The science of medicine developed slowly from very humble beginnings, and for this earliest period the historian has no records of any kind which may be utilized for his guidance. It is reasonably certain, furthermore, that this prehistoric period lasted for a very long time, probably several thousand years; and when, finally, some light on the subject appeared, it was found to emanate from several widely separated regions--_e.g._, from India, Mesopotamia, Egypt and Greece. Then, after the lapse of additional hundreds or even thousands of years, there was inaugurated the practice of making written records of all important events, and, among others, of the different diseases which affect mankind, of the means employed for curing them or for relieving the effects which they produce, and of the men who distinguished themselves in the practice of this art. While the “science of the spade” and that of deciphering the writing of the papyri, monuments and tablets thus brought to light, have already during the last half century greatly altered our ideas with regard to ancient medicine, there are good reasons for believing that much additional information upon this subject may be looked for in the not distant future. It is plain, therefore, that a history of the primitive period of medicine, if written to-day, may have to be modified to-morrow in some important respects. On the other hand, the facts relating to the later periods are now so well established that a fair-minded writer should experience no serious difficulty in judging correctly with regard to their value and with regard to the claims of the different men to be honored for the part which each has played in bringing the science and art of medicine to their present high state of completeness and efficiency. The subdivision of the history of medicine into separate periods is certainly desirable, provided it be found practicable to assign reasonably well-defined limits to the periods chosen. But, when the attempt is made to establish such subdivisions, one soon discovers that the boundaries pass so gradually the one into the other at certain points, or else overlap so conspicuously at other points, that one hesitates to adopt any fixed plan of classification. Of the four schemes which I have examined--viz., those of Daremberg, of Aschoff, of Neuburger, and of Pagel--that of Neuburger seems to me to be the best. That which has been adopted, however, in the preparation of the present outline sketch combines some of the features of both the Pagel and the Neuburger schemes. _Periods in the History of Medicine._--There are nine more or less distinctly defined periods in the history of medicine, to wit:-- FIRST EPOCH: _Primitive medicine_.--This period extends through prehistoric ages to a date which differs for different parts of the world. The duration of this period, in any case, is to be reckoned by thousands of years.