Then, again, he must be familiar not only with the physical properties of metals and the various materials used in plastic dentistry, nor expert alone in the operations about the teeth, but, inasmuch as he has to cope with various wounds, injuries, and operations about the soft parts, he must be thoroughly familiar with the principles of wound-healing; with the causes of sepsis and the agents which produce it, and the means of avoiding it; in other words, he must have a general training in operative surgery, and, according to my ideal, which may be high, he should be a man able to do almost any operation in surgery before he limits himself to surgery of the mouth. Unless he have this ability, he will not do such operation as well as a general surgeon can, because the underlying principles are the same, and the latter will have the greater command over them. When, then, this perhaps ideal man has become thoroughly familiar with the principles of surgical anatomy, operative surgery, surgical pathology, and bacteriology, in addition to the things already mentioned, then, and not until then, may he and should he assume to operate for harelip, cleft palate, cancer of the tongue, and various other lesions in the parts about the mouth. I{339} wish I could say and demonstrate more to impress upon you the important bearing of modern surgical pathology to dentistry. Perhaps I can give you no better illustrations than you can see in the studies and writings of Prof. W. D. Miller, of Berlin, of whom I am proud to say that he is an American, and that he is the only American occupying a professorship in a German university. In his studies on the causes of dental caries and upon the bacteria of the mouth he has identified and named nearly a hundred species of the bacteria, many of which he has shown to be the active causes of dental decay. He has done, then, for dental pathology in this direction what other eminent observers have done for the processes of suppuration and ulceration in other textures and tissues, and has helped to show that they are all evidences of pernicious germ activity. By his researches, also, upon inflammation in elephant-tusks, and the results of injury, mainly by bullet wounds, he has shown us that the phenomena attending these changes in dental tissues are practically identical with those in bone. His researches have done very much to explain the pathology of that common disease, pyorrhoea alveolaris, which is known to be but one expression of local infection, while the possibility of migration of infectious organisms and of metastatic lesions in other parts of the body, having their origin in infectious disease in or near the teeth, has been brilliantly demonstrated by his interpretation of well-known clinical facts.