2 BIOLOGICAL SOCIETY OF WASHINGTON. 



that the current of hypothesis most favored in America, though 

 not confined to our naturalists, is running in a wrong direc 

 tion, although they do not seem to have any satisfactory alter 

 native to offer. 



For convenience in discussion those who accept the ideas re 

 ferred to, in greater or less degree, may be termed Dynamic 

 Evolutionists. Their position has been very fairly and tem 

 perately stated by Osborne in his article on the paleontological 

 evidence of the transmission of acquired characters.* With 

 out attempting to speak for others I have felt that a statement 

 of the position to which I have been led by my own studies 

 might not be without use in the present status of the question. 



In the first place, in opposition to the notion that characters 

 acquired in other than the embryonic or larval condition are 

 not transmitted to the progeny ; I maintain that a direct or 

 indirect transmission of acquired characters is absolutely es 

 sential to any theory of evolution and that, speaking broadly, 

 the whole system of Darwinism must stand or fall with this 

 hypothesis. It is as axiomatic as the ' ' survival of the fittest ' ' 

 itself. 



It therefore becomes necessary to define what is meant by 

 " acquired characters " and their " transmission." 



The environment stands in a relation to the individual such 

 as the hammer and anvil bear to the blacksmith's hot iron. 

 The organism suffers during its entire existence a continuous 

 series of mechanical impacts, none the less real because invisi 

 ble, or disguised by the fact that some of them are precipi 

 tated by voluntary effort of the individual itself. So far as re- 



*Nature Jail. 9, 1890, p. 227; Science, 1890, p. no. The name Neo- 

 L,amarckian is objectionable, as it tends to connect with the modern 

 hypothesis the different and obsolete theory of the distinguished French 

 naturalist. 



