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 OF CALIFORNIA 
 
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 2631
 
 3 
 
 OUVBNIR. 
 
 OF THE 
 
 ^^s_ 
 
 
 ig^rtt^ 
 
 Fi:^^T Dl^miCr DE/^TpiL SOCIETY 
 
 W'^ 
 
 "^^^ 
 
 
 OF THE 
 
 STATE OF NEW YORK. 
 
 Oollego or rDontistrsr 
 W»V " ".F SOUTHERN CALIFOHNIA 
 
 DECEMBER 9, 1885. 
 
 COMPLIMENTS OF 
 
 THE S. S. WHITE DENTAL MANUFACTURING CO.
 
 Copyright, 1886, by 
 THE S. S. WHITE DENTAL MANUFACTURING CO. 
 
 
 -^G^ 
 
 PRESS OF PATTERSON k WHITK, 
 PHILADELPHIA.
 
 First District Dental Society 
 
 STATE OF ISTEW YORK. 
 
 Chartered and Organized in June, 1868. 
 
 V 
 
 I 
 
 OFFICERS, 1885-6. 
 
 President, 
 Dr. WILLIAM CAKK. 
 
 Vice-President, 
 Dr. J. F. P. HODSON. 
 
 Secretary, 
 De. B. C. NASH. 
 
 Treasurer, 
 Dr. CHARLES W. MILLER. 
 
 Librarian, 
 Dr. J. B. LITTIG. 
 
 ©lecutioe Committee. 
 
 Dr. a. L. NORTHROP, Dr. C. E. FRANCIS, 
 
 Dr. W. W. walker, Chairman. 
 
 ffilinic Committee. 
 
 Dr. W. H. ATKINSON, Dr. F. H. LEE, 
 
 Dr. C. F. W. BODECKER, Chairman. 
 
 Poorb of Censors. 
 
 Dr. E. a. BOGUE, Dr. W. A. BRONSON, 
 
 Dr. C. a. woodward. Secretary, Dr. FRANK ABBOTT, 
 
 Dr. a. L. NORTHROP, Chairman. 
 
 3
 
 LIST OF MEMBERS. 
 
 ACTIVE. 
 
 Abbott, Frank, 
 Albert, H., 
 Allan, Geo. S., 
 Allen, H. D., 
 Atkinson, Wm. H., 
 Baldwin, C. S. W., 
 Barnum, W. H., 
 Bishop, J. A., 
 
 BoDECKER, C. F. W., 
 
 Bogue, E. a., 
 Bronson, W. a., 
 buttner, h. "w. f., 
 Cadt, H. W. F., 
 Carr, Wm., 
 Chaim, M. L., 
 Clowes, J. W., 
 Davenport, W. F., 
 Day, J. B., 
 Deane, W. C, 
 Deqenhardt, Ch., 
 De Vries, Henry, 
 Dodge, M. H., 
 DUBAR, C. L., 
 DuBois, C. A., 
 Dwinelle, W. H., 
 EWING, H. J., 
 Farrar, J. N., 
 Feindel, J. H., 
 Fletcher, T. A., 
 Francis, C. E., 
 Gage, Arthur K., 
 Gates, C. B., 
 Gibson, K. C, 
 GooDwiLLiE, Jas., 
 gottschaldt, m. c, 
 Hassell, Samuel, 
 
 Henriques, J. M., 
 
 HiLLER, W. G., 
 
 Hoag, W. E., 
 HoDSON, J. F. p., 
 Howe, J. M., 
 
 HOWELLS, E. "W., 
 HOWLAND, S. F., 
 
 HoYT, E. p., 
 
 HURD, W. W., 
 
 Ives, C. F., 
 Jackson, V. H., 
 Keech, C. H., 
 Kidder, A. S., 
 Kingsley, N. W., 
 La Koche, W. T., 
 Latimer, C. E., 
 Latimer, J. S., 
 Littig, J. B., 
 McNaughton, S. H., 
 Meigs, G. S., 
 
 Merritt, Chas., 
 
 Mersereau, G. B., 
 
 Meyer, John H., 
 
 Miller, A. B., 
 
 Miller, C. W., 
 
 MiNNKR, E. E., 
 
 Moore, J. W., 
 
 Morse, D. E., 
 
 Nash, B. C, 
 
 Neymann, Olga, 
 
 NiSLEY, J. C, 
 
 Northrop, A. L., 
 Odell, F. M., 
 Palmer, Delos, 
 Palmer, Eugene, 
 Payne, E. T.,
 
 ACTIVE members-Continued. 
 
 Perry, B. J., 
 Perry, S. G., 
 Phillips, C. E. H. 
 Pressler, v.. 
 Price, S. B., 
 Eabell, C. F., 
 Keed, J. Howard, 
 Kemington, F. a., 
 Rhein, M. L., 
 Roy, F. Austin, 
 Sabater, D. M., 
 Sailer, Z. T., 
 
 SiCHEL, M. 
 
 Simon, Samuel, 
 SissoN, H. H. 
 Slocum, L. M., 
 Smith, Dwiqht, 
 
 Spooner, S. C, 
 Sproull, J. C, 
 Starr, A. R., 
 Stebbins, R. O., 
 Taylor, Jas. W., 
 Tenison, W. D., 
 Todd, E., 
 Toledo, M. V., 
 Wadsworth, T. a.. 
 Walker, W. W., 
 Wardwkll, C. S. 
 Wardwell, T. F. 
 Weld, G. W., 
 Williams, D. A., 
 Williamson, D. W., 
 Winkle, A. F., 
 Woodward, C. A. 
 
 HOIN-OEAEY. 
 
 Allen, John, 
 
 BURRAS, T. H., 
 
 Crowley, C. George, 
 
 Harmstad, Frank C. 
 Hawes, Arnold C, 
 Heitzmann, Carl. 
 
 Miller, Charles. 
 
 EOIST-RESIDEI^T. 
 
 Andrews, R. R., Cambridge, Mass. 
 Darby, Edwin T., Philadelphia, Pa. 
 Guilford, S. H., " " 
 
 Peircb, C. N., " " 
 
 Truman, James, " " 
 
 Gardiner, F. H., Chicago, 111. 
 Harlan, A. W., " " 
 
 Patrick, John J. R., Belleville, 111. 
 Levy, Fred. A., Orange, N. J. 
 Thomas, T. J., Glen Cove, N. Y. 
 
 OORRESPONDIIsrG. 
 
 Black, G. V., Jacksonville, 111. 
 Brown, E. Parmly, Flushing, N. Y, 
 Lee, F. H., Auburn, N. Y. 
 
 I
 
 SEVENTEENTH ANNIVERSARY, 
 
 First District Dental Society, 
 
 STATE OF E"EW YOEK. 
 
 " Palmam qui meruit feraty 
 
 PROGRAMME. 
 
 PRAYEK Brady Backus, D.D., New York 
 
 ADDRESS OF WELCOME Dr. Wm. Carr, New York 
 
 RESPONSE Wilbur F. Litch, M.D., D.D.S., Philadelphia 
 
 Professor of Prosthetic Dentistry, Materia Medica and Therapeutics, 
 Pennsylvania College of Dental Surgery. 
 
 PAPER. 
 
 J. L. WILLIAMS, D.D.S Philadelphia 
 
 Subject. —" The Development and Minute Anatomy of the Teeth in 
 Health and Disease." 
 
 DISCUSSION OPENED BY 
 FRANK ABBOTT, M.D New York 
 
 Professor of Operative Dentistry and Dental Therapeutics, 
 New York College of Dentistry. 
 
 FOLLOWED BY 
 W. XAVIER SUDDUTH, M.D., D.D.S Philadelphia 
 
 Demonstrator of Dental Histology, 
 Philadelphia Dental College and Hospital of Oral Surgery. 
 
 CARL HEITZMANN, M.D New York 
 
 Lecturer on Dental Histology, New York College of Dentistry. 
 
 C. F. W. BODECKER, M.D S., D.D.S New York 
 
 R. R. ANDREWS, D.D.S Cambridge, Mass. 
 
 Lecturer on Dental Histology, Boston Dental College. 
 
 G. V. BLACK, M.D., D.D.S Jacksonville, 111. 
 
 Professor of Dental Pathologj- and Therapeutics, Chicago College of Dental Surgery. 
 
 WM. H. ATKINSON, M.D., D.D.S New York 
 
 7
 
 FIRST DISTRICT DENTAL SOCIETY. 
 
 Special Anniversary Meeting, "Wednesday Afternoon and Evening, 
 
 December 9, 1885, at Mazzetti's, Nos. lOO and 102 "VATest 
 
 Forty-ninth street, New York City. The President, 
 
 Dr. Williann Carr, in the chair. 
 
 The proceedings were opened with prayer by the Kev. Dr. Brady 
 Backus, of New York. 
 
 President William Carr delivered the following address : 
 
 President Carr. Seventeen years ago a few earnest men met at 
 Cooper Institute and organized the First District Dental Society 
 of the State of New York, electing Dr. A. L. Northrop its first presi- 
 dent. A law had been recently enacted in this State which gave 
 dentistry a legal status. Prior to that it had none. Then it was 
 too often customary for persons who had failed in other vocations 
 to turn to dentistry as a respectable means of gaining a livelihood, 
 and, by a few days' or a few weeks' preparation in a dental office, 
 to launch out into the world as full-fledged " dental surgeons." At 
 that time our meetings were small, and but few of the represent- 
 ative dentists of our city took an active interest in our society. 
 The subjects discussed were usually of a mechanical, not of a scien- 
 tific, nature. Our colleges were but few and the curriculum limited. 
 Then we were obliged to look to Europe for our knowledge of his- 
 tology, pathology, and many of the higher branches of our specialty. 
 Mark the change! At our meetings the attendance, instead of 
 numbering from ten to fifteen, has steadil}^ increased until, during 
 the present year, the average attendance at our regular meetings 
 has been one hundred and thirty. With this steady numerical 
 growth there has been a corresponding increase of activity among 
 the members, each vying with the other to contribute his mite to 
 the science and literature of our profession. This activity has been 
 stimulated not only by the interchange of ideas, and the candid 
 statement of practical difficulties which each is called upon to meet 
 and treat intelligently in his own special practice, but also by an 
 
 9
 
 10 
 
 increase of knowledge due to the wider range of thought induced 
 by researches into the domains of science, especially with the aid of 
 the microscope, which has revealed many facts heretofore hidden 
 from our vision. 
 
 As regards our colleges, we find that one or more dental colleges 
 have been established in nearly every section of the Union, as the 
 direct result of the enactment of dental laws in nearly every State 
 and in some of the Territories. These laws clearl}^ define the requi- 
 sites for a dental practitioner, and they protect the interests both of 
 the practitioner and of the public. With this increased number of 
 colleges the standard of dental education has been raised. And I 
 am happy to express my belief that this society has been one of the 
 important factors in effecting these results, of which we should justly 
 be proud. 
 
 Gentlemen, I congratulate you upon the harmony and good-fellow- 
 shijD that exists among us as a society, and trust that this good- 
 fellowship may continue, and that we may increase in knowledge 
 and usefulness. 
 
 Gentlemen who are our guests, we are proud to extend to you a 
 warm greeting and a hearty welcome. It is a pleasant privilege for 
 me, as president of this society, to welcome so many gentlemen of 
 recognized ability and worth from sister cities, who have so kindly 
 and generously consented to come, and to give us the benefit of 
 their investigations on this occasion of our anniversary. We ap- 
 preciate the sacrifices that you have made in leaving homes and 
 business at this season of the year, and we cordially invite you to 
 participate in our discussions with the same freedom and earnest- 
 ness that you would exercise in your own societies. Again, gentle- 
 men, we welcome you ! 
 
 The President then introduced Dr. Wilbur F. Litch, of Philadel- 
 phia, who spoke as follows : 
 
 Dr. Litch. Mr. President, it is with sincere gratification that 1 
 rise to thank you on the behalf of those who, like myself, are invited 
 guests at this meeting, for the words of cordial welcome which you 
 have pronounced. The First District Dental Society of New York 
 has long been known as one devoted to practical work, and the 
 clinics which have been held under its auspices are justly regarded 
 as among the important educational influences of the day in the 
 domain of dental art. It is a pleasure to recognize the fact that 
 the usefulness of the society and the number of its members were 
 never greater than they are now, and that as it approaches the 
 period of legal manhood, now but some four years distant, it is
 
 11 
 
 displaying an exaltation of purpose and vigor of action which pre- 
 sage long years of usefulness to come. 
 
 I have spoken of the society as being eminently practical in its 
 work ; yet we have assembled here, some coming from distant States, 
 for the discussion of a question which to many minds may appear 
 as remote from the domain of practical dentistry, from the stand- 
 point of the mallet and the plugger, as to other minds the specula- 
 tive theories of the political economist, or even his exact deductions, 
 may be deemed foreign from the domain of practical politics; the 
 condemnation of both being summed up in the one phrase, "they 
 are not business." It can hardly be necessary, in this presence, that 
 I should enter into a dissertation on the importance of scientific truth 
 as such because it is truth, and not simply for the dole of dollars 
 that it will yield. 
 
 Bacon has finely said, "Just as we are deeply indebted to the 
 light because it enables us to enter on our way, to exercise arts, 
 to read, to distinguish one another ; and yet, nevertheless, the sight 
 of li Jht is itself more excellent and beautiful than the manifold uses 
 of it. So assuredly the very contemplation of things as they are, 
 without superstition or imposture, without error or confusion, is 
 in itself far more worthy than all the produce of discoveries." And 
 yet, apart from the grandeur of its simjile contemplation, there is 
 in science no truth, however abstract in its seeming, which has not, 
 or may not have, its practical bearing. No ascertained fact in any 
 science can be safely ignored, because while isolated it may appear 
 devoid of all practical significance and value, yet when joined to 
 other things, known or knowable, it may prove to be the one con- 
 necting link in the chain of inductive thought beneath the flash of 
 whose subtle currents new forms as from a menstruum are precipi- 
 tated from the creative brain, and new-born knowledge, Pallas-like, 
 again step forth, as in the myth she sprang from the forehead of 
 her sire. More and more surely is it becoming known that the 
 law of the atom is the law of the sphei-e, the law of the cell the law 
 of the organism, and that we can never grasp the full meaning of 
 the infinitely great until we have read the riddle of the infinitely 
 little. From this stand-point, then, the object of this meeting is far 
 from being impractical, and whatever light may be thrown upon 
 the law of the little as related to dental histology and dental pathol- 
 ogy by the essay and discussion to which we are to listen, and from 
 which I will no longer detain you, cannot fail to be of service to 
 science and mankind. 
 
 President Carr. Gentlemen, we now invite your attention to the 
 reading of a paper by Dr. J. L. Williams, of Philadelphia.
 
 12 
 
 THE DEVELOPMENT AND MINUTE ANATOMY OF THE TEETH 
 IN HEALTH AND DISEASE. 
 
 Dr. Williams. Mr. President and Gentlemen: If I acknowledge 
 the feeling of weakness which often prompts men to shrink from 
 the consequences of placing themselves in a position where they are 
 likely to be misunderstood or misinterpreted, I must also plead the 
 extenuating circumstance that such feeling of weakness is born of 
 past experiences, which have taught me that there are but few men 
 who are sincerely grateful to those who point out their errors of 
 opinion or belief. This is especially true of those who enjoy some- 
 thing of an intellectual reputation which may be founded, to a 
 greater or less extent, upon such errors. Therefore, to criticise with 
 perfect frankness opinions which have become a matter of fixed 
 intellectual pride is often j-egai-ded as an injudicious proceeding. 
 
 There is too frequently evident in all critical efforts a quality 
 which has regard chiefly for that artificial adaptation to environ- 
 ment known as expediency, — an attempt to conceal more than is 
 revealed, but often to those who read between the lines revealing 
 more than is concealed. 
 
 It is the rare exception that discussions of questions of truth or 
 error before scientific or professional associations are free from that 
 exhibition of intellectual gymnastics which seeks by some trick of 
 voice, or emphasis, or rhetoric, or what passes for logic, to win the 
 applause of the moment. At the last, however, only the simple 
 truth remains, and we shall all probably come to see that this exists 
 quite independently of our intentional or unintentional efforts to 
 elucidate or obscure it. But if I correctly apprehend the purposes 
 of those who are to take part in this discussion, the meeting is des- 
 tined to be a memorable one ; and I trust that it may also prove a 
 dignified exception to many former experiences in being animated 
 by and conducted in that spirit of kind earnestness which should 
 actuate all fellow students and lovers of the truth. 
 
 The principal object of this essay, as announced, is the considera- 
 tion of certain features in the minute anatomy or microscopic mor- 
 phology of the dental tissues in health and disease. 
 
 The reason why I shall preface this consideration with some re- 
 marks on the development of the teeth, is that I have grown more 
 and more to see the futility of any attempt to arrive at unanimity 
 of opinion concerning either morphology or function, except through 
 a careful study of the history of the development of the organism ; 
 and not only of the individual organism, which is the immediate 
 object of our studies, but of the lower forms of life which lead up 
 to it. 
 
 While I cannot believe that these higher and more complex
 
 13 
 
 organisms have evolved themselves by a process of slow but contin- 
 uous development from a more lowly condition, but i-ather that the 
 creation of each succeeding higher form of life has been effected by 
 the superposition, or rather the infusion, of a higher quality of life- 
 energy from the source of all life, yet I cannot but recognize that 
 there is an intimate bond of relationship between all forms of life, 
 and that, as I have before said, the complex and oftentimes obscure 
 conditions which prevail in higher forms of life are expressed in sim- 
 pler and therefore more easily comprehended terms in lower forms. 
 Therefore, I repeat a statement that every biologist of note of the 
 present day will confirm, — a comprehensive knowledge of the struc- 
 tural relationships and functions of an organism is only to be gained 
 by a careful study of the history of its development, both from the 
 stand-point of ontogeny and philogeny. This statement is quite as 
 applicable to the teeth as to the organism as a whole or to any of its 
 parts ; and upon it are based the views presented in this paper. 
 
 There is one other principle to which I wish to call your atten- 
 tion, and the importance of which I wish to emphasize. It is that, 
 while the organism is developed and exists as a unity, while it is 
 inter-dependent in all its parts to the extent that every molecular 
 change which occurs in the finger tips modifies, in its degree, other 
 changes which are occurring in remote parts of the body, yet the 
 development and maintenance of every part is under the special 
 domain of its own inherent typal energy and environment. There 
 are individuality and structural peculiarities as well as unity in 
 development, and this in accordance with the function or use to be 
 performed. This principle has not been observed by those who have 
 carried similarity of development, structure, and function so far that 
 it has become identity. The importance of this point will be seen 
 as we proceed. 
 
 If I were asked to express in a single sentence all that is meant 
 by the term development as applied to animal organisms, I should 
 say it is the focalizing of life energies in certain territories in ac- 
 cordance with typal ancestral endowments and limitations. In 
 elaboration of this, I would say that, in the development of complex- 
 ity from simplicity of structure, the first observable departure from 
 uniformity is an increased activity in the formation of the elements 
 or corpuscles at the point where the new departure is to take place, 
 or the point from which the development of the new organ begins. 
 And I would characterize the initiative impulse which leads to this 
 more rapid cell-proliferation, as it is usually called, as the focalizing 
 of life energies at this point. It is the formation of a new center 
 from which the circumference of the new organ will be unfolded, 
 and this in accordance with that great universal law, applicable
 
 14 
 
 alike to corpuscle, organism, or world, — '• creation proceeds from 
 center to circumference." 
 
 As the germ of every human tooth springs from two distinct 
 sources, it may be said to have two centers of origin, — the first 
 arising in the epithelial layers, from which the enamel-organ is 
 developed ; the second from the underlying dermal tissue, from which 
 the dentinal germ is developed. It may be well, at this point, to 
 call attention to one of those errors of comparison to which I have 
 referred. In a recent work on histology by a high authority the 
 statement is made that teeth are developed in the same manner that 
 hairs are. Other writei-s have asserted that the process of develop- 
 ment in nails, claws, hair, and teeth is the same. Such statements 
 show both a lack of close and careful observation and an absence of 
 fine perception of what development means. They have simpl}^ 
 glanced at the surface and seen certain similarities, and they go 
 away and say the processes are the same. They seem not to know 
 that if the processes by which a tooth is developed were the same as 
 those that result in the formation of a hair, there would be in the 
 end not a tooth, but a hair. There are important differences in the 
 methods of development, and those differences are determined by 
 the function or use which each organ or appendage is destined to 
 perform. While from observation we can predicate nothing from 
 the appearances of these centers of development at the commence- 
 ment of the process, yet we may see, if our observation be carefully 
 continued, that differences become more and more apparent at each 
 succeeding stage, and we know that this is determined at the 
 beginning. 
 
 It is not necessary for the purpose of this paper to go over all the 
 ground of the evolution of the dental tissues. Permit me, then, to 
 call your attention at once to this illustration of a developing tooth 
 at the commencement of the process of calcification of the dentine 
 and enamel. You see here the dentine and enamel-pulps inclosed in 
 a sac, in which these processes are taking place. This sac was for 
 a time connected with the epithelial layers of the mucous membrane 
 by means of a tubular cord of epithelium. This cord was simply an 
 elongation of the primitive bud from which the enamel-organ is 
 finally formed. After the developing tooth is completely inclosed in 
 its sac this epithelial cord is broken up, and there is seen to result 
 from its breaking up little whorls or globular masses of these epi- 
 thelial corpuscles. 
 
 As there is a deeply interesting subject which may have some con- 
 nection with this disappearance of the enamel-cord, you will permit 
 a little digression here. You know we not infrequently find depart- 
 ures from the normal number of teeth in the mouth ; we find extra
 
 15 
 
 or supernumerary teeth, as they are called. "We also sometimes find 
 teeth developing in other parts of the body. I have here for your 
 examination some specimens of quite perfectly formed teeth which 
 were taken from an ovarian cyst. The question at once arises in 
 our minds, What antecedent conditions have led to the formation of 
 these supernumerary teeth, whether in the mouth or in locations 
 remote from their usual position? In the development of the 
 second and third molars we observe that the germs fi"om which they 
 gi'ow arise as buddings from the cord of the first molar germ ; the 
 cord of the second molar arising from that of the first, and the third 
 from the second. This has led to the conclusion that under certain 
 conditions any portion of the epithelial cords of the tooth-germs 
 may develop into an enamel-organ or pulp. "We have also observed 
 that a dentinal germ is always foi-med directly beneath the enamel- 
 pulp wherever it drops down into the dermal tissue. It thus seems 
 that the presence of the enamel-pulp is the immediate antecedent 
 of the dentinal germ. This view is confirmed by the fact that in 
 the formation of the teeth of some of the lower forms of life, in 
 which the fully-developed tooth has no enamel, there is, at the 
 commencement of the process of development, the correlative of 
 what becomes the enamel-pulp of the teeth of higher organisms. 
 This is very strong evidence that the presence and position of an 
 enamel-pulp determines the formation of a tooth at that point. 
 This is a beautiful illustration of the statement before made, that in 
 the endeavor to unravel the complex relations existing in the higher 
 organisms we are often greatly assisted by a study of the lower 
 forms. Now, if any portion of the enamel-cord may develop into 
 an enamel-pulp, and if the enamel-pulp determines the formation of 
 a tooth, then there is a reasonable probability that those little 
 whorls or globular masses of epithelium which result from the 
 breaking up of the enamel-cord may, under unusual conditions, 
 result in the development of a tooth, and that these globular epi- 
 thelial masses may be carried to remote parts of the body and there 
 result in the formation of teeth. You may object that there are 
 too many " ifs " and probabilities sui'rounding this question ; but I 
 M have only to reply that, in the absence of all positive knowledge, 
 SI the highest probability stands as the next best thing, and the whole 
 ■ theory of evolution and many other modern scientific doctrines rest 
 ■^ on a less secure foundation. 
 
 ^ It is but proper to mention, however, that there is another theory 
 S for the formation of teeth in ovarian cysts, which is that in the for- 
 mation of the embryo some portion of the epiblast in the region of 
 . the mouth becomes caught and infolded within the body cavity as the 
 ■ body walls close together. If we turn now to our illustration of a
 
 16 
 
 developing tooth, we observe that it is completely surrounded by a 
 sac composed largely of spindled-shaped connective-tissue elements. 
 We see that its vascular supply is concentrated at two points, — in 
 the dentinal pulp and around the enamel-organ ; and this is pre- 
 cisely what we should expect, for the one is the formative organ of 
 the dentine, and the other of the enamel. It is seen that the forma- 
 tion of dentine begins at the line of its junction Avith the enamel, 
 and proceeds inward and downward, and that the formation of 
 enamel begins at the line of its union with the dentine and proceeds 
 outward. I believe there are those who do not regard this as the 
 manner in which these tissues are formed. But there is such una- 
 nimity of opinion among those who have done any considerable 
 practical microscopical work in this direction, that it is hardly 
 worth while to discuss the point with those who would not care to 
 be known as holding critical views on the development and histology 
 of the teeth. 
 
 What is the process by which dentine and enamel are formed? 
 We now approach the consideration of an important question, and 
 the one upon which my criticism of well-known and popular writers 
 upon the histology and pathology of the dental tissues is largely 
 based. The formation of dentine begins shortly before that of 
 enamel, and its first appearance is that of a cloudy, cartilaginous- 
 looking line, which is seen just outside of the odontoblasts, occupy- 
 ing the most prominent point or points in the developing tooth. At 
 the same time delicate fibrillae are seen sprouting from the outer 
 ends of the odontoblasts. As this line of forming dentine increases 
 in thickness the odontoblasts are observed to always remain just 
 beneath it. It is probable that the increase in thickness of the den- 
 tine is effected by the continued secretion of the cartilaginous ma- 
 trix, which has been called calco-globin, and the almost simulta- 
 neous deposit of the mineral constituents in this matrix. The 
 forming line of dentine is probably pushed upward and outward by 
 the continued deposit from the odontoblasts. As the process ap- 
 proaches completion the dentine is also increased in thickness from 
 within, thus reducing in size somewhat the pulp, — at least that por- 
 tion which remains in the roots. The growth of the fibrillee corres- 
 ponds with the increase in the thickness of the dentine, although 
 they sometimes seem not to be governed by this condition, but grow 
 on and penetrate between the ameloblasts, which lie just outside of 
 and in contact with the dentine. This penetration of the amelo- 
 blastic layer by the dentinal fibrillar is probably always effected 
 before the deposit of enamel begins. These dentinal fibrillaj some- 
 times continue to grow, their terminal points keeping just in advance 
 of the outer line of forming enamel, so that when the enamel is
 
 17 
 
 completely formed it8 entire thickness is traversed by these fibers. 
 This is not of common occurrence, but I think it can hardly be re- 
 garded as a departure from normality, for I have many times ob- 
 served the dentinal fibrillse penetrating the entire thickness of the 
 enamel in the teeth of animals. 
 
 Every appearance of the formed dentine in health and disease, 
 and every phase of its development, contra-indicates the view that 
 it is built up by the calcification of layers of odontoblasts or dentine 
 corpuscles. If this view were correct, we should everywhere see 
 partially calcified corpuscles, which we never do. The line between 
 the forming dentine and the outermost layer of the odontoblasts is 
 always strongly and sharply marked. There is no other possible 
 way of explaining the continuity of the dentinal fibrillae, now that 
 it is demonstrated beyond all i^ossibility of doubt that they are off- 
 shoots or prolongations of the odontoblasts. The building up of the 
 dentine by calcification of the successive layers of corpuscles was 
 necessarily accompanied by the theory that the dentinal fibrillaj 
 were offshoots of the reticulum of the pulp, which offshoots passed 
 between the odontoblasts into the dentine. The demonstration of 
 this error removed the only foundation upon which that whole 
 theory rested. The most logically constructed theory becomes 
 valueless when the premises upon which its first postulates rest are 
 disproved. I know that many regard all scientific theories as 
 matters of minor importance. But when we realize that the entire 
 practice of medicine, involving as it does the great practical ques- 
 tions of human life and happiness, rests almost entirely upon theory, 
 Ave see the importance of applying the most rigid tests to all assumed 
 basal principles. Our practice must depend upon our perception of 
 pathological conditions ; and the clearness of our perception of 
 these conditions grows out of our knowledge of structure and func- 
 tion, and this knowledge, we are growing more and more to see, 
 rests largely upon the history of the unfolding or development of 
 the organism. I do not wish to be understood as passing any criti- 
 cism upon the teachings of the honorable gentlemen whose theories 
 I am considering, except so far as they have relation to the develop- 
 ment and histology of the teeth. I must regard these teachings as 
 in many respects erroneous, and in other features as giving undue 
 importance to and emphasizing certain points in the histology of the 
 teeth which have long been familiar to practical microscopists in this 
 field. It is a tendency not infrequently manifested by scientific 
 workers in special directions to so magnify the importance of some 
 particular aspect of the truth that it is distorted out of all relation 
 to the many qualifying truths to which it is related. It has been 
 assumed that because bone and cementum are formed by the calcifi- 
 
 2
 
 18 
 
 cation of globulai' territories, and because dentine bears some slight 
 resemblance to bone and cementum, therefore it is built up in a 
 similar manner. This is but another evidence of that hasty deduc- 
 tion from inadequate study of which I have already spoken. Many 
 writers have labored to draw the most absurd comparisons between 
 bone and dentine. But dentine remains dentine just the same, and 
 the diiference in the completely developed tissues is the correlative 
 of the difference in the methods of their development. In the de- 
 velopment of bone, and to a considerable extent in cementum, the 
 original osteoblast or cementoblast remains as the persistent center 
 of the calcified territory, and the source from whence its continued 
 integrity is maintained. Now, in dentine the only thing correspond- 
 ing to this persistent center is the dentinal fibrillae. But the denti- 
 nal fibrillse are continuous processes running from the odontoblasts 
 on the surface of the pulp through the entire thickness of the den- 
 tine to the enamel. Neither are they the center of what was once 
 a larger territory occupied by the odontoblast, as I have shown 
 when speaking of the growth of the fibrillse. By a process of rea- 
 soning by exclusion, and by the evidences shown by the microscope 
 we reach the conclusion that the formation of dentine is effected by 
 a process of continual deposit from the enamel inward, until the 
 typal demands of each tooth are satisfied. One other fact, which in 
 itself is sufficient to demonstrate the impregnability of this position, 
 is the free branching of the fibrillse at their terminal points, while in 
 the deeper layers of the dentine and in the region of the pulp-canal 
 it is far less marked, and in many cases there is almost an entire 
 absence of this branching. There is one other feature of the his- 
 tology of a developing tooth which, if carefully studied, will also 
 demonstrate the impossibility of the theory under criticism. The 
 odontoblasts, as before mentioned, are observed to send a varying 
 number of fibers into the dentine, five or six of these fibers some- 
 times arising from a single corpuscle. These corpuscles or odonto- 
 blasts are also observed to be connected with the puljD reticulum b}^ 
 root processes arising from their inner ends, and these latter pro- 
 cesses do not correspond in number with the dentinal processes 
 arising from the same corpuscle. If the dentine were formed in the 
 manner described by Dr. Ileitzmann, there would be great irregu- 
 larity in the direction and arrangement of the dentinal fibers; which 
 is not true, the arrangement and continuity being, in normally 
 developed teeth, uniform throughout the entire thickness of the 
 dentine. 
 
 The enamel is formed from the amcloblasts. These bodies are 
 derived from the Malpighian layer of the epithelium of the mucous 
 membrane. They are the active secretory elements in the forma-
 
 19 
 
 tion of enamel. I have in former papers pointed out the relation- 
 ship existing between the enamel-organ and other glandular bodies 
 derived from the epithelium. As before mentioned, and as beauti- 
 fully shown in the drawing, there is a free supply of blood through 
 an intricate capillary plexus surrounding the enamel-organ. 
 
 The precise part played by the reticulum or interior portion of 
 the enamel-organ in the development of enamel has not yet been 
 fully determined, but it is quite probable, as pointed out by Dr. 
 Sudduth, that the presence of the reticulum of the enamel-organ is 
 not necessary throughout the entire process of enamel formation, 
 but rather that it is a matrix or receptacle in which is stored and 
 partly elaborated the material for the commencement of this pro- 
 cess. But the fact that we find, in sections of the persistent grow- 
 ing teeth of the Eodents, this same reticulum of the enamel-organ is 
 a demonstration of its importance. In the formation of enamel the 
 error of the teachings of Dr. Heitzmann is even more evident than 
 it is in dentine. There is never to be seen but a single layer of the 
 prismatic enamel-cells which surmount and surround the forming 
 enamel. The line which separates the ameloblasts from, the forming 
 enamel is even more strongly marked than in dentine. There are, 
 however, important differences between the formation of enamel 
 and dentine. Transverse and longitudinal sections of enamel show 
 that it is built up in the form of prismatic elements, which have a 
 Avavy and also in some locations — notably on the points of the cusps 
 — a spiral arrangement. Now, we know that the functional activity 
 of every corpuscle proceeds from its center outwards, the circum- 
 ference being less highly endowed than the center. We have seen 
 that the ameloblasts constantly recede outward before the line of 
 advancing enamel-formation. We know that the enamel-rods, as a 
 rule, are continuous throughout the entire thickness of the enamel, 
 and that each enamel-rod is ensheathed in a substance differing in 
 appearance from the rod itself. This covering of the enamel-rods is 
 also the cement-substance which unites them. 
 
 It seems that as the ameloblasts recede or grow outward they 
 leave behind, in the forming enamel, the intra-cellular cement-sub- 
 stance which forms the low-grade fixed material of which t'he ex- 
 ternal of every enamel-rod is formed, and this constitutes the matrix 
 of the enamel into which the active functioning portion of the 
 ameloblasts deposits the phosphate of lime and other mineral 
 elements. 
 
 If the cell of the honey-bee were continuous throughout the entire 
 thickness of the comb, and had that same wavy and twisted arrange- 
 ment which the enamel-prisms have, it would form a beautiful illus- 
 tration of the structure of enamel; the waxy substance of which
 
 20 
 
 the wall of these cells are composed corresponding with the organic 
 matrix or inter-prismatic cement-substance of the enamel, and into 
 this organic matrix the ameloblasts deposit the mineral constituents, 
 as bees deposit honey in the wax-cells of the comb. This view is 
 confirmed by all the appearances of developing enamel, and necessi- 
 tates no depai'ture from the functional order of every moi'phological 
 unit of which the body is composed. As the formation of the 
 enamel-prisms proceeds outwards, and as these prisms are not per. 
 ceptibly larger at the circumference than at the line of union with 
 the dentine, we may see that, if there were only a limited and definite 
 number of enamel-formers or corpuscles at the commencement of the 
 process, as the enamel-cap is a modified sphere, there would be 
 everywhere throughout its substance cone-shaped cavities. Extra 
 or supplementary cells are therefore provided for the filling-in of 
 these widening spaces, and in longitudinal sections of enamel we 
 may see where this process begins. These extra cells probably 
 arise by division of the ameloblasts. But it should be remarked 
 that this same appearance may be caused by the twisted enamel-rods 
 coming into view just at the point where the section was cut. 
 Many absurd blunders of intei-pretation arise from regarding the 
 plane of the section as a complete picture of the entire structural 
 arrangement. The enamel-organ is sometimes spoken of as having 
 a stirrup-shape, from the appearance of a section, v;hen it is, as a 
 whole, an invaginated, modified cone or sphere. What Dr. Abbott 
 has illustrated in Fig. 4 of his recent paper on the pathology of 
 enamel as an abnormal, irregular arrangement of the enamel-prisms 
 is due simply to the specimen having been cut through a territory 
 where the forward direction of the enamel-rods or prisms was 
 diverted by the spiral arrangement of which I have spoken. I have 
 many times seen the same appearance in normally developed teeth. 
 In truth, this arrangement of the enamel-prisms is one calculated to 
 give the greatest possible amount of strength, and is, as I have re- 
 marked, found at those points which must maintain the greatest re- 
 sistance in mastication. We should therefore always expect to find 
 such an arrangement in teeth of the highest organization — an anti- 
 cipation which, I believe, careful observation will confirm. Neither 
 can I regard the stratification or pigmentation of enamel, as elabo- 
 rated in Dr. Abbott's i-ecent paper, as a matter of much importance 
 from a pathological stand-point, for these appearances are common 
 in the teeth of animals in which caries is never found, so far as I 
 am aware. As the formation of enamel approaches completion we 
 find that the ameloblasts gradually disappear. We have observed, 
 during the formation of enamel, a layer of flat cells lying just out. 
 side the ameloblasts. This layer of cells I believe to be hardened
 
 21 
 
 by direct calcification as Nasmyth's membrane. It is this layer of 
 flat, calcified epithelial elements which gives the glossy, polished 
 surface of perfectly-formed enamel. This layer has been supposed 
 by some to be a continuation of the cement-forming organ. But 
 this is a mistake. The cement-forming organ is a modification of 
 the original tooth-sac, and, as this sac extends completely over the 
 enamel, some portion of it may become infolded in the formation of 
 the sulci of the teeth, and then be stimulated, perhaps by the supply 
 of lime-salts, to the formation of cement territories in the depres- 
 sions of the molars and bicuspids. But the calcified layer of cells 
 forming JJ^asmyth's membrane will never, I think, be found outside 
 of these cement territories. All of that portion of the tooth-sac 
 which covers the crown usually disa^jpears, or is modified, as I think, 
 into the so-called ligamentum dentium, without assuming that function 
 which is the special work of the lower part from which the cemen- 
 tum is formed, and which remains as the peridental membi'ane or 
 pericementum surrounding the completely-formed root. No one 
 who has studied the development of this last-mentioned tissue could 
 be led into the error of speaking of it as a double membrane. It 
 has, as I pointed out in my earlier papers, a double osteogenetic 
 function — that is, the inner portion lying next the cementum con- 
 tains the cementoblasts, while the outer portion lying next the alve- 
 olar walls contains or consists of the osteoblasts or bone-forming 
 cells. But no misuse of terms and comparisons can construe its 
 significance into that of a double membrane. 
 
 From this slight digression we again turn to a further consider- 
 ation of the structure of enamel and dentine in health and disease. 
 I must deny in toto the theory that there are special enamel-fibers in 
 the sense that the prolongation of the odontoblasts are fibers. 
 
 Enamel is, as we have already seen, formed in an entirely different 
 manner from dentine. Dentine is formed in territories of which the 
 odontoblast fibers are the centers. The method of the formation of 
 enamel is quite the reverse of this, for the only portion of enamel 
 which can be spoken of as organic surrounds the enamel-prisms- 
 When enamel is cut longitudinally there is an appearance of fibers, 
 but it seems very strange that those who have written so much 
 about enamel-fibers have not seen that this appearance results from 
 the division of this organic matrix which surrounds each prism. A 
 transverse section demonstrates this, and it is a notable fact that 
 the only transverse section of enamel shown in Dr. Ilcitzmann's 
 book presents no appearance of these hypothetical enamel-fibers- 
 Such an appearance would be utterly inconsistent with the method 
 of development and arrangement of the enamel-prisms, and yet 
 these fibers are shown in all of the longitudinal illustrations.
 
 22 
 
 There is sometimes, though not frequently, observed in developing 
 teeth, where the enamel-forming cells are pulled away from the par- 
 tially calcified enamel, an appearance of fibers. I have also occa- 
 sionally seen in developing teeth an appearance, in cross or transverse 
 sections, like a nucleus in the center of the enamel-rod. 
 
 Dr. Sudduth's explanation of this appearance is so concise and 
 clear, and so in harmony with ni}' own observations, that I quote 
 from him. He says, when speaking of the ameloblasts being torn 
 from the semi-calcified mass of forming enamel, " This semi-calcified 
 material, which adheres to the ameloblasts" as they are drawn out, 
 " gives the appearance of a fibril or prolongation of the cells them- 
 selves. These fibrils, which have been called Tomes's processes, I 
 consider as thus being mechanicall}- made, for they do not always 
 appear, but depend upon a certain condition of the calcific material. 
 They do not occur persistently, as do the fibrillte of the odontoblasts, 
 I have succeeded in demonstrating them in sections of pigs' teeth, 
 under favorable circumstances, where they showed very plainly 
 indeed, being nearly or quite as long as the ameloblasts themselves, 
 and several times longer than the enamel was thicks It is as though 
 one were to dip the ends of one's fingers in a thick syrup, and on 
 withdrawing them the syrup would be drawn out in strings as the 
 ameloblasts draw out the gelatinous matter on the surface of form- 
 ing enamel. This is the only appearance of fibers to be seen, and 
 this only in forming enamel. It is therefore seen that this appear- 
 ance has nothing in common with the so-called enamel-fibers de- 
 scribed in Dr. Heitzmann's work. To what conclusions are we forced 
 by the evidence? That enamel, once completel}' developed, under- 
 goes no structural change during life, and probably no molecular 
 change, — at least, not in that portion which constitutes ninety-seven 
 per cent, of its composition. There is the highest probabilit}' that 
 all changes which occur in enamel are the result of the slightly 
 increased or diminished amount of fluid which may penetrate from 
 the dentine or the surface. The human body is not the scene of a 
 hodge-podge of physiological activities. There is order and exact- 
 ness everj'where. Bile is not secreted in the kidneys if the liver 
 happens to be out of order; neither will the lungs elaborate chyle 
 out of food-material when the digestive tract refuses to perform its 
 functions. There is intimate relationship and mutual helpfulness 
 everywhere, but if evolution and development mean anything they 
 mean division of labor and specialization of function. Dentine is 
 not formed from osteoblasts or cementoblasts, nor is cemcntum 
 formed from the odontoblasts. Neither can the material from 
 which enamel is built up be elaborated in any other way than 
 through the ameloblasts. How careful the surgeon is to preserve
 
 23 
 
 the periosteum if he desires a reproduction of bone ! He knows, if 
 its formative organ is destroyed beyond recovery, that there will be 
 no further reproduction of bone at that point. Now, it must be 
 remembered that enamel is the only tissue of the body the formative 
 organ of which not only disappears, but the enamel itself is removed 
 fi"om the position of its development and completely isolated from 
 all tissue concerned in its formation. This is a fact of great signifi. 
 cance, and places enamel in a unique position, physiologically speak- 
 ing, in which it cannot be compared to any other tissue in the body. 
 The odontoblasts and their processes, the fibrillae, are the elements 
 by means of which the dentine is formed, and they remain after 
 development is completed to maintain the continued integrity of 
 the dentine. And thus it is also with bone and cementum, the forma- 
 tive organs of which remain as the source from whence these tissues 
 receive their nutritive supply. Not so with enamel, however. The 
 ameloblasts are the enamel-formers. Its peculiar morphology and its 
 molecular structure are impressed upon it by these histological ele- 
 ments. They completely disappear, after which there can be no 
 fui'ther formation of enamel. We have no evidence of structural 
 change in enamel after the eruption of the teeth, and structural 
 change, by which I mean change in molecular relationship, is the 
 only change which could improve defective enamel. The apparent 
 increased or diminished liability of the teeth to decay during life 
 must be very lai'gely attributed to changes in environment, changes 
 in the character of the secretions and fluids of the mouth, rather 
 than to any inherent change in the enamel itself. An increased pro- 
 portion of organic matter in enamel, within certain limits, by no 
 means necessarily implies increased liability to caries. Every 
 closely-observant dentist knows that a departure from the proper 
 proportion of organic and mineral matter in either direction may 
 result in increased liability to decay. But every dentist of thoughtful 
 experience also knows that more depends upon that initiative organ- 
 izing force which governs the formation of enamel than upon any 
 changes which ever occur during life. The fact that teeth which are 
 well developed will endure the adverse conditions of a lifetime with- 
 out serious damage, and on the other hand the fact that teeth poorly 
 developed cannot be changed into teeth of excellent structure, at 
 least so far as the enamel is concerned, by the continued good health 
 of a lifetime, is very strong evidence of the truth of my propositions. 
 Understand me. I say that those improved conditions which we all 
 observe and which decrease the liability of the enamel to caries are 
 largely, probably entirely, due to changes in the environment of the 
 teeth i-ather than to any change in the structure of the enamel. In 
 truth, change in environment is alone quite sufficient to explain the
 
 24 
 
 decreased liability of the teeth to deca}^. There is no one in our 
 profession to-day who has done more thoroughly scientific work in 
 the investigation of caries than Dr. Miller, of Berlin. I can hardly 
 speak too emphatically of my appreciation of his labors. Dr. Miller's 
 investigations have demonstrated, to the complete satisfaction of any 
 mind which can appreciate the significance of genuine scientific 
 work, that the active immediate causes of caries are acids, — largely 
 those generated in the mouth by fermentation, — which cause decalci- 
 fication of the mineral constituents, and certain micro-organismsi 
 which destroy the organic matter. Any change, therefore, whether 
 in the nature of local prophylactic or antiseptic treatment, or general 
 83'stemic treatment, which removes or improves those conditions 
 which are favorable to the formation of micro-organisms, is quite 
 sufiicient to explain all decreased liability of the teeth to decay. 
 The statement made by Dr. Abbott in his recent paper, that the 
 increased liability of the enamel to pathological changes which is 
 observed as accompanying change of climate and food-habits is due 
 to changes in the living matter of the enamel, will not for a moment 
 bear the light of real scientific investigation. In former papers, and 
 in his chart representing section of an incisor tooth in situ, Dr. Abbott 
 claims that embryonal or medullary corpuscles are formed in the 
 retrograde metamorphosis of enamel. Dr. Heitzmann also teaches 
 the same doctrine in his book. It might be regarded as needless 
 effort to do more than demonstrate that such a retrograde process 
 is impossible from the stand-point of the method of development of 
 the teeth, as I have already shown. But the so-called inflammatory 
 theory has taken such a strong hold upon many in the profession 
 that it can only be uprooted by placing the absurdity of its claims in 
 the strongest possible light. It may be that in the decay of living 
 teeth in the mouth there is a condition which is the correlative of 
 inflammation in the soft tissues, although the relation is probably 
 very distant and obscure; but this point, if admitted, has no bearing 
 upon the appearance of medullary bodies in caries of enamel and 
 dentine. 
 
 In the sixth statement of his summing up of his series of papers 
 on the relation of fermentation in the human mouth to caries of 
 the teeth Dr. Miller says: "I produced caries artificially, which, 
 under the microscope, cannot be distinguished from natural caries, 
 by subjecting sound dentine to the action of these fungi in fer- 
 mentable solutions." Dr. Sudduth will place under the microscopes 
 for your inspection some of these slides kindly sent me by Dr. 
 Miller, and also some of his own preparation, showing natural and 
 artificial decay of dentine. You will see that it is, as Dr. Miller says, 
 impossible to tell from the microscopic appearances which was
 
 25 
 
 naturally and which artificially produced decay. It can hardly be 
 necessary for me say that no intelligent person would think of 
 making the statement that a dead tooth out of the mouth could 
 return to an embryonal condition. If, then, it is not possible to tell 
 by microscopic examination natural decay from that artificially pro- 
 duced, what becomes of the inflammatory theory of decay ? If Dr. 
 Miller's work has any value, if any conclusions may be drawn from 
 it, then he has certainly demonsti-ated that the return of dentine and 
 enamel to an embryonal condition, even if these tissues were so 
 built up, is an impossibility ; but, as we have already seen, the tissues 
 are not so formed in the beginning. 
 
 Let us consider the question from still another stand-point. The 
 dentine of adult teeth may be said to contain from seventy to 
 seventy-two per cent, and the enamel from ninety-six to ninety- 
 eight per cent, of mineral matter, principally phosphate of lime. 
 The appearance of embryonal elements in enamel or dentine means 
 not only the liquefaction, but, to a great extent at least, the decalci- 
 fication, of these tissues. We might very pertinently inquire how 
 this delicate matrix of living matter, constituting in enamel but 
 three per cent, of the tissue, can be made to fill these decalcified 
 tracts. It is asking quite too much of a tissue which it is doubtful 
 if the most delicate methods of decalcification can discover. In an 
 illustration accompanying one of Dr. Abbott's papers the region of 
 enlarged canaliculi, which enlarged canaliculi are represented as 
 filled with nucleated bioplasson bodies (and the statement that they 
 are nucleated means that the living matter has undergone a complete 
 re-organization), corresponds exactly with the infected region of 
 Dr. Miller. The enlai-ged canaliculi are everywhere filled with 
 micro-organisms, which destroy the living matter as fast as the acids 
 effect the removal of the lime-salts, thus giving it no opportunity to 
 be re-organized into medullary corpuscles. In fact, these micro- 
 organisms, in destroying or digesting the living matter, effect this 
 enlargement of the canaliculi, and it is these enlarged canaliculi) 
 filled with micro-organisms and debris, that Dr. Abbott has mistaken 
 for fields of nucleated bioplasson and medullary corpuscles. 
 
 Gentlemen, the demonstration is under the mici'oscopes ; examine 
 the specimens for yourselves. But keep in mind the fact that I rest 
 my case upon the evidence shown in the development of the teeth- 
 This evidence I regard as conclusive and impregnable. To recapit- 
 ulate, then, the points against Drs. Ileitzmann and Abbott : 
 
 1st. In the formation of dentine there is never to be seen any 
 evidence of the coalescing of odontoblasts or dentine corpuscles. 
 
 2d. There is never to be seen any indication of partially calcified 
 corpuscles ; on the contrary, the line which separates the forming
 
 26 
 
 dentine from the odontoblasts is always strongly marked, and these 
 tissues are affected by staining agents in an entirely different manner. 
 
 3d. There is not uniformity in the branching of the fibrillse, this 
 peculiarity being much more strongly marked at their terminal 
 points than in the deeper parts of the dentine. 
 
 4th. The dentinal fibrillse are processes of the odontoblasts, and are 
 continuous, passing from these bodies through the entire thickness 
 of the dentine without break in their continuity. 
 
 5th. There is no pei'ceptible material change in the appearance 
 of the odontoblasts, from the commencement until the completion of 
 the formation of the dentine, except that they seem to decrease 
 slightly in size as the process of dentinification approaches com- 
 pletion. 
 
 6th. The microscopic evidences that enamel is not formed by a cal- 
 cification of successive layers of corpuscles are more clearly shown 
 than in the formation of dentine, there being never but a single 
 layer of ameloblasts outside the forming enamel, and the line which 
 separates the enamel from the enamel-formers being more sharply 
 marked than in dentine. 
 
 7th. The method of the development of enamel and the microscopic 
 morphology of the fully-formed tissue pi'ecludes the possibility of 
 the existence of enamel-fibers in the sense taught by Drs. Heitzmann, 
 Bodecker, and Abbott. 
 
 8th. The demonstrations upon which the foregoing propositions 
 are based, and the evidences furnished by a careful microscopic 
 study of caries of dentine and enamel, lead to the conclusion that 
 the so-called inflammatory theory of decay has grown out of errors 
 of interpretation, and is without foundation in fact. 
 
 In conclusion, I may repeat that the deductions to be drawn from 
 my studies of the development and minute anatomy of the teeth in 
 health and disease are in harmony with that practical experience, 
 gained by careful observation, that decreased liability of the teeth 
 to decay must result largely from change in environment; and this 
 is to be effected by cleanliness, local antiseptic ti'eatment by suitable 
 mouth-washes, by giving the teeth a proper amount of work to do> 
 and by such systemic treatment as will decrease the conditions 
 which favor fermentation in the mouth. 
 
 DISCUSSION, 
 President Carr. The discussion of Dr. Williams's paper will now 
 be opened by Professor Frank Abbott, of New York. 
 
 Dr. Abbott. Mr. President and Gentlemen : Truth is what we 
 are looking for, no matter whether it comes from Philadelphia,
 
 27 
 
 Berlin, or elsewhere. It is what we have been striving for during 
 the last eight or nine years, and many of us verj'- hard indeed 
 Possibly there may have been considerably more work done in this 
 direction by several other gentlemen present than by the reader of 
 the paper. That our opinions differ widely and emphatically as 
 to the facts in the case, considering our different stand-points, needs 
 not, perhaps ought not, to be doubted. That Dr. Miller, or anyone 
 else, can place under the microscope a section of a carious tooth, 
 whether the caries be artificially produced or otherwise, and make 
 it appear as if it were full of organisms, I have no doubt. But there 
 is one truth that we want to remember, in the first place, which 
 the doctor has kindl}' referred to, namely, — that there is organic mate- 
 rial in the teeth. He does admit that there is some twenty-two per 
 cent, of organic matter in the dentine, and that there may, possibly, 
 be a little in the enamel, although that is doubtful. I am glad he has 
 gotten along so far as to admit that it is not a solid crystal of phos- 
 phate of lime. I have so many times seen, in sections of enamel 
 magnified under the microscope 1000 to 1500 diameters, what cer- 
 tainly seemed to be fibers so clearly demonstrated that the idea of 
 doubting their existence appears almost too ridiculous to talk about. 
 To go back to the question of organization. Bone-tissue, as you 
 know, contains about thirty-three per cent, of organic material 
 (including the matrix into which the lime-salts are deposited, the 
 reticulum of living matter, blood-vessels, etc.). There is an inflam- 
 matory condition of bone called osteitis, a disease known to all sur- 
 geons, and every man who is familiar with the pathology of bone- 
 tissue understands it. Now, in dentine we have a tissue which 
 presents a little less organic material, it is true, but can anyone 
 sustain the position that because of this slight difference in or- 
 ganic material inflammation cannot occur in it? This is limiting 
 pathology with a degree of certainty quite startling. True, it has 
 no regular circulation, so far as blood-vessels proper are concerned, 
 but that there is a kind of circulation in dentine that we have not 
 yet seen, nor yet understand, I do not doubt for a moment. As an 
 evidence of it we have from the beginning of the deposit of lime- 
 salts in the odontoblasts, thi'ough the entire life of the pulps of teeth, 
 a constant accretion of inorganic material in that tissue. A similar 
 process is constantly going on in all the osseous structures of the 
 body. If there is no organic or living matter in the enamel, I would 
 like to know how it is that when the pulp of a tooth is dead the 
 enamel loses its peculiar life-like appearance and looks in every way 
 like dead tissue. How does it change in that manner if there be 
 not something going on in the way of death of the tissue, and how 
 can this occur if it is a solid "secretion" of lime-salts? I was un-
 
 28 
 
 fortunately called out for a moment, and did not hear all that was 
 said in the paper in reference to a recent article of mine upon the 
 subject of the pathology of the enamel of human teeth. There are 
 certain conditions, of course, which predispose teeth to decay, and 
 that their environment has much to do with it there is no question. 
 All that is necessary to say in answer to the reference is that a 
 perfect enamel will withstand an unfavorable environment much lon- 
 ger than an imperfect one. This fact, I think, even Dr. Williams 
 will admit. 
 
 There is one question in reference to the presence of micro- 
 organisms in the deeper portions of caries that has troubled my mind 
 quite considerably, viz : If great numbers of them ai'e left in teeth 
 when they are filled, as must be the case if they are present, as is 
 claimed by some observers, when a reorganization of the disor- 
 ganized territory of dentine takes place, — a process the results of 
 which are observed by all clinicians, — what becomes of these or- 
 ganisms? Do they enter into and form a part of the reorganized 
 dentine, or do they quietly steal away? They must be dependent 
 upon outside nourishment, or it is fair to presume that they would live 
 and thrive under a filling as well as before the filling was introduced. 
 This would seem to "checkmate" the theory that they live upon 
 the organic portion of the tooth, and that they necessarily " secrete" 
 lactic acid. 
 
 Mr. President, the opening of a discussion of this kind is a little 
 awkward, particularly after so lengthy a paper as we have heard 
 this afternoon, and one that requires so much thought in its discus- 
 sion. Perhaps I may ask the privilege of adding a few words later 
 on, or at the close, but I will leave the matter as it is for the time 
 being. 
 
 President Carr. We will now have the pleasure of listening to 
 Dr. W. Xavier Sudduth, of Philadelphia. 
 
 Dr. Sudduth. Mr. President and Gentlemen : Dr. Abbott has re- 
 iterated in your hearing to-night the same sentiment which he has 
 previously published, viz., — that decay of teeth, while differing 
 slightly from caries of bone, is essentially a similar process. He 
 finds in decay of teeth the analogue of osteitis. He further says 
 that " the idea of doubting the existence of the fibrils is too pre- 
 posterous to talk about." And again, both Drs. Abbott and Heitz- 
 mann say that by the technique which we use to demonstrate micro- 
 organisms we destroy the bioplasson bodies. I shall confine myself 
 this evening to these three propositions, and that we may correctly 
 discuss Dr. Abbott's position, I take the liberty of quoting from a 
 paper published by him in the Dental Cosmos, on " Caries of Human 
 Teeth" :
 
 29 
 
 " Caries of a living tooth, therefore, is an inflammatory process 
 which, beginning as a chemical process, in turn reduces the tissues 
 of the tooth into embryonic or medullary elements, evidently the 
 same as during the development of the tooth have shared in its forma- 
 tion ; and its development and intensity are in direct proportion to 
 the amount of living matter which they contain, as compared with 
 other tissues."* 
 
 Your attention is first called to the question. Is decay of the 
 teeth an inflammatory action? I use the term "decay" advisedly, 
 because the process of decay is so unlike that of caries of bone that 
 the same word should not be used to designate the two pathological 
 conditions. It has come to be a generally accepted fact that decay 
 of teeth is a separate and distinct pi'ocess. As such, it should be so 
 acknowledged. 
 
 Caries of bone, as is well known, is an inflammatory action. Decay 
 of teeth, in so far as the crowns are concerned, is a chemical ac- 
 tion: the inflammatory concomitant is a secondary element. In 
 caries of bone the disease begins in the organic substance, while in 
 decay of the teeth the inorganic material is first to be affected. 
 In caries of bone the process is vito-chemical. In decay of teeth 
 the order is reversed, and we see a chemico-vital action. 
 
 As regards the erosion of the cement and the dentine of the roots 
 of living teeth, when it does occur, I do not think there is any 
 reasonable doubt but that the process is analogous to absorption of 
 bone, and follows the same order. In caries of bone osteoclasts, or 
 giant cells, are an essential element to the carious process. These 
 cells are probably developed from the white blood-corpuscles which 
 have escaped from the capillary vessels. The nourishment of these 
 cells depends upon the close proximity of a vascular supply. In 
 decay of the teeth all these essentials are entirely wanting. Inflam- 
 matory caries of enamel or dentine is an utter impossibility when 
 considered from the above stand-point. 
 
 Let us see if we can substantiate our position. 
 
 The initial lesion in inflammation of bone and cement begins in 
 the vascular system. It may arise from traumatic injury or from 
 an extension of disease from previously affected tissue. An example 
 of the first may be found in cases of fracture; of the second, in con- 
 stitutional syphilis and tuberculosis. At first we notice a hyper- 
 emic condition, which is quickly followed by one of congestion, in 
 which there is an exudation of white blood-coi'puscles. The exuda- 
 tion may be resorbed and the equilibrium of the circulation restored. 
 On the other hand, the irritant may be so great, and the existing 
 
 *See the Dental Cosmos, Vol. xxi., April, 1879, page 179.
 
 30 
 
 lesion of such a grave nature, that the character of the exudation 
 ma}' be changed into a purulent condition. In this case the recu- 
 perative power of the tissue is entirely overcome and necrosis 
 results. There is an intermediate stage, however, in which the in- 
 flammation, once established, is more j^ersistent but less virulent in 
 character. This is designated caries, and a description of this pro- 
 cess particularly interests us now, in that we may compare it with 
 decay of the teeth and note the points of dissimilarity. 
 
 Dr. Heitzmann holds that erosion is produced by a pathological 
 condition of the fluids of the blood, which liquefies the bone, 
 thus freeing the bone cells, which then coalesce and form the giant 
 cells. He does not satisfactorily account for the presence of giant 
 cells in connection with the absorption of sequestra and other hard 
 tissues in which no living cells exist. Any fluid which has the 
 power of decalcifying bone or teeth, circulating in the vascular 
 system, would have a deleterious action on other parts of the body. 
 I hold that erosion is produced by the osteoclasts at the point of 
 irritation. 
 
 Absorption of tissues is a process w^hich is established by nature 
 for the removal of oifending particles, or tissues that have performed 
 their life-work, and is therefore physiological, although the process is 
 excited by pathological means. There is set up in the infected part 
 a condition of over-nutrition, caused by the local irritant. The ex- 
 uded cells tend to form granulation tissue ; rapid cell-multiplication 
 occurs, and numerous cells are found that contain more than one 
 nucleus. These are termed giant cells, or osteoclasts, if the body to 
 be removed is bone. Giant cells are found in diseases where great 
 cellular activity exists ; for example, in miliary tuberculosis, syph- 
 ilis, sarcoma, hyperplastic granulation tissue, and in connection with 
 absorption of bone and other bodies which nature wishes to remove. 
 They are developed in all such places, unless the exuded cells are 
 destroyed and a purulent condition produced. 
 
 Flemming has established beyond dispute that cell division is by 
 nucleus division. In some instances, however, the nucleus divides 
 and the subsequent cell division does not follow, in which case 
 "giant cells" are formed. We do not know positively just why 
 cellular activity occurs. It is highly probable that the cells are 
 stimulated to increased assimilation of cell-pabulum, since we do 
 not always find giant cells in all cases of over-nutrition, but 
 the fact of the appearance of giant cells in absorption of tissue, 
 whether the tissue contains bone cells or not, pi"etty clearly estab- 
 lishes the fact that giant cells have an identity entirely independent 
 of bone cells. Then, again, the giant cells or osteoclasts present a 
 similar appearance to giant cells found — as before mentioned — in
 
 31 
 
 syphilitic gummata and miliary tubercles. Ziegler uses the terms 
 " osteoclasts," " giant cells," and " resoi'ption cells" as synonymous 
 when speaking of erosion of bone, and says most emphatically that 
 they arise from the exuded blood cells. Exudation precedes the for- 
 mation of giant cells. Giant cells precede the decalcification of bone. 
 The bone cells are the last tissues to be liberated in the process of 
 caries; hence they cannot, with any degree of reason, be said to 
 form the resorption cells, giant cells, or osteoclasts. 
 
 A description of the process, from Woodhead's " Pathology," will 
 further elucidate the point to which I have reference: 
 
 " If the caries is situated in the shaft of a long bone, or in the 
 spongy bone of the alveolar process of the jaw, the trabeculae will 
 be found dilated and the vascularity of the tissue greatly increased. 
 In a picrc-carmine preparation of a malignant epulic growth we 
 see lying on the trabeculae numerous deeply-stained, rounded cells, 
 which appear to be partially imbedded in a layer of pink tissue. The 
 Haversian canals are much enlarged, and at the same time are very 
 irregular ; the irregularity being due to a process of excavation ex- 
 tending from the main cavity down into the bone of the surround- 
 ing Haversian system. These cavities, whether shallow or of 
 considerable depth, usually contain a number of small round cells 
 (exuded cells or granulation tissue) ; but, in addition, when the 
 excavation is rapidly progressing, numerous osteoclasts, which lie 
 in cup-shaped cavities, or depressions, are seen. The cup-shaped 
 depressions appear to be invariably associated with absorption of 
 bone, and are spoken of as Howship's lacunae. The osteoclasts may 
 be very lai*ge, may contain many nuclei, and are, in all respects, 
 similar to the giant cells in myeloid sarcoma. The cells and spaces 
 are much more numerous than they are in normal bone, where they 
 are also associated with a certain amount of absorption." 
 
 The roots of temporary teeth are an excellent example of physi- 
 ological absorption through the agency of the giant cells, but these 
 roots are situated in the jaw, surrounded by highly vascular tissue, 
 which latter is absolutely essential to a carious pi'ocess. In decay 
 of the crowns of teeth these latter essentials are entirely absent, 
 and the development of osteoclasts or " bioplasson bodies " is an 
 utter impossibility. The ability of the blood-vessels of the pulp to 
 furnish the cellular elements for the production of giant cells is not 
 denied, but if giant cells were produced we should have internal 
 caries. Even granting that the erosion of hard substances is pro- 
 duced by the action of a fluid which exudes from the blood-vessels 
 of the pulp, such erosion would result at the point where the den- 
 tine first came in contact with such fluid, so that the latter theory 
 will not apply to decay of the teeth, nor will it hold good in caries
 
 32 
 
 of bone. To the giant cells or osteoclasts is attributed the secretion 
 of a fluid which has the power of liquefying bone, — they themselves 
 sinking into the cavities which the}'- form. It mattei'S not whether 
 the offending tissue be living or dead, if it is soluble. The process 
 is slower when the tissue is dead. The lime-salts are removed in 
 advance of the organic portions in resorption of living bone. 
 Erosion may begin on the outer side and extend inward ; it may 
 commence in the medullary cavity and proceed outward ; or both 
 may occur at the same time. " A dead piece of bone inserted under 
 the skin of an animal, and examined a few weeks after, will be found 
 interpenetrated with vascular granulations, and the trabeculse will 
 be beset in many places with giant cells. The whole process is 
 very similar to that of physiological bone-resorption. * * * This 
 process is peculiarly modified when the foreign substance is firmly 
 connected with the surrounding tissue ; when it is in fact a necrosed 
 fragment of the tissue itself, such as bone or kidney. In this case 
 the first step is the separation of the living from the dead. Lang- 
 haus was the first to describe minutely the process by which larger 
 foreign bodies are absorbed. He pursued the subject experimen- 
 tally by producing extravasations of blood in various animals. He 
 thus discovered the 'giant cell.' Heidenhain also found them in 
 pieces of elder-pith which he had inserted in the abdominal cavity 
 of animals. Ziegler always met with them in connection with his 
 experiments in placing cover-glasses slightly separated under the 
 skin of a dog. Later experiments with sponge-grafting have 
 demonstrated their presence and active agency in the absorption 
 of pieces of sponge." * 
 
 In some instances of absorption of bone, in close proximity to the 
 osteoclasts may be seen osteoblasts building new bone. It is by this 
 after process that bones once formed are enlarged. The osteoblasts 
 on the outer side are adding to the circumference, while the osteo- 
 clasts are enlarging the medullary or marrow cavity. The develop- 
 ment of the antrum of Highmore may be cited as another example. 
 
 No one would think of attributing this action to a pathological 
 condition, yet the absorption is accomplished by the same agency that 
 operates in the removal of bone in caries. It is an undisputed fact 
 that cells have the power of secreting acid fluids to subserve the pur- 
 poses of nature, and in claiming this function for giant cells we do 
 not go beyond the domain of physiological action. The process of 
 absorption is a purely phj'siological one, in so far as the removal of 
 the tissue is concerned. The irritant, howevei", that excites the cells 
 to the secretion of the fluid is without doubt pathological ; but the 
 action of the cells thus stimulated is physiological. To admit that 
 
 *Ziegler's «' Pathology."
 
 33 
 
 by the blood-vessels, would be to admit that the process of develop- 
 ment depended upon a highly abnormal condition of the fluid of the 
 blood, and that a well known physiological condition is pathological. 
 There can be no doubt that cellular activity may be induced by dif- 
 ferent agents ; but no matter what agent incites the process, the re- 
 sult is always the same, provided the other conditions remain the 
 same. 
 
 Nature works through well-known channels to accomplish her 
 ends, and resorption of tissues is one of her many processes. When 
 pathological ends are arrived at, the initial irritant is pathological. 
 In caries of bone it may arise from constitutional disease, such as 
 miliary tuberculosis, in which disease it has been pretty conclu- 
 sively shown that the irritant is the tubercle bacillus. In caries 
 accompanying syphilis it has not been proven what the initial 
 vice is, but late discoveries point to a micro-organism. Suffice it to 
 say, in general, that in every case when pathological results are ob- 
 tained cellular activity arises from some irritant having a local ex- 
 pression at the point where the caries is produced, — in which case 
 the caries is the indirect and not the direct result. I cannot look 
 upon it in any other light than that the specific vice of syphilis and 
 tuberculosis acts as the local cause of irritation. It is the old story 
 of circumlocution and removal of a foreign body, — a ball in the flesh 
 or a sequestrum of bone, etc. The presence of the irritant gives rise 
 to a perversion of the equilibrium of the circulation, and the localiza- 
 tion of the congestion in the immediate neighborhood of the cause 
 of irritation. This increased flow of nutrition is not in itself suffi- 
 cient to account for the increased cellular activity, both as regards 
 cell-multiplication and function ; for we have congestion many times 
 without the formation of giant cells or the production of acid seci*e- 
 tions. No ; there is back of all that can be observed some innate 
 principle, which lies in the cells themselves, that leads to these spe- 
 cial attributes, — the "ego" in the cell itself, if you please, which 
 turns the local irritant into a cellular stimulant. 
 
 Inflammation of dentine may result from traumatic injury, frac- 
 ture, abrasion, or decay. We will not speak of pericementitis, which 
 may extend to the dentine of the root ; it differs in no manner from 
 extension of periostitis, the pericementum being the counterpart of 
 the periosteum. 
 
 We will confine ourselves to that portion of the tooth situated 
 above the gums ; claiming that the conditions in the decay of that 
 part are entirely different from those in the root. In caries of 
 bone the initial lesion is an inflammatory process, in which inflam- 
 mation precedes erosion of the osseous structure. Now, on the 
 
 8
 
 34 
 
 other hand, in decay of the teeth the order is reversed, and erosion 
 antedates the subsequent inflammation. As we have seen, caries of 
 bone depends upon a highly organic and vascular condition of the 
 surrounding tissue; in fact, a tj^pical inflammation is always depend- 
 ent upon such conditions. Now, the inflammatory process seen in 
 connection with dentine is of a very low grade, because of the small 
 amount of organic tissue found in dentine. Mind, I do not speak of 
 inflammation of the pulp, but of the dentine itself As regards in- 
 flammation of enamel, I have nothing to say, since to my knowledge none 
 exists. And right here comes in a marked diff'erence between those 
 who look upon decay as a vito-chemical action and those who hold 
 that the process is just the reverse, viz., chemico-vital. Those who 
 hold to the inflammatory view of decay claim that there is a direct 
 calcification of the organic or cellular tissues in the development ot 
 the dentine and enamel. I think that I have offered conclusive 
 argument to the contrary in the pages of the Dental Cosmos, and so 
 will not inflict them upon you here, but refer you to the November 
 and December numbers for 1884. 
 
 That Drs. Heitzmann and Abbott hold the theory that inflamma- 
 tory processes depend upon a large per cent, of organic tissue is 
 evidenced by the fact that they have tried to formulate a theory of 
 development that will fit such preconceived ideas of decay. They 
 have entered through the wrong door. They should have built their 
 teeth first, and afterwards torn them down. 
 
 A man once started on a wrong theory naturally seeks to bend 
 every appearance in support of the position he has taken and prove 
 its correctness. Thus it is that so many erroneous conclusions are 
 reached by those who reason from preconceived ideas. Dr. Abbott 
 claims that he has seen a fine net-work of reticular substance left 
 after decalcifying enamel. Now, I have tried faithfully to preserve 
 and demonstrate this " reticulum." I have taken teeth fresh from 
 the mouth and put them directly into Miiller's fluid, handling them 
 with as much care as I would nerve-tissues. After several days I 
 ground sections, not allowing the tooth to dry. After grinding I 
 placed them in alcohol to remove the acid, and then stained them by 
 the best technique known. I failed to discover any " reticulum. " 
 Again, I have taken sections thus prepared and decalcified them 
 under a cover-glass on a slide on the stage of a microscope, carefully 
 watching the process from time to time. Results negative. The fluid 
 used was one-half of one per cent, solution chi'omic acid. 
 
 Again, to avoid all possibility of error in technique, I imbedded sec- 
 tions of freshly-ground teeth in celloidin, and decalcified them in a 
 one-half of one per cent, solution of chromic acid, stained and after- 
 wards examined them with a Zeiss one-twelfth hom. oil im. lens, with-
 
 35 
 
 out being able to demonstrate any organic tissue. By the last-named 
 process it was not possible for the reticulum to disappear through 
 faulty technique. The celloidin, acting as a perfect imbedding mass, 
 was not affected by the acid in the least degree ; nor did it hinder in 
 the process of staining, for it is well known that it is more permeable 
 to stains than tissue itself Further, previous to decalcifying the 
 section, I placed it on a slide, and drew on the reverse side of the 
 slide, with a writing-diamond, the outline of the section. This I 
 used to compare the former outline of the enamel with, by placing 
 the section on it to study. I could thus tell exactly where the reticu- 
 lum should appear. I did not allow the enamel to be entirely 
 eroded by the acid. The line of demarkation where the decalcifying 
 process stopped was well defined, and no appearance of organized or 
 reticular tissue was to be seen between that portion of the enamel and 
 the line drawn on the back of the slide which marked the periphery 
 of the enamel before decalcification. On the strength of these and 
 numerous other experiments, made in decalcifying enamel, both in 
 mature and developing enamel, I deny the existence of such a re- 
 ticular substance. 
 
 There is another point of dissimilarity between caries of bone and 
 decay of teeth, — viz., the two processes do not give the same reaction 
 when sections of each are stained with picro-carmine. This fact is 
 mentioned by Dr. Miller, who says that " any one who has given time 
 to the study of inflammation, particularly of bone or cartilage, will 
 at once be impressed with the fact that there is not the slightest 
 similarity between it and caries dentium. Furthermore, the ac- 
 tion of different coloring matters upon carious dentine furnishes 
 information of considerable interest; for example, picro-carmine 
 colors the simply decalcified, otherwise unchanged, basis-substance 
 pink or red, while the distended tubules or round or oval cavities, 
 filled with debris and fungi, are stained yellow. This reaction is in 
 marked contrast to that of pulp-tissue, periodontium, bone cartilage, 
 etc." I have often noticed this point of difference, and can fully 
 agree with Dr. Miller. Here again comes in the need of broad ex- 
 perience in the action of the different stains in the various patho- 
 logical processes. 
 
 Differential diagnosis by means of stains is a point well-known to 
 those who are conversant with the different chemical reactions of tis- 
 sues. It is by reason of these variations th^ we are able to obtain 
 different colors from the same stain in a section which contains more 
 than one tissue. In accordance with this knowledge we can, with a 
 considerable degree of certainty, use stains as aids in diagnosis. 
 
 The result of inflammation in bone is aggressive, and is veiy apt 
 to be followed by loss of bone-tissue. Inflammation of dentine is a
 
 36 
 
 defensive process, and through its action barriers are thrown out to 
 stoj) or hinder the advance of disease. This is well known to every 
 observing dentist, and I need not stop to enter into its discussion ex- 
 cept to mention the translucent zone and the development of sec- 
 ondary dentine. In ni}^ opinion, enamel is nothing more nor less than 
 a coat of mail supplied by nature to protect the dentine, by furnish- 
 ing a hard surface, and to answer the process of mastication. The 
 presence of any considerable amount of organic material that would 
 entitle it to the dignity of accrediting to it an inflammatory action 
 would be just so much against the projDcr fulfillment of its otfice. 
 ]Srature, when left to herself, develops a beautiful and symmetrical 
 object, perfectly capable of subserving her purposes. But, then, you 
 say, why does not enamel resist decay? You might with equal 
 propriety ask why do we sicken and die? Simply because we have 
 transgressed nature's laws. God in his wisdom created man physi- 
 cally perfect. Man in his weakness has perverted this nature, and 
 disease has followed as a natural consequence of his transgressions. 
 The nearer we can put ourselves in harmony with nature the better 
 able shall we be to interpret her creations. If we enter upon our 
 investigations without preconceived ideas, with open and receptive 
 minds, we shall find that many of the processes which we are trying 
 to make out as intricate and obscure will be plain and easy to 
 understand. 
 
 The normal condition of the fluids of the mouth is neutral or 
 alkaline, and any deviation from this state is pathological. Enamel 
 was not intended to resist pathological conditions. It was created 
 to fulfill the requirements of nature when the surroundings are 
 normal. Decay of enamel is the result of the melting down of 
 the lime-salts that constitute it, by an acid condition of the saliva. 
 This pathological condition of the secretions of the mouth frequently 
 accompanies some form of general disease, as diabetes, gout, or gastro- 
 intestinal disorders. It is also often observed in parturition, which, 
 by reason of our present way of living, has come to be reckoned 
 among pathological conditions. Morning sickness is an almost 
 constant accompaniment of parturition, and there is seldom any at- 
 tempt made to neutralize the acid fluids of the stomach, which are 
 so frequently found in the mouth at such times. Local diseases of 
 the gums or mucous membrane of the mouth often give rise to acidity 
 of the secretions. Pathological conditions of the glands that empty 
 into the mouth, and acid foods and medicines, without doubt pla}^ an 
 important role in decay. I think that sea-sickness has a great deal 
 to do with the rapid destruction of the teeth of foreigners (servant 
 girls) which is noticed soon after their arrival in this country, rather 
 than the oft-repeated explanation of change in habits and diet. The
 
 37 
 
 fluids of the stomach are normally acid, but are decidedly pathological, 
 when brought into contact with the teeth for any great length of time. 
 I have never seen any attempt at cleanliness evinced by steerage 
 passengers after paying their debts to Neptune, and I think that all 
 will admit that the use of the tooth-brush is an art that is acquired 
 after their arrival in this countr}-, if learned at all. The idea that 
 all foreigners have good teeth is fallacious. I saw more toothless 
 women in Europe last summer than I ever saw in America in the 
 same length of time. The latter appearance, however, may be 
 partially accounted for in the fact that the masses in America can 
 better aiford to have lost teeth replaced, and do so. 
 
 Above all the before-mentioned conditions which favor decay, I 
 consider the most active agent to be an acid developed at the seat of 
 decay b}^ acid fermentation. Dr. Miller, of Berlin, has very conclu- 
 sively shown that this fermentation is produced by micro-organisms. 
 He has isolated twenty-two separate forms, and has cultivated 
 them suflSciently to classify them and note their principal reactions, 
 whether acid or otherwise. He says, " Sixteen produce an acid re- 
 action in a solution of beef extract, pepton, and sugar, and for the 
 rest the results were not satisfactory ; sometimes the reaction being 
 acid, at other times neutral or alkaline, depending upon the material 
 used for their culture. Some which have an acid reaction in a fer- 
 mentable solution give rise to an alkaline reaction in non-ferment- 
 able solutions. " According to Dr. Miller, " decalcification is pro- 
 duced chiefly by acids resulting from the action of these organisms 
 upon certain of the carbohydrates in the human mouth, while the 
 peptonization is produced either by the direct action of the pi'oto- 
 plasm of the organisms upon the decalcified dentine or by a ferment 
 which they produce." Three jears ago I gave considerable time to 
 the study of micro-organisms found in cavitiesof decay, staining them 
 by the best-known methods at that time. I succeeded in satisfying 
 myself that no micro-organisms ever penetrated the dentinal tubuli 
 beyond the point of decalcification. The dentinal tubuli are imper- 
 vious to the entrance of these organisms while they are in a healthy 
 state. As a contribution to this part of dental discussion, I presented 
 these slides, with others, at a lantern exhibit given before the Illi- 
 nois State Dental Society, and stated my convictions on the subject 
 at that time. These were ground sections. I have since cut sections 
 of the decalcified mass found in cavities, and demonstrated several of 
 the micro-organisms figured by Dr. Miller. My sections also fully 
 confirm his statements regarding their presence in the tubuli of this 
 portion of decay. I can fully substantiate what Dr. Miller says, viz., 
 that " micro-organisms can, and often do, not only distend separate 
 tubules, but push whole tubuli aside, and these foci are the points 
 figured by Dr. Abbott as ' bioplasson bodies. ' "
 
 38 
 
 For the demonstration of micro-organisms of decay we take as 
 large a portion of the soft decalcified mass found in the cavities of de- 
 caj* as we can detach by aid of a broad, hoe-shaped, or other suitable 
 excavator, and place it in alcohol. After the water has thus been re- 
 moved we imbed in mucilage or celloidin upon cork, and cut sections 
 with a microtome or razor. These can be cut quite thin, as they are 
 completely decalcified by the acids of the mouth. After cutting sec- 
 tions, place them in an aqueous solution of any aniline dye, prefer- 
 ably^ fuchsine. After staining, place in absolute alcohol and remove 
 excess of stain ; then dehydrate in oil of cloves or cedar, and mount 
 in balsam. The only acids that come in contact with the spe- 
 cimens are those found in the cavity of deca}'. The methods neces- 
 sary for the examination of these micro-organisms are about the 
 simplest of any in use in the study of mycology ; and their demon- 
 stration the easiest of all the forms we are called upon to stud3^ 
 For some forms of bacteria, however, the methods are more difficult, 
 and their demonstration has taxed the knowledge of our best chem- 
 ists. Among the most difficult to study have been the tubercle ba- 
 cillus and the bacillus of lepra. Spores have always been extremel}' 
 difficult of demonstration, but are now pi-etty generally understood, 
 thanks to the untiring efforts of such men as Koch and Hueppe. 
 
 The bacillus lepra, spores, and tubercle bacilli can be put into a 
 twenty-five per cent, solution of nitric acid, then through two sepa- 
 rate baths of absolute alcohol, and yet hold their stains, — provided 
 the staining fluid which contains the sputum or spores is brought 
 to a boil or left for twenty -four hours. It is the knowledge of 
 these properties of bacteria in general upon which we base our 
 assertions that certain foci indicate micro-organisms. But it is not 
 essential that we depend even upon this knowledge. We can take 
 portions of the suspected material, while it is fresh, and cultivate it 
 upon gelatine or other suitable media. After cultivating it through 
 several generations, until we have produced a pure culture, we can 
 prepare a cover-glass, stain and study the isolated organisms. But 
 even this is not sufficient to establish the fact of their being the 
 active agents in decay of teeth. The demonstration of the persist- 
 ent occurrence of these organisms is of ver}^ little import unless 
 the investigator cultivates them and produces decay by their 
 action upon teeth placed in the culture solution. Dr. Miller has 
 done this by the action of some of these organisms on dentine, which 
 I cannot distinguish from decay produced in the mouth. And, fur- 
 ther, he has by difficult chemical analyses proven that the special 
 acid concerned in decay is lactic. In this latter direction he has 
 gone farther than most mycologists. Not only is it necessary to pro- 
 duce decay b}^ the fungi, but the destructive acid must also be deter- 
 mined.
 
 39 
 
 I have studied nearly all the pathogenic bacteria in tissues, and 
 have cultivated quite a number of the non-pathogenic, together with 
 a few pathogenic forms, and so feel capable of judging the charac- 
 ter of the work done by Dr. Miller. Very few are aware of the 
 immense amount of labor involved in the study of micro-organisms. 
 My reason for quoting Dr. Miller so extensively on the point under 
 discussion is that I have not sufficiently studied the special fungi 
 concerned in decay to offer an opinion unsupported by corroborative 
 testimony. I believe in the reliability of Dr. Miller as a scientific 
 investigator, and my belief is based upon the scientific manner in 
 which he has done his work, and the uniform willingness he has 
 shown in allowing others to see the slides and cultures from which 
 he has drawn his conclusions. The fact that he is quoted by such 
 an author as Ziegler. shows that he is regarded by his colleagues as 
 an original and trustworthy investigator. Dr. T. Mitchell Prudden 
 met Dr. Miller last summer in the laboratory of Dr. Koch, and 
 speaks very highly of his work. I have in my possession a culture 
 of a comma bacillus which was discovered in the mouth by Dr. 
 Miller, and which has received the name of Miller's comma. The 
 standing of a scientific man is in proportion to the honesty and in- 
 dustry with which he works, and I think that I have now cited 
 points enough to prove that Dr. Miller may be safely quoted as 
 reliable authority on the subject of decay. 
 
 In conclusion, it may not be inappropriate to speak very briefly 
 of the position of dentistry in regard to scientific research. I fear 
 that we do not as a body realize the importance of putting all our 
 statements on a scientific basis, and submitting them in a scientific 
 manner. We are too apt to base our theories upon information 
 about different phenomena, instead of building them securely upon 
 active knowledge of visible results. Gentlemen, this may have done 
 in the past, but it will not do now. Scientific investigation is con- 
 stantly changing the points of view from which we have been in 
 the habit of regarding various pathological conditions ; it keeps on 
 presenting new suggestions and new discoveries. To meet this 
 advancement it is required that we subject all our theories to the 
 crucial test of careful experiment. Nor is this all : we must be able 
 to show the results from which we draw our conclusions. 
 
 The day is passed when simple assertions or drawings of other 
 men's work will suffice to establish a scientific point, and our pro- 
 fession will never be the power it might be until as a body we recog- 
 nize the true value of the experimental investigation of actual facts 
 wherever these are accessible to study, and demand that all patho- 
 logical questions connected with our work shall bo pursued from a 
 scientific stand-point, and the visible results presented for investiga-
 
 40 
 
 tion. If we would be forceful men in the domain of science we 
 must present facts for authority, not authority for facts; we must 
 freely give the methods by which our knowledge is augmented, and 
 allow others to study and weigh our work. Above all must we be 
 prepared to modifv our views or abandon them if errors should be 
 discovered and plainly pointed out. 
 
 Let us take as capital examples of the true scientific spirit the 
 researches of Dr. Koch and his school. The preparations upon 
 which their inferences are based have been fi'eely shown to others, 
 and they have done their utmost to extend the boundaries of 
 medical science by publicly revealing new facts as they have 
 gathered them from various experiments. Compare the attitude ot 
 these men with that of Dr. Ferran. He rose like a meteor and sunk 
 as rapidly, not because he was incapable of performing the experi- 
 ments in which he was ensaired, — for he had studied in some of the 
 best laboratories in France and Germany, — but simply because his 
 methods did not bear the stamp of true scientific investigation. He 
 refused to demonstrate the facts upon which his theory was based, 
 and consequently scientific opinion was against him. 
 
 These thoughts ax-e offered as a mere outline of the direction 
 which conscientious inquiry in dental pathology is now taking. 
 The attendance here this evening shows the interest that is being 
 awakened in scientific dentistry, and I trust that it will be the 
 means of exciting an increased desire for scientific information- 
 Many difficult problems are now awaiting the patient student. He 
 who would solve them must first learn his a, b, c's in the field as 
 taught in normal histology ; his x, y, z's in general pathology. Then, 
 having just learned the use of the tools which will constitute him a 
 novitiate in science, he may pass into the field of special pathology, 
 including mycology, where he will find at least a pailial key to the 
 solution of some pathological problems. Until he has done this no 
 man is entitled to high rank as a scientist. Let us, then, as a 
 dental profession aspire to true scientific attainments, and prove 
 ourselves worthy of the title of a scientific profession. 
 
 President Carr. Gentlemen, we will now have the pleasure of 
 listening to Professor Carl Heitzmann, of this city. 
 
 Dr. Heitzmann. Mr. President and Gentlemen : There was a 
 young man in the far West who did farm work until he had grown 
 to be twenty-four or twentj'-five years of age. Then he made up 
 his mind to learn to read and write, and he began to learn the a, 
 b, c's. His name was Bob. He found another young man who 
 could read and write, and engaged him to teach him his a, b, c's.
 
 41 
 
 The teacher's name was John, and when Bob, who was a very intelli- 
 gent fellow, reached the letter k he suddenl}^ jumped up and ran out 
 of the door. John shouted after him, "Bob, where are you going?" 
 Bob turned to his teacher and boastfully said, "Now I am going to 
 teach the a, b, c's, John." The gentlemen who have attempted to 
 talk about the history of the development of the teeth this evening 
 have only reached the letter k of the a, b, c's, and that includes 
 myself, because in my twenty-five years' work on the teeth I have 
 not 3^et reached the letter z in the alphabet of their histology. Dr. 
 Williams in his paper does me the honor of repeatedly quoting me, 
 and especially alludes to things that I am assumed to say regarding 
 the history of development in mj' book. But there I say very little, 
 for all that is published in my book about the teeth emanated from 
 Dr. Bodecker and Dr-. Abbott. The little I say of the history of their 
 development is that we don't know anything about it. Whether 
 this is worth quoting or not I don't know. I feel thankful to Dr. 
 Williams that he does quote me, but I don't deserve it. The few 
 points that I have looked into in connection with this subject are 
 just those which Dr Williams ignores entirely in his paper. Dr. 
 Williams has said some things of great wisdom indeed. For in- 
 stance, one of the important points he brought forwai"d was that 
 the bone-formers will not produce dentine, and the dentine-formers 
 will not produce bone. That is just as good as to say that a white 
 man will not produce a black child and a negro will not produce a 
 white child. I ask what is gained by such speculations on vital 
 forces? Of course there will be a few who still believe that there 
 may be an exception to the rule that a black man cannot produce a 
 white child. 
 
 Dr. Williams's explanation of teeth being found in the ovarian 
 cyst is that remnants of previous epithelia, which once helped 
 to form teeth, were transported into the ovary, there developing 
 teeth. Then he admits another theory, that perhaps the epiblast 
 which produces the tooth originally might have caused some mis- 
 chief in the ovary, giving rise to teeth in the ovarian cyst. But, 
 gentlemen, a white man cannot beget a black child. How is it pos- 
 sible that in the ovar}^ not only teeth are present, but there are hairs, 
 bone, cartilage, and even muscles? We know a theory that will 
 explain it, — viz., that in the earliest period of the development of the 
 embryo there was developing another one, inclosed in the ovary > 
 and parts of the inclosed embryo developing in the ovar}^ were left 
 and grew there, just the same as if present in the womb. 
 
 Quite recently I was asked to see a tumor which was removed 
 from the abdominal cavity of a living woman by Dr. Munde, replac- 
 [liil one of the ovaries. I cut into and found it hollow. I examined
 
 42 
 
 it undei' the microscope, and, much to my surpi'ise, I found this to be 
 the chorion, with its villosities, of a six-weeks embryo. This fact 
 gives a positive hint as to the development of teeth in the ovary. 
 But why should we speculate and argue about the presence of teeth 
 in the ovaries of women ? If we only knew the history- of their 
 development in the mouths of men we were a very happy people 
 indeed ; but we do not. In the last twenty-five years I have seen 
 plenty of specimens, — more, perhaps, than any other person present, 
 — but notwithstanding such a large experience I cannot say that 1 
 am ready to settle this matter positively. 
 
 Dr. Williams says it is mere speculation to maintain that the den- 
 tine is kindred to bone- tissue, because in the latter there are globu- 
 lar territories which he thinks are lacking in dentine. I will ask 
 Dr. Williams if he has ever seen the so-called interglobular spaces of 
 Czermak, by no means a pathological condition ? They often occur 
 some distance below the enamel traversed by canaliculi. I ask Dr. 
 Williams whether he has ever seen the bay-like excavations of den- 
 tine of temporary teeth, invariably present in the process of disso- 
 lution, preceding the falling of such teeth ? I ask Dr. Williams if 
 he has seen sj)ecimens of inflammation of the dentine, where bay- 
 like or globular excavations occur, traversed first by dentinal canali- 
 culi, and later broken up into medullary corpuscles? Still he asks. 
 Is there any such thing as a globular structure of the dentine ? I 
 was prepared for almost any attack, gentlemen, but not for that ; 
 because I had supposed there was not the least doubt that the den- 
 tine is globular in its structui-e, the same as bone. That, however, 
 dentine is not bone, and bone is not dentine, is one of those ingenu- 
 ous assertions of Dr. Williams which can scarcel}^ be discussed. 
 
 Let us inquire about the history of the development of the den- 
 tine. I will draw here the boundary line of the dentine towards the 
 pulp, and close to the dentine the odontoblasts, which send offshoots 
 into the dentinal canaliculi ; two or three dentinal fibers, sometimes 
 only one. Can Dr. Williams explain how, by the calcification of these 
 odontoblasts, the globular basis-substance of dentine will arise? For 
 it seems not only antique, but almost antediluvian, to speak of a 
 secretion as causing the formation of the basis-substance. How can 
 he explain the fact that in the recently-formed dentine there are 
 fields of basis-substance much narrower than the original odonto- 
 blasts ? I have studied this question over and over again, and have 
 come to the conclusion that the odontoblasts cannot be direct den- 
 tine-formers. To explain the formation of the globular character 
 we must take another ground, — namely, that the odontoblasts are not 
 permanent, stable forms at all. They are forms which arise and are 
 visible during the period of rest of the pulp-tissue. As soon as den-
 
 43 
 
 tine is about to form the odontoblasts break down or split up into 
 medullary corpuscles ; and we often see directly the globular shape 
 ■of groups of such corpuscles. Between the medullary corpuscles 
 the dentinal fibers are formed, although they were originally in con- 
 nection with the odontoblasts. The odontoblasts are not direct 
 formers of the dentine, but the medullary corpuscles are, just the 
 same as in any other variety of tissue. The odontoblasts are mate- 
 rially the same formations in relation to future dentine as the osteo- 
 blasts in forming bone-tissue. 
 
 The second point which Dr. Williams alluded to was the forma- 
 tion of the enamel. I purposely left his sketch on the blackboard, 
 because I am sorry for it. The greatest achievement of scientific 
 American dentistry is the knowledge of the minute anatomy of the 
 teeth. Up to the time of the studies of Bodecker and Abbott the 
 histology or minute anatomy of the teeth was about at the level at 
 which the Philadelphia gentlemen seem to be to-day. Their histol- 
 ogy is a little yellowish with age, — a little musty. We have learned 
 something from the careful researches of Dr. Bddecker, and it does 
 not make an}'- difference that they were made in my laboratory. 
 Dr. Bodecker was the first to find out that the enamel and the den- 
 tine are both living tissues. Then Dr. Williams comes with the as- 
 sertion that about ninety-seven per cent, of lime-salts are present 
 in the enamel, and that the rest is organic material. What is the 
 chemist doing when he goes to measure or weigh his lime-salts ? 
 Surely destroying the living matter first, either by fire or by some 
 reagent. To positively state how much organic matter the enamel 
 contains is impossible. That it is very little I admit, but that there 
 is some living matter in the enamel is quite certain. A celebrated 
 worker in dental histology was here three years ago. Prof Wedl, my 
 old teacher. He visited my laboratory, and we discussed this enamel 
 question. He was then sixty-nine years of age, somewhat older 
 than our friend Dr. Williams. I asked Professor Wedl to please 
 tell me his opinion about the enamel-fibers which Dr. Bodecker has 
 discovered and described. He said in answer: "There is not the 
 least question in my mind that the enamel-prisms are separated 
 from each other bj^ narrow interstices." Said 1 to him, " Who tells 
 you that? Where have j^ou read that?" Because we had looked over 
 the whole literature of the subject, including his own book, and 
 every author gives that unfortunate picture that Dr. Williams gives, 
 illustrating that the enamel-prisms are in close contact with one 
 another. I am very much afraid that Dr. Williams is looking at the 
 enamel from a stand-point that has been abandoned for at least ten 
 years. An authority, whom Dr. Williams will scarcely doubt, is Dr. 
 Tomes, of London. He was here last year, and was shown enamel
 
 44 
 
 in Dr. Bodecker's house. He drew the fibers between the rods of 
 the enamel just as we see them. Take a temporary tooth and grind 
 it, and you can easily see the enamel-fibers. Or take a section of 
 pigmented enamel, and you will see the fibers, because in the pig- 
 mented enamel the difference in color is greater than it is in ordinary 
 white enamel; the intei'stices are wider and the fibers positively 
 plainer. 
 
 Now we come to the question of the development of enamel. It 
 is the most difficult question of all. Dr. Williams justly alludes to 
 the presence of ameloblasts, nucleated bodies, and he admits that not 
 infrequently we see in a section long fibei's which go to and from the 
 already formed enamel. He gives a beautiful explanation of this 
 fact. He says, if j'ou put your fingers into syrup and draw them 
 out, you will have a thread of syrup from each finger. But that is 
 Philadelphia syrup. I do not like it. Has Dr. Williams forgotten 
 that we harden our specimens first in chromic acid? There is nothing 
 of the consistence of sj^rup any more. When we make the sections 
 the fibers are really present, not only when drawn out by the razor, 
 but also in situ between the ameloblasts. 
 
 Now, gentlemen, we come to the point that, according to Dr. 
 Williams, there is no similarity between the development of the 
 enamel and that of dentine. He asserts that the ameloblasts directly 
 form the enamel-rods. One point, as I said, is very superficially 
 touched upon in my book ; and although Dr. Williams does me 
 the honor of repeatedly quoting me in his paper, he gives no expla- 
 nation of what is to be seen. After the sixth week of embryonal 
 life a prolongation of the stratified epithelium of the oral cavity 
 is formed, a solid peg, and Avhich is admitted to be the future 
 enamel ; whereas from the embryonal connective-tissue is formed a 
 button-like projection, the papilla, viz., the future dentine. The 
 epithelial peg is originally solid. Does it remain solid ? No; in the 
 third, fourth, or fifth month of the embryo, befoi-e any dentine 
 begins to grow, you distinctl}^ sec that the epithelial peg becomes 
 hollowed out, and in its interior begins to show a myxomatous tissue, 
 consisting of a beautiful reticulum, long since known. Whence 
 is that myxomatous tissue? Nobody has maintained that myxoma- 
 tous tissue is epithelial tissue, but it is admitted to be a variety of 
 connective-tissue. Nobody will maintain that migrating corpuscles 
 have crept through the epithelium in order to produce myxoma- 
 tous tissue; therefore we must argue that the latter has developed 
 from the epithelia. But now comes a learned man and says that 
 epithelium will never produce connective-tissue, for these are tissues 
 of their own, independent from each other. Such a man overlooks 
 one thing, however, viz., that the whole nervous system of the
 
 45 
 
 embryo is developed from the epiblast, which is distinctly epithelial. 
 The original bi-ain and spinal cord is a prolongation of the epiblast. 
 From that arises the nerve-tissue, which is freely mixed with con- 
 nective-tissue and freely vascularized. I deny that there is no trans- 
 ition from epithelial to connective-tissue and vice versa, although I 
 concede that nobody else would admit such a liberal view, contrary 
 to all that the books teach. 
 
 Do not forget the instructive story of the Austrian peasant, who 
 had a vineyard and raised sour wine year after year. One day an 
 expert in wine-making came there and said to him, " My dear fellow, 
 why don't you take into consideration the new methods of cultiva- 
 tion ? Why don't you import some seedlings and get a better wine? 
 Your soil is splendid, and you could have a brilliant wine if you 
 would just adopt the improved methods of culture." And the con- 
 servative old peasant replied, " My father and my grandfather did 
 as I do, and raised wine without these new methods. Why should I 
 change what they found good enough?" And of course the man 
 still raises sour wine. A great many histologists are in the same 
 situation. They have learned the old doctrines and stick to them. 
 Nature does not narrow herself to any one idea of a histologist. From 
 this point of view, gentlemen, all the previous assertions as to the 
 formation of the enamel-prisms directly from the ameloblasts must 
 fall to the ground. Before the ameloblasts are formed there are 
 present medullar}^ corpuscles ; and before enamel-rods do form the 
 ameloblasts are again broken up into medullary corpuscles. Then 
 the same rule holds good in respect to the history of development 
 of the enamel that applies to the history of develojiment of the den- 
 tine. In one case it goes toward the center, centripetally, and in the 
 other toward the periphery, centrifugally. The ameloblasts are 
 merely provisional forms, similar in aspect to ej)ithelia, the same as 
 are the odontoblasts and osteoblasts. 
 
 That already formed tissues of a certain type do change their 
 character by falling back into the medullary or embryonal condition, 
 afterward giving rise to an entirely new tissue, is a well established 
 fact in histology. Look into the history of development of bone. 
 In the embiyo there is no bone, but cartilage only ; for the first tis- 
 sue that forms from the medullary tissue is cartilage. This, before 
 being transformed into bone, falls back into its medullary condition, 
 and the medullary tissue at last forms bone. If you break a bone 
 purposely, in order to find out how the fracture heals, the same thing 
 will happen. What we call provisional callus is nothing but carti- 
 lage. The medullary or inflammatory corpuscles in this instance first 
 form cartilage, — not directly bone, — but the cartilage breaks down 
 into medullary tissue afterwards, and at last arises bone-tissue, the 
 permanent callus.
 
 46 
 
 Now, gentlemen, comes the question of caries. Dr. Williams takes 
 three victims. Dr. Abbott, Dr. Bodecker, and myself, and tries to 
 twist our heads off and put them in his pocket. Dr. Bodecker is to 
 follow me, but I am very much alive yet to defend myself and kick 
 against Dr. Williams. These three men, he says, have made up a 
 theory regarding the cause of caries, and thej^ give certain figures, 
 just because it suits their theory of the development, formation, and 
 anatomy of dentine and enamel. He speaks with gi'eat emphasis of 
 what a horrid thing such a procedure is. One thing, however. Dr. 
 Williams has overlooked, — that Dr. Abbott has not insisted upon the 
 fact that caries is primarily an inflammatory action. He says in a 
 foot-note first that a dead tooth decays, — is destroyed in a chemical 
 way, — meaning by an acid, of coui"se. Dr. Abbott says that in living 
 teeth the first impulse to decay is an acid that works upon the 
 enamel, and from that impulse comes the process of disintegration. 
 He speaks several times of micro-organisms in his paper. He simply 
 claims that in living dentine and enamel there is a reaction upon the 
 irritation, and that you can see, before the dentine and enamel de- 
 cay, a zone containing medullary corpuscles. He claims that there 
 is a reaction upon the injury done by decay. Of course, to say that 
 caries is primarily an inflammatory process would be a mistaken 
 ground ; and nobody is willing to claim that there was inflammation 
 in an entirely dead tooth. Now, these gentlemen from Philadelphia 
 almost kneel down before the great god Miller and worship him ; 
 forgetting that all that was said long before Miller by Leber and 
 Rottenstein. There is not the least question to my mind that the 
 enlargement of the tubules is not caused by the gi"Owth of leptothrix 
 and micrococci alone ; but there is a decalcification before decay, and 
 decaying material is just crowded with such micro-organisms; and 
 upon the irritation of this decaying material sets in an inflammatory 
 reaction in a secondary way. You can see in Miller's specimens that 
 the growth of micro-organisms does not go so far as the decalcifica- 
 tion goes. Therefore, there is first decalcification ; then a growth of 
 leptothrix. Nevertheless, they say that all decay depends upon the 
 leptothrix. Behind all this decalcified zone you invariably see, in 
 specimens taken from live teeth of man, and preserved in a chromic- 
 acid solution, inflammatory changes. Such specimens of caries are 
 to be seen in my laboi'atory in any number. Dr. Sudduth says God 
 made man perfect, and man makes himself imperfect. I doubt that 
 very much, for nobody is born perfect. Neither is life an enjoyment, 
 but rather misery and hard work. As Dr. Sudduth says, a scientist 
 must show what he afiirms. It is not enough that he makes draw- 
 ings only ; he must prove them by specimens. I have such speci- 
 mens ; and my laboratory is, year after year, crowded by students.
 
 47 
 
 including many dentists, who come to me to see these things, and I 
 believe that all of them leave satisfied. Does Dr. Sudduth doubt 
 that what we represent is correctly done from nature ? Most of the 
 drawings I made myself, because I am an old draughtsman, and I 
 think everybody has admitted that I can draw. These illustrations 
 are made with the utmost care as to details. We do not take it easy 
 in our laboratory. It is very hard work indeed. Will Dr. Sudduth 
 do me the favor to come and look at these details ? He says he can- 
 not see them; and that I believe, word by word. He cannot see, 
 I am satisfied. 
 
 Dr. Williams. Mr. President and Gentlemen : Dr. Heitzmann's 
 remarks remind me of the reply which a talented young Congress- 
 man, a fellow-townsman of yours, made in answer to certain critical 
 remarks of Mr. Blaine, — that he had yet to learn that it was a crime 
 to be a young man. I have the highest respect for the wisdom and 
 experience which comes with years, but I submit that the time is 
 past when the value of a man's scientific opinions is to be based 
 upon the number of summers and winters which have passed over 
 his head. I think we may all appreciate the extremities to which 
 the professed champion of scientific truth is driven, when he finds it 
 necessary to resort to the recital of funny stories in order to dis- 
 tract the attention of his audience from the weakness of his position. 
 In a different sense from that intended by Dr. Heitzmann I accept 
 the rebuke ; it is well for a young man not to know too much. The 
 obstinate pride of opinion which sometimes leads men of years to turn 
 away from the new truth which is constantly coming into the world 
 has doubtless often grown out of the puffed-up, conceited wisdom 
 of earlier years. Therefore, if a young man does not place too high 
 an estimate upon his present acquirements, he is likely to learn 
 something as he grows older. Besides, I believe with Josh Billings 
 that " it is better not to know so much than to know so many things 
 that ain't so." 
 
 There is another and a better reason why I will not occupy your 
 time in replying to the very few points of significance in Dr. Heitz- 
 mann's remarks. We have with us to-night a gentleman who is 
 older than I am, who is older than Dr. Heitzmann, and who has 
 spent his entire life in the study of the development and histology 
 of the teeth. If this gentleman, for whose scientific attainments I 
 have the highest respect, shall confirm the position which I have 
 taken, it will at least be a complete answer to the silly story of the 
 country youth who desired to pose as a teacher before having himself 
 learned the alphabet. The attitude which Dr. Heitzmann has as- 
 sumed in this discussion forces me to mention a little incident which
 
 48 
 
 occurred several months ago, and which I should not feel like mention- 
 ing but for his misrepresentations of the position which I have taken 
 He correctly says that I spent some time in his laboratory as a 
 student, but his statement that I was in agreement with all of his 
 vague theorizing is quite unwarranted. I went there, not to contra, 
 diet his statements, but in the hope of gaining some new light on the 
 subjects in which I was most deeply interested at that time. But Dr. 
 Heitzmann has evidently forgotten that several months after I left 
 his laboratory I returned and exhibited some specimens to him, in 
 the presence of Drs. Atkinson and Bodecker, in which the dentinal 
 fibrillae were shown to be offshoots of the odontoblasts. At that 
 time Dr. Heitzmann frankl}^ admitted that the point was clearly 
 demonstrated, and that he had been mistaken in his teaching that 
 these fibers originated in the pulp reticulum and passed between the 
 odontoblasts. 
 
 Dr. Heitzmann. Will Dr. Williams remember that I drew off- 
 shoots of the odontoblasts on the blackboard, — not only one, but 
 two or three ? 
 
 Dr. Williams. Do you mean before I exhibited the specimens to 
 which I have just referred ? 
 
 Dr. Heitzmann. Yes. 
 
 Dr. Williams. I remember that some time before this you at- 
 tempted to reconcile the observations of all our recognized teachers 
 of this subject with your own views. Are there any drawings in 
 your book showing the dentinal fibinllse as offshoots of the odonto- 
 blasts ? 
 
 Dr. Heitzmann. Several are drawn there between the rows. 
 
 Dr. Williams. No such appearance is shown in any of the engrav- 
 ings in your book, and I have never seen any of your drawings 
 remotely resembling the sketch which I have made on the black- 
 board. 
 
 President Carr. Gentlemen, the discussion of this subject will 
 now be continued by Dr. C. F. W. Bodecker, of this city. 
 
 Dr. Bodecker. Mr. President and Gentlemen : It is well known, 
 ever since the publication of Franz Boll, of Bonn, that when- 
 ever a fiber develops from a protoplasmic body it is always from its 
 periphery, and never in any instance from its center. Fibers may 
 appear as though coming from the end of a protoplasmic body, but 
 they are peripheral formations sometimes joining at a point in one 
 of the ends of these corpuscles, either the front or the back. This 
 may have led to the belief that the fibers extending from protoplas- 
 mic bodies called odontoblasts are developed from their center. I have
 
 49 
 
 seen many specimens of odontoblasts and other tissues, but I have 
 never in a single instance been able to observe that a fiber from the 
 point of the odontoblast has been traced through the center, nor 
 do I believe Dr. Williams has. Dr. Williams and Dr. Sudduth both 
 claim that there are no enamel-fibers present in any preparation of 
 human enamel. If these gentlemen will take the trouble to split 
 a freshly-extracted tooth and throw it into a solution of osmic acid 
 which will stain the living protoplasm and nerve-fibers, they will 
 find that it has stained the enamel-fibers as well as the dentine-fibers 
 in their proper situation. The history of the development also 
 shows this. The fibers are quite plainly vi«dble in every embryonic 
 specimen of enamel. In fact, it was such specimens that led me 
 to the study of enamel-fibers; although I have to admit that the 
 enamel-fibers in adult teeth, when stained with other reascents 
 than osmic acid, do not appear very distinctly, for when studying 
 enamel with Dr. Heitzmann, on calling his attention to the fibers in 
 a ground section of enamel, very slightly stained with an aramo- 
 niacal solution of carmine, he laughed and pronounced it to be dirt 
 from the process of grinding; but after studying another specimen, 
 stained with chloride of gold, he fully admitted the presence of 
 enamel-fibers. Dr. L. Waldstein — a gentleman who has been an 
 histologist and was the assistant of Professor Arnold, of Heidelberg, 
 for years — saw some preparations which I had arranged for the 
 microscope, and I asked him to tell me whether he was able to ob- 
 serve any fibers within the enamel. I informed him that the speci- 
 mens were prepared and stained in the following manner : The teeth, 
 immediately after extraction, were split and immersed in a one per 
 cent, solution of hyperosmic acid for twenty-four hours, and then 
 put in absolute alcohol for two or three days, ground thin upon a 
 corundum-wheel, and mounted in the usual manner. After a careful 
 examination, Dr. Waldstein pronounced the dark fibers lying between 
 the enamel-rods to be protoplasmic formations. Therefore, unless 
 there is something mysterious about the osmic acid, or the lenses I 
 employed (which were made by Zeiss) are unreliable, I must hold 
 to the assertion that there are enamel-fibers between the calcified 
 rods of enamel in the human subject. 
 
 I have examined many specimens of ground teeth the peripheries 
 of which were slightly attacked by caries. In one specimen I noticed 
 places where a little of the enamel was rubbed away, — hardly per- 
 ceptible to the naked eye. In the fissures of the tooth there was 
 very slight decay. I observed at the boundary between the dentine 
 and enamel a reaction in the enamel-fibers which made them 
 appear much swollen at a point corresponding to the enamel that 
 had been rubbed away at the periphery ; also, at a point corre- 
 
 4
 
 50 
 
 spending to the fissure which was slightly decayed. Some of the 
 fibers thus afi'eeted could be followed for quite a distance, and they 
 appeared the thickest or most swollen towards the boundary of 
 the enamel and dentine. Gentlemen, can you imagine that bacteria 
 would have crawled in at the periphery of the enamel along the 
 fiber without leaving a trace or track, and only produce a reac- 
 tion near the dentine ; or, to use an expression of Dr. Abbott's, 
 without "using their acid bottle" in the beginning? Evidently 
 they did not use it at the beginning, because I observed no enlarge- 
 ment of the interstices or reaction of the enamel-fibers at the pe- 
 riphery, but only between the boundary of the enamel and dentine, 
 and corresponding in width to the place of injury. Of course, it is 
 quite evident from this that there must be living matter in the 
 enamel ; for, if there were no living fibers in the enamel, how could 
 such a reaction occur? Dr. Sudduth acknowledges that the enamel 
 is absolutely closed at the periphery, and that nothing can get 
 through. If there is no living matter there, what produces that re- 
 action ? I have never observed it in specimens with perfectly sound 
 enamel around the periphery of a tooth. I have shown these speci- 
 mens to Dr. Heitzmann and Dr. Abbott, and anyone who chooses to 
 come to my house or Dr. Heitzmann's laboratory can see them. 
 
 With regard to the elucidation of the question of necrosis, spoken 
 of by Dr. Sudduth, I have to mention that one of my first attempts 
 to study special subjects in Dr. Heitzmann's laboratory was the 
 observation of necrosis. Both Dr. Heitzmann and myself were much 
 surprised at the slight difference, under the microscope, of normal 
 and necrosed specimens of bone. It is all very well for gentlemen 
 to say that necrosis of bone is an entirely different process from 
 caries of teeth, and in a certain measure that is so ; but I do 
 not believe that caries can be so very widely distinguished from 
 necrosis. I do not, therefore, object to the term caries in compar- 
 ison with caries of bone, although it must be acknowledged that 
 bacteria must necessarily exert an immense influence upon caries of 
 the teeth, because they are present wherever putrefaction is going 
 on. May the patient be ever so healthy, they are there ; and the 
 conditions are nowhere in the body so favorable, probably, to the 
 production of caries as in the mouth. But, at the same time, I can- 
 not believe that caries is the immediate and only result of these 
 organisms, and that the reaction of the living protoplasm which is 
 visible during caries should have no influence in this process. In 
 specimens of caries of dentine which I showed to Dr. Waldstein, — 
 who is a perfectly impartial obsen^er, and who has had much expe- 
 rience in the study of bacteria ; has written several essays on that 
 subject, and is frequently quoted in medical literature, — although he 
 
 I
 
 51 
 
 did not at the time know anything about the dental tissues, he at 
 once acknowledged that the reaction in the dentine was inflammatory 
 in its character. I asked him, "Are there any bacteria present ? " 
 He replied, " There are plenty, but the i*eaction of the protoplasm is 
 80 evident that I am perfectly convinced it cannot be from bacteria 
 alone." 
 
 Dr. W. W. Walker. Gentlemen, our president. Dr. William Can*, 
 has seen fit to provide, between the hours of six and eight o'clock 
 this evening, a collation for our guests who have so kindly volun- 
 teered to come here from distant cities to assist in this debate. 
 Therefore, if those who have been furnished with tickets will be 
 kind enough to remain after adjournment of this meeting we will 
 be very much obliged to them. 
 
 Adjourned until eight oclock p. m. 
 
 EVENING SESSION. 
 
 Dr. J. L. Williams. Mr. President and Gentlemen : I crave your 
 kind indulgence just two or three minutes. There seem to me to be 
 only two points in Dr. Heitzmann's paper that I care to make any 
 reply to, — two points that seem to me so manifestly absurd that I 
 must say just a word or two. I have cut a good many hundred 
 specimens of pulps of embryo and adult teeth, and I never saw any 
 different appearance from that presented there [ illustrating on the 
 blackboard ] of the odontoblast layer of cells before the commence- 
 ment of the process of calcification. There are present here at least 
 four gentlemen who have made almost a life-study of this subject, and 
 I think they will bear me out in the statement that in all the speci- 
 mens they have cut they have never seen any other appearance than 
 substantially that, — the cells having that form of a prolongation of 
 the dentinal fibrillae coming out from there in this manner, some- 
 times one, sometimes more, to the extent of a dozen, more or less. 
 This is, as nearly as my memory serves, a representation of it on 
 the board. May be Dr. Heitzmann has, but in all the specimens I 
 have cut I have never seen an appearance like that which he has 
 shown, not one ; and I think the gentlemen who have spoken before 
 me will bear me out, and say that they have never seen, after the 
 commencement of calcification, an appearance like that. Now, in 
 regard to the fibers in enamel. (You see I have a teachable dispo- 
 sition. I may remark that this drawing is after the improved style 
 of Dr. Heitzmann.) Now, suj^pose the section of enamel represented 
 had been cut directly through at the point which I indicate. This
 
 52 
 
 represents a transverse section of the enamel, and these are the 
 enamel-fibers cut transversely. This, Dr. Heitzmann says, is the 
 position which the enamel-fibers occupy. Suppose the section should 
 have been cut through there. The result would be that we would 
 not have touched a single enamel-fiber. But the appearance is so 
 nearly the same in the enamel-fibers that I am not able to detect the 
 difference in appearance of that which he regards as enamel-fibers. 
 You see it is almost impossible, on the theory of enamel-formation 
 given in my paper, to cut a section and not get the appearance here 
 shown. This represents a longitudinal section; this represents the 
 intercellular formation, — interprismatic layer. 
 
 Dr. Atkinson. Don't say cellular. 
 
 Dr. Williams. Suppose we cut through here in this direction ; the 
 result is that we have cut two fibers ; if we have been fortunate 
 enough to cut straight through we will get the appearance of two 
 fibers at that point ; but nowhere else in this section will we get any 
 appearance of fibei'S. On the contrary, the appearance is as repre- 
 sented here. But in all the longitudinal sections I have ever cut 
 the appearance is substantially the same, and there is no possibility 
 of explaining that appearance except that what has been mistaken 
 for fibers is simply the interprismatic cement-substance which 
 unites the cells in that manner. 
 
 Dr. Heitzmann. Dr. Williams certainly has made a grand im- 
 provement in that drawing. I claim the merit of that. That looks 
 more natural than the specimen indeed. I do not know how Dr. 
 Williams, who claims to have studied these things for several years, 
 can change his mind in five minutes in that matter. I have not much 
 to say about the coi'rectness of this view, except I would add with 
 red chalk a few corrections in the appearance of the transverse sec- 
 tion. If Dr. Williams says this would be a longitudinal section, to 
 use his own words, it would be absurd. If this is a transverse sec- 
 tion, I presume that would be a longitudinal section ; but the trans- 
 verse section that he drew here with red chalk will correspond to 
 the fibers running here. 
 
 Dr. Williams. Suppose it is cut in this point, here ? 
 
 Dr. Heitzmann. You cannot cut such a section at all. 
 
 Dr. Atkinson. Extending between those yellow points through 
 there. 
 
 Dr. Heitzmann. Certainly. That is what we claim. 
 
 Dr. Williams. Suppose this to represent a transverse section ; if 
 we cut in that direction, how can we get a single enamel-fiber ? 
 
 Dr. Atkinson. That which has been called a fiber is the sheath 
 that surrounds the fibril. Dr. Williams clearly showed in his first 
 diagram that it was the enamel or organic matrix in which the in-
 
 53 
 
 organic substance was deposited, and that you could not cut through 
 there without coming in contact with and bisecting one of those. 
 
 Dr. Williams. That is the point. 
 
 Dr. Heitzmann. Dr. Williams maintains that if he cuts a lonffi- 
 tudinal section it is impossible to see the enamel-fibers. 
 
 Dr. Williams. I say if it is made through this transverse seaction 
 you cannot strike the enamel-fibers at all. 
 
 Dr. Atkinson. If the enamel-fiber does not involve the entire 
 periphery of the prism. 
 
 Dr. Heitzmann. That is the point. There are fibers in the lon- 
 gitudinal section, but it is impossible to see the fibers everywhere. 
 In no drawing that Dr. Bddecker ever made is such a relation 
 present. 
 
 Dr. Abbott. Mr. President, in further answer to Dr. Williams, I 
 will give as briefly as possible what I understand to be the manner 
 in which the enamel and dentine are formed, and their destruction 
 by caries. Then I will try and answer some of the points made by Dr. 
 Sudduth. Instead of a secretioti from the ameloblasts, as suggested 
 by Dr. Williams, enamel is formed by the calcification of successive 
 layers or rows of these corpuscles, and the reticulum of living 
 matter contained in them is preserved and exists in the formed 
 enamel. Dentine, likewise, is formed by the calcification of suc- 
 cessive rows of odontoblasts, and the reticulum of living matter 
 which is plainly visible in them remains as the living matter (Tomes's 
 fibers) in the formed dentine. I will here state that I cannot con- 
 ceive of the slightest injury to any living tissue, no matter where 
 located or from whatever source the injury may come, without its 
 producing an irritation of such tissue. The first lesion in the ca- 
 rious process of human teeth is a solution of the lime-salts of the 
 surface of the enamel by some acid, generally produced by the fer- 
 mentation of particles of food, saliva, etc. As soon as the living 
 matter is reached it becomes irritated, which irritation if allowed to 
 proceed soon assumes the condition of inflammation of that tissue, 
 and advances along the enamel fibers in advance of the solution of 
 the lime-salts by acids. When it reaches the dentine this inflamma- 
 tory condition advances more rapidly, and is much more intense, in 
 consequence of the greater amount of living matter to become 
 aff'ected. The lime-salts, after having been dislodged by the swell- 
 ing of the living matter, are dissolved by acids and washed away. As 
 they are carried away the reticulum of the former odontoblasts 
 again presents itself and is eventually destroyed by putrefaction. 
 Duiing the latter process this portion of the decaying tooth becomes 
 filled with " organisms of decomposition." 
 
 In the drawing which has been so timely exhibited by Dr. Sudduth
 
 54 
 
 of a specimen sent him by Dr. Miller a zone or territory of inflamed 
 dentine is plainly shown far beyond that occupied by organisms. 
 This is the territory claimed by Leber and Rottenstein, and since 
 by Dr. Miller and others, to be in a condition of decalcification by 
 the solvent action of some acid. Now, this view, so far as I have 
 been able to learn, is a mere supposition, its substantiation being 
 based upon the experiments in "pure culture " conducted by Dr. 
 Miller, and of course out of the mouth, which proves nothing as to 
 the actual conditions in the mouth. The experiments of Prof Mayr 
 (New England Journal of Dentistry, Vol. ii., No. 1), which most em- 
 phatically disprove such a position, seem to be altogether lost sight 
 of by these gentlemen. It is a mistake on their part vjhen they state 
 that caries of dentine differs from caries of bone in that the process ad- 
 vances by the solution of the lime-salts and the subsequent destruction of 
 the organic portion by organisms. It is also claimed hj these gentle- 
 men that the usual features of inflammation are not present in a 
 decaying tooth. I would ask, what portion of the organism is sub- 
 ject to irritation? Is it not the living matter? The heat, redness, 
 swelling, and pain are effects, not causes, of inflammation. 
 
 It has been stated that we do not show our siDccimens. In answer 
 I would state that they have been shown to every one who would 
 take the trouble to look at them on every occasion that has presented 
 itself; that Dr. Heitzmann has used them on all occasions in his 
 classes, so that probably not less than one hundred gentlemen have 
 become more or less familiar with their appearance under powers 
 ranging from two hundred to fifteen hundred diameters. When Dr. 
 Miller was here a 3^ear ago last summer he promised to send me 
 some of his specimens for examination, but while he has sent them 
 to others at diff'erent times none have come either to Dr. Heitzmann, 
 Dr. Bodecker, or myself. I asked Dr. Williams to kindly afford me 
 an opportunity to study the specimens from which these drawings 
 were made; but no! Dr. Sudduth needed them at least a month to 
 have drawings made which would take at most but a few hours 
 to do. What does all this mean ? We ai"e accused of " forming a 
 theory" in i*eference to the formation and caries of teeth to suit our 
 peculiar ideas previously conceived. In view of these facts, I would 
 like to ask if it would not be more in the interests of fair play, to 
 say the least, if these gentlemen would take this charge to them- 
 selves. As far as the " cell theory " vs. the '' bioplasson theory " is 
 concerned, I hardly need refer to it, as my views upon the structure 
 of tissues are well known to the reading portion at least of the dental 
 profession. 
 
 President Carr introduced Professor R. R. Andrews, of Cambridge, 
 Mass. 
 
 I
 
 26;vi 
 
 55 
 
 Dr. Andrews exhibited a number of stereopticon views of the 
 development of the tissues of the teeth, and spoke as follows: 
 
 Gentlemen of the First District Dental Society : The invitation of 
 your committee came to me in the midst of a very busy professional 
 season. I fear that I have not had sufficient unoccupied time to do 
 justice to your confidence. But the subject of the evening, " The 
 Development of Teeth," is of such importance that I could not deny 
 myself the pleasure of being with you, and I very cheerfully offer 
 the results of my study. 
 
 Having become personally interested in photography, I have been 
 enabled to prepare specimens of my collection illusti-ating this sub- 
 ject ; and from the negatives of these photographs I have produced 
 the lantern slides which are to be exhibited to you this evening. 
 They do not show the details of a careful drawing ; they do show 
 the condition of the tissue as the microscope reveals it to us. I trust 
 the demonstration which I am to give may make the discussion 
 which is to follow more tangible to those of us who are not already 
 familiar with the various stages of growth in a developing tooth. 
 
 At so early a period as the second and third month human embryos 
 are rarely available for histological work ; they seldom come to me 
 in a perfect condition. I have, therefore, prepared my specimens 
 from fresh embryos of pigs, in which the processes of development 
 are nearly identical with those of the human embryo. 
 
 The tissues from which a tooth is derived originate in two of the 
 three germinal layers. From the epiblast we have the epithelium ; 
 from the mesioblast the embryonic connective-tissue. In Plate I, 
 Nos. 1 and 2, we see a mass of epithehal cells covering the embryonic 
 connective-tissue. The darker line in the central portion of the 
 picture, appearing to separate the two tissues, really belongs to the 
 epithelium, and is its lowest and most important layer. From it 
 come the first indications of tooth-growth. It has been called the 
 mother layer ; it is the stratum Malpighii. The cells of this laj^er 
 are usually described as columnar or prismatic ; at this early stage 
 they are only approximately so. They vary from the spherical to 
 the ovoid, and it is difficult to find the perfect columns shown in 
 some illustrations. Another tissue has been spoken of as being very 
 important during the early stages of development, — the basement 
 membrane. I have never been able to demonstrate the presence of 
 this tissue at this time, nor do I believe it has any influence whatever 
 in the formation of a tooth. 
 
 Over that portion of the jaw corresponding to Avhat will be the 
 alveolar border, just prior to the appearance of the anterior enamel- 
 organs, we shall find that the cells of the epithelium have multiplied
 
 56 
 
 and are heaped up, foi*ming what is known as the dental ridge of the 
 authorities. The new cells seem to have their origin from the cells 
 of the stratum Malpighii, and not from the central or cuboidal layer 
 of cells. I think this is proved by the intensity of the stain taken 
 up by the cells nearest the Malpighian layer, and by their being of 
 a form nearer the simple bioplast. These are both evidences of new 
 growth. The rapid increase of cells at this point has apparently 
 forced the stratum Malpighii inwards, something like the letter V 
 when the tissue is seen in section. This V-shaped groove [Plate I; 
 No. 3] has been called, and by some recent writers, the primitive 
 dental groove, but in the sense which they would convey it does not 
 exist. Their error shows them to be students of a by -gone literature) 
 and not searchers after actual truth from the living tissues. This 
 folding in of the Malpighian layer extends but part way around the 
 alveolar border. It is much more marked in the anterior portions 
 of the jaw. The large increase of epithelial tissue at this point 
 [Plate I, No. 8] has not been clearly accounted for, nor have the 
 different foldings of the Malpighian layer. Many writers give these 
 folds a significance which, as yet, I do not recognize. Those of us 
 who have cut many sections from this tissue know that the enamel- 
 organs of the temporary molars are formed where there is an almost 
 entire absence of either fold, groove, or ridge [Plate III, No. 36]. May 
 not the condition of the tissue at this time, during its very rapid 
 growth, account for it. The expansion by growth of the surround- 
 ing tissue takes it all up, smoothing it all out. 
 
 The crimpled petals in their prisoned bud. 
 In time unfolding, form the perfect flower. 
 
 There are many folds at the base of the dentine-germ, just after 
 calcification has commenced, which as yet have not been accounted 
 for. I think they have only the significance of existence. [Plate 
 III, No. 32]. 
 
 Let us now pass to a consideration of the illustrations showing 
 the various stages from the first appearance of tooth-formation to 
 the perfected organ. 
 
 Plate I. 
 
 No. 1. Tissue from which tooth-structure is developed. The 
 lower epithelial cells, shown by the dark central line, form the 
 Malpighian layer, and separate the epithelial from the embryonic 
 tissue below. 
 
 No. 2. An enlarged view of the same structure, with the Malpig- 
 hian layer perpendicular. 
 
 No. 3. Section of lower jaw, showing the first stage in the devel- 
 opment of the enamel-organ. The dental groove is here seen with
 
 57 
 
 the enamel-organ budding from the right of it. The Malpighian 
 layer at the right is not covered with its epithelial layer, it having 
 been removed by the action of the knife in cutting the section. In 
 this picture there is as yet no appearance of any formation of bone. 
 
 No. 4 shows the enamel-organ a little further developed, the 
 epithelial covering being almost intact. Below the organ we see the 
 first indications of the formation of the jawbone. 
 
 No. 5. The enamel-organ still further advanced in its growth by 
 a multiplication of cells at the base of the organ. 
 
 No. 6 shows still further progress in the growth of the enamel- 
 organ, the cells in its central portion having enlarged, causing it to 
 assume a flask shape. The action of the knife has separated it 
 somewhat from the tissue beneath, which shows beautifully the 
 zone of embryonic tissue from which is to be developed the dentine- 
 germ. [To place this view in the correct position, turn the top to 
 the right.] 
 
 No. 7. The knife has here caused a separation of the dental tis- 
 sues. The dentine-germ is here shown in the form of a papilla 
 pushing up into the enamel-organ. 
 
 No. 8. Small view of the same, a little farther advanced, but from 
 the embryo of a sheep. 
 
 No. 9.* Section of the lower jaw, showing a larger growth of the 
 dentine-germ, capped by the enamel-organ, with part of the tongue 
 at the upper right corner ; the dark line at the left of the enamel- 
 organ being the developing jaw. 
 
 No. lO.f Cross-section of the lower jaw and tongue, showing 
 tooth-development in the second stage at the right, and in the third 
 stage at the left. 
 
 No. 11. Enamel-organ and dentine-germ of a bicuspid or molar. 
 
 No. 12. Dentine germ, nearly surrounded by the enamel-organ, 
 and entirely surrounded by the walls of the sacculus. On the left is 
 seen a budding off from the enamel-organ. This is the germ of the 
 enamel-organ of the corresponding permanent tooth. The walls of 
 the sacculus are very finely shown in this section, and around this 
 is seen the developing bone. 
 
 Plate II. 
 
 No. 13. Similar to the preceding, but farther developed. Calcifi- 
 cation has commenced on the apex of the dentine-germ. 
 
 No. 14.| Developing molar of kitten with commencing calcifica- 
 tion. 
 
 * Section by Dr. Sudduth. 
 f Section by Dr. Sudduth. 
 X Section by Mrs. E. N. Whitman.
 
 /^" 
 
 ^^x 
 
 /». 
 
 
 If 
 
 p
 
 59 
 
 Plate II.
 
 60 
 
 No. 15. Here we have the breaking up into epithelial clusters of 
 the cord which connects the enamel organ with the Malpighian 
 layer. On the left is the permanent enamel-organ. The apex of 
 the dentine-germ is covered with a cluster of enamel-cells, only a 
 portion of the enamel-organ being present. 
 
 No. 16.* Section of rabbit's jaw, showing the temporary tooth, 
 with the germ of the permanent tooth just beneath. 
 
 No. 17. Section of human jaw, showing calcification of the apex 
 of the dentine-germ, all epithelial tissue having been washed away 
 except the Malpighian layer. 
 
 No. 18. Section of growing tooth, with tissues teased out to show 
 a fold of calco-globin between the calcified dentine and the layer of 
 ameloblasts or enamel- forming cells. [To place this view in the cor- 
 rect position, turn the top to the right.] 
 
 No. 19. Section of growing tooth, showing folds at the base of 
 the dentine-germ. 
 
 No. 20. Section of growing tooth with folds at the base of the 
 dentine-germ, and folds of the calco-globin layer seen as a fine, dark 
 line near the base of the dentine-germ, extending from the enamel 
 which caps the apex of the germ. 
 
 No. 21. Greatly enlarged view of the odontoblasts or dentine- 
 forming cells. 
 
 No. 22. Another view of dentine-forming cells. 
 
 No. 23. Another view of odontoblasts. 
 
 No. 24. Section of normal dentine and enamel, showing beauti- 
 fully the termination of the tubuli at the junction. 
 
 Plate III. 
 
 No. 25. Cross-section of the tubuli of the dentine. 
 
 No. 26. Ameloblasts, or enamel-cells. 
 
 No. 27. Section of normal enamel ; tooth of kitten. Shows clearly 
 the enamel-rods. 
 
 No. 28. Crown of bicuspid showing evidences of calcification of 
 the pulp. 
 
 No. 29. Eoot of bicuspid, showing hypertrophy of cementum, and 
 dental excrescence or pulp-stone within the pulp-chamber. 
 
 No. 30. Jaw of kitten with teeth and tissues in place. 
 
 No. 31. Section of developing tooth, showing fold of calco-globin, 
 which is a continuation of tissue from the forming enamel at the 
 apex, between the formed dentine and the layer of enamel-cells or 
 ameloblasts. To my mind this is a strong evidence that the enamel 
 is a secretion rather than the direct calcification of the ameloblasts. 
 
 * Section by Dr. Sudduth.
 
 62 
 
 No. 32. An enlarged view of the folds seen at the base of a devel- 
 oping tooth. 
 
 No. 33. View of the point of a developing tooth, with a fold of 
 ealco-globin faintly seen at the right. 
 
 No. 34. Haversian or vascular (3anal in human dentine running 
 from the pulp-chamber toward the cementum. 
 
 No. 35. Section of embrj^onic tissue, showing differentiation of 
 the cells into osteoblasts and formed bone. These are in clusters, 
 which by calcifying form the jaw-bone. 
 
 No. 36. First stage in the development of enamel-organ, with 
 almost entire absence of dental groove. 
 
 President Carr. Gentlemen, we have heard from Massachusetts, 
 New York, and Pennsylvania, and now we will have the pleasure 
 of hearing from the West. I will call on Professor Black, of Jack- 
 sonville, 111. 
 
 Dr. G. V. Black. Mr. President and Gentlemen : This has been 
 a funny meeting so far, and a funny discussion ; but I hope you will 
 not expect anything funny from me, because I am not a funny 
 man. We have had here a repetition in its most essential phases 
 of a discussion that occurred in London fifty years ago, and I sup- 
 pose they were as well satisfied that their views were correct as we 
 are to-day. Some peculiax'ities have entered into this discussion 
 that did not enter into that. There were some quibbles over tech- 
 nical points that were diflTerent, not yielding exactly the same pro- 
 duct, but the trend of thought in that discussion and in this was 
 very similar, in that one party was arguing for the vitality of the 
 dentine, and the manifestation of that vitality in its diseases ; while 
 the other party was arguing as earnestly for the chemical nature of 
 those diseases, and that vitality at most only modified them. 
 
 Discussion involving these points has been going on from that 
 day to this, one party losing ground continuously, and never tak- 
 ing a step forward ; the other party gaining ground as continu- 
 ously, and never taking a step backward. When Mr. Tomes came 
 into the field he came into it — that is, before he began writing — as 
 a vitalist. When our French investigator in Paris (Magitot) came 
 into the field — before he wrote — he came into it as a vitalist. They 
 both worked with an earnestness that perhaps has not been equaled 
 by many workers in the dental profession, with certain results which 
 you all know. They yielded continuously upon the one side, and 
 went forward as continuously upon the other. We know the result 
 to-day. Tomes, through his son, has yielded the last point. Our 
 French brother has yielded all but one, and if God preserves him
 
 63 
 
 he will soon yield that. Possibly the expression is not quite clear, 
 as it stands in Magitot's work, but as I understand him he still sup- 
 poses there is some resistance to the progress of dental caries by the 
 vitality of dentine. It is very little that he has not yielded. This con- 
 troversy was begun in earnest by Wm. Eobertson, of Birmingham, 
 England. There had been some skirmishing before, but the first 
 big gun that was fired was by our friend Robertson, who wrote and 
 published his book in 1835. Many men had talked and had pub- 
 lished articles upon this subject before, but here was a book that, I 
 may say, unsettled the world, and yet it never was fully received 
 by the profession. The bottom facts were written down by him in 
 such plain language, so true to nature, that it will yet be received. 
 He was followed by Eegnard, in Prance, in 1838, who perhaps wrote 
 more exactly and more forcibly in relation to caries of the teeth — 
 although in exceedingly quaint language, if his translator does him 
 justice — than even Eobertson. They agx'ee precisely. Desirabode 
 then took up the matter, denying the propositions of Eegnard. At 
 that moment the voice of the profession of medicine, and of dentistry 
 so far as we can call it then a profession, was with Desirabode, and 
 he seemed to succeed. Even then he brought up the old idea, so 
 popular, that the decay began in the interior of the dentine, as a 
 conclusive proof that decay of the teeth could not be caused by 
 acids produced by fermentation. Now, gentlemen, I wish to speak 
 of this matter of caries beginning within the dentine, not simply 
 because those men thought so, but for another purpose. From the 
 time of Hunter, or fifty years before, — one hundred years ago, if 
 you please, — it was held by men who had made this subject a study 
 that caries of the teeth — decay (I like that expression better) — be- 
 gins within the substance of the dentine, and works its way to the 
 surface, possibly to the pulp. You will all say, " What dunces ! What 
 nonsense ! " Why should they have held this theory, and worked 
 over it, and struggled over it, until the time of Eobertson? For he 
 was the man who broke the backbone of this foolishness, though 
 others had denied it before him. Were they not men of good ob- 
 servation, of sound judgment, and were they not careful men, let me 
 ask you? Will we say that Hunter was not a careful man, or that 
 Fox was not a careful man, and many others whom I might men- 
 tion ? Now, what is my purpose in bringing this up ? Simply to 
 show that men whom we regard as exceedingly good men, whose 
 opinions we value very highly, are often — what shall I say ? — mis- 
 taken. At least, they have come to hasty conclusions. This was a 
 thing, seemingly, that any man of reasonably good observation 
 might have decided for himself. And yet that was the first thing 
 that was thrown at Eobertson, and was considered a strong argu-
 
 64 
 
 raent. He denied in toto that any such thing could occur, because, 
 said he, decay of the teeth is the result of fermentation, with the 
 formation of an acid which acts upon tooth-substance, and must be- 
 gin upon the surface. He could not explain fermentation in that 
 day ; the knowledge of the world was not suflScient to give a ra- 
 tional explanation of fermentation. They used the words " fermen- 
 tation" and "putrefaction." It required all the work of Schwan, 
 Schroeder, Pasteur, Lister, Koch, Miller, and others who have 
 worked in that field, to give us a rational explanation of the pro- 
 cess of fermentation. And that explanation has come ; and if, as 
 dentists, we do not understand it, we are to blame for it. It is a 
 purely physiological process. As students of physiology we should 
 study it, even if it were not related to us in another way. Physi- 
 ology is one thing the world over. 
 
 This brings us to another point. Physiology in its principal 
 points is the same throughout all the manifestations of life, and we 
 must get down to bedi'ock in this mattei' — study physiological prin- 
 ciples — if we would understand that which we see, and the diseases 
 W'ith which we must deal. Now I will get into trouble, for I know 
 my friend over there will not agree with me in what I am about to 
 say. 
 
 The cell is the unit of physical life. No matter whether that cell 
 represents a complete individual as we see it in the amoeba, or is a 
 component of the complex individual, one among the multitude that 
 make up the sum of the higher animal forms, or their individual 
 parts, as we see it in the stellate reticulum of the enamel-organ, as 
 depicted by my friend here on the blackboard. But then this doc- 
 trine has been taught so long and so well that everybody under- 
 stands it. 
 
 Voices. Not much. Not in that way. That thcorj' is exploded, 
 etc. 
 
 Dr. Black. Everybody understands it, — outside of New York. I 
 have said the cell is the unit of physical life, — I am not talking of spir- 
 itual life, — and it has certain characteristics in its dealings with 
 matter which are common to all units of physical life that exist on 
 this planet. These are its physiological attributes, and they may be 
 summarized in four propositions. 
 
 First. Each cell is capable, when in contact with certain material, 
 of furnishing or elaborating a substance capable of digesting food- 
 material, or preparing it for absorption and assimilation. This you 
 may call diastase, soluble ferment, unorganized ferment, enzyme, or 
 by any of the words in use to represent the digestive agent. 
 
 Second. It is capable of assimilating the food so prepared. As- 
 similation results in growth.
 
 65 
 
 Third. Every individual unit of life is capable of de-nutrition. 
 This consists in shedding out, in the form of waste products, ma- 
 terial that has once been formed into protoplasm, or used in con- 
 nection with the nutritive process. 
 
 Fourth. It has the power of reproduction in a definite line of 
 forms. 
 
 These four powers may be — ^yes, they are — varied widely among 
 the different organisms with which we meet. They are capable of 
 living on widely different foods, and the digestive agent elaborated 
 is different — that is to say, adapted to the digestion of different 
 foods. Then the waste products differ widely among the different 
 organisms, and yet they have much in common, as we find them in 
 the animal, the vegetable, and the so-called third class, the kingdom 
 of the microbes. They are urea in the animal ; alkaloids and the or- 
 ganic acids in the vegetable ; the alcohols, organic acids, and the 
 ptomaines in the microbes ; alcohol as seen in the torula or vinous 
 yeast fungus; acetic acid in the fungus of that name, and in case of 
 another micro-organism, as the bacillus anthracis, it is a ptomaine 
 that is exceedingly poisonous. This class we call septic poisons. 
 When we see certain peculiar symptoms in connection with a wound 
 we say septic micro-organisms have invaded that wound, and ob- 
 servation teaches us that the patient is in almost as much danger as 
 if stung by a viper. These substances are in every case the result 
 of re-moleculizations of matter under the influence of the vital pro- 
 cesses of living cells, — and this is fermentation. 
 
 In this we have the explanation in brief of the process of fermen- 
 tation which Eobertson and his contemporaries could not explain. 
 The organism which produces caries has been found, and its essentials 
 of physiology made out; the waste product — lactic acid — found, and 
 its action in the production of caries explained. Some seem to regard 
 this as a new theory, but it is only the further development of the 
 theory of Eobertson, propounded in 1835, — namely, that caries re- 
 sults from fermentation, with the production of an acid that acts 
 upon the lime-salts of the teeth, and acts independently of the vitality 
 of the dentine. 
 
 Now, these propositions are true, not only of the units of life as 
 represented in the lowly organisms, the microbes, but they are true 
 also of those high in the scale of life as well. In the lower forms, 
 where the cells fall apart, each performs all of these functions for 
 itself; but in those organisms that are formed by the union of many 
 units of life there is a certain dependence the one upon the other, — 
 a certain tendency to divide the work, — a tendency to specialization 
 and the formation of spociaJized organs. Each cell makes a part of a 
 certain group composing an organ, — and we have one group forming 
 
 6
 
 66 
 
 bile ; another forming pepsin for the purpose of digesting food ; an- 
 other forming mucus; another separating the waste product of all 
 (urea) from the blood ; another doing this and another that in the gen- 
 eral work of organism. Among these some little groups are for a time 
 employed in building teeth. We find it stated by good authority in 
 matters of physiology that these cells are never mixed up in the work 
 they perform, — that each group attends to its own special duties. 
 This leads to another proposition. There is a certain impress made in 
 the fertilization of the ovum or seed that preordains just how far this dif- 
 ferentiation shall go. Epithelium remains epithelium, though it is mod- 
 ified for the formation of the glands and various structures, includ- 
 ing the brain, as my friend has stated (more properly the nerve or 
 brain-cells, including those of the spinal cord), but never becomes 
 connective-tissue. The connective-tissues, on the other hand, form 
 the tissues of support and motion, and the blood vascular system, 
 and never under any circumstances form epithelial tissue. There is 
 a drawing on the blackboard representing the enamel-organ. We 
 have heard this evening that these tissues get mixed up, or changed 
 the one into the other. We have had a mixed representation of the 
 manner in which these ingrowths from the epithelial layer come 
 down into the connective-tissue; extend more and more as the cells 
 are multiplied, and form the enamel-organ ; and how that in doing 
 80 these cells put out processes and recede from each other, the pro- 
 cesses extending across the spaces. You have heard the terms " myx- 
 oma," " myxomatous tissue," and the statement that this becomes 
 connective-tissue. Oh, dear, that is too bad ! I was sorry he said it. 
 Where did it come from ? From what tissue was it developed ? 
 What is its purpose and destiny ? 
 
 We have heard during this discussion the parable of John and 
 Bob. Now, let me say that these boys are at it in earnest, and they 
 are after the old man, my friend here, and unless he gets his foot 
 out of that rut [pointing to the illustration of the enamel-organ] the 
 boys will catch him and use him up completel3^ 
 
 That is all I want to say about that, except that this statement 
 seems to be an outgrowth of a doctrine that appears to have ema- 
 nated from New York, and of which I want to speak while talking 
 about the jumbling of cell-forms, — a doctrine, if you please, that 
 denies the existence of the cell as an entity in physical life ; depreci- 
 ating it to the position of a mere node of the so-called reticulum of 
 bioplasson ; and asserts that this reticulum is the life, or the life resides 
 in this reticulum ; that this reticulum runs continuously from node to 
 node, mixing in around in every direction, pervading in continuity 
 the entire animal. The man, according to this view, is a great big 
 amoeba, reaching out his arms and legs — a great amoeba, not made 
 up of units, but one life throughout, — spiritually, perhaps.
 
 67 
 
 Dr. Atkinson. Even so. 
 
 Dr. Black. But he is made up of cells ; and each of these cells has 
 its peculiar individual life. My friend says " No." He tells you he 
 sees these protoplasmic strings with his microscope. Let me say 
 that it makes but little difference what this or that man may claim to 
 see. The important factor is the interpretation of the thing seen. 
 The interpretation placed upon these protoplasmic strings is sub- 
 stantially that in them resides the life of the organism, and that 
 these threads are continuous throughout, uniting the life in one con- 
 tinuous whole, and it is also a denial of the individual life of cells 
 of whi(ih physiologists have claimed that the bod}^ of the man is 
 composed. And in the book that my friend here has given to the 
 world this is distinctly extended to the vegetable kingdom as well, 
 and illustrations are. given of these strings connecting the life of the 
 vegetable cells. This doctrine must stand or fall not alone upon what 
 this man or that may claim to see in his microscopic preparations, 
 but upon the broader observation of physiological processes as well. 
 To establish it, these different forms of observation must coincide 
 in their results. 
 
 Now we are ready for some illustrations of physiological pro- 
 cesses. First, in vegetable life. We will take a very simple thing, 
 one that all of you can understand. I think you all know of the process 
 of grafting of budding fruit-trees. All know of the bell-flower apple, 
 and of the crab-apple. Now, a long time ago some man, seeing the 
 difficulty of obtaining a given kind of apple from the seed, on ac- 
 count of the mixtures of pollen by which the flowers are fertilized, 
 hit upon the conception of snipping off a little bud from the bell- 
 flower tree — any kind of an apple will answer the purpose of illus- 
 tration as well — and planting it in the tissues of the crab-apple. He 
 knows nothing about cells or protoplasmic strings, but he snips off 
 the little bud composed of only a few cells, comparatively, and plants 
 it in among a multitude of cells composing the tissue of the crab- 
 apple tree. He ties it — fixes it there — and hopes it will grow. It 
 does grow. Now we have a few cells from the bell-flower mixed with 
 the many of the crab-apple, and according to this string theory the 
 Hfe becomes one throughout. Our experimenter watches the growth 
 of the little bud into a branch ; after awhile a flower comes ; and finally 
 the fruit is developed. It looks like a bell-flower apple. It is a 
 bell-flower apple, having the form and flavor. How is this? It is 
 one life. The tree is a crab-apple tree, but the new branch is like 
 the bell-flower, and the fruit is bell-flower. We see by this that 
 while there is a physical union of those cells there is no life union. 
 Each of the individual cells has a life of its own, and its progeny 
 retains forever the impress made in the fertilization of the seed ; no mat-
 
 68 
 
 ter how often it may be transplanted to and mixed in with cells 
 of a different nature. Therefore, the interpretation our friend places 
 on the strings which he claims to see cannot be true. 
 
 Dr. Charles Miller. When you put the crab into the bell-flower 
 what do you get ? 
 
 Dr. Black. You will get the crab-apple every time. Now, an il- 
 lustration in animal life. Let us suppose that by any kind of acci- 
 dent I have the skin torn off the back of my hand, — every bit of the 
 epithelium is removed. 
 
 Dr. Atkinson. Every bit? 
 
 Dr. Black. Yes, ever}' bit. Even the sweat-glands are destroyed, 
 and no epithelial cells whatever remain. Now, we have certain cells 
 in this body of ours that seem to be set apart for making repairs in 
 case there is a breach of continuity such as this, — the wandering 
 cells. They are continually creeping, amoeba-like, through the tis- 
 sues and floating in the blood-streams, and in case of such an acci- 
 dent they collect at the point, and are built up into granulations to 
 fill the breach. But epithelium does not grow upon these granula- 
 tions. What is the matter? We have heard this evening that 
 epithelium produces connective-tissue, and on the same principle 
 connective-tissue ought to produce epithelium when it is needed. 
 The life is all one ; there is no individuality ! But it does not. The 
 covering must await the slow process of the projection of the epithe- 
 lium by growth from the margins of the wound. 
 
 Dr. Atkinson. You did not know how to treat it. 
 
 Dr. Black. We found out how to do it. We clipped off the epithe- 
 lium from somewhere else, or from the body of another person, and 
 stuck it down among the granulations. It grew from each point 
 where we planted a few cells, and spreading out from these points 
 soon covered the wound with new epithelium. It did not produce 
 connective-tissue ! At one time we had a negro with a great burn 
 on his back. We clipped off little bits of epithelium from a white 
 man and stuck them down among the granulations, and they grew. 
 Now, if life is all one, if these cells have no individual life, the living 
 matter of the cells grafted in should become mixed with the gen- 
 eral life of that negro, and the effect would be imperceptible. But, 
 no; the result was the production of a patch of skin just as white 
 as that of the white man from whom it was taken. 
 
 This does not look much like sustaining the doctrine that there 
 are no individual units of life that are maintained in the make-up of 
 the individual man. That epithelium retains its individual life, — 
 carries with it the impress made in the fertilization of the ovum 
 from which the white man was developed, and carries its peculiar 
 characteristics into strange places.
 
 69 
 
 I think these illustrations sufficient'to show you that this bio- 
 plasson doctrine will not bear the test of physiological scrutiny. 
 No matter what claims may be made as to seeing this reticulum 
 connecting the cells, the interpretation placed upon it is wrong, and 
 all theories based upon it topple and fall to the ground. 
 
 Now, I want to talk of some other things, — this matter of the 
 dentinal fibrils passing out between the odontoblasts. [Drawing 
 on the blackboard, reproducing a sketch made b}'' a former speaker 
 of the dentinal fibrils passing from the pulp into the dentine, and 
 passing between the odontoblasts, instead of arising from them.] 
 You see these lines passing out between the odontoblasts with little 
 offshoots here. Let me say that it required a hundred yeai'S of ob- 
 servation and discussion before a man arose who observed suf- 
 ficiently well to declare that caries did not begin within the den- 
 tine. Should we fall out with a man because he is mistaken ? No. 
 We should hope that he will look further. This is the result of 
 faulty observation. I have certainly done enough of this class of 
 dissecting to have some right to speak. I had stained sections of 
 teeth with chloride of gold, and studied them while my friend here 
 was still in Europe making illustrations from sections cut from the 
 frozen cadaver, — which, I must say, was a beautiful work, and I wish 
 he had done more of it. And when this reticulum business was 
 first introduced to the American Dental Association I had some 
 chloride of gold stainings there to show. I remember that Dr. 
 McQuillen made a speech about it at the time, and my brother here 
 on my right and I got into a row about it. 
 
 Dr. Atkinson. I was there. 
 
 Dr. Black. And we have been good friends ever since. I know 
 just how my brother got into this difficulty with the dentinal fibrils. 
 His picture is made from a diagonal section, and it deceived him. 
 He saw the things he describes, but he did not get the true view of 
 them. But before asserting that the dentinal fibrils do not arise 
 from the odontoblasts, as has been held by the best observers of 
 the world, he should have obtained every possible view of them ; 
 he should have taken them apart one by one and examined them 
 individually, so as to prevent all possibility of error. 
 
 Several Voices. It can't be done. Tell us how to do it, etc. 
 
 Dr. Black. It is a simple matter of technique. I can tell you 
 how if you wish me to. When you have extracted a tooth, throw 
 it at once into Mueller's fluid, and let it stay about a week. Then 
 crack it in a vice. A little experience will enable you to split 
 the tooth lengthwise without crushing the pulp. Now, catch the 
 pulp with a pair of pliers, and pull it out of its bed. Some of the 
 odontoblasts will adhere to the pulp, and the fibrils to a consider-
 
 70 
 
 able length will be pulled out of the dentine, while some of the 
 odontoblasts will remain, adhering to the dentine, with the fibrils 
 pulled out considerably from the canals. By placing the pulp in a 
 freshly-filtered solution of Mueller's fluid, and examining it with a 
 good hand-lens, you can tell where the fibrils have pulled off, or 
 remained attached to the pulp, by the fuzzy appearance of its mar- 
 gins produced by the fibrils. If it is found that some have adhered 
 to the dentine, which is usually the case, you may put that part of 
 the tooth into staining-fluid, and stain before removing them if you 
 like. To remove them, take a knife with a rounded point with 
 which you can plow along down that part of the canal or pulp- 
 chamber in which the odontoblasts have remained ; have fluid in 
 the canal, — glycerine is the best, — and bring the blade down on a 
 glass slide. You will be pretty sure to get a good many odonto- 
 blasts, and the most of them will hang together in flakes so that 
 the individual cells cannot well be seen. Using now your dissect- 
 ing glass, break up these with needles somewhat, or simply shako 
 them about to detach any loosened cells ; then lift out the larger 
 flakes and lay them aside. Lay a cover-glass over the remainder, 
 and examine it with a one-fourth or one-eighth inch glass. The 
 chances are that you will find a considerable number of single 
 odontoblasts with fibrils attached, that are four or five times as long 
 as the odontoblasts ; or the fibril may be short, or there may be no 
 fibril at all; for in some cases they will not be stretched out in the 
 canals in withdrawing the pulp. Some failures will be made, but 
 usually it does not require many trials to get good views of these 
 cells with a considerable length of fibrils. You never get the true 
 form of the odontoblast in sections cut from tissues hardened in situ^ 
 
 Now, as to the enamel and the diseased condition described here 
 to-day, I do not care to talk. This interpretation is based upon the 
 theory of protoplasmic strings, and of that I have said enough. If 
 my friend here wants to picture wire screens all over his histologi- 
 cal drawings, let him do so. It is not so much what one sees, after 
 all, as his interpretation of what the tissues do, that is important; 
 and of this I want to talk for a moment. 
 
 The odontoblasts line the pulp-chamber, or cover the tissues of the 
 pulp, and their processes, the dentinal fibrils, extend into the den- 
 tinal tubes and through them to the periphery of the dentine. "We 
 have an affection beginning on the surface of the tooth ; caries, or 
 erosion, or absorption has exposed the distal ends of the fibrils. 
 What is the result? We get hyperesthesia. Where do we find vital 
 changes? John Tomes has been through this course of study long 
 ago, and he began with the inflammatory theory. But he found 
 that none of the elements necessary to produce the morphological
 
 71 
 
 changes which we know as inflammation could get into the dentine. 
 The leucocytes could not get in ; the blood could not get in. No 
 morphological changes of the tissue itself could be discovered that 
 in anywise resembled inflammation. Therefore, he concluded that 
 dentine could not inflame. Still, he was not willing to give up the 
 idea, and he searched this tissue to see whether or not it manifested 
 any changes peculiar to itself And the more he studied the subject 
 the less he found of the doings of vitality, until he yielded every- 
 thing. Still, the dentine is sensitive, and sensation is a manifesta- 
 tion of vitality. It is a law of physiology that the processes of cells 
 are especially receivers of impressions. This is most strongly man- 
 ifested in the nervous system, — the nerves are processes of cells. 
 But it is true of other tissues as well. Where is the pathological 
 change accompanying that sensitiveness manifested ? The dentinal 
 fibrils reach through the dentine ; they are processes of living cells ; 
 and the morphological changes are found in the pulp-chamber, in or 
 about the cells of which the fibrils are processes. In one case of 
 erosion the pulp lays down more dentine ; in another the layer 
 of odontoblasts becomes atrophied ; in another the whole pulp 
 may become hyperemic, etc. But you cannot demonstrate changes 
 attributable to vitality in the dentine. Now, I know there have 
 been some such claims based on the protoplasmic string notion, but 
 these findings may be duplicated in teeth that have never given any 
 history of disease whatever. The things seen were there from the 
 time of the development of the teeth. It is another case of faulty 
 interpretation. 
 
 The term " fixed material" has been used in this discussion. The 
 term is a good one. What do we mean by it ? The word organic 
 is sometimes used to represent anything that has been built by the 
 life-process. Fixed material is an organic material forming a part 
 of the organism, but not possessed of life, and is incapable of per- 
 forming any vital function. It is passive. 
 
 Dr. Atkinson. Tell me what you mean by life. 
 
 Dr. Black. That which does the four things I talked about a while 
 ago. 
 
 Dr. Atkinson. Do you mean energy ? 
 
 Dr. Black. No, sir; that word does not explain it. 
 
 Dr. Atkinson. What is life, then ? 
 
 Dr. Black. I don't know. 
 
 Dr. Atkinson. And I don't know. 
 
 Dr. Black. These enamel-prisms are fixed material. This den- 
 tine, the hard portions, all except the dentinal fibrils, is fixed ma- 
 terial, and is entirely passive. It may be acted upon, but it cannot 
 itself act. We have had this afternoon a description of the forma-
 
 72 
 
 tion of the enamel, and the organ which forms it, and have seen it 
 illustrated by those beautiful photo-micrographs. It is formed from 
 within outward, and the organ from which it has derived its nutri- 
 tion has disappeared. The life-process has built this enamel, — laid 
 it down there ; and old Dame Nature, life, has stepped backward on 
 tiptoe and gone off and left it, as a good mother would do with her 
 sleeping child for fear of waking it ; but, unlike the good mother, 
 has never returned. 
 
 Dr. William H. Atkinson. I rejoice at the excellence of the va- 
 rious pronouncements] that we have had before us to-night. I am 
 happy in the growth that has been manifested, and I wish to bid 
 God speed to each one who has spoken, in his effort to present the 
 truth as it appears to him. Would that we were all large enough 
 to enjoy the presentments and conclusions of our fellows, and not 
 attempt to assert a domination over them. It would take hours to 
 go through all that has been pi-esented before us in an effort to 
 harmonize the differences, albeit we are brothers, each seeking to 
 give the highest expression to his apprehensions and interpretations. 
 We should accord to every man the same liberty of interpretation of 
 what he sees that we feel entitled to ourselves. The enamel-rod 
 as here represented is to each individual truthful according as he 
 sees it ; but, if his attention has always been directed to one par- 
 ticular aspect, he is not likely to see so distinctly other aspects of 
 it, and his ideas will depend on what he sees, and not upon all that 
 is before him, and so his interpretation will be based upon what he 
 supposed he had seen. My good brother Black still sees that which 
 leads him to retain the old, mouldy interpretation of the effete cell- 
 doctrine as to the primal steps in organization. Gentlemen, you had 
 all better go to Carl Heitzmann's laboratory and get the true inter- 
 pretation. You can see in Eichard Owen's work a delineation of 
 Max Schultz's thorns, because Owen's workmen cut sections and 
 made drawings and engravings that properly represented the struc- 
 ture of the teeth, but for lack of discrimination Owen failed to describe 
 in the text that which his pupils clearly delineated. What is that red 
 line in the drawing? It is the representation of the fibril in partial 
 view. The trouble with my brethren here to-night is that they have 
 confined their attention to that portion of the presentment which 
 met their vision. If the other part had been called to their atten- 
 tion they would have seen it. They said they were fibrils. Carl 
 Heitzraann and I have had some combats with regard to what proto. 
 plasm is. I tell him these are nothing but little sacs of organized 
 material holding a fluid substance differing in degree of life-endow- 
 ment. He says the fibrils are living matter, and the intermediate
 
 73 
 
 fluid is non-living. Dr. Williams makes his interpretation of what 
 he sees, and Heitzmann makes a different interpretation. What will 
 solder them together? This, I presume, is the periphery of the rod 
 or prism that grows out of the ameloblast. Now, there is a calcific 
 tendency in the protoplasm that loves aggregation, and the organiz- 
 ing presence in the animal economy consolidates the calcigerous struc- 
 ture, lining this impoverished portion that forms the periphery of 
 the organ that is called inorganic, and that I call calco-globine. My 
 brother said it was doubtful whether it was organic or not. It is so 
 intimately combined Avith the animal elements that it cannot be dis- 
 charged, even with hydrochloric acid. That is the increment of 
 energy which awakens those beautiful six-sided prisms that we call 
 the enamel-rods, and that remain perpetual in the enamel, and he 
 leaves that out in the drawing. 
 
 And now, Mr. President and fellow-members and invited guests, we 
 should be profoundly thankful for this unprecedented opportunity for 
 comparison of views in the interpretation of microscopical present- 
 ments of the steps in formation, nutrition, and exercise of the factors 
 of function in granules, molecules, corpuscles, organs, and systems, 
 which make up the sum of our lives as individuals and as members 
 of the human race. And in conclusion let me say that to Drs. Carr, 
 Northrop, Francis, and Walker, who arranged this pleasant and profit- 
 able entertainment, the credit is due for its unprecedented success. 
 
 Dr. W. W.Walker. In addition to the regular papers and discussions, 
 the committee has made arrangements for a microscopical exhibit. 
 Notice has been sent to all who were to take part in the discussion to 
 bring slides to demonstrate the ^^oints at issue. Mr. J. Grunow, the 
 well-known optical instrument maker, of West Thirty-ninth street, 
 has kindly sent up forouruse microscopes and lenses, including his new 
 one-twelfth oil im. For his courtesy we desire to express the thanks 
 of the committee, and as well, I am sure, of all who are in attendance. 
 Opportunity will now be given to those who have come prepared to 
 present their slides. There has also been prepared up stairs a colla- 
 tion, to which all are invited. 
 
 [Dr. Sudduth spent an hour and a half exhibiting slides cover- 
 ing all the ground gone over in the papers read by Dr. Williams 
 ^ and himself The slides shown included some which had been sent 
 fi to Dr. Williams by Dr. W. D. Miller, of Berlin, showing artificial 
 J decay produced by the action of micro-organisms ; and also some 
 e mounted by the exhibitor ; showing tubuli distended and in some 
 u instances pushed aside by the growth of fungi. The exhibit was 
 . witnessed by a large proportion of those in attendance, who seemed 
 • to be deeply interested in examining the numerous slides submitted 
 » for their inspection.] 
 
 B. C. Nash, D.D.S., Secretary. 
 
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