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 larvee which were near 
the stage of pupation to different colors, the correspond- 
ing colors were produced in the chrysalids developed. 
In another experiment larve, which were in the act of 
weaving cocoons, on exposure to certain colors were 
induced to weave cocoons of corresponding colors. 
“Tn 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- 
