been refuted. As regards crowns causing death of the pulp, these questions arise: First, is it caused by grinding down the tooth? Second, is it caused by the medium with which the crown is set? Third, is it caused by a pathological condition outside these mentioned? Before we can arrive at any conclusion as to the best method to be adopted in crown and bridgework we must ascertain definitely what causes death of the pulp.

Dr. Rhein: Dr. Bryant spoke about a form of removable bridgework which I devised. It was never my intention to introduce it as something which should become a system, but it was intended to take the place of the sort of bridgework that he mentioned, where the bridge could not be seen because of the filth covering it. The form of bridgework which I introduced has been used by a number of men, and from the principles then elucidated the Griswold system has been evolved. Proper judgment should be used in determining whether a fixed or removable bridge should be inserted. Dr. Bryant certainly condemned himself when stating that he put a fixed bridge in the mouth of a patient who would not keep it in a sanitary condition.

Dr. G. D. Sitherwood, Bloomington, Ill.: Bacteriologists tell us that certain germs are always present in the mouth, and that under given conditions they become pathological and do harm, so Dr. Hungerford has advocated this particular style of bridgework, not only for mechanical and other reasons, but so that no lodgment will be afforded for debris that will feed these germs and cause them to become pathological. Dr. Hungerford did not set forth a specific plan for making bridges, but he laid down universal principles that we should all recognize and work out in our own individual way.

Dr. Crouse: I consider the cause of failure in bridgework to be the loss of the peridental membrane. This is what makes bridges come out with the roots and all attached, and anything that will obviate this inflammation and loss of tissue should be looked into.

Dr. Bryant: In answer to Dr. Rhein, I have done something myself in the line of removable bridgework, and as regards the patient with a filthy mouth, the same trouble existed with a removable as with a permanent bridge, for he would not take out the removable bridge to clean it.

Dr. A. C. Hewett, Chicago: We can all earn a lesson by looking

at the three bridges which span the Niagara river. One is a suspension, another a cantilever, and the third an arch. The engineers who planned them knew exactly what was needed at the various points; also what would best meet the needs, and each bridge is doing its work perfectly. It would be senseless to make them all alike or to substitute one for another. It is just as senseless to say that all bridges in the mouth must be made just the same and upon the same principles. So long as there are differences in the teeth, gums and alveolar processes upon which we operate, so long there must be differences in the structures which we build and the methods we employ. We might just as well plead for uniformity in the shapes of fillings as for the uniformity in bridges.

Dr. S. W. Foster, Atlanta, Ga.: The cause of many failures in bridgework is the irritation of the periosteal lining of the roots by the edge of the crown impinging upon the gingival margin and periosteum. Frequently we do not use sufficient care in shaping the edge of the crown which goes below the gum line. I am strongly in favor of retaining the pulp in its normal, vital condition as long as possible, but if we adopt the essayist's statement that in preparing abutments all the lines must be parallel, we must devitalize the pulp much more frequently than where inclined planes are used. It is a principle in mechanics that two approaching inclines are stronger than two parallels, and in many cases, especially with the second and third molars, better results are obtained from inclines than from parallels.

Dr. Hungerford, closing discussion: In no great movement of science or industry can you expect to find all your confreres broadminded. The surest sign of progress is when you can be kindly disposed toward those who are opposed to you, and an infallible indication of retrogression is when you expect every man to think and act as you do. It would take a week for me to answer all the points that have been brought up, and as my advocates and opponents have been about equal in numbers I will leave the matter. to you for settlement. However, there was not the appreciation of the effort which I made in pleading for uniformity that I hoped for. It is well recognized in medicine that while one physician may prescribe quinin, another phenacetin, and a third antifebrin, all agree that in certain diseases antipyretics are necessary, and those

diseases are well established. As a profession we should unite upon certain standards and say when certain operations should or should not be performed. Until we can do so our practice of necessity will be more or less empirical.

!. I believe that most bridges are lost because of periostitis, and I think that fifty per cent of the diseases of the periosteum could be prevented if the teeth were deprived of their placenta after they are born. When the pulp has fulfilled its normal function of depositing dentin it ceases to perform any further physiological action. After the tooth has grown the pulp is as useless as the enamel membrane, but fortunately for the individual the latter is worn off shortly after the tooth is erupted. The pulp, on the other hand, remains on the inside until some dentist irritates the terminals of the fibers either chemically or mechanically, when it makes a more determined effort to eradicate itself, and in that effort dies, and through continuity of structure, irritation and loss of the peridental membrane naturally follow.

It seemed to me that Dr. Noyes took both sides with reference to the biology of bacteria. How is it possible to believe in the consistency of bacteria or of any class of living things if you believe in évolution, for the germs must change with their environment and under the conditions in which they live, and and where they arc hampered in their growth they must undergo changes. If there was one thing that I especially emphasized it was the idea that these new theories, while perhaps not thoroughly true, are worthy of our most earnest consideration. Dr. Black does not like to hear any new theories promulgated that will tend to disrupt the profession. If the new ideas are true they will not disrupt the profession and we want to know them, and if they are false we shall soon find it out. There is such a thing as clinging to old methods because we do not know anything else, and because we have journeyed so far along one ne that the dust of the road has blinded us and so clogged our wheels that we cannot bend our energies to the newer things.

SECTION II.

Dental Education, Literature, Nomenclature, Histology and Microscopy.

Some Thoughts on the So-Called "Preliminary Requirements."

PAPER BY A. J. FLANAGAN, OF THE SECTION.

For some years there has been a seeming unrest in educational matters of all kinds, and this may well be considered from many points of reasoning as being simply in harmony with the world's evolution in general-an evolution which has progressed from the beginning and which we may well hope is to continue for all time. This evolution of educational thought and method must necessarily have a cause, and the discovery of a cause is the beginning of a rational and logical system of betterment. Time was when education concerned but a fraction of this world's population, for we were then in what might well be termed the constructive or bare living stage, but as changing conditions brought us up from this period we had the time and means for something beyond a mere existence. The older countries have been beyond this mere existence stage for some time, but we here in America are only emerging from it, yet coming forth in such strength and numbers that the world stands aghast at the shadow cast before. America to-day is the center of the greatest interest in all that which may be classed under educational advancement for a specific purpose. The present sees us taking the fundamentals of the past and present of the old world's brightest minds and transplanting them into an entirely new environment, with results that other countries are beginning to admit if they do not understand. In a broad sense we can divide educational

thought into two fields: Ist. That which is represented by the United States; 2d. All outside the United States. Of course, in a strict sense objections can be made to this division, but in a general way it will stand the test. The one great cause for this division is, that all that which makes up our system of government is arrayed in a general way against the many systems outside this country.

Dentistry has been keeping apace with the world's advancement along the lines of education, and this progression has brought forth varying ideas, methods and results. At the present time we may say that we are coming forth from the period of construction and recognition into the broader and no less important one of system and science. This has not been accomplished without many misgivings as to results, and even the present attainments of dentistry are questioned by not a few. The logical mind must, however, admit one great truth, namely, that we have arrived at our present condition because of our own labor and inherent worth. We have borrowed many ideas and thoughts from other callings, and yet have founded a new one, which, in its broadest and best sense, is the equal of any in the alleviation of humanity's ills. Is not our use to humanity the only true guiding star for the future? In fact, will not the lasting history of dentistry depend on it? If we admit these truths we have a path of progress which is blazed in no uncertain manner-a progress which will bring forth the only lasting attention of the world-for the needs of humanity and science.

The foundation of education in our calling has been said to be our "preliminary education." An understanding of the word preliminary would indicate that it was something which leads up to the calling of dentistry, or which is, in other words, the primary part of dentistry. A logician would say it was the cellar on which was erected the main structure. Thoughtful men are questioning the worth of the present preliminary requirements to the college life; there is even a class of practitioners who question the methods of teaching in some of our colleges, and not a few do not believe in four terms. Four terms are frequently erroneously expressed as four years. These men are at least honest in their convictions. Let us reason a little. The various acceptable colleges are supposed at the present time to have as a requirement a minimum preliminary education equal to two years in high school. This is a very elastic