v FACTORS OF EVOLUTION 231 



which has more or less departed from the parental 

 type. For some time an important discussion has 

 been carried on, especially in England, Germany, and 

 the United States, concerning these factors between 

 Lamarckians and Darwinians, as to their efficiency 

 and frequence. 



I cannot enter upon the discussion, which would 

 require much time, and in fact it might seem rather 

 early yet to discuss the quoinodo of a fact whose exist- 

 ence is not proved to the satisfaction of all whose 

 opinion is of any weight. Lamarckian views arc held 

 especially by American and some French evolutionists, 

 while in England and in Germany strict Darwinian 

 theory prevails. It must be said, however, as concerns 

 the Lamarckian theory, that, as Lc Conte has well 

 remarked, the Lamarckian factors of environment and 

 use and disuse, arc the most fundamental in importance, 

 and first in order of appearance. Selective factors are 

 conditioned by reproduction, and on sexual reproduc- 

 tion particularly in which the characters of two diverse 

 individuals are blended in different proportions in the 

 individuals of the same progeny; sexual generation 

 thus provides material for selection to operate upon. 

 But where no sexual generation occurs and this is the 

 case with the lower forms of life which were first evol- 

 ved, and out of which the higher forms are supposed 

 to have developed Weismann urges that selection is 



