permits of a total yearly income of $25,000.00. Federal Charters cannot be secured. The Research Institute of the National Dental Association differs from the Research Commission, chiefly, in having a membership of about twice that of the Commission and its Board of Trustees corresponding to the Executive Board having nine instead of five. The additional or permanent members are selected by the members of the Institute and are necessary to give permanency to the Institute.

We greatly desire that the members of the National Dental Association shall freely advise and counsel with the members of the Commission to the end that we may have every possible assistance and contribution of wisdom. We believe that this intensive dental and oral re

search is the most vitally important work of the dental profession of today, because of its direct constructive relation to the host of unborn generations. Respectfully submitted,

THE RESEARCH COMMISSION OF
THE NATIONAL DENTAL AS-

SOCIATION.

Signed by:

THE EXECUTIVE BOARD.

WESTON A. PRICE,

Chairman.

THOMAS P. HINMAN,

Vice-Chairman.

CLARENCE J. GRIEVES,
Secretary-Treasurer.

JOHN V. CONZETT.
EUGENER WARNER.

Mr. President, Ladies, and Gentlemen of the National Dental Association and the PanamaPacific Dental Congress:

T

HE work of the Minnesota corps of the Scientific Foundation and Research Commission for the year past has been a continuation of our original problem; namely, a closer study of the relationships growing out of the transplantation of mouth infections to other parts of the body and a study of the areas of inflammation in the human and animal body which have been induced by these transplanted organisms.

We have been able to verify the statement that para-apical abscesses and pyorrhea pockets both harbor streptococci, which will induce in animals inflammation of the heart muscle, vegetations on heart valves, infected joints, inflammation in blood vessels, inducing

vascular lesions, and both focal and diffused infections of kidneys.

Tho I have brought with me for your inspection a series of recent dissections showing lesions in animals which have been inoculated with streptococcus viridans, we are not at this time ready to publish this work, as much remains to be accomplished in order to make sure beyond all reasonable doubt that the work will stand the test of time.

Within the past two months we have inoculated one hundred and twelve rabbits with twenty-two different strains of streptococci. Many lesions have been produced by these inoculations which work we hope to report upon finally within the coming year. Our work thus far points strongly to the probability that streptococcus viridans, which is of the salivarius type found in focal abscesses,

pyorrhea pockets, and in the saliva are alike capable of producing grave lesions. During the past year, we have been able to find post-mortem human lesions particularly of heart valve, heart muscle, and kidney, which compare very closely with the experimental lesions produced in animals which human lesions, we believe, are produced by the same organism as that used to produce the experimental lesion in animals.

During the coming year, the work in the University hospital will be carried on by Doctor William Grey, who will do the practical work in the mouths of patients, while Doctor Harold J. Leonard will devote his attention to keeping up the records of the work.

I wish to direct your attention to an analysis of the work of the hospital division by Doctor S. Marx White, acting head of medicine in the University Medical School, whose paper dealing with this matter will be read in a section of the Congress. One of Doctor White's important conclusions from analysis of our case records is that twelve per cent of those individuals admitted to the hospital are suffering from conditions due to mouth infection. The hospital authorities are convinced that the work is sufficiently valuable to continue it and will during the coming year give it every possible aid. As director of this research, I desire to emphasize the fact that much harm may result from the too early publication of investigations of the type we are carrying forward and we beg your indulgence for withholding from publication until a later date, part of the material reported upon orally, at this session. We expect to go steadily forward in the preparation of pathologi

cal sections of the human jaw, as we have accumulated, from recent post-mortems, much valuable material.

THOMAS B. HARTZELL.

The following is Henrici's partial report of the year's activities in his field. "A large proportion of our work has consisted in a continuation of the studies of mouth streptococci reported upon a year ago, a summary of which has been published during the last year in the Journal of the American Medical Association (1) and the National Dental Journal. (2) Bacteriological examinations of approximately two hundred additional cases of peridental infection have been carried out, and sufficient data accumulated to establish definitely the tentative conclusions presented to the commission a year ago, namely, that the streptococcus viridans is constantly present in chronic dental abscesses and in pyorrhea alveolaris, frequently in pure culture in the former, and that haemolytic streptococci are absent.

We have been able to make cultures from eight additional healthy teeth and have constantly found them sterile. We are, therefore, satisfied that our technic excludes salivary contamination.

The sugar fermentation reactions of thirty additional strains have been examined, in a more satisfactory medium. This is broth containing beef serum sterilized by filtration thru porcelain, to which one per cent of the various sugars has been added, together with acid fuchsin decolorized by potassium hydroxide, for an indicator. This medium, devised by W. L. Holman, gives very sharp and clear cut results. The fermentation reactions of these thirty strains are shown in the following table:

It will be seen that the majority of strains are either streptococcus salivarius or streptococcus mitis, raffinose and salicin fermenters respectively. Only once has the streptococcus fecalis, a mannite fermenter, been met in this series. The constantly negative results with inulin indicate that the pneumococcus is not a factor in these infections. These results, especially the constant absence of haemolytic streptococci, are of more than academic interest, since they indicate clearly the source of these infections; for we find constantly only those streptococci which inhabit the oral mucous membrane and the saliva, namely the S. salivarius and S. mitis. Peridental inflammations are primary lesions, the organisms gaining access to the tissues either thru the pulp canal or at the gingival margin, and not secondary to some other focus.

We have for purposes of comparison, inoculated thirteen rabbits with strains of streptococcus viridans obtained direct

COMPLEMENT FIXATION WITH
STREPTOCOCCUS ANTIGENS.

We have attempted to demonstrate further the pathogenicity of dental streptococci and their relationship to rheumatoid conditions by complement fixation tests. Besredka, (3) apparently, was the first to demonstrate antibodies against streptococci by this method, in immunized horses. Swift and Thro (4) carried out similar experiments and found the reaction specific; they pointed out the fact that fresh streptococci are highly anti-complementary and devised a method for evercoming this difficulty.

Hastings (5) has conducted an extensive series of experiments with the sera of cases of arthritis deformans, performing the complement fixation test with streptococcus viridans as antigen. Many of his strains were from dental sources. He found positive reactions in most of the cases of arthritis and negative reactions consistently in the control cases. He did not prepare his antigens according to the method of Swift and Thro, but used merely fresh suspensions of dead streptococci. Hastings points out the fact that group reactions do not occur, and for this reason, a polyvalent antigen is necessary.

Our work along these lines has been beset with difficulties. We first prepared our antigens by the method of Hastings, but found them too anti-complementary; that is, minute quantities of the streptococcus suspension would destroy guinea pig complement even in the absence of specific serum. We then used the method of Swift and Thro. Ten to fifteen different strains of streptococci were grown on agar in large flasks, washed off in salt solution, centrifuged and mixed. The mixed cultures were then dried over anhydrous calcium chloride in an ice box for some days, then ground

in an agate mortar, suspended in

salt solution and shaken with glass beads for twenty-four hours. This method reduced the anti-complementary

properties considerably, and satisfactory reactions were obtained with immunized rabbits. Several rabbits were injected intraperitoneally with suspensions of dead streptococci, in some cases using a number of strains, in others individual strains. These rabbits all gave positive reactions, while untreated rabbits gave negative reactions. In examining human sera, we used as large an amount of antigen as possible without affecting the complement, a titration for anticomplementary substances being performed at each experiment. Several batches of antigen were prepared, using in all over thirty strains of streptococci. Forty cases of dental infection, many having clinical evidences of chronic rheumatism, were examined but in only three did we obtain a satisfactory positive reaction. This work has been laborious and time consuming, but has yielded only negative results. We are forced to conclude that these patients do not produce antibodies in sufficient quantity to be demonstrated by the method of complement fixation.

STUDIES OF ENTAMOEBA BUCCALIS

During the last year a series of papers have appeared on this parasite by Barrett and Smith and by Bass and Johns. Both of these groups of observers have arrived independently at the same conclusions, namely, that since this protozoon is constantly present in pyorrhea pus and relatively absent in healthy mouths, it is probably an etiologic factor in that disease. They have farther strengthened their claims by the observation that treatment with a specific amebicide, viz., emetine, has resulted in improvement, often amounting to a cure of the local suppurative process.

We have attempted to confirm these important observations. The results of our work have already been published in part in the Journal of the National Dental Association, (5) and a summary will suffice here. We found the amoeba practically always present in diseased