278 Theories Treating of Inheritance 



quently upon all stages of development and upon all 

 cells of the organism, call forth the same result as 

 if it had come to act upon only a very definite point and 

 at a very definite time of the development of this organ- 

 ism? It seems to us that we ought much rather to 

 conclude that these results must be very different and 

 that with them there can be no question of any similarity 

 whatever. 



This impossibility of explaining the inheritance of 

 acquired characters by Roux's earlier theory is not limited 

 to it alone, but pertains to all theories of chemical develop- 

 ment in general. And the fault lies not only in the above 

 mentioned impossibility of the reversibility of the 

 phenomena of inheritance which we have just considered 

 but also in a still more generally characteristic circum- 

 stance, which is likewise common to all these theories of 

 chemical development, and which we have elsewhere 

 already stated for other theories. And it is mostly from 

 it that this impossibility of reversibility comes. It con- 

 sists in this, that according to all of these theories as soon 

 as the germinal substance has once given the initial 

 impulse to development it is unable to exercise even the 

 slightest influence upon the further course of this develop- 

 ment. If thus the reins by which development is directed 

 are let fall, and each bond severed which connects the 

 changes of the soma with those of the germ and vice 

 versa, then it is impossible to conceive how this union 

 could later be re-established, as soon as the need was felt 

 of transmitting to the germ and fixing in it the requisite 

 variation, corresponding to that which appeared in the 

 soma as the result of a new functional adaptation. 



Hofmeister's theory can be considered as an especially 

 typical example of this complete abandonment of develop- 



