variations. In general they are more perfectly developed and nearer the typical form of the other molars in the lower races than in the higher. In the latter they are usually very erratic and degenerate in form and structure, but beyond this we can say but little, as no special value can be placed upon their variations. Indeed, these teeth begin to be deficient in size as compared with the other molars in the chimpanzee, but that also "is another story."

In the Peruvians we found great variation and deformity of the upper third molar, quite as much as among a similar number of Europeans. Of the number examined it was found that only six per cent were of full form like the other molars; forty per cent were tritubercular in form, large and small; fifteen per cent were

Lower second molar-occlusal face. a. Five cusped form of normal first molar, found (as ancestral type) as a reversion in second molar. b. Degenerate but usual form of quadri-cuspid type of lower second molar in higher races.

trapezoid, with four tubercles more or less irregular; ten per cent were of bicuspid form; ten per cent were totally suppressed, etc. So that the irregularity was very conspicuous and with little value as regards the ethnic significance of the variations. We can only say that they were very degenerate and indicated an advanced stage on the path toward suppression.

The lower third molars were generally larger than the uppers and somewhat better developed. They were not so regular in eruption, however, as they presented more cases of diverted direction and impaction. Of the number examined, five per cent were irregular in eruption and impacted, most being tipped against the second molars some above and below were directed outward, and but very few to the inside; five per cent were totally suppressed, and of these some probably yet remained in the jaw; sixty-five per cent were full size, with four or five tubercles like the other molars; twenty

per cent were small, with four tubercles or irregular; five per cent had the wrinkled occlusal face sometimes found, which is a reversion to the form of these teeth in the orang. A small proportion had abnormally large crowns, as if an attempt to produce the fourth molar had been made and the abortion was fused to the third molar, as is sometimes distinctly observed. Altogether the lower third molars were better developed, but yet were very erratic and irregular, like those of the higher races.

In conclusion, I will offer nothing in the way of a summary, for this study has been only in the way of an experiment, with the purpose of assisting in discovering characteristics that might possibly be considered ethnic. For this purpose, however, we have not yet sufficient data and cannot have without much more extensive observations, so my work must be considered as suggestive merely and as an effort to blaze the way for more elaborate studies and investigations. My mission will have been accomplished if 1 shall have interested students in the subject of ethnographic odontography sufficiently to induce one here and there to take up and pursue the work among different races. Years of study and masses of material will be required before we can safely venture upon definite generalizations and deductions. I can only hope that this imperfect contribution to the great subject will stimulate the study and gathering of that material.

Discussion. Dr. C. N. Peirce, Philadelphia: I have been with Dr. Thompson in the study of the crania and teeth, and know the close attention he has given to the subject and the immense amount of work involved in preparing this paper. It requires much care and ability to discriminate between and fully appreciate the modifications that are taking place in the different races with regard to the teeth. I was especially interested in these particular researches of Dr. Thompson's, because after going over the crania to which I had access in the study of the third molar of the Peruvians I was surprised to find so large a proportion of these molars that were so much reduced in size. Not until after I had made this examination, and then attempted to learn something of the history of the Peruvians, did I see what I thought was the reason for the change that had taken place in these teeth. The Peruvians have been civilized for many generations, and their food, besides being cooked, has been

vegetables and fruit. I have always maintained that a vegetable and fruit diet has a marked influence in the modification of the size of the third molars, simply because less force is required in mastication. There is also greater development of the lower jaw when the tribe has lived on raw food. You will remember I stated in my paper that I found more than one-half of the third molars reduced in size, which surprised me greatly, and it was not until I had obtained the history of these people that I could see why it should be. The fact was fully explained by their civilization and food habits. For many years I have held the theory that the food habit is instrumental in modifying not only the size and prominence of the lower jaw, but also the size of the teeth. The force exercised by the muscles in mastication has a greater influence than you imagine on the molar processes as well as on the maxillary bones.

Dr. Cor: I wish simply to add one more link to this chain in regard to the Indians. The Columbia Indians are divided into various tribes, one of which is known as the Flatheads. The shape of the head is similar to that of the Incas, but the form is brought about by binding the child's head to a board, producing a sloping forehead. The number of skulls to be procured is not very great, as it is a small tribe, and almost extinct at the present time, and the habit has practically disappeared, but in those skulls that I have examined I have found, as in the Incas, absolutely no displacement of the teeth on account of the shaping of the head, also that the teeth are uniformly large and sound.

Dr. Brigham: Dr. Thompson spoke of trephining practiced among the Incas and called it a fad, but I believe it was a necessity with them, and that they were practicing what might be termed the high art of brain surgery. They probably found that in some cases the brain was injured by the pressure brought to bear upon it in the changing of the form of the skull, and that it was necessary to practice trephining in order to relieve the brain of that pressure. This would be my explanation why so many examples of trephining are found.

Dr. Thompson, closing discussion: This practice of trephining among the Peruvians is very interesting. Squier in his "Travels in Peru" says he believes that they performed the operation not only for surgical reasons but for pathological conditions. Of course it is

a question as to how much they understood about it. Trephining has extended among various savage peoples, and is practiced today by some of the tribes of the Pacific Islands. They perform the operation for very simple lesions, even for the relief of a headache. The shaman will uncover the scalp and scrape a hole in the skull with a seashell. It is something of a fad among them as a treatment for almost all kinds of diseases and disturbances. There are other matters of interest about trephining which I could not elaborate in the paper. Trephining was practiced considerably among savage tribes on dead bodies in order to secure amulets or rondells, little round pieces which were worn as charms. There is also no doubt that living victims, as prisoners, were subjected to this operation.

When reading the paper I did not have time to speak in regard to other facts which were outside its scope. I did say, however, that in my recent studies I had noticed the exceedingly small size of the bicuspids among the Mexicans, and that so far I have found the same thing true of other American tribes. This fact would seem to militate against what is called the Mongolian theory of the origin of the American races, because the bicuspids among the Mongolian tribes, and especially among the Chinese, are exceedingly large in comparison with the other teeth. There are many other things that could be brought out, but I do not want to make any generalizations or deductions as yet, because we are in want of reliable data. The microscopic anatomy of the teeth should arouse our interest, and I hope that dentists in this and foreign countries will study the subject in relation to peoples with whom they may come in contact.

SECTION V. Continued.

Surgical Procedures in Abscess of the Maxillary Sinus.

PAPER BY J. D. PATTERSON, OF THE SECTION.

It would be presumptuous for me to endeavor to instruct the members of this body upon a subject which is dealt with in text-books on surgery and dental surgery, and in the literature of journals and society proceedings, were it not that much of what I shall say is based upon the results of practical experience with a considerable number of cases during the last thirty-five years.

The point I desire to make is, that in disease of the maxillary sinus I am opposed to the so-frequently advocated penetration of that cavity immediately above the buccal roots of the first molar through the external wall of the sinus, and the reason I address you to-day is to give the history of a recent case in my practice in support of my opposition to this surgical procedure.

As regards opening at the point indicated I will make four criticisms-First, perfect drainage sought is not obtained. Second, if a sufficient opening, necessary for exploration and treatment, is made the thin wall removed is not reformed and an objectionable cicatrix of soft tissue results. Third, the origin of the masseter muscle and the attachment of the buccinator muscle are sometimes seriously impaired. Fourth, if the opening thus made extends to the lowest level of the sinus, the buccal roots of the molar teeth which the operation seems to conserve are laid bare and placed in an undesirable condition.

The advocates of this operation, on the other hand, put forward a