240 COOK 



The accumulation of variations without isolation agrees with 

 the other evidences of evolution by the continuity and gradual 

 transformation of the characters of species. It shows that the 

 phenomena of mutations and of Mendelism do not justify the 

 theory of saltatory or discontinuous transformation by leaps 

 from one species into another. The latter assumption requires 

 the formation of a new species to preserve each new character, 

 while the former permits simultaneous progress in the constructive 

 combinations of many characters inside the network of descent 

 of a single, undivided species. 



