Coe — A Century of Zoology in America. 367 



A moment's consideration of the fact that all these 

 topics are excellently treated will show how great had 

 been the progress of zoology in the first half of the 19th 

 century. The sixty years that have elapsed since the 

 publication of this book have served principally to 

 develop these separate lines of biology into special fields 

 of science without reorganization of the essential princi- 

 ples here recognized. This remained for many years 

 the standard zoological and physiological text-book, and 

 was republished in several editions here and in England. 

 Another popular book is entitled "Methods of Study in 

 Natural History'' (1864). 



More than 400 books and papers were written by 

 Agassiz, over a third of which were published before he 

 came to America. They cover both zoological and 

 geological topics, including systematic papers on living 

 and fossil groups of animals, but most important of all 

 are his philosophical essays on the general principles of 

 biology. 



One of Agassiz 's greatest services to zoology was the 

 publication of his " Bibliographia Zoologise et Geologise" 

 by the Ray Society, beginning with 1848. The publica- 

 tion of the Lowell lectures in Comparative Embryology 

 in 1849 gave wide audience to the general principles now 

 recognized in the biogenetic law of ancestral remin- 

 iscence. As stated in the Journal (8, 157, 1849), the 

 "object of the Lectures is to demonstrate that a natural 

 method of classifying the animal kingdom may be 

 attained by a comparison of the changes which are passed 

 through by different animals in the course of their devel- 

 opment from the egg to the perfect state; the change 

 they undergo being considered as a scale to appreciate 

 the relative position of the species." These "principles 

 of classification" are fully elucidated in a separate pam- 

 phlet, and are discussed at length in the Journal (11, 

 122,1851). 



One of the most interesting of Agassiz 's numerous 

 philosophical essays, originally contributed to the Jour- 

 nal (9, 369, 1850), discusses' the "Natural Relations 

 between Animals and the elements in which they live." 

 Another philosophical paper contributed to the Journal 

 discusses the "Primitive diversity and number of Ani- 

 mals in Geological times" (17, 309, 1854). Of this sys- 

 tematic papers, those on the fishes of the Tennessee river, 



