inductive research period when these natural philosophical speculations sought to establish themselves. Once again it was the return to the inductive method and to the principle of the division of labor which cleared the way to real progress. There came about a sharp sundering of morphology from the doctrine of function—so sharp that it was regarded as dangerous and punishable for one of these subjects to deal with things pertaining to the other. Under the chastisement of Schleiden no one attempted to demonstrate the functional significance of a morphological structure. Narrow minded as this method of procedure appeared, it was to the purpose. Embryology of plant organs arose out of these conditions, and physiology was gathering richly of usable constructive material for the future.
Only a small part of morphology, which we botanists call anatomy, but which is identical with the histology of the zoologists, developed along with physiology. The greater part of morphology, which corresponds to what zoologists call anatomy, pursued its way independently of physiology.
I venture to raise the question here as to why zoology and botany have not chosen the same expression for analogous branches of their science; why under the term "anatomy" botanists and zoologists designate different things. The cause of this lies again in the principle of division of labor, which at first always leads to a sharp separation, and only after advances in scientific work does it bring about union. The development of botany proceeded independently of zoology, and vice versa.
Terminology, taken at the beginning, is not of such serious importance, but subsequently it would be in accord with the "economy of science" if in related subjects similar expressions were employed to express similar concepts. That will come to be the case; and even now in botany the expression "histology" begins to be used in the same sense as in zoology.
The collaboration of working material in the form of demonstrated facts on the side of morphology, as well as in the realm of the doctrine of function, has aided in bringing the two nearer together, and the solution of the questions as to the functional significance of morphological structures is in full tide. The most successful has been the union of morphological and physiological knowledge as regards plant tissues, the study of which, as previously mentioned, was from the first often entangled with the doctrine of function. In this way has arisen in recent times the much cultivated branch of botany to which has been given the name of physiological plant anatomy.
No field of research stands so near plant physiology as does animal physiology. Where run, above all, the boundaries of these two territories, when, in the lower stages of plant and animal organisms, it is no longer possible to distinguish with certainty between plant and animal, and when investigations are ever revealing new
