure of the enamel, takes place at once over 
 the greater part of it, the dentine is but slightly softened, 
 and to but a very little depth. The most superficial layers 
 of the dentine are removed, and by friction upon the smooth 
 surface the work of the caries is arrested, the surface becomes 
 more and more polished, and offers less opportunity for the 
 accumulations of mucus and particles of food undergoing 
 acid fermentation ; finally there results from all this a sta- 
 tionary condition. The tooth presents a polished surface, 
 but of a brownish color, as if to attest that the substance at 
 the surface has been the seat of caries. 
 
 The considerations presented by Mr. Tomes and M. Magitot 
 upon the cause which determines the stationary state of 
 
64 INQUIRIES INTO DENTAL CARIES. 
 
 caries are founded upon the presence of calcareous deposits 
 in the minute dentinal canals. As we explain the matter, 
 the calcareous salts deposited in the canals should have the 
 ability to arrest the work of the caries, and give the already 
 softened dentine a greater density. Yet, as the formation 
 of these calcareous deposits cannot be attributed to a vital 
 action, we are led to believe that they are secondary, and 
 that they become abundant only when, from some cause, the 
 action of the acids has ceased ; then the calcareous salts 
 which existed in a state of solution are precipitated. Neither 
 do we believe that the dentine can become harder in station- 
 ary caries, excepting, perhaps, the surface, where mechanical 
 means, such as friction or pressure, may produce a slight 
 condensation. To explain the facts it is sutficient to admit 
 that the dentine had not yet lost its normal hardness, or at 
 least had lost it in but a very slight degree. 
 
 In these cases of slow and stationary caries we also very 
 often find the formation of new. dentine at the inner surface 
 of the dental cavity. We can explain this phenomenon by 
 the fact of a long irritation which the pathological action of 
 the caries exercises upon the pulp. It contributes very much 
 in the given circumstances to the preservation of the tooth. 
 
 When the caries is farther advanced there are formed in 
 the dentine cavities, generally rounded, which communicate 
 with the surface of the tooth by a greater or less opening: 
 or the morbid action occasions loss of substance more exten- 
 sive, and without depth. Little b}' little the disorganization 
 reaches the cavity of the pulp; this is exposed at some point, 
 and very often, in consequence of its irritation, successive in- 
 flammations are excited Avhich end in its destruction. 
 
 It has been observed that when the pulp is destroyed the 
 caries proceeds much more rapidly, and from this fact the 
 proof has been sought to be drawn that, as long as the i)ulp 
 retains its vital properties, it contributes to the preservation 
 of the tooth; while the contrary happens immediately upon 
 its ceasing to exist. But the more rapid progress of the 
 caries after the destructif)n of the pulp is explained by the 
 fact of there then being a much greater surface exposed to 
 
STATIONARY CARIES. 65 
 
 its action, inasmuch as now the destruction works in every 
 direction, not only from the ancient cavity, but from the 
 pulp-cavity which corresponds to it. It is not necessary, 
 therefore, to attribute to the pulp a conservatory action for 
 the tooth, excepting, indeed, the dentine of new formation 
 which it builds up, and which really protects the tooth. 
 
 While the caries continues its ravages the walls of the 
 cavity, which are formed by the sides of the crown, break 
 down, so that the tooth is destroyed down to tlie level of the 
 roots. Starting from this point we observe, in most cases, 
 the caries take up anew a slower action, such that the roots 
 which remain may be preserved for a long time in their 
 alveoli. It may be that the friction which must l)e con- 
 tinually acting ma}^ be the cause of this, in part at least, 
 opposing itself to the progress of the disease by offering a 
 more polished surface. Another reason which seems to us 
 still more important is that which is derived from the direc- 
 tion of the dentinal canals. These proceed at the surface of 
 the teeth more or less vertically from the pulp towards the 
 exterior, so that, taking this part for its point of departure, 
 the caries is able to propagate itself easily to the interior, 
 following the direction of the canals. 
 
 At the commencement of the surface of the roots, on the 
 contrary, these little canals have a direction oblique, and 
 parallel to this surface. Then, when the tooth is decayed 
 away up to the root, the direction of the canals no longer 
 favors the introduction of the acids and the elements of lep- 
 tothrix into the deeper parts. This explains the slower prog- 
 ress of the caries when it reaches this point. In the same 
 way ma}' be explained the fact that caries is never seen to 
 be developed around the walls of a canal artificially pierced 
 at the neck of a tooth (Ilulihan's operation); the little den- 
 tinal canals, following a direction parallel to that of the walls 
 of the artificial canal, also in this case, do not permit the in- 
 troduction of injurious elements. 
 
 The sensibility of carious dentine may be occasioned by a 
 greater irritability of the pulp. Yet it is difHcult to explain 
 
66 INQUIRIES INTO DENTAL CARIES. 
 
 v:hy the superficial ]a3'ers of the dentine are very often more 
 sensitive than those which are deeper. 
 
 To Mr. Tomes this consideration appeared to have great 
 weight. We observe, in fact, that quite frequently the least 
 touch causes the acutest pain in the carious dentine, at a 
 stage when the cavity of the pulp is still far from being 
 reached. At such times the removal of the superficial lay- 
 ers of carious dentine occasions excessive pain ; but as soon 
 as this layer is removed the sensibility of the subsequent 
 layers is seen to be very much less. The greatest sensibility 
 ordinarily exists at the extremity betw^een the enamel and 
 the dentine AVe especially remark this in the incisors at 
 their acute angle, where the anterior and posterior surfaces 
 come together. ]\Ir. Tomes has concluded from these facts 
 that the dentine itself is endowed W'ith sensibility, and that 
 this is not due, at least exclusively, to contact with the 
 pulp. He believes that this sensibility is occasioned by the 
 soft fibrils which he has discovered in the interior of the 
 dentinal canaliculi; he does not consider them as true ner- 
 vous fibrils, but thinks they may be agents of sensibility. 
 This o[iinion cannot be reconciled with the actual state of 
 physiology. Either the fibrils of Mr. Tomes are truly en- 
 dowed with sensibility, and are therefore true nervous fibrils, 
 or thej' have no nervous nature, and cannot transmit sensi- 
 bility, inasmuch as this function belongs essentiallj' to the 
 nature of nerves. But every consideration is opposed to 
 considering tliem as nerve fibrils, and their origin above all. 
 They are prolongations of the cells of the dentine, a fact 
 which establishes their analogy with the ramifications of 
 osteoplasts, or the plasmatic cells of the cornea. Xerves 
 have not been found in the dentine, and, in the absence of 
 all anatomical proof, wc must not be too hasty to attribute 
 sensilnlity to it. Assuredly the facts we have mentioned 
 would be easily explained if the dentine had a sensibilit}- of 
 its own, because then certain diseased parts would acquire 
 more sensibility than others. This sensibility may be ex- 
 plained, perhaps, by a certain direction of the canaliculi, or 
 at least by a more considerable expansion at the surface, 
 
STATIONARY CARIES. 67 
 
 wliicli may be more accessible to mechanical actions, and 
 may transmit them to the pulp. Experiments, whose object 
 should be to inquire into the rapidity with which the slight- 
 est contacts are followed by pain, would perhaps give new 
 enlightenment upon the subject. But until nerves are dis- 
 covered in the dentine, and clinical experiment has furnished 
 us with authentic facts, we shall feel more inclined to at- 
 tribute the sensibility to the irritated pulp than to the den- 
 tine itself. 
 
IV. 
 
 CAUSES OF CARIES. 
 
 From what has been said it results that two principal pihe- 
 nomena manifest themselves in the formation of dental caries, 
 viz., the action of acids ^ and the rapid developmeyit of a jxtrasitic 
 plants the leptothrix huccalis. In the following chapter we 
 shall have to examine more in detail the mode in which these 
 agents proceed and the conditions of their appearing. 
 
 The action of injurious elements is favored by predisposing 
 circumstances which consist mainly in the structure and in 
 the incomplete development of the dental tissues. The in- 
 fluence exercised upon the formation of caries by constitu- 
 tional anomalies and by certain coexisting maladies may be 
 referred principally to two circumstances: first, we very 
 often remark troubles in the development of the teeth 
 during the existence of certain maladies, or when there exist 
 constitutional anomalies. The tissue of the teeth is, in such 
 cases, incompletely formed, and unsuited to resist the action 
 of injurious agents ; then local conditions of the buccal cavity 
 may favor the formation of acids, as well as of the para- 
 sitic plant, the leptothrix. Likewise many maladies of the 
 mouth and certain states of the stomach cause to arise in the 
 buccal cavity an abnormal work of fermentation which is 
 accompanied by a more abundant formation of acids, and 
 favors the production of the fungi. The progress of the 
 caries is equally favored when, in consequence of sickness or 
 from any other cause, the saliva is secreted in too small a 
 quantity, thus preventing the neutralizing or diluting of the 
 acids. 
 
CAUSES OF CARIES. 69 
 
 I. Pkedisposing Causes of Caries due to the Form and 
 Structure of the Teeth. 
 
 We have first to examine the incomplete development of 
 the dental tissues, above all of the enamel and the dentine, 
 which is a predisposing cause of the greatest importance. 
 
 In congenital anomalies of the enamel we may distinguish 
 anomalies quantitative and anomalies qualitative. 
 
 The quantitative anomalies are manifested under very 
 diverse forms. The surface of the enamel is irregular, pre- 
 sents inequalities and depressions more or less developed, and 
 which may he few in number, or scattered over the whole 
 surface of the crown. These teeth are sometimes designated 
 as " honeycombed " teeth, from their resemblance to that 
 article. In other cases we see the cutting edge of the incisors 
 notched or toothed, and sometimes of a conical shape, both 
 which forms are caused by deficiency of the enamel ; or the 
 teeth present parallel furrows crossing them horizontally. 
 
 The name of erosion is given to those lesions which show 
 themselves at once upon several teeth, and yet they are but 
 incomplete developments of the enamel which have of erosion 
 only the form. Finally, the enamel is sometimes completely 
 wanting upon a greater or less extent of the crown. 
 
 The anomalies just described must be only too favorable 
 to the establishment of caries, inasmuch as the agents of an 
 injurious nature deposited in the cavities and irregularities 
 • of the tooth can extend their action withont obstacle, and 
 much better than on a polished surface. The fissures of the 
 enamel occasioned by sudden changes of temperature may 
 exercise the same infiuence. Doubts have been raised upon 
 the possibility of seeing fissures of the enamel caused by 
 changes of temperature, but these fissures are sufliciently 
 frequent. In many cases the enamel of the greater number 
 of the teeth, and sometimes even of all, is seen covered with 
 chinks in every direction. They are most frequently caused 
 by sudden changes of temperature, but sometimes are due to 
 a traumatic action. We have convinced ourselves of the 
 
70 INQUIRIES INTO DENTAL CARIES. 
 
 direct influence of the first of these causes by plunging the 
 teeth alternately into hot liquids of a temperature about 
 equal to that of hot meats, and then into iced water. It 
 seems, nevertheless, that these fissures liave less influence 
 than the defects of the enamel upon the formation of caries, 
 supposing that it possesses a normal density and hardness. 
 "We find, in fact, teeth whose enamel shows fissures in every 
 direction, and which, after a long time, have not been at- 
 tacked by caries. But if the fissures appear in teeth whose 
 enamel is primitively less resistant, it is clear that they offer 
 greater opportunity to the action of injurious agents. 
 
 The qualitative anomalies which depend upon an incom- 
 plete development of the enamel often coincide with the 
 quantitative; they may, however, exist separatel3^ They 
 are distinguished, in general, by a less hardness and by an 
 opaque appearance of the enamel. Mr. Tomes distinguishes 
 two kinds : in one the enamel presents a brownish and dead 
 color, showing itself more particularly upon teeth which are 
 marked, as has been said above, with congenital fissures and 
 depressions, and the excavations are marked in general by a 
 somewhat darker color. The other kind presents itself under 
 the form of white spots of greater or less extent. 
 
 In the first kind were discovered by Mr. Tomes deposits 
 of minute calcareous granulations in the interior of the 
 enamel prisms, at the same time that the peripheric layers 
 of the prisms were impregnated with calcareous salts in a 
 homogeneous manner. We speak here of an insufiicient 
 quantity of calcareous salts in the central portions of the* 
 enamel prisms, a circumstance which is but an exaggeration 
 of the physiologic condition. In fact, according to Mr. 
 Tomes, the central portions of the prisms in the normal state 
 become impregnated more slowly with calcareous salts, and 
 are therefore more promptly deprived of them by weak acids 
 than are the layers of the periphery. In some cases ]\Ir. 
 Tomes observed minute excavations in the interior of the 
 prisms of this incompletely developed enamel. 
 
 In the congenital white patches of the enamel Mr, Tomes 
 found the fibrillary structure of this tissue more or less well 
 
CAUSES OF CARIES. 71 
 
 preserved, inasmuch as the prisms are less strongly united to 
 one another, while this structure is lost ordinai-ily hy the 
 fusion of the peripheric layers of the prisms of the enamel. 
 
 We have had very little opportunity of examining these 
 anomalies ; our experience being confined to two cases of 
 congenital patches upon the enamel. But these two teeth 
 presented in the middle of the patches a dark brown color, 
 like the sign of commencing caries ; yet the sharp contour 
 of the spots and the well-marked white color left nothing in 
 doubt. They were really congenital patches which were 
 commencing to be aifected by caries. 
 
 The consistency of the enamel had considerably diminished, 
 the lightest pressure suthcing to reduce to powder the de- 
 tached fragments. Very rarely a column was seen to separate 
 from the neighboring columns, and then only for a small ex- 
 tent; the contours of the prisms being very distinct, while 
 the oblique strife were so in only one of the two cases. 
 
 The prisms of the enamel were strongly enough united in 
 the two cases, and their cohesion was not diminished, as Mr. 
 Tomes has asserted. In view of the paucity of observations, 
 we will not venture to draw from these facts other conclu- 
 sions, still less as it is impossible to establish with certainty 
 what ought to be placed to the account of caries and what 
 to congenital alterations of structure. 
 
 As for the rest, the predispqsition to caries in these con- 
 genital anomalies of the enamel is sufficiently j^roved by the 
 lesser hardness of the parts. 
 
 It is remarked also that there is often a coincidence be- 
 tween these anomalies of structure of the enamel and an 
 incomplete development of the dentine, yet the anomalies of 
 structure show themselves less often in the dentine than in 
 the enamel. In most cases there exists in the dentine a 
 great number of interglobular spaces; according to the dis- 
 covery of M. Magitot, these are seen sometimes in several 
 laj-ers parallel to the surface of the dentine, and spaced in a 
 pretty uniform manner. This anomaly has for cause a defect 
 of development which, in its turn, hinders the calcareous 
 
72 INQUIRIES INTO DENTAL CARIES. 
 
 salts from penetrating certain parts of the tootli in sufficient 
 quantity. 
 
 We meet this anomaly more particularly in cases of those 
 more considerable defects of the enamel which go by the 
 name of erosion ; while there, where the enamel presents 
 cracks, holes, and furrows, such as we see in " honeycombed" 
 teeth, the dentine very often oifers a great resistance. 
 
 The causes of the trouble in the development of the tissues 
 of the tooth, as well of the enamel as of the dentine, are of 
 several kinds. Some local affections of the mouth and gen- 
 eral maladies of very different nature may cause perturbations 
 in the development of the teeth. Mr. Hutchinson has marked, 
 as a very frequent cause of this anomalj', constitutional 
 sj'philis. Xevertheless, it is well proved that many other 
 maladies occasion the same phenomena. Setting aside the 
 greater defects of development, the dental tissues present, in 
 their hardness and chemical composition, varieties which 
 render them more or less fitted to resist external influences- 
 This is easily seen by the difierence in the color of the teeth, 
 and by the appearance they present, and it is from these 
 different properties that classifications have been made. 
 
 Considering the lack of positive observations upon the 
 subject in question, we can give only our suppositions upon 
 the causes of the varieties of color and of appearance in 
 teeth. The relative quantity of organic substances, and of 
 substances inorganic, seems to be of especial importance. A 
 priori, the existence of these varieties of enamel as well as of 
 dentine could not be doubted, and analysis has confirmed the 
 supposition. JSTevertheless, the teeth offer us no physical 
 indication by which we are enabled to recognize with cer- 
 tainty one or other variety in their chemical composition. 
 The teeth of different individuals offer in general aspects 
 sufficiently various, but we may say that they diverge in 
 two different directions from that which we have taken as 
 a standard, viz., a white color combined with a moderate 
 transparency of the enamel. The teeth are either much 
 l>luer and more transparent than the average, or else yellow 
 and more opaque. There is among them every variety of 
 
CAUSES OF CARIES. 73 
 
 different t^'pe. The blue and transparent teetli have little 
 power of resistance, while those of a yellow and much less 
 agreeable tinge are distinguished by their very great resist- 
 ance to the attacks of caries. 
 
 It is generally believed that the less power of resistance a 
 tooth has to caries the more organic substance it should 
 possess in proportion to the inorganic; and, in the contrary 
 case, that the inorganic substances should predominate. A 
 friori^ this theory cannot be admitted. In the experiments 
 which we give farther on concerning the action of acids upon 
 the teeth, it has been demonstrated that the enamel is always 
 the seat of the first changes, while the dentine and the cement 
 are attacked only after some time. It is eas}" to conceive 
 that a slight diminution of the calcareous salts may become 
 very sensible in the enamel, because the quantity of organic 
 substance is too weak to preserve the form and consistence 
 of the tissue after the subtraction of a portion of the salts; 
 the dentine, on the contrary, preserves, even after the total 
 loss of the calcareous salts, its former shape, and presents a 
 consistency not unlike that of cartilage. Yet are we not 
 permitted to draw from this the conclusion that the richer 
 the dentine or the enamel are in organic matters, the more 
 capable are they of resisting the attacks of caries, inasmuch 
 as many other causes may act at the same time. In spite of 
 this it appears to us probable that the bluish and transparent 
 teeth are relatively less well provided with organic matters, 
 especially in the enamel, than the yellow teeth, which resist 
 better. 
 
 Are there still other anomalies of composition, especially 
 in what concerns the quantity of the ditferent salts which 
 influence the predisposition to caries? We as yet know^ 
 notliing positive thereupon. As for the enamel, the most 
 recent analyses of M. Iloppe have shown that the relative 
 quantities of phosphate and carbonate of lime are sufficiently 
 constant in animals belonging to the most varied species. 
 There are, on the average, three elementary molecules of 
 phosphate of lime for one of lime united with chlorine, fluo- 
 
 6 
 
74 INQUIRIES INTO DENTAL CARIES. 
 
 riue, or carbonic acid.* According to this, at least as regards 
 tbe enamel, it will be less probable that variations of the 
 proportions of the diiferent salts will ever be proved. 
 
 It appears that thei-e exist, also, in the physical hardness 
 of teeth diti'erences which may naturally have a great impor- 
 tance in the predisposition to caries. 
 
 II. Influence op Acids upon the Production of Caries 
 OF the Teeth. 
 
 ISTo one at this day can refuse to believe in the necessity of 
 the action of acids to occasion caries of the teeth. The salts 
 contained in the enamel and in the dentine cannot be dis- 
 solved in water; acids are indispensable to work their solu- 
 tion. But it is not at all necessary to employ strong acids 
 for the purpose of separating the carbonic, or even the phos- 
 phoric acid from the lime with which they are combined. 
 The calcareous salts of the tooth, as well the carbonate as the 
 phosphate of lime, are dissolved in some acid, even in water 
 which contains carbonic acid, as they are changed into acid 
 salts which water dissolves with sufficient ease. In fact it 
 is acknowledged that the surface of carious teeth very often 
 l^resents an acid reaction. This reaction is constant upon 
 the contents of carious cavities in which the disease is in 
 active progress. Mr. Spence Bate cites an observation from 
 which we might draw the conclusion that pure water can 
 dissolve the teeth. 
 
 A lady had two cases of artificial teeth ;t she wore one of 
 these until the teeth were carious, while the otlier was care- 
 fully kept in water. After a period of seven years, wishing 
 to change the worn out case for that which she had preserved 
 in water, she found this latter just as corroded as the one she 
 had worn in her mouth. Does not this case find its explana- 
 tion in the observations cited by MM. Wedl and lleider, ac- 
 
 * Rccherchcs sur la comiiositioii do remail des dents (Vircliow's Aivliiv, 
 xxiv, p. 13). 
 f Human teeth. 
 
PRODUCTION OF CARIES. 75 
 
 cording to Avhich, at the end of only ten days, fungi had at- 
 tacked the enamel and the dentine of teeth placed in pure 
 water? A few weeks sufficed to change the tissues to such 
 a point that they were pierced with holes like a sieve. If 
 the action of acids alone could occasion caries of the teeth, 
 it should be easy to demonstrate the phenomena out of the 
 mouth. It is not so. Acids cause, it is true, a i)ortion of 
 the alterations of caries, but its totality differs essentially 
 from the effects which they produce. Several authors have 
 studied the influence of acids, and of different other agents, 
 upon the tissues of the teeth. We will mention especially 
 experiments made in 1843, in I^orth America, by Mr. A. 
 AVestcott, with the assistance of ]Mr. Dahymple. These au- 
 thors obtained the following results: 
 
 1st. All the mineral, as well as the vegetable acids, act 
 promptly upon the teeth. Acetic and citric acids, for ex- 
 ample, in forty-eight hours, corroded the enamel to such a 
 degree as to permit a great portion of it to be scratched 
 awa}^ with the nail; malic acid also produced very rapid 
 effects. 
 
 2d. The salts whose acids have a greater afhnity for lime 
 than for their own bases also acted upon the teeth. The 
 acid tartrate of lime very rapidly destroyed the enamel ; 
 grapes, at the end of forty-eight hours, had alreadj' acted so 
 strongly that the surface of the enamel presented the appear- 
 ance of chalk. 
 
 3d. Vegetable substances have no action until they fer- 
 ment, and acetic acid is formed. Sugar, for example, which 
 by itself had no action, produced its effects only in a state of 
 acid fermentation. 
 
 4th. Animal substances acted very slowly, and onlj- when 
 they had reached a very advanced stage of putrefaction 
 
 Mr. Allj^ort obtained identical results* in his researches 
 into the action of different acids upon the teeth, making use 
 of very dilute acids, such as are used in medicine. All the 
 mineral acids, as well as citric and acetic acids, in a few hours 
 produced very marked action upon the enamel. 
 
 * Vide American Journal of Dental Science, April 30th, 1858. 
 
76 INQUIRIES INTO DENTAL CARIES. 
 
 M. ]\rantegazza engaged in the same investigations, and 
 obtained identical results.* Sugar acted upon the teeth 
 on!}' when, by efiect of fermentation, it was partially changed 
 into acetic or lactic acid. Lactic acid, vinegar, strong or 
 diluted, and lemon-juice, acted on the teeth. 
 
 We had begun our investigations upon caries of the teeth 
 when the book of M. Magitot appeared. f The results of his 
 experiments which are there given should prove not only 
 that acids and the acid salts act upon the teeth, but also 
 that these are the sole agents of caries, and that the phe- 
 nomena produced upon the teeth by their action are entirely 
 identical with those of caries of the teeth. 
 
 The substances employed by M. Magitot in his experi- 
 ments were, at first, solutions of a great number of acids, of 
 some acid salts, and, moreover, solutions of sugar, albumen, 
 table-salt, and alum. He submitted teeth to the action of 
 these agents for two year;?, At the end of this time, the 
 solutions which contained the teeth, in many cases, were 
 covered with thick coatings of mould ; the acid solutions 
 had sometimes become neutral, and the teeth were more or 
 less attacked, softened, and destroyed. In a great number 
 of cases the enamel presented a white, earthy appearance. 
 It was chalky and profound!}' changed. The dentine was 
 brown or yellow, deprived of its salts, and softened, thus 
 having the aspect of carious dentine. 
 
 Moreover, remarkable differences were observed in the 
 action of agents upon the difi'erent tissues of the teeth. M. 
 Magitot distinguishes, from the results of his experiments, 
 four categories of substances in relation to their action upon 
 teeth. 
 
 These are, according to him, 
 
 1st. Substances which attack (dike aU. the tissues of teeth. In 
 this categor}^ belong the varieties of sugar (but only in a 
 state of fermentation), lactic acid, butyric acid, citric acid, 
 
 * Miintegftzzii sur ruction dii .^iicrc d do certains acids siir los dents. 
 Milan, 18G2. Trans, in Hrit. Jdiir. of Dent. Sc, 18()4, vol. viii, No. O'i. 
 
 f Etudes ct experiences sur la salive consideroo comme agent de la carie 
 dcntaire. Paris, 1800. 
 
PRODUCTION OF CARIES. 77 
 
 malic acid, carbonic acid, tlie products of the decomposition 
 of albumen and albuminoid substances. 
 
 2d. tSub^^t'Oices tcluch hove the particular and exclusive prop- 
 erty of destroying the enamel: Alum, oxalic acid and its acid 
 salts. 
 
 od. Substances which act exclusively upon, the dentine and 
 upon the cement: Acetic acid, tartaric acid and their acid 
 salts, and tannin. 
 
 4th. Substances ivhich have no action upon the dental ti.::ssues^ 
 as common salt and the great majority of other neutral sub- 
 stances which are found in the mouth. 
 
 These results do not entirely agree with those of MM. 
 Westcott, Allport, and Mantegazza. In order to verify the 
 experiments of M. Magitot, we submitted a series of teeth 
 to the action of the principal substances used by this author, 
 but we have not been able to convince ourselves that the 
 action of acids alone can produce changes identical with 
 those of caries. 
 
 In repeating the experiments of M. Magitot, we have ab- 
 stained from using the same time. If caries depends upon 
 simple chemical action upon the teeth, it is not necessary to 
 wait years in order to see the eifect. When there is a suf- 
 ficient quantity of the acid solution, we are able to perceive, 
 at the expiration of but few days, a very considerable alter- 
 ation in the dental tissues, even with the feeble solutions 
 which M. Magitot has used in his experiments. If we leave 
 for years in the liquids the teeth upon which we are experi- 
 menting, without assuring ourselves of the quantity of acids 
 which they contain, and without restoring to them the por- 
 tion of these same acids which they lose by their neutraliza- 
 tion in combining with the calcareous salts, it will not he- 
 possible to attribute the results obtained to the sole influence 
 of the acids; but it will be necessary also to take account of 
 the decomposition taking plac^e in the organic substance of 
 the tooth, of the putridity of the fermentation, and of the 
 action of the vegetable and animal microscopic growths 
 which are there developed. 
 
 The acid reaction of the liquids in which the teeth had 
 
78 INQUIRIES INTO DENTAL CARIES. 
 
 been placed had given place to a neutral one in several of 
 the experiments made by M. Magitot. This proves that in 
 the last portion of time and perhaps for a considerable period 
 the acids had taken no part in the destruction produced. 
 
 If the work of caries is, in general, much slower in the 
 month, this may depend on the habitual want of a sufficient 
 quantity of acids. Perhaps these exert their action only in- 
 termittentl}^, and each time during a rather short period. 
 Our own researches upon the penetration of leptothrix into 
 the interior of dental substances, and the observations of 
 M^^. "Wedl and Heider upon the introduction of fungi into 
 teeth which have been extracted, demonstrate, according to 
 the evidence, the part which may be due to these agents in 
 M. Magitot's experiments. 
 
 Nevertheless, as no investigations upon these corroded 
 teeth have been made with the microscope, we have noth- 
 ing but presumptions. The resemblance to caries which 
 has been found in these experiments relates therefore only 
 to the diminution of the consistency of the enamel, which 
 became tender and friable as in caries, with a brown or yel- 
 low color, and to a more or less advanced softening of the 
 dentine. This softening sometimes reached a very high 
 degree. 
 
 But these external resemblances do not prove that this 
 was veritable caries, and, even if, by microscopical research, 
 symptoms had been found identical with those of caries, it 
 would not then be demonstrated that they are due exclu- 
 sively to the action of acids. 
 
 It follows that the results of our experiments are not com- 
 pletely accordant with those of M. Magitot, while they con- 
 firm precisely those obtained by MM. Westcott, Allport, and 
 Mantegazza. 
 
 We have found that all substances capable of changing 
 the dental tissues produce, at first, a deterioration of the 
 enamel, which is soon followed by that of the dentine. The 
 enamel, which, in its normal state, is transparent, becomes 
 white and oi)aque, milky, and, in a more advanced state, 
 chalky. At the begiimiiig, and, above all, when the enamel 
 
PRODUCTION OF CARIES. 79 
 
 is very hard, there is sometimes seen only a whitish color 
 and the disappearance of the transparency. The surface 
 may, in such cases, remain polished and shining ; later, it 
 becomes rougVi and uneven, and the enamel thus acquires an 
 earthen, chalky appearance. The softening increases little 
 by little, and gains in depth ; so that in a short time we can 
 scratch away the enamel with the nail, or break it off in 
 bits. In using certain acids, which form salts difhcult of 
 solution, we see the enamel and also the root covered with 
 innumerable and very beautiful crj-stals. 
 
 "When the enamel presents the iirst degree of alteration, 
 the appearance of the dentine and also that of the cement is 
 normal, and its hardness has not as yet undergone any 
 change ; we recognize the alteration which follows by a 
 more transjiarent look to the roots, which, at iirst, caii be 
 cut with a knife at the surfoce ; soon after we can cut them 
 more deeply ; at a more advanced period we can even bend 
 them. It is true that sound dentine can also be slightly cut 
 with a knife, but, in doubtful cases, it has alwaj'S been our 
 habit to compare the dentine submitted to the action of 
 acids with normal dentine. 
 
 In proof of our statements we give here a few extracts 
 from our experiments. 
 
 Isl. Tartaric Add. 
 (a.) Solution -Jy in 100. 
 
 At the end of two days the enamel was seen to be covered 
 with minute crystals; these removed, the enamel had lost 
 its brilliancy and taken a white, earthy aspect. Xo change 
 remarked at the root. 
 
 At the end of eight days the alteration of the enamel was 
 increased : with a knife slices could be taken from the 
 surface. 
 
 At the end of a fortnight the alteration of the enamel had 
 made new progress, while the root was only slightly softened 
 at the surface. 
 
80 INQUIRIES INTO DENTAL CARIES. 
 
 {Ij ) Grapes. 
 
 Some teeth were placed among crushed grapes whose juice 
 was rather acid. 
 
 Aftei' forty-four hours the surface of the enamel was very 
 rough and covered with numerous crystals. Upon hrushing 
 these away, the enamel appeared uneven and slightly clialky ; 
 its brilliancy was gone. The root was likewise slightly cov- 
 ered with Uiinute crystals; it had not yet undergone notice- 
 able change. 
 
 At the end of eleven days the experiment was ended. The 
 divided enamel presented, throughout its whole thickness, 
 an earthy, white appearance, and was porous ; the root was 
 scarcely changed. 
 
 M. Acetic Acid. 
 
 Solution jL in 100. 
 
 At the end of ten days the enamel was found to have on its 
 anterior surface an earthy, white appearance ; it could be 
 removed with the finger-nail; while, on the posterior sur- 
 face, it remained almost in its normal state. The surface of 
 the root could be cut with a knife. 
 
 At the end of seventeen days the enamel could everywhere 
 be broken off in great pieces; the subjacent dentine was also 
 decalcified. With a knife the root could be easily cut. 
 
 Sd. Oxalic Acid. 
 Solution J^ in 100. 
 
 After seven days the bottom of the glass was covered with 
 a thick laj'er of white powder composed of minute crystals 
 of oxalate of lime. The enamel, of an earthy white, could 
 be removed with the finger-nail ; a part of the crown had 
 preserved its polish. The root did not seem altered. 
 
 At the end of fourteen days the enamel was everywhere of 
 an 'earthy white, and could l^e easily removed with the nail. 
 The root could be cut with a knife, especially at the ends, 
 with greater ease than in its normal state. 
 
PRODUCTION OP CARIES. 81 
 
 /fth. Allan. 
 
 Solution 1 in 100. 
 
 At the end of two daysi no trace of change. 
 
 After six days the polish at the lower part of tlie enamel 
 was seen to be diminished, and the enamel was covered at 
 the same part witli a light earthy layer which was easily 
 removed. The root appeared to remain intact. 
 
 At the end of twenty days the enamel could he easily re- 
 moved with the nail ; no other changes. The root could be 
 cut more readily than in the normal state. 
 
 5th. Lactic Acid. 
 (rt.) Solution J^ in 100. 
 
 At the end. of ten days it was impossible to perceive any 
 alteration in one of the teeth, a very strong molar; in another 
 tooth the enamel was everywhere whitened, part roughened, 
 part still polished ; everywhere it was easily removed. The 
 root was not sensibly altered. 
 
 After seventeen days, on the first tooth was seen, at the 
 extremity of the crown, a slight milky color w^ithout loss of 
 polish. At this part, with a knife, small shavings could be 
 removed. Koot intact. On the second tooth the alteration 
 of the enamel had increased ; its root could be cut with a 
 knife more easily than in its normal state. 
 
 (/).) Solution 1 in 100. 
 
 After two days the enamel was earthy and without polish ; 
 the root was normal. 
 
 At the end of thirteen days the enamel could Ije everywhere 
 removed with the nail. The root was decalcified on the sur- 
 face ; it was easily cut with a knife, but only to a slight 
 depth. 
 
 It appeared to us superfluous to prolong further our ex- 
 periments ; we usually interrupted them after having become 
 well satisfied that the dentine Avas beginning to be decalcified ; 
 
82 INQUIRIES INTO DENTAL CARIES. 
 
 any ulterior action possessed no interest for ns, and we cared 
 little to know if it was possible to completely decalcify the 
 teeth or not by the aid of diflerent concentrations of acids. 
 We have been able to convince ourselves, in some of our ex- 
 periments in which the teeth have remained subjected to the 
 action of acids for a long time, that it is possible even with 
 very weak acid solutions to decalcify teeth pretty completely. 
 
 It results, from the experiments which have just been 
 related, that tartaric and acetic acids, even very weak, pro- 
 duce upon the enamel the same changes as other, especially 
 the lactic and oxalic acids, while M. Magitot asserts that 
 tartaric and acetic acids attack only the dentine and never 
 the enamel. AVe know not how M. Magitot has obtained 
 such opposite results; we content ourselves with remarking 
 that he also noticed that tartaric acid had produced a layer 
 of little crystals upon the surface of the enamel, and that 
 they adhered to it sometimes very strongly. Yet, according 
 to him, beneath these crystals the enamel was found in a 
 normal state. We, on the contrary, have noticed, after 
 having removed these crystals, that the surface was left un- 
 even and roughened ; the enamel was transformed to an 
 earthy mass even to a great depth. Perhaps this ditference 
 of results can be explained by the supposition that in the 
 experiments of M. Magitot, although there may have been 
 no loss of substance in the enamel, yet it may have been 
 transformed into a chalky mass. On the other hand, it is 
 possible that the dillerences in the consistency and perhaps 
 also in the chemical composition of the enamel, from which 
 results a different resistance to the action of acids, have acted 
 in the manner described in our experiment Xo. 5. 
 
 Our experiments are in harmony witli those of Mr. Wcst- 
 cott, of Mr. Allport, and of M. Mantegazza, who found that 
 all the vegetable acids, without distinction, attacked the 
 enamel of the teeth. 
 
 Our experiments do not permit us to admit, as ^I. Magitot 
 asserts, that oxalic acid and alum attack neither the cement 
 nor the dentine. It is true that the diminution of the hard- 
 ne.-8 of the dentine begins always later than the first altera- 
 
PRODUCTION OF CARIES. 83 
 
 tion of tlie enamel, but all the acids produce tlie same eiFect; 
 so we stopped pushing farther our ex[)erinients, with the end 
 of decalcifying more completely the dentine. It would l)e 
 easy to show the diminution of the hardness of the root of 
 the tooth by the action of oxalic acid, or of a solution of 
 alum; nevertheless, it appeared to us that oxalic acid, tar- 
 taric acid, and solutions of alum, attack the dentine a little 
 more slowly than does acetic acid, for example; lactic acid 
 much weakened, acts also very slowly. 
 
 The specific action which M. Magitot has attributed to 
 certain substances upon the dental tissues must therefore 
 have for cause some fortuitous circumstance, inasmuch as 
 subsequent experiments, made in the same manner, entirely 
 fail to confirm it. 
 
 As for the action of sugar, all experiments result in show- 
 ing that in its normal state it never attacks the teeth; it 
 acts only on passing into the state of acid fermentation. We 
 have obtained identical results. The most decisive experi- 
 ments upon this point have been made by M. Magitot. He 
 boiled a solution of sugar, deposited the teeth in it, and closed 
 the neck of the bottle hermeticall}^, by heating it to a Avhite 
 heat, drawing out and twisting it. l^o fermentation was 
 then possible, and at the expiration of two years the teeth 
 were found entirely untouched. 
 
 The diiierent action of acids upon the difl:erent tissues of 
 the teeth is explained by the presence of variable proportions 
 of organic substances which enter into the composition of 
 the enamel, the dentine, and the cement. 
 
 In the enamel, where the oro-anic substances enter onlv in 
 the proportion of some hundredths, the least diminution of 
 the salts should produce great disorder in the molecular com- 
 position, and, consequently, upon the physical properties of 
 this tissue; while a slight loss of inorganic substance would 
 not be easily perceived in the dentine, for the organic mat- 
 ters which it contains would suffice to maintain its consis- 
 tence. 
 
 The enamel, stripped of its calcareous salts, possesses only 
 a minute quantity of organic elements, which, placed under 
 
84 INQUIRIES INTO DENTAL CARIES. 
 
 the microscope, present for only an instant the enamel struc- 
 ture; they are seen promptly to dissolve. The dentine, 
 deprived of its salts, has, on the contrary, the consistence 
 of cartilage, and entirely keeps the form of nndecalcitied 
 dentine. 
 
 The acids produce upon the enamel plienomena which are 
 likewise found in caries of the enamel ; thus, these latter 
 may be explained by the action of acids. In both cases the 
 enamel, being deprived of a portion of its salts, becomes por- 
 ous, opaque, and softer. 
 
 Out of the mouth the action of acids is always perceived 
 first upon the enamel. It remains to be ascertained if the 
 dissolution of the calcareous salts of the dentine does not 
 take place at the same time as that of the enamel, although 
 not manifesting itself to the observer until later. AVe are in- 
 clined to thiidc so, inasmuch as we have no reason for admit- 
 ting that the salts of the dentine are less soluble than those 
 of the enamel. As for the rest, there are in the hardness of 
 the enamel and of the dentine differences which predispose 
 them to be more or less rapidly attacked, and wdiose influence 
 upon the production of caries w^e have long appreciated. 
 
 As to the utility of all these experiments, they teach us 
 that sugar and sugared liquids, placed in circumstances 
 favorable to acid fermentation, are able to exercise by this 
 alteration an injurious action upon the teeth. In the mouth 
 are found all conditions favorable to tliis fermentation, there- 
 fore all solutions of sugar are capable of acting in precisely 
 the same manner as acids. 
 
 To sugar is very generally attributed an injurious action 
 upon the teeth. That this O[)inion is well founded is con- 
 firmed by the oft-repeated observation that caries is especi- 
 ally common and intense with persons of certain professions, 
 such as confectioners and cooks, who eat or taste many sweets, 
 and who, moreover, take sugar into the mouth in the form 
 of dust while pulverizing or sifting it. 
 
 It is true that other observations would seem to prove the 
 contrary. The blacks of the East Indies who eat enormous 
 quantities of sugar are remarkable for yery beautiful and 
 
PRODUCTION OF CARIES. 85 
 
 very sound teeth. M. Afantegazza confirms this fact by his 
 own experience, and adds further that the Indians, who eat 
 constantly the sugar cane and other products of their coun- 
 try rich in sugar, have likewise excellent teeth. Neverthe- 
 less, M. Mantegazza does not attach much weight to these 
 observations; he thinks that these populations difi'er from 
 ns in their whole organization too much for us to be justified 
 in drawing from them conclusions applicable to civilized 
 people. Yet we may deduce from these tacts the consequence 
 that teeth well developed, hard, and strong, A>ill not suffer 
 from even tlie freest use of sngared aliments, while those of 
 a less dense structure may suffer from it considcrablj'. 
 
 It would seem to result from all this that the Euro[)eans, 
 and the races sjDrung from them, as for example, the North 
 Americans, have teeth less perfectly developed, and less re- 
 sistant than the negroes and the natives of America. From 
 this we are not permitted to attribute the great amount of 
 caries of the teeth which is found among the Europeans and 
 North Americans solely to their more refined manner of liv- 
 ing, and to the use of substances little favorable, and even 
 injurious to the teeth; but we are compelled to admit that, 
 with them,tlie disposition and the development of the teeth 
 are|less perfect. 
 
 It is impossible for us here to enlarge further upon the 
 causes of these singular phenomena, which refer evidently to 
 the characteristic development of the races. AVe must, how- 
 ever, refer in this connection to the remarkable differences 
 in frequency of caries in the different parts of France ; M. 
 Magitot has given special attention to this point.* 
 
 The experiments which we have made upon the action of 
 acids upon teeth have led us on to a series of other observa- 
 tions which have reference to the origin of caries of the teeth. 
 
 Some observations establish that, at tlie end of a somewhat 
 prolonged course of grape cure, patients have perceived that 
 their teeth have become affected. Their surfaces have be- 
 come rough, a superficial la^er of enamel has ])een destroyed, 
 
 * Tniitc dc la c:\rie dentaire, p. 61-66. 
 
 \ 
 
86 INQUIRIES INTO DENTAL CARIES. 
 
 and, ill some cases, true caries lias been developed. ^Ve can 
 confirm from our own experience the fact of the roughness 
 of the teeth, and the production of caries as a result of courses 
 of o-rape cure. In one case, where the teeth were extraordin- 
 arily hard and dense, and where the cure had been interrupted 
 at the moment when the teeth began to grow rough, there 
 was no caries, and the roughness gradually disappeared. In 
 other cases, on the contrary, a greater or less loss of enamel 
 was observed, and caries appeared. The roughness is, with- 
 out doubt, the consequence of the alteration of the superficial 
 layers of the enamel, and the deposit of very minute crystals 
 of tartrate of lime, as we have seen produced in our experi- 
 ments with tartaric acid and the juice of the grape. It will 
 therefore be well to caution those whose teeth are of poor 
 quality against the use of such cures, except with the utmost 
 precaution, forewarning them that the juice of the grape may 
 injure their teeth. 
 
 After having established by our experiments that acids of 
 the most various kinds attack the teeth, it behooves us to 
 inquire what are the acids which take part in the caries of 
 the teeth, and how^ they get into the mouth. We know 
 that acids are always introduced into the mouth with our 
 food and drink: acetic acid is associated with great numbers 
 of viands as a condiment ; malic, citric, and tartaric acids 
 are found in different kinds of fruits, and in the drinks 
 which are made from them ; oxalic acid is found in certain 
 plants; lactic acid in sour milk, and so on. We have, more- 
 over, pharmaceutic remedies which contain mineral acids 
 and their acid ethers; then tannin, some salts, alum, for in- 
 stance, are able to attack the teeth. All these substances 
 may easily bring on caries or contribute to hasten its i>rog- 
 ress ; but we think that the acids formed in the mouth as 
 the result of decomposition, or those which are found in the 
 buccal secretions, play in this matter a mucl>more important 
 part. The liquid which exists in the buccal cavity is com- 
 posed, as is well known, of a mixture of the secretions of the 
 salivary glands and of the mucous follicles of the mouth. 
 The secretions of these different glands are almost all, at 
 
PRODUCTION OF CARIES. 87 
 
 least in the normal state, neutral or alkaline ; the liquids, 
 then, -which are in the mouth, cannot he acid, not taking 
 into consideration the acids which are directly introduced 
 either hy an anomaly in the secretion, or else in consequence 
 of fermentation caused by particles of food remaining in the 
 mouth. 
 
 Among the secretions of the salivary glands, that of the 
 parotid alone may he feebly acid ; that of the submaxillary 
 and sublingual glands is, on the contrary, constantly alkaline. 
 This fact has been proved by the aid of sounds introduced 
 into the efferent canals of these glands. The secretion of 
 the parotid is sometimes acid when first collected ; but this 
 reaction passes promptly to the neutral state, or to one 
 slightly alkaline, when the liquid loses the clearness which 
 it possessed at first. This acid reaction arises, according to 
 M. CEhl," from the carbonic acid absorbed in the liquid, 
 which holds in solution the carbonate of lime with which 
 the liquid secreted by the parotid is abundantly provided. 
 When the carbonic acid disappears, the acid reaction ceases 
 to take place and the carbonate of lime which it holds in 
 solution is precipitated. 
 
 This circumstance explains the formation of the tartar 
 upon the teeth. The fact that this sometimes contains a 
 large quantity of phosphate of lime at the same time with 
 the carbonate is not in contradiction with this explanation, 
 inasmuch as the carbonic acid may hold phosphate as well 
 as carbonate of lime in solution. The precipitates of the 
 calcareous salts inclose numerous elements of leptothrix and 
 of other products which are met with in the mucosities of 
 the mouth, such as epithelial cells, leucocytes, &c., as we 
 have hereinbefore shown. 
 
 The numerous minute follicles of the buccal cavity secrete 
 a liquid which goes by the ordinary name of buccal mucus, 
 and which, very probably, in its properties resembles the 
 secretions of the submaxillary and sublingual glands. Ac- 
 
 * * La saliva hiimana, «&c. Pavia, 1864. Vide Meissner's Jahresber. 
 (Meissner's Annalen f. rat. Med., xxv Bd. 2 H., S. 242.) 
 
88 INQUIRIES INTO DENTAL CARIES. 
 
 cording to their seats they are called follicles of the lips, of 
 the cheeks, of the palate, of the tongue. Their structure is 
 perfectly identical with that of the salivary glands, and their 
 secretions contain, like those of the submaxillary and sub- 
 lingual glands, a great quantity of mucus which comes from 
 the epithelial cells of the follicles, while the secretion of the 
 parotid is very liquid and contains no mucus. 
 
 The particular reaction of the mucous secretion furnished 
 by the buccal cavity naturallj^ cannot be established in a 
 direct manner in man; nevertheless, from the fact that the 
 mixture of all the secretions of the mouth, which constitutes 
 the ordinary saliva, has, as a rule, an alkaline or neutral re- 
 action, we may conclude that the secretion of the mucous 
 follicles of the mouth is in like manner neutral or alkaline. 
 This has been proved directly by an experiment made on a 
 dog by M. CI. Bernard. After having made a section of all 
 the salivary conduits, he found that the liquids contained in 
 the mouth, which clearly could no longer be mixed with 
 secretions supplied by the salivary glands, were alkaline ; 
 the secretion of the mucous follicles, at least of dogs, must 
 then be alkaline. 
 
 It has also been asserted that the mucous membrane of 
 the buccal cavity can, independently of tlie mucous follicles 
 wdiich it contains, give out an acid secretion, especially when 
 irritated. 
 
 Mr. Tomes shares this opinion, which he rests principally 
 on the fact that cotton placed between the teeth, in such a 
 manner as to irritate the gum, evidentlj^ fjivors the progress 
 of the caries which exists at any point. But these facts can 
 be refuted by considering that the cotton, as a porous sub- 
 stance, must necessarily favor the work of decomposition 
 and of fermentation which is going on at this spot. It has 
 not as yet been shown directly, and we may say that it is 
 not Ycry probable, that the mucous membrane of the mouth, 
 aside from the secretions of the glands which it contains, 
 secretes a fluid iK'culiar to itself in any great abundance. 
 
 It is, nevertheless, a fact which is commonly observed, 
 that the interior of the mouth, but above all, the surface of 
 
PRODUCTION OF CARIES. 89 
 
 the teeth and gums, shows an acid reaction. This reaction 
 may, a priori^ be attributed to two causes : fii^t, to the ab- 
 normal nature of the secretions of the mouth, and, second, 
 to an acid fermentation of particles of food. 
 
 As for the reaction of the liquids of the mouth, we have 
 already remarked that the secretions of the parotid possess, 
 in most cases, an acid reaction ; hence it ma}^ be presumed 
 that, in given circumstances, the acidity of the saliva may 
 be sufficient!}^ iucreased for the teeth to be [vffected by it. 
 The momentary acid reaction w^hich the secretion of the 
 parotid possesses in the normal state, and which is caused by 
 carbonic acid, can naturally have no injurious influence upon 
 the teeth, seeing that it is even powerless to prevent the tar- 
 tar from precipitating from it. If this acid saliva were able 
 to dissolve a greater quantity of calcareous salts than that 
 which it already holds in solution, we should never see any 
 portion of these salts form a precipitate ; but, as all saliva 
 deposits more or less tartar, it is very improbable that it can, 
 in general, attack the teeth. 
 
 It is true that cases are found, where the caries has a very 
 rapid progress, in which there is almost a total absence of 
 deposits of tartar ; but we generally find in such cases a 
 diminution of the salivarj' secretion,. Avhich explains the ab- 
 sence of tartar. The acids which form in the mouth are no 
 longer neutralized and diluted by the saliva ; therefore they 
 have a greater facility for attacking the teeth. We believe, 
 on the contrary, that the saliva protects the teeth against 
 the action of acids, from whence arises the particular immu- 
 nity which the canines and incisors of the lower jaw seem to 
 possess; teeth which are constantlj' bathed in saliva. Those 
 persons who secrete but a snuiU quantity of saliva have pre- 
 dispositions to caries of the teeth ; a particular predisposition 
 to this affection springs, in like manner, from the diminution 
 of the saliva which takes place during the course of certain 
 maladies. 
 
 The action of tobacco-smoke, which favors the salivary 
 secretion, appears to be salutarj- ; in no case does it ever 
 
 . 7 
 
90 INQUIRIES INTO DENTAL CARIES. 
 
 exert an injiirions effect upon the teeth, although, in time, 
 it o;ives them a color far from ao-reeable. 
 
 An acid reaction has often l)een attributed to the secretion 
 of the mucous follicles of the buccal cavity. This opinion is 
 based upon a layer of mucus situated upon the surface of the 
 interior of the mouth, and, especially, upon the gums and 
 teeth, which has an acid reaction, and in which are found 
 the elements of leptothrix, the epithelial cells of the mouth, 
 leucocytes, &c. It appears, nevertheless, that the acid reac- 
 tion has nothing in common with the follicular secretion ; it 
 should be attributed to the acid fermentation which takes 
 place in this secretion, or in the saliva mixed with starchy 
 or sugary liquids. It is when fasting that the acid reaction 
 is the most marked ; that is to say, at the moment when the 
 salivary secretion is reduced to its minimum, so that the 
 acids which form are not at once neutralized and diluted. 
 M. CEhl, nevertheless, found that, even when fasting, no 
 acid reaction took place when the mouth had been scrupu- 
 lously rinsed after eating. 
 
 M. (Ehl has made a comparison between the changes which 
 take place in pure saliva and that mixed with alimentary 
 debris, when exposed to the air. He collected one portion 
 of saliva after the ingestion of amylaceous substances, and 
 another after the mouth had been thoroughly rinsed. The 
 two liquids destined for the experiment were then filtered, 
 and left to themselves. The former, which contained starch, 
 reduced sulphate of copper, proving that a portion of the 
 starch had been converted into sugar. It remained several 
 days in a state of acid fermentation before passing to the 
 state of putrefaction with alkaline reaction. In the second 
 liquid, which contained only pure saliva, there was no acid 
 reaction, but on adding starch or sugar to this saliva, primi- 
 tively pure, in like manner as in the former, an acid fermen- 
 tation was seen to take place. Nevertheless, the presence of 
 the saliva was necessary to produce this acid fermentation, 
 inasmuch as a solution of starch paste, or of sugar, free from 
 all other mixture, and placed in the same conditions, did not 
 become acid in tlie same space of time. Where sugar or 
 
PRODUCTION OF CARIES. 91 
 
 starch was held in the mouth, when its reaction was alkaline, 
 an acid reaction was found at the end of from twenty to 
 forty minutes, and even sooner, Avhen grape sugar was used. 
 The acid reaction of the saliva which we meet in persons 
 atflicted with diabetes is, according to M. CElii, due to the 
 same cause, inasmuch as sugar is found not only in the urine 
 of such persons, but in nearly all the secretions, and especi- 
 ally in the saliva. The secretion of the })arotid was able in 
 the first experiments to give by itself an acid reaction, which 
 w^as not the case with the saliva coming from the submax- 
 illary glands, but was from a mixture of the two, especially 
 when mixed with mucus. The acid arising from this fer- 
 mentation is, according to ]\[. CEhl, probably the lactic. 
 
 It results from these experiments that the saliva of man, 
 when starch or sugar is mixed with it, can produce an acid 
 fermentation, and that an identical fermentation can take 
 place in the mouth. The possibility of the acid fermentation 
 of a solution of starch is subordinated to the })roperty pos- 
 sessed by the saliva of changing starch into sugar, which, in 
 contact with a ferment, undergoes an acid fermentation. It 
 is now acknowledged that, in man, it is not only the mixture 
 of the diiferent secretions of the mouth, but also the isolated 
 secretion of the parotid and that of the submaxillary glands 
 which are able to change starch into sugar. 
 
 If, according to this, the acid reaction of the mouth should 
 be attributed chiefly to the presence of alimentary debris, we 
 should always take into consideration the relative quantity 
 of saliva and of mucus. Besides the influence exercised by 
 the quantity of the saliva, whose action is to dilute and to 
 neutralize the acids, a greater quantity of mucus may also 
 possess importance, inasmuch as, by its viscosity, it hinders- 
 the too rapid mixture with the saliva, a fact which explains- 
 the possibility of tinding locally, at the surface of the teeth,, 
 for example, acids inclosed in a thick mucus; whilst, in other 
 portions of the buccal cavity, a neutral reaction can be founds 
 or even one slightly alkaline. 
 
 In opposition to our oi)inion, which consists in asserting 
 that the acid reaction is caused chiefly by alimentary debris 
 
92 INQUIRIES INTO DENTAL CARIES. 
 
 in the mouth, it may be objected that during the course of 
 certain acute diseases, and especially in typhoid fever, the 
 teeth are strongly attacked by caries, and that, in spite of 
 the diet habituallj' prescribed, there is an increase of acidity. 
 It must, nevertlieless, be considered that the diet is never 
 absolute, and that constantly sugar, and very often acids, 
 are introduced into the mouth by means of medicines: the 
 amount of this sort of drinks is indeed considerable, on ac- 
 count of the thirst from which patients suffer. A cause, in 
 like manner very important in the production of an acid fer- 
 mentation in these maladies, is the diminution of the salivary 
 secretions, which are more concentrated, and contain more 
 mucus, so that the elements necessary to fermentation are 
 not wanting; whilst the acids which are formed, on account 
 of the small quantity of saliva, cannot be properly diluted or 
 neutralized. 
 
 The lack of mastication must at the same time fiivor in 
 certain parts of the buccal cavity tlie accumulation of viscous 
 mucus in a state of acid fermentation. Under the influence 
 of like causes there is established in the mouth an enormous 
 mass of elements of leptothrix^ which form upon the tongue 
 and teeth a portion of the sooty layer, whitish at first, after- 
 wards drj' and brown, which is found there. 
 
 The most various irritations of the buccal cavity, and gen- 
 erally all the acute or chronic aft'ections of the digestive 
 canal, as well as the acute idiopathic maladies, exercise an 
 influence upon the production of caries. Likewise, in these 
 maladies, the mouth contains a greater quantity of this vis- 
 cous coating, which gives an acid reaction. It appears that, 
 in these cases, the mucus mixes in considerable proiK)i'tions 
 with the secretions of the buccal cavity, whilst the quantity 
 of saliva is not positively diminished. But it is just the 
 great viscosity of the mucus which hinders the mingling of 
 the liquids in the mouth, and favors the production of par- 
 tial fermentation. We have already called attention to the 
 acids which come directly from the stomach to the mouth 
 in cases of dyspepsia. We have likewise had occasion to 
 remark the frequent cases of caries of the teeth which are 
 
PRODUCTION OF CARIES. 93 
 
 met with in persons atHicted Avitb diabetes; they are attrib- 
 uted to the sugary matters which the saliva contains, and 
 which are changed, according to Al. CEhl, into hictic acid. 
 
 Nearly all observers have remarked the frequency of caries 
 of the teeth in pregnant females. This is sufticiently ac- 
 counted for by the troubles which they experience with their 
 digestion, which are accompanied by the formation of acids 
 in the mouth during the continuance of this condition. I 
 think it is not necessary to find here any analogy, as many 
 observers have done, with the osteomalacia^ sometimes met 
 with in pregnant women. There are seen, it is true, in preg- 
 nant women, cases of osteomalacia^ which must be caused by 
 their state of pregnancy. Cases of cure of this malady have 
 been recorded where it had affected the pelvis, and which 
 recurred again during another pregnancy, to be again cured 
 after delivery. But aside from the extreme raritj' of these 
 cases it is not proved, it is not even probable, that the calca- 
 reous salts of the dentine can be taken up again in the same 
 manner as the salts of the bony tissue in general; we must 
 therefore refuse to admit such an explanation. 
 
 If we recapitulate, we shall find in the work of fermenta- 
 tion which takes place in the mouth a continual source of 
 acidity. This acidit}-, by its action on the teeth, without 
 doubt acts with much greater energy than the acids formed 
 transiently by the alimentary debris, or by any other sub- 
 stance introduced into the mouth. The i^ole of the saliva is 
 here to change into sugar the starch contained in the food ; 
 moreover, the sugar contains fermentable substances which 
 produce an acid reaction. jSTevertheless, the saliva dilutes 
 and neutralizes the acids, when it exists in sufficient quan- 
 tity, and thus hinders their action on the teeth. AVe cannot, 
 then, justify the assertion of M. Magitot that the saliva is 
 the veritable agent of caries of the teeth. He contradicts 
 himself, adding, in the same phrase, that the saliva cannot 
 produce this efiect when it retains its original composition, 
 but only in consequence of certain modifications occasioned 
 by the presence of injurious substances formed spontaneouslj^, 
 or introduced from without. It appears, then, evident that 
 
94 INQUIRIES INTO DENTAL CARIES. 
 
 it is not the saliva, but rather these injurious substances 
 which should be considered as the agents of caries of the 
 teeth. 
 
 As far as we know, the veritable nature of the acids found 
 in the mouth has not yet been demonstrated b}- any direct 
 experiment; nevertheless, it is generally thought to be lactic 
 acid, and this opinion has the greatest probabilities in its 
 favor. 
 
 As a general rule, it is lactic acid which is produced by 
 the fermentation of sugared liquids and others, when there 
 are present at the same time albuminoid substances. This 
 fermentation is particularly favored by the presence of the 
 carbonate of lime, which neutralizes the acids gradually as 
 they are formed ; whilst the fermentation itself is hindered 
 by a little more considerable abundance of acids. 
 
 ]^ow all these conditions are fulfilled in the buccal cavity ; 
 the saliva and the mucus contain albumen, and carbonate of 
 lime exists in great quantity in tartar and the dental tissues. 
 We know not whether or not there are formed still other 
 acids. AVe might expect to find in the mouth the fungi 
 which, according to M. Pasteur, should accompany and pro- 
 duce the lactic fermentation, " ferment de Tacide lactique de 
 Pasteur." But the opinions of authors upon the ferment of 
 lactic acid difter so greatly that it is impossible for us to at- 
 tribute any great value to the presence of this ferment in the 
 mouth. According to M. Pasteur the elements of the ferment 
 of lactic acid are molecular corpuscles, very minute, which pre- 
 sent a very marked Brunonian movement whose dimensions 
 he does not state on account of their extreme minuteness. 
 In the work of one of his pupils, M. Van Tieghem, upon the 
 fermentation of urine, there is a figure of one of these fungi 
 in which these latter are contracted in the middle and larger 
 than the spores of the urine ferment which are pictured by 
 their side, and have a diameter .0015 millimetre. The form 
 of these fungi, according to M. Van Tieghem, is identical 
 with that of the mycoderma aceti of ^M. Pasteur, of which the 
 diameter is likewise .0015 millimetre. This figure, then, 
 does not at all agree with those given by ^\. Pasteur. 
 
PRODUCTION OF CARIES. 95 
 
 The observations of M. Ilallier upon the ferment of lactic 
 acid {oidiiim hn-tis, Fresenius) are entirely different from 
 those of j\r. Pasteur. According to him the elements of this 
 ferment consist of great cells of a rounded quadrangular 
 form ; they should be constantly found in the acid fermenta- 
 tion of milk, and, moreover, upon all substances in a state of 
 acid fermentation. 
 
 We have ourselves found, in milk soured at a low temper- 
 ature, minute corpuscles endowed with power of very rapid 
 motion, which appeared to us to be identical with those de- 
 scribed by ]\r. Pasteur. We have also encountered elements 
 of this kind in saliva containing sugary matters, which had 
 passed into a state of fermentation ; united, these elements 
 presented the appearance of granular masses of leptothrix, 
 especiall}' near the margins of the preparation, where, in 
 consequence of the evaporation of the liquid portions, their 
 movements had been arrested. N^evertheless, in no one of 
 these cases have we been able to obtain a reaction either 
 with iodine or with the acids. 
 
 We greatly regret that there are so few methods of dis- 
 tinguishing with exactness the different species of fungi, and 
 we cannot set ourselves the task of undertaking researches 
 so extensive, and demanding so much time. We confine 
 ourselves in consequence to presenting some observations 
 upon the possible coincidence of the acid fermentation in 
 the mouth with the presence of a development of fungi. 
 
 Besides the presence of a great quantity of leptothrix, we 
 see in the mouth but a very small number of spores and fila- 
 ments of a fungus which bears a resemblance to oidiuin. 
 But the masses of leptothrix are so predominant that we are 
 disposed to believe in their participation. If, in general, the 
 fungi play a )-6le in the acid fermentation of the mouth, 
 which is not proved, we are inclined to attribute it to the 
 leptothrix. This opinion is founded upon the resemblance 
 which the corpuscles in movement during the fermentation 
 of the saliva and of milk present to the lactic acid ferment 
 of M. Pasteur, and to the masses of leptothrix which are 
 really formed in the mouth. 
 
96 INQUIRIES INTO DENTAL CARIES. 
 
 Tlie absence of the violet reaction, so characteristic, which 
 we find in the former case, depends perhaps upon a dift'erent 
 degree of development. 
 
 IIT. Influence of Leptothrix upon the Production of 
 Caries of the Teeth. 
 
 We have already several times remarked that the action 
 of acids alone does not account for all the phenomena which 
 appear in caries of the teeth. It is true that acids, even very 
 much dikited, can attack the dental tissues ; but we find, in 
 their mode of action, difterences which distinguish them 
 from the phenomena and from the progress of dental caries. 
 The acids attack first the enamel and rapidly change it to a 
 chall>:y mass ; later only, their action is felt in a marked 
 manner upon the dentine, which becomes more transparent 
 and, in fine, as if cartilaginous, by the very slow but pro- 
 ficressive loss of its calcareous salts. 
 
 Caries, on the contrary, proceeds slowly in the enamel ; it 
 is much swifter in the dentine, where it proceeds promptly 
 along the canaliculi. This difterence of progress must be at- 
 tributed to the participation of the fungi in the work of the 
 caries. The elements of the fungus glide easily into the in- 
 terior of the canaliculi, which they dilate, and thus favor 
 the passage of the acids into the deeper parts ; these same 
 elements cannot penetrate a compact enamel, or at least they 
 enter more slowly, and only when the elements which form 
 it have been greatly changed by the action of acids. 
 
 Leptothrix is found almost constantly in the buccal cavity, 
 if great care is not taken to rinse the mouth frequently. 
 Mr. Bowditch, in examining forty persons of different pro- 
 fessions, and living difiercnt kinds of life, found in almost 
 all vegetable and animal parasites. Those only were found 
 to be free who cleaned their teeth several times a day, and 
 at least once with soap. The parasites were numerous in 
 proportion to the neglect of cleanliness. The means ordina- 
 rily employed to clean the teeth had no eft'ect upon these 
 parasites, whilst soap appeared to destroy them. 
 
PRODUCTION OF CARIES. 97 
 
 M. Kolliker, out of twenty to thirty young and well per- 
 sons, found hardly one the papilhie of whose tongue was free 
 from a gi-ayish and granular coating; he more rarely met 
 with filaments of the fungus. It is true that regard must 
 be had to the hour of the day at which the examinations 
 were made ; it is natural that all these matters should always 
 be more abundant when the individual is fasting. 
 
 But, while in ordinary circumstances, the fungi are found 
 only at the surface of the buccal cavity, they are seen to 
 penetrate into the interior of teeth during the progress of 
 caries. For them to be able to penetrate thus it is necessary 
 that the teeth be in a suitable condition; the enamel and 
 the dentine must have lost their density by the action of 
 acids. 
 
 It seems that the fungi are not able to penetrate an enamel 
 of normal consistency. The dentine itself, in its normal con- 
 dition of density, olFers great difficulties to their entrance, 
 and we are not yet sure that the leptothrix could triumph 
 over this resistance. We do not speak here of the greenish 
 deposit found upon teeth, which differs from caries, and upon 
 which we have not yet sufficiently experimented. It may 
 happen that, under favor of this deposit, fungi may penetrate 
 into the superficial layers of the enamel, which does not 
 appear to be the case in ordinary caries. Habitually the 
 teeth expose to the action of injurious agents only their 
 crowns covered with enamel, and this protects them from 
 the attacks of the fungus. We cannot decide, at present, if 
 the leptothrix is able to penetrate sound dentine, when from 
 any abnormal circumstance it happens to be denuded. But 
 if the enamel or the dentine are become less resistant at any 
 point through the action of acids ; or if, at the surface of 
 the dentine, a loss of substance has occurred, then the ele- 
 ments of the fungus can pass into the interior of the dental 
 tissues, and produce by their extension, especially in the den- 
 tine, effects of softening and destruction much more rapid 
 than the action of acids alone is able to accomplish. 
 
 The participation of the fungus is constant in the progress 
 of caries which has reached this stajje. As soon as a loss of 
 
98 INQUIRIES INTO DENTAL CARIES. 
 
 substance can be shown there is found the presence of the 
 fungus, so that the question whether or no the acids alone 
 could produce ravages more considerable is without impor- 
 tance. But in the early stage, when the surface of the tooth 
 is still polished and intact, we have never been able to prove 
 the presence of the fungus ; it appears, therefore, that at this 
 stage of the malady, Avhich constitutes the dry caries, prop- 
 erly so called, all the disorders must be attributed to the sole 
 action of acids. 
 
 The development of the fungus seems to be favored b}' a 
 neutral or sliglitly acid medium, whilst it cannot flourish in 
 a strongly alkaline liquid. We have already called attention 
 to the observation of Dr. Bowditch, who has seen the para- 
 sites disappear upon rinsing the mouth with a solution of 
 soap. M. A. Yogel found that the fungus, oidium albicans, 
 continued to develop in pure Avater, in solutions of salts with- 
 out alkaline reaction, and especiall}^ in solutions of sugar; 
 whilst no proliferation could take place in solutions slightly 
 alkaline. These observations, to judge of them by analogy, 
 seem likewise to prove that alkaline liquids may exercise a 
 destructive action upon the leptothrix. 
 
 IV. Therapeutic Conclusions. 
 
 It is not without importance to cast an eye, before con- 
 cluding, upon the therapeutic conclusions which should be 
 drawn from the results which we have reached, and to see 
 if they are in accord with the experience of practitioners. 
 
 Before all, as regards the prophylactic indications, it can 
 be said that we should seek to neutralize the acids which 
 form in the mouth, and to prevent all work of fermentation 
 and of development of fungi by proper care for cleanliness. 
 Teeth well formed may be spared by caries in spite of the 
 greatest negligence; but we should take the greater care of 
 our teeth in proportion as they are badly developed or irregu- 
 larly arranged. \\\\\\ great care even malformed teeth may 
 be preserved from caries. In cleaning the teeth such brushes 
 should be used as are not too hard, and which^ by a slight 
 
THERAPEUTIC CONCLUSIONS. 99 
 
 pressure, can Ije made to enter tlie spaces between the teetli. 
 We may advise, as useful for this purpose, the employment 
 of soap, which, by imparting a sliglitly alkaline cpiality to 
 the water, neutralizes tlie acids and hinders the development 
 of fungi. "•'■ 
 
 In many cases the soap does not suffice to remove entirely 
 the deposit formed upon the teeth; in such case there should 
 be added to it powders which act mechanically, but care 
 should be taken that they are not too gritty ; the disagree- 
 able taste of soap may be easily corrected. 
 
 We can also recommend the permanganate of potassa dis- 
 solved in water as an excellent mouth wash, inasmuch as 
 this remedy is a very excellent antiseptic, and at the same 
 time the best means of preventing fermentation; this water 
 exorcises a beneficial action upon the mucous membrane of 
 the mouth. 
 
 As regards the artificial treatment of caries our observa- 
 tions are at every point in accordance with the experiments 
 made up to this time. In filling the teeth the air and liquids 
 are hindered from penetrating, and all work of fermentation, 
 and all development of fungi, become impossible. 
 
 There has appeared lateh' in the Archives of Virchou\ vol. 
 xli, an article by Dr. Hertz upon "Dental Caries." This 
 author, having no knowledge of our experiments, has not 
 discussed our opinions, although his memoire appeared some 
 time after ours. In a note added to the end of his work he 
 wrongly accuses us of rejecting all vital action of the den- 
 tine in the production of caries. 
 
 As for the rest, the opinions of Hertz are nearlj- in agree- 
 ment with those of iSTeumann. He asserts that he has never 
 observed alteration of dentinal fibrils in natural teeth of 
 substitution. We maintain the correctness of our observa- 
 tions on this subject. It only remains to determine if the 
 alterations we have described are constant, or if they are 
 wanting in certain cases. 
 
 * Vide i . B. Kottenstein. Des soins a donner aux dents. Frankfort-sur- 
 lc-.M;iino, 18-37. 
 
.,f 
 
 i/-j 
 
 illsliiliil 
 
 >:!!!;li||!;|i!;iHiii); 
 
 100 
 
 FlaieJ 
 
 DR. LEBEF. r/JOM NA TUPE DEL. 
 
 TSINClAIPaSCK ilTH. rH/I. 
 
EXPLANATIOiT OF THE PLATES. 
 
 PLATE I. 
 
 Fig. 1. (Magnified three diameters.) 
 
 Longitudinal section of a carious bicuspid. The section is slightly slanted 
 across a large carious cavity ; upon the left side of the crown a cone of a 
 dark color is seen in the dentine altered by caries ; this cone extends in the 
 direction of the dentinal canals from the surface even to the pulp-cavity, and 
 presents a radiated striation which corresponds to these canals. Upon the 
 surface of the section the loss of substance extends only upon the enamel, 
 whilst upon the neighboring parts it penetrates deeply into the interior of 
 the dentine. Upon the masticating surface of the enamel are seen two 
 fissures. 
 
 Fig. 2. (Magnified three diameters.) 
 
 A longitudinal section of a canine tooth with commencing caries. In the 
 centre of the crown is a small carious point in a depression of the enamel ; the 
 caries has not as yet attacked more than a superficial layer of the enamel. 
 A similar point exists at the left side of the crown, also without loss of sub- 
 stance, and it is from this point that the caries has extended across the whole 
 thickness of the enamel, and nearly across the whole thickness of the dentine 
 to the neighborhood of the pulp-cavity. 
 
 The outermost layers of the dentine are of a darker color than the deepest 
 layers of the enamel, the color diminishing in both from the surface inwards. 
 There are, moreover, three small carious cavities which reach to the surface 
 of the dentine ; also cones of carious dentine are seen to start from these 
 cavities and point to the pulp-cavity; one of these cavities exists at the right 
 side of the crown, the two others are found at the neck of the tooth. 
 
 Fig. 3. (Magnified three diameters.) 
 
 Section of a human molar with caries commencing. In the middle of the 
 crown a loss of substance in the enamel (the enamel has been broken away 
 at the sides in the process of preparation) ; in the dentine a cone of a clear 
 color altered by caries; this clear color is due to the transparency of the 
 
102 EXPLANATION OF THE PLATES. 
 
 tissue ; the brownish color cannot be perceived on account of the thinness of 
 the specimen. 
 
 Fig. 4. 
 
 A fragment of this same section magnified one hundred diameters. A 
 very thin lajer of enamel is seen on a level with the loss of substance; the 
 most superficial layers are very transparent in consequence of the disappear- 
 ance of the calcareous salts. It is seen, also, that the surface is irregular and 
 covered with fissures and cracks. The layer of I eptoihrix is not preserved at 
 the surface, but there exi.st at one point masses of granular leptothr-ix which 
 have penetrated the dentine across a fissure of the enamel. The outer layers 
 of dentine are dark and the canals more difiicult to distinguish ; in the deeper 
 layers are found little deposits of calcareous salts in the canals and inter- 
 globular spaces. 
 
 PLATE II. 
 
 Fig. 1. (Magnified one hundred times.) 
 
 Section of the surface of a carious cavity. The dentine is reduced to frag- 
 ments enveloped with leptothrix. On the free surface delicate filaments of 
 the fungus are seen crossing the granular masses. 
 
 Fig. 2. (Magnified one hundred times.) 
 
 The decomposition of the dentine has made still greater progress. The 
 debris are much smaller and less voluminous than the masses of le/ifol/irix 
 which surround them. 
 
 Fig. 3. (Magnified one hundred times.) 
 
 Transverse section made at the surface of a cavity across the carious den- 
 tine. The dentinal canals are greatly thickened (which is difiicult to observe 
 in the longitudinal section of Figs. 1 and 2) ; at the surface is a thick layer 
 of very fine filaments of ieptoihrix. 
 
 Fig. 4. (Magnified two hundred and fifty times.) 
 
 Transverse section of an artificial human tooth attacked by caries. The 
 changes are idisntical with those of the natural teeth. The canals are more 
 or less dilated ; some are considerably so and have thickened walls, that 
 which could not be distinguished upon those of the canals which were the 
 most thickened. 
 
PlalrJf 
 
 ■''. .-m- ^ 
 
 700 
 
 
 
 7af' 
 
 
 ^ ^i 
 
 200 
 
 wg iV 
 
 Off l£B£/i FRO/ilMTtlFIEDCl 
 
 T. SINCLAIR 8 SON UTH.PHIl'' 
 
EXPLANATION OF THE PLATES. 103 
 
 Fig. 5. (Magnified two luiiulrcd and fiftj' times.) 
 
 Canals isolated by hydrochloric acid, and coming from the carious dentine 
 of man. These canals show various degrees of thickening; their contents 
 are divided in the form of little bundles. In a a minute canal is seen greatly 
 dilated, from which spring several undihited ramifications which are de- 
 tached near their point of origin by the act of preparation. In b two small 
 tubes very slightly dilated, one of which becomes gradually thicker. 
 
 Fig. G. (Magnified two hundred times.) 
 
 Transverse section of a carious tooth, one made of hippopotamus ivorj'. 
 A layer of leptoihrix at the surface; similar ma.sses penetrate (in n), pro- 
 ceeding from the surface, into the interior of the tissue (in b) ; they seem 
 separate from the surface, because they have been crushed obliquely by the 
 section. The dentinal canals are for the most part dilated (c) ; some of them 
 still present the normal state [d). 
 
 Fig. 7. (Magnified two hundred and fifty times.) 
 
 Canals of the same tooth (hippopotamus) greatly dilated and presenting 
 varicose sinuosities. At the right some of them are still united by very fine 
 fibril<, which apj)ear to be the residue of the dentine. 
 
London, New Burlington Street. 
 February, 1878. 
 
 SELECTION 
 
 MESSRS J. & A. CHURCHILL'S 
 
 ^encnil Catiikgitc 
 
 COMPRISING 
 
 ALL EECENT WOEKS PUBLISHED BY THEM 
 
 AET AND SCIENCE 
 
 MEDICINE 
 
INDEX 
 
 PAGE 
 
 Acton on the Reproductive Organs . 8 
 
 Adams (W.) on Clubfoot . . . fi 
 
 — (R.) on Rlieuniatic Gout .18 
 Allen on Aural Catarrh . . .6 
 AUingliam on Diseases of Rectum . 7 
 Anatomical Remembrancer . . 11 
 Anderson (McC) on Eczema . . 19 
 
 — (McC.) on Parasitic Affec- 
 tions .... 
 Arnott on Cancer .... 
 Aveling's English Midwives 
 Balfour's Diseases of the Heart 
 Barclay's Medical Diagnosis 
 Barker's Puerperal Diseases 
 Barnes' Obstetric Operations 
 
 — Diseases of Women 
 Basham on Renal Diseases 
 
 — on Diseases of the Kidneys . 
 Beale on Kidney Diseases . 
 
 — on Microscojie in Medicine 
 Bellamy's Guide to Surgical Anatomy 10 
 Bennet's Winter and Spring on the 
 
 Mediterranean . . .16 
 
 — Pulmonary Consumption . 16 
 
 — Nutrition . . . .18 
 Bennett (J. R.) on Cancerous Growths 19 
 
 11 
 
 Bigg's Orthopraxy 
 
 Binz's Elements of Therapeutics 
 
 Black on the Urinary Organs . 
 — on Bright's Disease 
 
 Bose's Rational Therapeutics . 
 — Recognisant Medicine . 
 
 Braune's Topographical Anatomj' 
 
 Brodhnrst's Orthopajdic Surgery 
 
 Bryant's Practice of Surgery 
 
 Bucknill and Tuke's Psychological 
 Medicine ..... 
 
 Burdett's Cottage Hospital 
 
 Burnett on the Ear .... 
 
 Buzzard on Syphilitic Nervous Affec- 
 tions ...... 
 
 Carpenter's Human Physiology . 
 
 Carter on Mycetoma 
 
 Canty on Diseases of the Skin , 
 
 Chapman on Neuralgia 
 
 Charteris' Practice of Medicine 
 
 Clark's Outlines of Surgery 
 
 — Surgical Diagnosis 
 Clay's Obstetric Surgery . 
 Cobbold on Worms . . . . 
 Coles' Dental Mechanics . 
 Cooper's Sursrical Dictionary 
 Corniack's CUnical Studies 
 Cottle's Hair in Health a)id Disease . 
 Coulson on Syphilis .... 
 
 — on Stone in the Bladder 
 Cullingwortii's Nurse's Companion . 
 
 11 
 
 11 
 
 11 
 
 6 
 
 4 
 
 21 
 
 15 
 
 G 
 
 9 
 
 10 
 
 20 
 
 20 
 
 18 
 
 11 
 
 4 
 
 5 
 
 13 
 
 20 
 
 23 
 
 4 
 
 12 
 
 28 
 
 8 
 
 8 
 
 14 
 
 Curling's Diseases of the Rectum 
 Dalby on the Ear 
 Dalton's Human Physiology 
 Daj' on Children's Diseases 
 
 — on Headaches . 
 De Valcourt on Cannes . 
 
 PAGE 
 
 . 7 
 . 6 
 . 9 
 . 13 
 
 . 18 
 . 16 
 
 Dobell's Lectures on Winter Cough . 15 
 
 — First Stage of Consumption 15 
 Domville's Manual for Hospital Nurses 14 
 Druitt's Surgeon's Vade-iMecum . 4 
 Dunglison's Medical Dictionary . 22 
 Ellis's Manual of Diseases of Children 12 
 Fayrer's Observations in India . . 4 
 Fergusson's Practical Surgery . . 4 
 Fenwick's Guide to Medical Diagnosis 11 
 
 — on the Stomach, &c. . . 18 
 Flint on Phthisis . . . .15 
 
 — on Percussion and Auscultation 15 
 Flower's Nerves of the Human Body 10 
 Foster's Clinical Medicine . . 12 
 
 Fox (T.) Atlas of Skin Diseases . 19 
 Fox and Farquhar's Skin Diseases 
 
 of India 20 
 
 Prey's Histology ... .9 
 Gamgee on Fractures of the Limbs 4 
 
 — on Treatment of Wounds . 4 
 Gant's Science and Practice of Surgery 4 
 
 — Diseases of the Bladder . . 8 
 Gaskoin on Psoriasis or Lepra . . 19 
 Glenn's Laws affecting Medical Men . 20 
 Godloe's Atlas of Human Anatomy . 11 
 Gordon on Fractures . . .6 
 Habershon on Diseases of the Liver . 17 
 
 — on Diseases of the Stomach 17 
 
 — onthePneumogastricNerve 17 
 Hancock's Surgery of Foot and Ankle 
 Harris on Lithotomy . . .7 
 Hayden on the Heart . . .15 
 Heath's Minor Surgery and Bandaging 5 
 
 — Diseases and Injuries of Jaws 5 
 
 — Operative Surgery . . 5 
 
 — Practical Anatomy . . 10 
 Higgens' Ophthalmic Practice . . 23 
 Holden's Landmarks . . .10 
 Holt on Stricture of the Urethra . 7 
 Hood on Gout, Rheumatism, &c. . 18 
 Hooper's Physician's Vade-Mecum , 11 
 Horton's Tropical Diseases . . 17 
 Hutchinson's Clinical Surgery . . 5 
 Hutli's Marriage of Near Kin . . 9 
 
 •Ireland's Idiocy and Imhei'ility . 21 
 
 Jones (C. H.) and Sieveking's Patho- 
 logical Anatomy . . .10 
 
 — (C. H.) on Functional Nervous 
 
 Disorders . . . 17 
 
 Jones (Wharton) 0]ihthalmic Medi- 
 cine and Surgery . . 23 
 
INDEX 
 
 PAOE 
 
 Jordan's Surgical Inflammations . 6 
 
 — Surgical Inquiries . . 6 
 Lawson on Sciatica, &c. . . .18 
 Lee (H.) Practical Pathology , , 8 
 
 — on Sypliilis . . .8 
 Leared on Imperfect Digestion . . 18 
 Liebreich's Atlas of Ophthalmoscopy 22 
 Liveing on Megrim, &c. . . .18 
 Macdonald's Examination of Water . 22 
 Mackenzie on (Irowths in the Larynx 15 
 Macnamara on Diseases of the Eye . 22 
 Maddcn's Health Resorts . . .16 
 Marsden on certain Forms of Cancer 19 
 Mason on Harelip and Cleft Palate . 5 
 Mauuder's Operative Surgery . . 4 
 
 — Surgery of Arteries . . 4 
 Mayne's Medical Vocabulary . . 22 
 Meryon's System of Nerves . . 18 
 Moore's Family Medicine for India . 17 
 Ogston's Medical Jurisprudence . 20 
 Parkes' Manual of Practical Hygiene 21 
 Parkin's Epidemiology . . ,23 
 Pavy on Food and Dietetics . . 18 
 Peacock's Valvular Disease . . 15 
 Phillips' Materia Medica . . .12 
 Pirrie's Surgery . . . .4 
 Ramsbothara's Obstetrics . . .13 
 Reynolds' Uses of Electricity . . 22 
 Roberts' Practice of Midwifery . 13 
 
 Roussel's Transfusion of Blood . . 5 
 Routh's Infant Feeding . . .12 
 Roy's Burdwan Fever . . .17 
 Royle and Harley's Materia Medica . 12 
 Rutherford's Practical Histology . 9 
 Sabben and Browne's Handbook of 
 
 Law and I-unacy . . .21 
 Salts' Medico-Electric Appai-atus . 22 
 Sanderson's Physiological Handbook . 9 
 Sansom's Diseases of the Heart . 16 
 
 Savage on the Female Pelvic Organs 5 
 Savory's Domestic Medicine . . 14 
 Sayrc's Orthopa;dic Surgery . . 6 
 Schroeder's Manual of Midwifery . 13 
 Semple on the Heart . . .15 
 
 Sewill's Dental Anatomy . . .23 
 Shapter's Diseases of the Heart . 16 
 Shaw's Medical Remembrancer . 12 
 
 Sheppard on Madness . . .21 
 Sibson's Medical Anatomy . . .10 
 Sieveking's Life Assurance . . 21 
 Smith (E.) Wasting Diseases of 
 
 Children 12 
 
 — Clinical Studies . . 12 
 Smith (Henry) Surgery of the Rectum 7 
 Smith (Hey wood) Gynaecology . . 13 
 Smith (J.) Dental Anatomy . . 23 
 Smith (W. R.) Nursing . . .14 
 Spender's Bath Waters . . .16 
 
 FAOB 
 
 Steiner's Diseases of Children . . 13 
 Stowe's Toxicological Chart . . 20 
 Sullivan's Tropical Diseases . . 16 
 Swain's Surgical Emergencies . . 5 
 Swayne's Obstetric Apliorisms . . 14 
 Taft's Operative Dentistry . . 23 
 Tait's Hospital Mortality . . .14 
 Taylor's Principles of Medical Juris- 
 prudence . . . .20 
 
 — Manual of Medical Juris- 
 
 prudence . . . .20 
 
 — Poisons in relation to Medical 
 
 Jurisprudence . . .20 
 Thompson's Stricture of Urethra . 7 
 
 — Practical Lithotomy and 
 
 Lithotrity . . .7 
 
 — Diseases of Urinary Organs 7 
 
 — Diseases of the Prostate . 7 
 
 — Calculous Disease . . 7 
 Thornton on Tracheotomy . . 16 
 Thorowgood on Asthma . . .15 
 
 — on Materia Medica . 12 
 
 Thxidichum's Patliology of Urine . 9 
 
 Tibbits' Medical Electricity . . 22 
 
 — Map of Motor Points . . 22 
 Tilt's Uterine Therapeutics . . 13 
 
 — Change of Life . . .13 
 
 — Health in India . . .17 
 Tomes' (C. S.) Dental Anatomy . 23 
 
 — (J. and C. S.) Dental Surgery 23 
 Tufnell's Internal Aneurism . . 7 
 Tuke on the Influence of the Mind 
 
 upon the Body . . . .21 
 Van Bui-en on Diseases of the Genito- 
 urinary Organs . . .9 
 Veitch's Handbook for Nurses . . 14 
 Virchow's Post-mortem Examinations 10 
 
 Wagstaffe's Human Osteology 
 Walton's Diseases of the Eye . 
 Ward on Aflectious of the Liver 
 Wariug's Practical Therapeutics 
 
 — Bazaar Medicines of India 
 Waters on Diseases of the Chest 
 Wells (Soelberg) on Diseases of the Eye 23 
 
 — Long, Short, and Weak Sight . 23 
 Wells (Spencer) on Diseases of the 
 
 Ovaries .... 
 Wife's Domain .... 
 
 Wilks' Diseases of Nervous System . 
 
 — Pathological Anatomy . ■»- . 
 Wilson's (E.) Anatomist's Vade- 
 
 Mecum ..... 
 
 — Diseases of the Skin 
 
 — Lectures on Ekzema 
 
 — Lectures on Dermatology . 19 
 Wilson's (G.) Handbook of Hygiene . 21 
 Woodman & Tidy's Forepsic Medicine 21 
 
 10 
 22 
 17 
 12 
 17 
 15 
 
 13 
 14 
 
 17 
 10 
 
 11 
 
 19 
 19 
 
CATALOGUE OP RECENT WORKS 
 
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 MINOR SURGERY AND BANDAGING : 
 
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 [1875] 
 
CATALOGUE OF EEOEXT "WORKS 
 
 FRACTURES OF THE LOWER END OF THE RADIUS, 
 
 Fractures of tlie Clavicle, and on the Reduction of the Recent Inward 
 Dislocations of the Shoulder Joint. By Alexander Gordon, M.D., 
 Professor of Surgery in Queen's College, Belfast. With Engravings, 
 8vo, 5s. [1875] 
 
 DISEASES AND INJURIES OF THE EAR, 
 
 by W. B. Dalby, F.R.C.S., M.B., Aural Surgeon and Lecturer on 
 Aural Surgery at St. George's Hospital. Crown 8vo, with 21 Engi*av- 
 ings, 6s. Gd. [1873] 
 
 THE EAR : 
 
 its Anatomy, Physiology, and Diseases. A Practical Treatise, by 
 Charles H. Burnett, A.M., M.D., Aural Surgeon to the Presby- 
 terian Hospital, and Surgeon in Charge of the Infirmary for Diseases 
 of the Ear, Philadelphia. With 87 Engravings, 8vo, 18s. [1877] 
 
 AURAL CATARRH; 
 
 or, the Commonest Forms of Deafness, and their Cure, by Peter 
 Allen, M.D., F.R.C.S.E., late Aural Surgeon to St. Mary's Hospital. 
 Second Edition, crown 8vo, with Engravings, 8s. 6d. [1874] 
 
 CLUBFOOT : 
 
 its Causes, Pathology, and Treatment; being the Jacksonian Prize 
 Essay by Wm. Adams, F.R.C.S., Surgeon to the Great Northern Hos- 
 pital. Second Edition, 8vo, with 106 Engravings and 6 Lithographic 
 Plates, 15s. [1873] 
 
 ORTHOPAEDIC SURGERY : 
 
 Lectures delivered at St. George's Hospital, by Bernard E. Brod- 
 HURST, F.R.C.S., Surgeon to the Royal Orthopsedic Hospital. Second 
 Edition, 8vo, with Engravings, 12s. 6d. [1876] 
 
 OPERATIVE SURGERY OF THE FOOT AND ANKLE, 
 
 by Henry Hancock, F.R.C.S., Consulting Surgeon to Charing Cross 
 Hospital. 8vo, with Engravings, 15s. [1873] 
 
 ORTHOPEDIC SURGERY: 
 
 and Diseases of the Joints. Lectures by Lewis A. Sayre, M.D., 
 Professor of Orthopaedic Surgery, Fractures and Dislocations, and 
 Clinical Surgery, in Bellevue Hospital Medical College, New York. 
 With 274 Wood Engravings, 8vo, 20s. [1876] 
 
 THE TREATMENT OF SURGICAL INFLAMMATIONS 
 
 by a New Method, which greatly shortens their Duration, by Furneaux 
 Jordan, F.R.C.S., Professor of Surgery in Queen's College, Birming- 
 ham. 8vo, with Plates, 7s. 6d. [18701 
 
 BY THE SAME AUTHOE, 
 
 BURGICAL INQUIRIES. 
 
 With numerous Lithographic Plates, 8vo, 5s. [1873] 
 
 ORTHOPRAXY : 
 
 the Mechanical Treatment of Deformities, Debilities, and Deficiencies of 
 the Human Frame, by H. Heather Bigg, Associate of the Institute of 
 Civil Engineers. Third Edition, with 319 Engravings, 8vo, 15s. [1877] 
 
PUBLISHED BY J. AND A. CHURCHILL 
 
 INTERNAL ANEURISM : 
 
 Its Successful Treatment by Consolidation of the Contents of the Sac. 
 By T. JoLiFPE TuFNELL, F.R.C.S.I., President of the Royal College 
 of Surgeons in Ireland. With Coloured Plates. Second Edition, 
 royal 8vo, 5s. [1875] 
 
 DISEASES OF THE RECTUM, 
 
 by Thomas B. Curling, F.R.S., Consulting Surgeon to the London 
 Hospital. Fourth Edition, Revised, 8vo, 7s. 6d. [1876] 
 
 STRICTURE OF THE URETHRA 
 
 and Urinary Fistuke ; their Pathology and Treatment : Jacksonian 
 Prize Essay hy Sir Heney Thompson, F.R.C.S., Emeritus Professor 
 of Surgery to University College. Third Edition, 8vo, with Plates, 
 
 10s. [1869] 
 
 BY THE SAME ATJTHOE, 
 
 PRACTICAL LITHOTOMY AND LITHOTRITY; 
 
 01-, An Inquiry into the best Modes of removing Stone from the 
 Bladder. Second Edition, 8vo, with numerous Engravings. lOs. [1871] 
 
 ALSO, 
 
 DISEASES OF THE URINARY ORGANS : 
 
 (Clinical Lectures). Fourth Edition, Svo, with 2 Plates and 59 
 Engravings, 12s. [1876] 
 
 ALSO, 
 
 DISEASES OF THE PROSTATE : 
 
 their Pathology and Treatment. Fourth Edition, Svo, with numerous 
 Plates, 10s. [1873] 
 
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 THE PREVENTIVE TREATMENT OF CALCULOUS DISEASE 
 and the Use of Solvent Remedies. Second Edition, fcap. Svo, 2s. 6d. 
 
 STRICTURE OF THE URETHRA ^^^^^^ 
 
 and its Immediate Treatment, by Barnard Holt, F.R.C.S., 
 Consulting Surgeon to the Westminster Hospital. Third Edition, 
 
 Svo, 6s. [1868] 
 
 LITHOTOMY AND EXTRACTION OF STONE 
 
 from the Bladder, Urethra, and Prostate of the Male, and from the 
 Bladder of the Female, by W. Poulett Harris, M.D., Surgeon-Major 
 H.M. Bengal Medical Service. With Engravings, Svo, 10s. 6d. [1876] 
 
 THE SURGERY OF THE RECTUM : 
 
 Lettsomian Lectures by Henry Smith, F.R.C.S., Professor of Surgery 
 in King's College, Surgeon to King's College Hospital. Fourth 
 Edition, fcap. Svo, 5s. [1876] 
 
 FISTULA, HAEMORRHOIDS, PAINFUL ULCER, 
 
 Stricture, Prolapsus, and other Diseases of the Rectum : their Diagnosis 
 and Treatment, by Wm. Allingham, F.R.C.S., Surgeon to St. Mark's 
 Hospital for Fistula, &.G. Second Edition, Svo, 7s. [i87iJj 
 
CATALOGUE OF RECENT WORKS 
 
 KIDNEY DISEASES, URINARY DEPOSITS, 
 
 and Calculous Disorders by Lionel S. Beale, M.B., F.R.S., F.R.C.P., 
 Physician to King's College Hospital. Third Edition, Svo, with 
 70 Plates, 25s. [1868] 
 
 DISEASES OF THE BLADDER, 
 
 Prostate Gland and Urethra, including a practical view of Urinary 
 Diseases, Deposits and Calculi, by F. J. Gant, F.R.C.S., Senior Sur- 
 geon to the Royal Free Hospital. Fourth Edition, crown 8vo, with 
 Engravings, 10s. 6d. [1876] 
 
 RENAL DISEASES : 
 
 a CUnioal Guide to theii- Diagnosis and Treatment by "W. R. Basham, 
 M.D., F.R.C.P., late Senior Physician to the Westminster Hospital. 
 Post 8vo, 7s. [1870] 
 
 BY THE SAME AUTHOR, 
 
 THE DIAGNOSIS OF DISEASES OF THE KIDNEYS, 
 
 with Aids thereto. 8vo, with 10 Plates, 5s. [1872] 
 
 THE REPRODUCTIVE ORGANS 
 
 in Childhood, Youth, Adult Age, and Advanced Life (Functions and 
 Disorders of), considered in their Physiological, Social, and Moral 
 Relations, by William Acton, M.R.C.S. Sixth Edition, Svo, 12s. 
 
 [1875] 
 
 URINARY AND REPRODUCTIVE ORGANS : 
 
 their Functional Diseases, by D. Campbell Black, M.D., L.R.C.S. 
 Edin. Second Edition. Svo, 10s. 6d. [IS'W] 
 
 BY THE SAME AUTHOE, 
 
 LECTURES ON BRIGHTS DISEASE, 
 
 delivered at the Royal Infirmary of Glasgow. Svo, with 20 Engrav- 
 ings, 6s. 6d. [1875] 
 
 PRACTICAL PATHOLOGY : 
 
 containing Lectures on Suppurative Fever, Diseases of the Veins, 
 Hsemorrhoidal Tumours, Diseases of the Rectum, Syphilis, Gonor- 
 rheal Ophthalmia, &c., by Henry Lee, F.R.C.S., Surgeon to St. George's 
 Hospital. Third Edition, in 2 vols. Svo, 10s. each. [1870] 
 
 BY THE SAME AUTHOR, 
 
 LECTURES ON SYPHILIS, 
 
 and on some forms of Local Disease, affecting principally the Organs 
 of Generation. With Engravings, Svo, 10s. [1875] 
 
 SYPHILIS : 
 
 A Treatise by Walter J. Coulson, F.R.C.S., Sur_jeon to the Lock 
 Hospital. Svo, 10s. [1869] 
 
 BY THE 6AME AUTHOB, 
 
 STONE IN THE BLADDER: 
 
 Its Prevention, Early Symptoms, and Treatment by Lithotrity. 8to, 
 6s. [1868] 
 
PUBLISHED BY J. AND A. CHURCHILL 
 
 PATHOLOGY OF THE URINE, 
 
 including a Complete Guide to its Analysis, by J. L. W. ThudichuIvi, 
 M.D. Second Edition, rewritten and enlarged, with Engi-avings, 8vo, 
 15s. C1877] 
 
 GENITOURINARY ORGANS, INCLUDING SYPHILIS: 
 
 A Practical Treatise on tlieir Surgical Diseases, designed as a Manual 
 for Students and Practitioners, by W. H. Van Buren, M.D., Pro- 
 fessor of tbe Pi'inciples of Sui-gery in Bellevne Hospital Medical Col- 
 lege, New York, and E. L. Keyes, M.D., Professor of Dermatology in 
 Bellevue Hospital Medical College, New York. Royal 8vo, witb 140 
 Engravings, 21s. [1874] 
 
 SYPHILITIC NERVOUS AFFECTIONS : 
 
 Their Clinical Aspects, by Thomas Buzzard, M.D., F.R.C.P. Lond., 
 Physician to the National Hospital for Paralysis and Epilepsy. Post 
 8vo, 5s. tl874] 
 
 HISTOLOGY AND HISTOCHEMISTRY OF MAN : 
 
 A Treatise on the Elements of Composition and Structure of the 
 Human Body, by Heinrich Frey, Professor of Medicine in Zurich. 
 Translated from the Fourth German Edition by Arthur E. J. 
 Barker, Assistant-Surgeon to University College Hospital. And 
 Revised by the Author. Svo, with 608 Engravings, 21s. [1874] 
 
 HUMAN PHYSIOLOGY: 
 
 A Treatise designed for the Use of Students and Practitioners of 
 Medicine, by John C. Dalton, M.D., Professor of Physiology and 
 Hygiene in the College of Physicians and Surgeons, New York. Sixth 
 Edition, royal Svo, with 316 Engra\ings, 20s. Cl87»] 
 
 HANDBOOK FOR THE PHYSIOLOGICAL LABORATORY, 
 
 by E. Klein, M.D., F.R.S., Assistant Professor in the Pathological Labo- 
 ratory of the Brown Institution, London ; J. Burdon-Sanderson, 
 M.D., F.R.S., Professor of Practical Physiology in University College, 
 London ; Michael Foster, M.D., F.R.S., Prajlector of Physiology 
 in Trinity College, Cambridge; and T. Lauder Brunton, M.D., 
 D.Sc, Lecturer on Materia Medica at St. Bartholomew's Hospital ; 
 edited by J. Burdon-Sanderson. 8vo, with 123 Plates, 24s. [i878] 
 
 PRACTICAL HISTOLOGY : 
 
 By William Rutherford, M.D., Professor of the Institutes of 
 Medicine in the University of Edinburgh. Second Edition, with 
 
 63 Eno-ravini's. Crown 8vo (with additional leaves for notes), 6s. 
 
 "=■ ° [1876] 
 
 THE MARRIAGE OF NEAR KIN, 
 
 Considered with respect to the Laws of Nations, Results of Experience, 
 and the Teachings of Biology, by Alfred H. Huth. 8vo, 14s. [1875] 
 
 § 
 
10 CATALOGUE OF RECENT WOEKS 
 
 PRINCIPLES OF HUMAN PHYSIOLOGY, 
 
 by W. B. Carpentek, C.B., M.D., F.R.S. Eiglitli Edition by Henry 
 Power, M.B., F.R.O.S., Examiner in Natural Science, University of 
 Oxford, and in Natural Science and Medicine, University of Cambridge. 
 8vo, witli 3 Steel Plates and 371 Engravings, 31s. 6d. [1876] 
 
 STUDENTS' GUIDE TO HUMAN OSTEOLOGY, 
 
 By William Warwick Wagstafpe, F.R.C.S., Assistant-Surgeon 
 and Lecturer on Anatomy, St. Thomas's Hospital. WitL. 23 Platea 
 and 66 Engravings. Fcap. 8vo, 10s. 6d. [^STo'] 
 
 LANDMARKS, MEDICAL AND SURGICAL, 
 
 By Luther Holden, F.R.C.S., Senior Surgeon to St. Bartholomew's 
 Hospital. Second Edition, 8vo, 3s. 6d. [1877] 
 
 PATHOLOGICAL ANATOMY: 
 
 Lectures by Samuel Wilks, M.D., F.R.S. , Physician to, and Lec- 
 turer on Medicine at, Guy's Hospital ; and Walter Moxon, M.D., 
 F.R.C.P., Physician to, and Lecturer on Materia Medica at, Guy's 
 Hospital. Second Edition, Svo, with Plates, IBs. [1875] 
 
 PATHOLOGICAL ANATOMY : 
 
 A Manual by 0. Handfield Jones, M.B., F.R.S., Physician to St. 
 Mary's Hospital, and Edward H. Sieveking, M.D., F.R.C.P., 
 Physician to St. Mary's Hospital. Edited by J. F. Payne, M.D., 
 F.R.C.P., Assistant Physician and Lecturer on General Pathology 
 at St. Thomas's Hospital. Second Edition, crown Svo, with 195 
 Engravings, 16s. [1873] 
 
 POST-MORTEM EXAMINATIONS : 
 
 a Description and Explanation of the Method of Performing them^ 
 with especial Reference to Medico-Legal Practice. By Professor 
 Rudolph Virchow, of Berlin. Fcap Svo, 2s. 6d. [i^^^] 
 
 STUDENT'S GUIDE TO SURGICAL ANATOMY : 
 
 a Text-book for the Pass Examination, by E. Bellamy, F.R.C.S., 
 Surgeon and Lecturer on Anatomy at Charing Cross Hospital. Fcap 
 Svo, with 50 Engravings, 6s. 6d. [1873] 
 
 DIAGRAMS OF THE NERVES OF THE HUMAN BODY, 
 
 Exhibiting their Origin, Divisions, and Connexions, with their Distri- 
 bution, by William H. Flower, F.R.S., Conservator of Museum, 
 Royal College of Surgeons. Second Edition, roy. 4to, 12-s. [W2] 
 
 PRACTICAL ANATOMY : 
 
 a Manual of Dissections by Christopher Heath, F.R.C.S., Surgeon 
 to University College Hospital, and Holme Professor of Surgery in 
 University College. Fourth Edition, crown Svo, with 16 Coloured 
 Plates and 264 Engravings, 14s. [1877] 
 
 MEDICAL ANATOMY, 
 
 by Francis Sibson, M.D., F.R.C.P., F.R.S. Imp. folio, with 21 
 coloured Plates, cloth, 42s., half-morocco, 50s. [1869] 
 
PUBLISHED BY J. AND A. CHUECHILL 11 
 
 AN ATLAS OF HUMAN ANATOMY : 
 
 illustrating most of the ordinary Dissections, and many not usually 
 practised by the Student. To be completed in 12 or 13 Bi-monthly 
 Parts, each containing 4 Coloured Plates, with Explanatory Text. By 
 RiCKMAN J. GODLEE, M.S., F.ll.CS., Assistant Surgeon to University 
 College Hospital, and Senior Demonsti-ator of Anatomy in University 
 College. Imp. 4to, 7s. 6d. each Part. [1877-8] 
 
 THE ANATOMIST'S VADE-MECUM : 
 
 a System of Human Anatomy by Erasmus Wilson, F.R.C.S., F.R.S. 
 Ninth Edition, by G. Buchanan, M.A., M.D., Professor of Clinical 
 Surgery in the University of Glasgow, and Henky E. Clakk, F.F.P.S., 
 Lecturer on Anatomy at the Glasgow Royal Infirmary School of 
 Medicine. Crown Svo, with 371 Engravings, 14s. [1^873] 
 
 ATLAS OF TOPOGRAPHICAL ANATOMY, 
 
 after Plane Sections of Frozen Bodies. By Wilhelm Braune, 
 Professor of Anatomy in the University of Leipzig. Translated by 
 Edward Bellamy, F.R.C.S., Surgeon to, and Lecturer on Anatomy, 
 &c., at. Charing Cross Hospital. With 34 Photo-lithographic Plates 
 and 46 Woodcuts. Large Imp. Svo, 40s. [1877] 
 
 THE STUDENT'S GUIDE TO THE PRACTICE OF MEDICINE, 
 by Matthew Charteris, M.D., Professor of Medicine in Anderson's 
 College, and Lecturer on Clinical Medicine in the Royal Infirmary, 
 Glasgow. With Engravings on Copper and Wood, fcap. Svo, 6s. 6d. [1^77] 
 
 THE MICROSCOPE IN MEDICINE, 
 
 by Lionel S. Beale, M.B., F.R.S., Physician to King's College 
 Hospital. Fovirth Edition, with S6 Plates, Svo, 21s. [1«77] 
 
 THE STUDENT'S GUIDE TO MEDICAL DIAGNOSIS, 
 
 by Samuel Fenwick, M.D., F.R.C.P., Physician to the Londdn 
 Hospital. Fourth Edition, fcap. Svo, with 106 Engravings, 6s. 6d. [1876] 
 
 A MANUAL OF MEDICAL DIAGNOSIS, 
 
 by A. W. Barclay, M.D., F.R.C.P., Physician to, and Lectm-er on 
 Medicine at, St. George's Hospital. Third Edition, fcap Svo, 10s. 6d. 
 
 THE ANATOMICAL REMEMBRANCER; ^^^''^^ 
 
 or. Complete Pocket Anatomist. Eighth Edition, 32mo, 3s. 6d. [W6] 
 
 HOOPER'S PHYSICIAN'S VADE-MECUM ; 
 
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 by W. A. Guy, M.B., F.R.S., and John Harley, M.D., F.R.C.P. 
 Fcap Svo, with Engravings, 12s. 6d. [1874] 
 
 A NEW SYSTEM OF MEDICINE ; 
 
 entitled Recognisant Medicine, or the State of the Sick, by 
 Bholanoth Bose, M.D., Indian Medical Service. Svo, 10s. 6d. [1877] 
 
 BY THE SAME AUTHOK. 
 
 PRINCIPLES OF RATIONAL THERAPEUTICS. 
 
 Commenced as an Inquiry into the Relative Value of Quinine and 
 Arsenic in Ague. Svo, 4s. 6d. [is''] 
 
13 CATALOGUE OF EECENT WORKS 
 
 THE MEDICAL REMEMBRANCER; 
 
 or, Book of Emergencies. By E. Shaw, M.R.C.S. Fiftli Edition by 
 Jonathan Hutchinson, F.R.C.S., Senior Sm-geon to the London 
 Hospital. 32mo, 2s. 6d. [1867] 
 
 MATERIA MEDICA AND THERAPEUTICS : 
 
 (Vegetable Kingdom), by Charles D. F. Phillips, M.D., F.R.C.S.E. 
 8vo, 15s. [1874] 
 
 CLINICAL MEDICINE : 
 
 Lectures and Essays by Balthazar Foster, M.D., F.R.C.P. Lond., 
 Professor of Medicine in Queen's College, Birmingliam. 8vo, iOs. 6d. 
 
 [1874] 
 
 CLINICAL STUDIES: 
 
 Illustrated by Cases observed in Hospital and Private Practice, by Sir 
 J. Rose Oormack, M.D., F.R.S.E., Physician to the Hertford British 
 Hospital of Paris. 2 vols., post 8vo, 20s. [1876] 
 
 ROYLE'S MANUAL OF MATERIA MEDICA AND THERAPEUTICS. 
 Sixth Edition by John Harley, M.D., Assistant Physician to, and 
 Joint Lecturer on Physiology at, St. Thomas's Hospital. Crown 8vo, 
 with 139 Engravings, 15s. [1876] 
 
 PRACTICAL THERAPEUTICS : 
 
 A Manual by E. J. Waring, M.D., F.R.C.P. Lond. Third Edition, 
 fcap 8vo, 12s. 6d. [i87i] 
 
 THE ELEMENTS OF THERAPEUTICS. 
 
 A Clinical Guide to the Action of Drugs, by C. BiNZ, M.D., Professor 
 of Pharmacology in the University of Bonn. Translated and Edited 
 with Additions, in Conformity with the British and American Phar- 
 macopoeias, by Edward I. Sparks, M.A., M.B. Oxon., formerly 
 Radcliffe Travelling Fellow. Crown 8vo, 8s. 6d. [1877] 
 
 THE STUDENT'S GUIDE TO MATERIA MEDICA, 
 
 by John C. Thorowgood, M.D. Lond., Physician to the City of 
 London Hospital for Diseases of the Chest. Fcap Svo, with Engrav- 
 ings, 6s. 6d. [1874] 
 
 THE DISEASES OF CHILDREN : 
 
 A Practical Manual, with a Formulary, by Edward Ellis, M.D., 
 late Senior Physician to the Victoria Hospital for Children. Third 
 Edition, crown 8vo, 7s. 6d. [1878] 
 
 THE WASTING DISEASES OF CHILDREN, 
 
 by Eustace Smith, M.D. Lond., Physician to the King of the Belgians, 
 Physician to the East London Hospital for Children. Second Edition, 
 post 8vo, 7s. 6d. [1870] 
 
 BY THE SAME AUTHOR, 
 
 CLINICAL STUDIES OF DISEASE IN CHILDREN. 
 
 Post 8vo, 7s. 6d. [1876] 
 
 INFANT FEEDING AND ITS INFLUENCE ON LIFE ; 
 
 or, the Causes and Prevention of Infant Mortality, by Charles H. F. 
 Routh, M.D., Senior Physician to the Samaritan Hospital for Women 
 and Children. Third Edition, fcap Svo, 7s. 6d. [1876] 
 
PUBLISHED BY J. AND A. CHURCHILL 13 
 
 COMPENDIUM OF CHILDREN'S DISEASES : 
 
 A Handbook for Practitioners and Students, by Johann Steiner, 
 M.D., Professor in the University of Prague. Translated from the 
 Second German Edition by Laavson Tait, F.R.C.S., Surgeon to the 
 Birmingham Hospital for Women. 8vo, 12s. 6d. [1874] 
 
 THE DISEASES OF CHILDREN: 
 
 Essays by William Henry Day, M.D., Physician to the Samaritan 
 Hospital for Diseases of Women and Children. Fcap 8vo, 5s. [187S] 
 
 PUERPERAL DISEASES: 
 
 Clinical Lectures by Foedyce Barker, M.D., Obstetric Physician 
 to Bellevue Hospital, New York. 8vo, 15s. [1874] 
 
 THE STUDENT'S GUIDE TO THE PRACTICE OF MIDWIFERY, 
 by D. Lloyd Roberts, M.D., Physician to St. Mary's Hospital, Man- 
 chester. Fcap. Svo, with 95 Engravings, 6s. 6d. [1875] 
 
 OBSTETRIC IHEDICINE AND SURGERY, 
 
 Their Principles and Practice, by F. H. Ramsbotham, M.D., F.R.C.P. 
 Fifth Edition, Svo, with 120 Plates, 22s. [18G7] 
 
 OBSTETRIC SURGERY: 
 
 A Complete Handbook, giving Short Rules of Practice in every Emer- 
 gency, from the Simplest to the most Formidable Operations connected 
 with the Science of Obstetricy, by Charles Clay, Ext.L.R.C.P. Lond., 
 L.R.C.S.E., late Senior Sui-geon and Lecturer on Midwifery, St. 
 Mary's Hospital, Manchester. Fcap Svo, with 91 Engravings, 6s. 6d. 
 
 [1874] 
 
 SCHROEDER'S MANUAL OF MIDWIFERY, 
 
 including the Pathology of Pregnancy and the Puerperal State. 
 Translated by Charles H. Carter, B.A., M.D. Svo, with Engrav- 
 ings, 12s. 6d. [1873] 
 
 A HANDBOOK OF UTERINE THERAPEUTICS, 
 
 and of Diseases of Women, by E. J. Tilt, M.D., M.R.C.P. Third 
 Edition, post Svo, 10s. [1868] 
 
 BY THE SAME AUTHOH, 
 
 THE CHANGE OF LIFE 
 
 in Health and Disease : a Practical Treatise on the Nervous and other 
 Affections incidental to Women at the Decline of Life. Thii-d Edition, 
 Svo, 10s. 6d. [1870] 
 
 DISEASES OF THE OVARIES : 
 
 theii- Diagnosis and Treatment, by T. Spencer Wells, F.R.C.S., 
 Surgeon to the Queen's Household and to the Samaritan Hospital. 
 Svo, with about 150 Engravings, 21s. [1872] 
 
 PRACTICAL GYNECOLOGY: 
 
 A Handbook of the Diseases of Women, by Heywood Smith, M.D. 
 Oxon., Physician to the Hospital for Women and to the British Lying- 
 in Hospital. With Engi'avings, crown Svo, 5s. 6d. [1877] 
 
14 CATALOGUE OF RECENT WORKS 
 
 OBSTETRIC OPERATIONS, 
 
 including the Treatment of Hsemorrliage, and forming a Guide to the 
 Management of Difficult Labour; Lectures by Robert Barnes, M.D., 
 F.R.C.P., Obstetric Physician and Lecturer on Obstetrics and the Dis- 
 eases of Women and Children at St. George's Hospital. Third Edition, 
 8vo, with 124 Engravings, 18s. , [1875} 
 
 BY THE SAME AUTHOR, 
 
 MEDICAL AND SURGICAL DISEASES OF WOMEN : 
 
 a Clinical History. Second Edition, Svo, with many Engravings. 
 
 [Ill the Press] 
 
 OBSTETRIC APHORISMS: 
 
 for the Use of Students commencing Midwifery Practice by J. G. 
 SwAYNE, M.D., Consulting Physician-Accoucheur to the Bristol 
 General Hospital, and Lecturer on Obstetric Medicine at the Bristol 
 Medical School. Sixth Edition, fcap Svo, withSEngravings, 3s. 6d. [1876] 
 
 HANDBOOK FOR NURSES FOR THE SICK, 
 
 by Zepherina P. Veitch. Second Edition, crown Svo, 3s. 6d. f^^"^] 
 
 A MANUAL FOR HOSPITAL NURSES 
 
 and others engaged in Attending on the Sick by Edvv'Ard J.'Dom*- 
 ville, L.R.C.P., M.R.C.S. Second Edition, crown Svo, 2s. 6d. [1875] 
 
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 A Manual of General and Monthly Nursing, by-CHARLES J. Culling- 
 vvoRTH, Surgeon to St. Mary's Hospital, Manchester. Fcap. Svo, 
 2g. Gd. [1876] 
 
 LECTURES ON NURSING, 
 
 by William Robert Smith, M.B., Honorary Medical Officer, 
 Hospital for Sick Children, Sheffield. Second.^ Edition, with 26 En- 
 gi'avings. Post Svo, 6s. [1878] 
 
 HOSPITAL MORTALITY: 
 
 being a Statistical Investigation of the Returns of the Hospitals of 
 Great Britain and Ireland for fifteen years, by Lawson Tait, F.R.C.S., 
 F.S.S. Svo, 6s. [1877J 
 
 ENGLISH MID WIVES : 
 
 thcir-History and Prospects, by J. H. Aveling, M.D., Physician to 
 the Chelsea Hospital for Women, Examiner of Midwives for the 
 Obstetrical Society of London. Crown Svo, 5s. [1873] 
 
 A COMPENDIUM OF DOMESTIC MEDICINE 
 
 and Companion to the Medicine Chest ; intended as a Source of Easy 
 Reference for Clergymen, and for Families residing at a Distance 
 from Professional Assistance, by John Savory, M.S.A. Ninth 
 Edition, 12mo, 5s. [1878] 
 
 THE WIFE'S DOMAIN: 
 
 The Yfnmg Couple— The Mother— The Nurse— The Nursling, by Phi- 
 LOTHALOS. Second Edition, post Svo, 3s. 6d. [187^] 
 
PUBLISHED BY J. AND A. CHURCHILL 1&- 
 
 THE COTTAGE HOSPITAL: 
 
 Its Origin, Progress, Management, and Work, l>y Heney C. Burdett, 
 the Seaman's Hospital, Greenwich. "With Engravings, crown 8vo, 
 7s. 6d. [1877J 
 
 WINTER COUGH : 
 
 (Catarrh, Bronchitis, Emphysema, Asthma), Lectures by Horace 
 DoBELL,M.P.,ConsultingPhysicianto the Royal Hospital for Diseases 
 of the Chest. Third Edition, with Coloured Plates, 8vo, Is. 6d. [1^5] 
 
 BY THE SAME AUTHOE, 
 
 THE TRUE FIRST STAGE OF CONSUMPTION. 
 
 (Lectures.) Crown Svo, 3s. 6d. [1867] 
 
 DISEASES OF THE CHEST : 
 
 Contributions to their Clinical History, Pathology, and Treatment, by 
 A. T. H. Waters, M.D., F.R.C.P., Physician to the Livei-pool Royal 
 Infirmary. Second Edition, Svo, with Plates, I5s. [1873] 
 
 NOTES ON ASTHMA ; 
 
 its Forms and Treatment, by John C. Thorowgood, M.D. Lond., 
 F.R.C.P., Physician to the Hospital for Diseases of the Chest, Victoria 
 Park. Third Edition, crown Svo, 4s. 6d. [1878] 
 
 PROGNOSIS IN CASES OF VALVULAR DISEASE OF THE 
 Heart, by Thomas B. Peacock, M.D., F.R.C.P., Honorary Consult- 
 ing Physician to St. Thomas's Hospital. Svo, os. 6d. [1877] 
 
 DISEASES OF THE HEART: 
 
 Their Pathology, Diagnosis, Prognosis, and Treatment (a Manual), 
 by Robert H. Semple, M.D., F.R.C.P., Physician to the Hospital for 
 Diseases of the Throat. Svo, 8s. 6d. [1875] 
 
 DISEASES OF THE HEART AND AORTA, 
 
 By Thomas Hayden, F.K.Q.C.P. Irel., Physician to the Mater 
 Misericordiee Hospital, Dublin. With SO Engravings. Svo, 25s. [1875] 
 
 PHTHISIS : 
 
 In a series of Clinical Studies, by Austin Flint, M.D., Professor of 
 the Principles and Practice of Medicine and of Clinical Medicine in 
 the Bellevue Hospital Medical College. Svo, I6s. [1875] 
 
 BY THE SAME AUTHOE, 
 
 A MANUAL OF PERCUSSION AND AUSCULTATION, 
 
 of the Physical Diagnosis of Diseases of the Lungs and Heart, and of 
 Thoracic Aneurism. Post Svo, 6s. 6d. [1876] 
 
 GROWTHS IN THE LARYNX, 
 
 with Reports and an Ajialysis of 100 consecutive Cases treated since 
 the Invention of the Laryngoscope by Morell Mackenzie, M.D. 
 Lond., M.R.C.P., Physician to the Hospital for Diseases of the 
 Throat. Svo, with Coloured Plates, 12s. 6d. [iS7i] 
 
16 CATALOGUE OP RECENT WORKS 
 
 DISEASES OF THE HEART 
 
 and of tlie Lungs in Connexion tlierewitli— Notes and Observations 
 by Thomas Shapteb, M.D., F.R.O.P. Lond., Senior Physician to the 
 Devon and Exeter Hospital. 8vo, 7s. 6d. [I874j 
 
 DISEASES OF THE HEART AND AORTA : 
 
 Clinical Lectures by Geokge W. Balfoue, M.D., F.R.C.P., Physician 
 to, and Lecturer on Clinical Medicine in, the Royal Infirmary, Edin- 
 burgh. 8vo, with Engravings, 12s. 6d. [1876] 
 
 PHYSICAL DIAGNOSIS OF DISEASES OF THE HEART. 
 
 Lectures by Arthur E. Sansom, M.D., Assistant Physician to the 
 
 London Hospital. Second Edition, with Engravings, fcap. 8vo, 4s. 6d. 
 
 [1876] 
 
 TRACHEOTOMY, 
 
 especially in Relation to Diseases of the Larynx and Ti-achea, by 
 PuGiN Thornton, M.R.C.S., late Surgeon to the Hospital for Diseases 
 of the Throat. With Photographic Plates and Woodcuts, Svo, 5s. 6d. 
 
 [1876] 
 
 SKETCH OF CANNES AND ITS CLIMATE, 
 
 by Th. De Valcourt, M.D. Paris, Physician at Cannes. Second 
 
 Edition, with Photographic View and 6 Meteorological Charts. 
 
 Crown Svo, 2s. 6d. [1873] 
 
 WINTER AND SPRING 
 
 on the Shores of the Mediterranean ; or, the Genoese Rivieras, Italy, 
 Spain, Greece, the Archipelago, Constantinople, Corsica, Sardinia, 
 Sicily, Corfu, Malta, Tunis, Algeria, Smyrna, Asia Minor, with 
 Biarritz and Arcachon, as Winter Climates. By Henry Bennet, 
 M.D. Fifth Edition, post Svo, with numerous Plates, Maps, and 
 Engravings, 12s. 6d. [1874] 
 
 BY THE SAME AUTHOR, 
 
 TREATMENT OF PULMONARY CONSUMPTION 
 
 by Hygiene, Climate, and Medicine. Second Edition, Svo, 5s. [1871] 
 
 PRINCIPAL HEALTH RESORTS 
 
 of Europe and Africa, and their Use in the Treatment of Chronic 
 Diseases. A Handbook by Thomas More Madden, M.D., M.R.I.A., 
 Vice-President of the Dublin Obstetrical Society. Svo, 10s. [187G] 
 
 THE BATH THERMAL WATERS: 
 
 Historical, Social, and Medical, by John Kent Spender, M.D., 
 Surgeon to the Mineral Water Hospital, Bath. With an Appendix 
 on the Climate of Bath by the Rev. L. Blomefield, M.A., F.L.S., 
 F.G.S. Svo, 7s. Gd. [1877] 
 
 ENDEMIC DISEASES OF TROPICAL CLIMATES, 
 
 with their Treatment, by John Sullivan, M.D., M.R.C.P. Post Svo, 
 «s. [1877] 
 
PUBLISHED BY J. AND A. CHURCHILL 17 
 
 FAMILY MEDICINE FOR INDIA : 
 
 A Manual, by William J. Moore, M.D., Surgeon-Major H.M. Indian 
 Medical Service. Published under the Authority of the Government 
 of India. Third Edition, post 8vo, with 60 Engravings. [in the press] 
 
 DISEASES OF TROPICAL CLIMATES 
 
 and their Treatment : with Hints for the Preservation of Health in the 
 Tropics, by James A. Horton, M.D., Surgeon -Major, Army Medical 
 Department. Post 8vo, 12s. 6d. [1874] 
 
 HEALTH IN INDIA FOR BRITISH WOMEN 
 
 and on the Prevention of Disease in Tropical Climates by Edward J. 
 Tilt, M.D., Consulting Physician-Accoucheur to the Fan-ingdon 
 Genei'al Dispensary. Fourth Edition, ci*own 8vo, 5s. [1875] 
 
 BURDWAN FEVER, 
 
 or the Epidemic Fever of Lower Bengal (Causes, Symptoms, and 
 Treatment), by Gopaul Chunder Roy, M.D., Surgeon Bengal 
 
 Establishment. New Edition, Svo, 5s. [1*76] 
 
 BAZAAR MEDICINES OF INDIA 
 
 and Common Medical Plants : Remarks on their Uses, with Full Index 
 of Diseases, indicating their Treatment by these and other Agents pro- 
 curable throughout India, &c., by Edw^ard J. Waring, M.D., F.R.CP. 
 Lond., Retired Surgeon H.M. Indian Army. Third Edition. Fcap 
 Svo, 5s. [1875] 
 
 SOME AFFECTIONS OF THE LIVER 
 
 and Intestinal Canal ; with Remarks on Ague and its Sequela^, Scurvy, 
 Purpura, &c., by Stephen H. Ward, M.D. Lond., F.R.CP. , Physician 
 to the Seamen's Hospital, Greenwich. Svo, 7s. [1873] 
 
 DISEASES OF THE LIVER : 
 
 Lettsomian Lectures for 1872 by S. O. Habershon, M.D., F.R.CP., 
 Senior Physician to Guy's Hospital. Post Svo, 3s. 6d. [1872] 
 
 BY THE SAME AUTHOE, 
 
 DISEASES OF THE STOMACH : DYSPEPSIA. 
 Second Edition, crown Svo, 5s. 
 
 BY THE SAME AUTHOE, 
 
 PATHOLOGY OF THE PNEUMOGASTRIC NERVE, 
 
 being the Lumleian Lectures for 1S7G. Post Svo, 3s. 6d. [1877] 
 
 FUNCTIONAL NERVOUS DISORDERS : 
 
 Studies by C Handfield Jones, M.B., F.R.CP., F.R.S., Physician 
 to St, Mary's Hospital. Second Edition, Svo, ISs. [187C] 
 
 LECTURES ON DISEASES OF THE NERVOUS SYSTEM, 
 
 by Samuel Wilks, M.D., F.R.S., Physician to, and Lecti;rcr on 
 Medicine at, Guy's Hospital. Svo, 15s. [1878] 
 
18 CATALOGUE OP KECENT WORKS 
 
 NUTRITION IN HEALTH AND DISEASE : 
 
 A Contribution to Hygiene and to Clinical Medicine. By Henby 
 Bennet, M.D. Third Edition. 8vo, 7s. [1877] 
 
 THE STOMACH AND DUODENUM : 
 
 Their Morbid States and their Relations to the Diseases of other 
 Organs, by Samuel Fekwick, M.D., E.R.C.P., Physician to the 
 London Hospital. 8vo, with 10 Plates, 12s. [1868] 
 
 FOOD AND DIETETICS, 
 
 Physiologically and Therapeiitically Considered. By Frederick W. 
 pAvr, M.D., F.R.S., Physician to Guy's Hospital. Second Edition, 
 8vo, 15s. [1875] 
 
 HEADACHES : 
 
 their Causes, Nature, and Treatment. By WlLMAM H. Day, M.D., 
 Physician to the Samaritan Free Hospital for Women and Children. 
 Second Edition, crown Svo, with Engravings. 6s. 6d. [1878] 
 
 IMPERFECT DIGESTION: 
 
 its Causes and Treatment by Arthur Leared, M.D., F.R.C.P., 
 Senior Physician to the Great Northern Hospital. Sixth Edition, 
 fcap Svo, 4s. 6d. [1875] 
 
 MEGRIM, SICK-HEADACHE, 
 
 and some Allied Disorders : a Contribution to the Pathology of Nerve- 
 Storms, by Edward Liveing, M.D. Cantab., Hon. Fellow of King's 
 College, London. Svo, with Coloured Plate, 15s. [1873] 
 
 NEURALGIA AND KINDRED DISEASES 
 
 of the Nervous System : their Nature, Causes, and Treatment, with a 
 series of Cases, by John Chapman, M.D., M.R.C.P. Svo, 14s. [1873] 
 
 THE SYMPATHETIC SYSTEM OF NERVES, 
 
 and their Functions as a Physiological Basis for a Rational System of 
 Therapeutics by Edward Meryon, M.D., F.R.C.P., Physician to the 
 Hospital for Diseases of the Nervous System. Svo, os. 6d. [1873] 
 
 RHEUMATIC GOUT, 
 
 or Chronic Rheumatic Arthritis of all the Joints ; a Treatise by 
 Robert Adams, M.D., M.R.I.A., late Surgeon to H.M. the Queen in 
 Ireland, and Regius Professor of Surgery in the University of Dublin. 
 Second Edition, Svo, with Atlas of Plates, 21s. [1872] 
 
 SCIATICA, LUMBAGO, AND BRACHIALGIA: 
 
 Their Nature and Treatment, and their Immediate Relief and Rapid 
 Cure by Hypodermic Injection of Morphia. By Henry Lawson, 
 M.D., Assistant-Physician to St. Mary's Hospital, and Lecturer on 
 Physiology in its School. Second edition, crown Svo, 5s. [1877] 
 
 GOUT, RHEUMATISM, 
 
 and the Allied Affections; a Treatise by Peter Hood, M.D. Crown 
 Svo, 10s. 6d. [i^'i] 
 
PUBLISHED BY J. A^D A. CHURCHILL 1^ 
 
 CANCER : 
 
 its varieties, tlicir Histology and Diagnosis, by Henky Arnott, 
 F.R.C.S.,late Assistant-Surgeon to, and Lecturer on Morbid Anatomy 
 at, St. Thomas's Hospital. 8vo, with 5 Plates and 22 Engravings, 
 5s. 6d. ^1872] 
 
 CANCEROUS AND OTHER INTRA- THORACIC GROWTHS : 
 
 their Natural History and Diagnosis, by J. Risdon Bennett, M.D., 
 F.R.C.P., Member of the General Medical Council. Post 8vo, with 
 Plates, 8s. ti872] 
 
 CERTAIN FORMS OF CANCER, 
 
 with a New and successful Mode of Treating it, to which is prefixed a 
 Practical and Systematic Description of all the varieties of this Disease, 
 by Alex. Maksden, M.D., F.R.C.S.E., Consulting Surgeon to the 
 Royal Free Hospital, and Senior Surgeon to the Cancer Hospital. 
 Second Edition, with Coloured Plates, 8vo, Ss. 6d. [18^3] 
 
 ATLAS OF SKIN DISEASES : 
 
 a series of Illustrations, with Descriptive Text and Notes upon Treat- 
 ment. By TiLBUKY Fox, M.D., F.R.C.P., Physician to the Department 
 for Skin Diseases in University College Hospital. With 72 Coloured- 
 Plates, royal 4to, half morocco, £6 6s. [15111 
 
 DISEASES OF THE SKIN : 
 
 a System of Cutaneous Medicine by Erasmus Wilson, F.R.C.S., 
 F.R.S. Sixth Edition, 8vo, 18s., with Coloured Plates, 36s. [18"] 
 
 BY THE SAME AUTHOB, 
 
 LECTURES ON EKZEMA 
 
 and Ekzematous Affections : with an Introduction on the General- 
 Pathology of the Skin, and an Appendix of Essays and Cases. 8vo, 
 10s. 6d. [iS'O^ 
 
 ALSO, 
 
 LECTURES ON DERMATOLOGY: 
 
 deHvered at the Royal College of Surgeons, 1870, 6s. ; 1871-3, 10s. 6d., 
 1874-5, 10s. 6d. 
 ECZEMA : 
 
 by McCall Anderson, M.D., Professor of Clinical Medicine in the 
 University of Glasgow. Third Edition, 8vo, with Engravings, 7s. 6d. 
 
 [1874] 
 
 BY THE SAME AUTUOE, 
 
 PARASITIC AFFECTIONS OF THE SKIN 
 
 Second Edition, Svo, with Engravings, 7s. 6d. [1868] 
 
 PSORIASIS OR LEPRA, 
 
 by George Gaskoin, M.R.C.S., Surgeon to the British Hospital for 
 Diseases of the Skin. 8vo, 5s. [1^75] 
 
20 CATALOGUE OF RECENT WORKS 
 
 MYCETOMA ; 
 
 or, the Fungus Disease of India, by H. Vandyke Carter, M.D., Sur- 
 
 ffeon-Maior H.M. Indian Army. 4to, with 11 Coloured Plates, 42s. 
 " •' [187-1] 
 
 OERTAIN ENDEMIC SKIN AND OTHER DISEASES 
 
 of India and Hot Climates generally, by Tilbury Fox, M.D., and 
 T. Farquhar, M.D. (Published under the sanction of the Secretary 
 of State for India in Council). 8vo, 10s. 6d. [18'6] 
 
 DISEASES OF THE SKIN, 
 
 in Twenty-four Letters on the Principles and Practice of Cutaneous 
 Medicine, by Henry Evans Cauty, Sm-geon to the Liverpool Dis- 
 pensary for Diseases of the Skin, 8vo, 12s. 6d. D-^H'] 
 
 THE HAIR IN HEALTH AND DISEASE, 
 
 by E. Wyndham Cottle, F.R.C.S., Senior Assistant Surgeon to the 
 Hospital for Diseases of the Skin, Blackfriars. Fcap. 8vo, 2s. 6d. [1877] 
 
 WORMS: 
 
 a Series of Lectures delivered at the Middlesex Hospital on Practical 
 Helminthology by T. Spencer Cobbold, M.D., F.R.S. Post Svo, 
 
 5s. tlS72] 
 
 THE LAWS AFFECTING MEDICAL MEN : 
 
 a Manual by Robert G. Glenn, LL.B., Barrister-at-Law ; with a 
 Chapter on Medical Etiquette by Dr. A. Carpenter. Svo, 14s. [1871] 
 
 MEDICAL JURISPRUDENCE, 
 
 Its Principles and Practice, by Alfred S. Taylor, M.D., F.R.C.P., 
 F.R.S. Second Edition, 2 vols., Svo, with 189 Engravings, £1 lis. 6d. 
 
 [1873] 
 
 BY THE SAME ArTHOE, 
 
 A MANUAL OF MEDICAL JURISPRUDENCE. 
 
 Ninth Edition. Crown Svo, with Engravings, 14s. U.6U] 
 
 Also, 
 
 POISONS, 
 
 in Relation to Medical Jurisprudence and Medicine. Third Edition, 
 crown Svo, with 104 Engravings, 16s. [1875] 
 
 MEDICAL JURISPRUDENCE : 
 
 Lectures by Francis Ogston, M.D., Professor of Medical Juris- 
 prudence and Medical Logic in the University of Aberdeen. Edited 
 hj Francis Ogston, Jun., M.D., Assistant to the Professor of 
 Medical Jurisprudence and Lecturer on Practical Toxicology in the 
 University of Aberdeen. Svo, with 12 Copper Plates, ISs. [1S78] 
 
 A TOXICOLOGICAL CHART, 
 
 exhibiting at one View the Symptoms, Treatment, and mode of 
 Detecting the various Poisons — Mineral, Vegetable, and Animal : 
 with Concise Directions for the Treatment of Suspended Animation, 
 by William Stowe, M.R.C.S.E. Thirteenth Edition, 2s.; on 
 roller, 5s. [187.^] 
 
PUBLISHED BY J. AND A. CHUllCHILL 21 
 
 A HANDY-BOOK OF FORENSIC MEDICINE AND TOXICOLOGY, 
 by W. Bathurst Woodman, M.D., F.R.C.P., Assistant Physician 
 and Co-Lectiirci- on Physiology and Histology at the London Hospital ; 
 and C. Meymott Tidy, M.D., F.C.S., Professor of Chemistry and of 
 Medical Jurisprudence and Public Health at the London Hospital. 
 With 8 Lithographic Plates and 11 G Engravings, 8vo, 31s. 6d. [1877] 
 
 THE MEDICAL ADVISER IN LIFE ASSURANCE, 
 
 by Edward Henry Sieveking, M.D., F.R.C.P., Physician to St. 
 Mary's and the Lock Hospitals; Physician-Extraordinary to the 
 Queen; Physician-in-Ordinary to the Prince of Wales, &c. Crown 
 8vo, 6s. . [1874] 
 
 IDIOCY AND IMBECILITY, 
 
 by William W. Ireland, M.D., Medical Superintendent of the 
 Scottish National Institution for the Education of Imbecile Children 
 at Larbert, Stirlingshire. With Engravings, 8vo, 14s, [1877] 
 
 PSYCHOLOGICAL MEDICINE : 
 
 a Manual, containing the Lunacy Laws, the Nosology, Etiology, 
 Statistics, Description, Diagnosis, Pathology (including Morbid His- 
 tology), and Treatment of Insanity, by J. C. Bucknill, M.D., 
 F.R.S., and D. H. Tuke, M.D., F.R.C.P. Third Edition, Svo, with 
 10 Plates and 31 Engravings, 25s. [1873] 
 
 MADNESS : 
 
 in its Medical, Legal, and Social Aspects, Lectures by Edgar 
 Sheppard, M.D., M.R.C.P., Professor of Psychological Medicine in 
 King's College; one of the Medical Superintendents of the Colney 
 Hatch Lunatic Asylum. Svo, 6s. 6d. [1873] 
 
 HANDBOOK OF LAW AND LUNACY; 
 
 or, the Medical Practitioner's Complete Guide in all Matters relating 
 to Lunacy Practice, by J. T. Sabben, M.D., and J. H. Balfour 
 Browne, Barrister- at -Law. 8vo, 5s. [1872] 
 
 INFLUENCE OF THE MIND UPON THE BODY 
 
 in Health and Disease, Illustrations designed to elucidate the Action 
 of the Imagination, by Daniel Hack Tuke, M.D., F.R.C.P. 
 
 Svo, 148. tl873] 
 
 A MANUAL OF PRACTICAL HYGIENE, 
 
 by E. A. Parkes, M.D., F.R.C.P., F.R.S. Fifth Edition. Edited by 
 F. De Ohaumont, M.D., Professor of Military Hygiene in the Army 
 Medical Service. Svo, witli 9 Plates and 112 Engravings, 18s. [1878] 
 
 A HANDBOOK OF HYGIENE AND SANITARY SCIENCE, 
 
 by George Wilson, M.A., M.D., Medical Officer of Health for Mid- 
 Warwickshire. Third Edition, post Svo, with Engravings, 10s. 6d. 
 
 [1377] 
 
122 CATALOGUE OF RECENT WORKS 
 
 MICROSCOPICAL EXAMINATION OF DRINKING WATER : 
 
 A Guide, by John D. Macdonald, M.D., F.R.S., Assistant Proi 
 fessor of Naval Hygiene, Army Medical School. 8vo, with 24 Plates, 
 7s. 6d. [1875] 
 
 HANDBOOK OF MEDICAL AND SURGICAL ELECTRICITY, 
 
 by Hekbert Tibbits, M.D., F.R.C.P.E., Medical Superintendent of 
 the National Hospital for the Paralysed and Epileptic. 8vo, with 95 
 Engravings, 9s. [1877] 
 
 BY THE SAME AUTHOE. 
 
 A MAP OF ZIEMSSEN'S MOTOR POINTS OF THE HUMAN BODY : 
 a Guide to Localised Electrisation. Mounted on Rollers, 35 x 21. 
 With 20 Illustrations, 5s. [1877] 
 
 CLINICAL USES OF ELECTRICITY; 
 
 Lectures delivered at University College Hospital by J. Russell 
 Reynolds, M.D. Lond., F.R.C.P., F.R.S., Professor of Medicine 
 in University College. Second Edition, post 8vo, 3s. 6d. [1873] 
 
 MEDICO-ELECTRIC APPARATUS : 
 
 A Practical Description of every Form in Modern Use, with Plain 
 Directions for Mounting, Charging, and Working, by Salt & Son, 
 Birmingham. Second Edition, revised and enlarged, with 33 Engrav- 
 ings, Svo, 2s. 6d. [1877] 
 
 A DICTIONARY OF MEDICAL SCIENCE ; 
 
 containing a concise explanation of the various subjects and tenns of 
 Medicine, &c. ; Notices of Climate and Mineral Waters ; Formulas for 
 Officinal, Empirical, and Dietetic Preparations ; with the Accentuation 
 and Etymology of the terms and the French and other Synonyms, by 
 RoBLEY DuNGLisON, M.D., LL.D. New Edition, royal Svo, 28s. [1874] 
 
 A MEDICAL YOCABULARY ; 
 
 being an Explanation of all Terms and Phrases used in the various 
 Departments of Medical Science and Practice, giving their derivation, 
 meaning, application, and j)ronunciation, by Robert G. Mayne, M.D., 
 LL.D. Fourth Edition, fcap Svo, 10s. [1875] 
 
 ATLAS OF OPHTHALMOSCOPY, 
 
 by R. LiEBKEiCH, Ophthalmic Surgeon to St. Thomas's Hospital. 
 Translated into English by H. Rosborough Swanzy, M.B. Dub. 
 Second Edition, containing 59 Figures, 4to, £1 10s. [1870] 
 
 DISEASES OF THE EYE : 
 
 a Manual by C. Macnamara, Surgeon to Westminster Hospital. Third 
 Edition, fcap, Svo, with Coloured Plates and Engravings, 12s. 6d. [i876] 
 
 DISEASES OF THE EYE : 
 
 A Practical Treatise by Haynes Walton, F.R.C.S., Surgeon to St. 
 Mary's Hospital and in charge of its Ophthalmological Department. 
 Third Edition, Svo, with 3 Plates and nearly 300 Engravings, 25s. 
 
 [1876] 
 
PUBLISHED BY J. AND A. CHURCHILL 23 
 
 HINTS ON OPHTHALMIC OUT-PATIENT PRACTICE, 
 
 by Charles Higgens, F.R.C.S., Oplitlialmic Assistant Surgeon to, 
 and Lecturer on Ophthalmology at, Guy's Hospital. 87 pp., fcap. 8vo, 
 i2s. 6d. [1877] 
 
 OPHTHALMIC MEDICINE AND SURGERY: 
 
 a Manual by T. Wharton Jones, F.R.S., Professor of Ophthalmic 
 Medicine and Surgery in University College. Third Edition, fcap 
 8vo, with 9 Coloured Plates and 173 Engravings, 12s. 6d. [1805] 
 
 DISEASES OF THE EYE: 
 
 A Treatise by J. Soelberg Wells, F.R.C.S., Ophthalmic Surgeon to 
 King's College Hospital and Surgeon to the Royal London Ophthalmic 
 Hospital. Third Edition, 8vo, with Coloured Plates and Engravings, 
 25s. [1873] 
 
 BY THE SAME AUTHOE, 
 
 LONG, SHORT, AND WEAK SIGHT, 
 
 and their Treatment by the Scientific use of Spectacles. Fourth 
 Edition, 8vo, 6s. [1873] 
 
 A SYSTEM OF DENTAL SURGERY, 
 
 by John Tomes, F.R.S., and Charles S. Tomes, M.A., Lecturer on 
 Dental Anatomy and Physiology at the Dental Hospital of London. 
 Second Edition, fcap 8vo, with 268 Engravings, 14s. [1873] 
 
 DENTAL ANATOMY, HUMAN AND COMPARATIVE : 
 
 A Manual, by Charles S. Tomes, M.A., M.R.C.S., Lecturer on 
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 179 Engravings, crown 8vo, 10s. 6d. [187G] 
 
 A MANUAL OF DENTAL MECHANICS, 
 
 with an Account of the Materials and Appliances used in Mechanical 
 Dentistry, by Oakley Coles, L.D.S., R.C.S., Surgeon-Dentist to 
 the Hospital for Diseases of the Throat. Second Edition, crown 8vo, 
 with 140 Engravings, 7s. 6d. [1876] 
 
 HANDBOOK OF DENTAL ANATOMY 
 
 and Surgery for the use of Students and Practitioners by John 
 Smith, M.D., F.R.S. Edin., Surgeon-Dentist to the Queen in Scotland. 
 Second Edition, fcap 8vo, 4s. 6d. [1871] 
 
 STUDENT'S GUIDE TO DENTAL ANATOMY AND SURGERY, 
 by Henry Sewill, M.R.C.S., L.D.S., Dentist to the West London 
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 OPERATIVE DENTISTRY: 
 
 A Practical Treatise, by Jonathan Taft, D.D.S., Professor of Opera- 
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 thoroughly revised, with many additions, and 134 Engravings, 8vo, 
 18s. [1877] 
 
 EPIDEMIOLOGY ; 
 
 or, the Remote Cause of Epidemic Diseases in the Animal and in the 
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 Contagion — Modern Theories — Cholera— Epizootics. 8vo, 5s. [1873] 
 
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