Dr. RHEIN: As the chairman of Section V., I would like to place on record the thanks that I feel to be due to Dr. Williams for the admirable paper which he presented to us the other evening. He is a young man who is and has been for a great many years working with the microscope, and under the most adverse circumstances. The PRESIDENT: The Chair would call the gentleman to order, and would suggest, in doing so, that it is not in order in discussing a paper to discuss the gentleman who is its author.

Dr. RHEIN: I think everybody who heard the paper the other evening will bear me out in the view that it would not be out of place to say a few words in commendation of the author of the paper to which we listened.

Dr. CUSHING: It is not in order to discuss the merits of the writer of a paper. If we are discussing a paper we should confine our discussions to it.

The PRESIDENT: I think the point is well taken, and that the gentleman should discuss the subject under consideration, and not the writer of the paper.

Dr. RHEIN: If the Chair refuses to hear the report of Section V., I retire.

Dr. ABBOTT: Unfortunately for me, I was not present the other evening to listen to this paper, but there are one or two points in it that I want to speak of particularly, because they differ from what seems to have been the prevailing opinion of a few of us in New York previous to this time.

I would premise my remarks by saying that some one, I do not know who, said in Dr. Williams's hearing that the ground he had gone over was almost the same that Dr. Black had been over. I would state, in justice to Dr. Williams, that he has been over the same ground that Dr. Black went over; and that he was inspired to do so from seeing what Dr. Black had done; but he had no idea of detracting one single iota from anything Dr. Black has done.

I will state some points in which he claims priority. The first is the development of ameloblasts immediately under the flat layer of epithelial cells, which eventually forms over the crown of the tooth Nasmyth's membrane; the columnar layer of cells that was there when the enamel cap was first formed disappearing entirely, and what are called the enamel-formers, or ameloblasts, forming in their place, and the flat layer of cells which eventually forms Nasmyth's membrane, covering it up,-this, he claims, is his individual discovery. The next is, as shown by his first view, a section of the entire tooth

cut through longitudinally, showing the interdental tissues with the surrounding tissues in continuity. The next is the development of the dentinal fibres as branches from odontoblasts, several coming from one odontoblast. You who have read the article of Dr. Bödecker upon this subject will remember that he claims that, instead of the dentinal fibre starting out at the end of the odontoblast, and passing on into the canaliculi of the dentine, the nonmedullated nerve-fibre runs from the pulp up between the fibres of the myxomatous tissue, going to the odontoblasts themselves, there becoming a part of the wall of the odontoblasts on either side, and then passing up between the ends of the odontoblasts, and so on, forming the dentinal fibre. Tomes's idea formerly was that the odontoblasts started off like links of sausage, something as Dr. Williams's illustration showed; and the point running out from the end was known as Tomes's dental fibre. Dr. Bödecker took the opposite position, viz., that the dentinal fibres passed out between the odontoblasts; and I must confess that in the examination of many specimens I have seen exactly the same thing, and it was seemingly as plain as my hand is to you to-day. I have not seen the specimens of Dr. Williams's, but I have seen the drawings; and those drawings indicate but a slight difference from Dr. Bödecker's, so slight that it is not worth disputing about. He shows one, two, and sometimes three branches from one odontoblast, which penetrate the dentine and form the dentinal fibre. Now, we do not find the same form in every case. If we could have, in the same tooth even, in each mouth, a state of things in every case alike, it would be different. Then we could say that so and so is to be seen in certain kinds of teeth, etc. But instead of that you will find in every tooth varieties of particular things differing from others. The fact is, it is almost impossible to get two teeth that give us the same appearances; in fact, it would be difficult to cut two specimens from the same tooth, put them under the microscope, and have a view which would lead you to the conclusion that both were cut from the same tooth. I simply make these remarks to show that, no matter how carefully men may investigate and study this question, they will very often see things differently. I think we shall at no distant day arrive at a point, when no publication will be made of any histological work by any gentleman of a Section, without its having been carefully scrutinized by all the others of the Section, so that, when we present a paper here, we shall present it as a body, believing that we are right, and that we all see the specimens the same.

That is what we desire to do. In that way I think we can form a team to work which would have a better effect and influence than could possibly come from working by ourselves.

Dr. PEIRCE: I wish to say a few words in regard to the paper under consideration. I feel sorry that the gentleman who read the excellent paper gave so much importance to the views that had been. advanced by Dr. Garretson and Dr. Cryer. It is well known to those who have studied the subject that in 1838 Mr. Goodsir published in England a very minute account of what he deemed the correct history of the development of the teeth; that is, that a tooth passed through three important stages, which he termed, first, the follicular stage, when the teeth were in this open groove; second, the saccular stage, when the groove closed; and third, the eruptive stage, when the teeth advanced and cut through the gums. He advanced the primitive dental groove theory in 1838, and for years it was the popular idea; but previous to 1868 Huxley and Magitot and others came to the conclusion that he was all wrong, and that the mistake which Goodsir had made was in the imperfect preparation of his tissues, or rather the imperfect manipulation of them; that he had wiped off the enamel cap, and left the dental groove. What I wished to express to you was that the views which Dr. Williams combated so skillfully were given more importance than they are entitled to, for they are not the results of the investigations of Garretson and Cryer, but were advanced by Goodsir, and have been entirely abandoned under the light of more recent investigations. These men were not original investigators: they had accepted those views simply because they had become familiar to them.

The work that has been done in this direction has not been easily done; and we in this country, as well as in England and on the Continent, have a proper appreciation, I think, of the credit due for the careful manipulation of material which has brought out the facts; and I know of no one who has pursued the subject more independently and faithfully than our friend Dr. Williams. I know of no one to whom greater credit is due for the results of his investigation. He has given us clearer ideas of the odontoblast and formation of the fibrille and tubuli than anyone else, I think, though his views are not widely different from those of others who have been over the same ground.

Dr. SPALDING: I did not understand Dr. Williams in his paper to consider it necessary to combat the old dental groove idea of Good

sir. I understood that he merely made the explanation and exposi tion which he did to show the manner in which Goodsir and others

were misled. I believe that was his object; because I am sure nearly every dentist in this country knows that that theory is pretty thoroughly exploded.

In regard to the layer of flat cells which lie in contact with the ameloblasts, that, I believe, is in accordance with what we know of the histology of other tissues. We know that the epidermic tissues are renewed from the layers below, and we know that the cells of the layers beneath are entirely different from the epidermic cells in form, and that conversion takes place whenever the cells from below rise and take the place of the epidermic cells. This case of the ameloblasts is in exact agreement with that idea.

Dr. ABBOTT: Only they are not reproduced; they do not wear off.

Dr. SPALDING: That is a question,-whether they are reproduced. We have a great many instances where the ameloblasts are destroyed, or at any rate where they fail to perform their office, where there is a fissure or something of that kind, which is closed subsequently. Now, the question is, whether the fissure is not closed from the transformation of flat cells to produce new ameloblasts. How otherwise can it be closed? It must be done in that way or by the budding process, or by the generation of new ameloblasts from themselves in some way; and we have no evidence of that. Therefore, it is not unreasonable to suppose that this flat layer should supply the material for ameloblasts when there is occasion for it. That there is frequent occasion for it is seen in the many teeth defective as to enamel, which we so often see and which seem to be increasing on our hands.

STANDING RESOLUTIONS.

The following standing resolutions are in force at this time, August 1, 1885.

Resolved, That henceforth no person shall be received as a delegate who is in arrears for dues, or until he has paid to the Treasurer the full amount due at the time his name was dropped for non-payment.

Adopted August, 1874.

Resolved, That hereafter no dental college shall be entitled to representation in this Association that does not require a good English education as a preliminary qualification for its matriculants, to be ascertained by examination.

Adopted August, 1879.

Resolved, That in order to secure representation in this Association, dental colleges must, subsequent to October, 1881, require all students entering therein to take two full courses of lectures previous to coming forward for examination and graduation, and must also state these conditions in their next annual announcement.

Adopted August, 1880.

Resolved, That hereafter no society shall be entitled to representation in this Association that does not require its members to live up to the requirements of our Code of Ethics.

Resolved, When it comes to the knowledge of the Committee on Credentials that any applicant for membership is violating our Code, said applicant shall not be received, and all such applicants shall be referred by the committee to the societies whose delegates they are, and in no case shall this Association be compelled to treat with violations of the Code, except where the violator is a member of this body and has no membership in any local society.

Adopted 1881.