256 Theories Treating of Inheritance 



indefinite the theory of Orr may be, it contains a clearly 

 expressed and very remarkable idea, namely: the con- 

 ception that nervous activity is the only general phe- 

 nomenon and basis of life. Orr attributes to it therefore 

 the great function of forming by itself the whole mechan- 

 ism of development as well as of the inheritance of 

 acquired characters, and seeks to explain through it the 

 striking analogy between this mechanism and the 

 mnemonic phenomenon. 



Cope 



In order to explain the inheritance of acquired char- 

 acters Cope starts out with the following investigations 

 upon butterflies. By exposing larvae which were near 

 the stage of pupation to different colors, the correspond- 

 ing colors were produced in the chrysalids developed. 

 In another experiment larvae, which were in the act of 

 weaving cocoons, on exposure to certain colors were 

 induced to weave cocoons of corresponding colors. 



"In the first experiment/' explains Cope, "the dynamic 

 effect produced by the exposure was stored for the period 

 which elapsed between the exposure of the larva and 

 the full development of the pupa. The second experi- 

 ment demonstrates that a stimulus may be transmitted 

 to a gland so as to modify the character of its secretion 

 in a new direction. From both experiments we learn 

 the transmissibility of energy from the point of stimulus 

 to a remote region of the body, and its conversion into 

 growth energy (in this case by physiogenesis). This 

 prepares us to look upon heredity as an allied phe- 

 nomenon, i. e. the transmission of a special energy from 

 a point of stimulus to the germ cells, and its compo- 



