PROCEEDINGS OF THE OHIO ACADEMY OF SCIENCE. 357 



hypothesis.") but also variation. This variation, however, was 

 congenital and fortuitous or undirected, — very different from 

 the acquired and directed variation of Lamarck. While the in- 

 heritance of Lamarckian variation would in itself be evolution, 

 the inheritance of Darwinian variations would lead to chaos ex- 

 cept for the introduction of an additional directive factor, which 

 Darwin found in over-production, struggle for existence, natural 

 selection. Darwin with his usual catholicity had pointed out 

 clearly that these two theories are in no wise logically mutually 

 exclusive and that both may be true ; but his followers and 

 Lamarck's had been far less cautious and had established the 

 Neo-Darwinian and Neo-Lamarckian schools, respectively out- 

 Darwining Darwin and out-Lamarcking Lamarck. 



In the early Nineties, at least in America, the Neo-Lamarck- 

 ians were clearly in the ascendancy under the brilliant leadership 

 of Cope, ably seconded by Hyatt, Dall, H. F. Osborn and a 

 score of other lieutenants. Cope's "Origin of the Fittest" ap- 

 peared in 1887, and his "Primary Factors of Organic Evolution" 

 in 1896. Victory seemed imminent; but the battle was not to be 

 won so easily. 



In 1883 Weismann had published an essay entitled "Ueber 

 die Vererbung," which was rapidly followed by a series of writ- 

 ings culminating in "Das Keimplasma" of 1892. This is not the 

 time for a detailed discussion of Weismann's theory; perhaps 

 there is no need even of outlining his sharp distinction of germ- 

 plasm and somatoplasm, — somatoplasm, the protoplasm of the 

 somatic or body cells, carrying on the life of the individual and 

 subject to modification through environment; germ-plasm, or 

 the protoplasm of the germ cells, unused in the individual ac- 

 tivity but set apart for the production of the new generation, and 

 so shielded by the soma that it is practically freed from environ- 

 mental influence. From this the corollary is evident, — only 

 variations in the germ-plasm can affect the new generation, and 

 these variations are not and cannot be the result of environmental 

 influence, — acquired characters are non-inheritable. The con- 

 tradiction of the Lamarckian theory is absolute. Today, un- 

 doubtedly, the trend of opinion is toward the Weismannian 



