356 Coe — A Century of Zoology in America. 



zoological studies toward problems concerning the rela- 

 tionships of animals as indicated by their structure and 

 developmental history. 3, Period of evolution, 1870- 

 1890, when the principle of natural selection received 

 general recognition and the zoological studies were 

 largely devoted to the applications of the theory to 

 all groups of animals. 4, Period of experimental biol- 

 ogy, since 1890, during which time have occurred the 

 remarkable advances in our knowledge of the nature of 

 organisms through the application of experimental 

 methods in the various branches of the modern science of 

 biology. 



American Zoology in 1818. 



At the beginning of the century which this volume 

 commemorates, the accumulated biological knowledge of 

 the world consisted mainly of what is to-day called 

 descriptive natural history. The zoological treatises of 

 the time were devoted to the names, distinguishing char- 

 acters and habits of the species of animals and plants 

 known to the naturalists of Europe either as native 

 species or as the results of explorations in other parts 

 of the world. This required little more than a super- 

 ficial knowledge of their general anatomical structures. 



The naturalists of those days had no conception of the 

 life within the cell which we now know to form the basis 

 of all the activities of animals and plants, nor had they 

 even the necessary means of studying such life. The 

 compound microscope, so necessary for the study of even 

 the largest of the cells of the body, was not adapted to 

 such use until 183*5, although the instrument was invented 

 in the 17th century. With the perfection of the micro- 

 scope came a period of enthusiastic study of microscopic 

 organisms and microscopic structures of higher animals 

 and plants. It was not until twenty years after the 

 founding of this Journal that the cell theory of structure 

 and function in all organisms was established by the 

 discoveries of Schleiden and Schwann. 



At the beginning of the century there was great zoolog- 

 ical activity in Europe, and particularly in France. Buf- 

 fon's great work on the Natural History of Animals had 

 recently been completed, Cuvier had only one year before 

 published his classic work in comparative anatomy, 

 "Le Regne Animal," and Lamarck's "Philosophic 



