Elementary Human Anatomy

"It is in the nature of things" is surely, today, just as good an explanation of a biological phenomenon as it ever was; and now, as always, it is singularly unilluminating. That some of the problems to which such an explanation is usually given are susceptible to analysis appears obvious; at least an approach can be made toward segregating the many factors which, acting independently ox through other agencies, may contribute to understanding. In this text will be found description of experimental procedures, and discussion of the inferences to be drawn from them, of a study of a considerable number of microcosms under widely varying conditions. Only through intensive investigation of such systems of relative simplicity under controlled conditions can we ever hope to attain an insight into .the struggle-whereby the fittest survive-as it occurs under the extreme complexity of natural conditions. The struggle for space-for still vacant places-and that for energy, in homogeneous and in mixed populations are described upon the basis of experiment, not the least interesting of the facts disclosed being the demonstration that in mixed populations under conditions of competition the properties possessed by a given species-properties which give it the ascendancy-are not merely a reflection of the properties exhibited by the species when alone. Predator-prey relationships present features which may be of far-reaching importance, not only to the biologist interested in protozoan and bacterial systems and the like, but to the epidemiologist as well. To review the text is impossible; each paragraph offers material worthy of discussion. GEO. H. SMITH.