302 Explanation of Inheritance 



hypothesis is able to explain particulate inheritance com- 

 pletely, without requiring the help of any preformistic 

 germs whatever. Concretely : let us imagine two exactly 

 similar phonographs, and let us have the same singer 

 render the same melody in exactly the same way first 

 before one then before the other. Only let us suppose 

 that one hears at a certain moment during the second 

 song, for example, one of the audience cough, or a door 

 slam, or clapping of applause. Obviously both phono- 

 graphs now will reproduce the same melody in the same 

 way, with the single difference of the accessory noise, 

 which will not destroy in the slightest the otherwise com- 

 plete conformity of the two phonographic reproductions. 

 Thus we have here an actual and characteristic case of 

 particulate inheritance for the production of which it is 

 mechanically sufficient that the series of successive specific 

 vibrations of the middle point of the membrane differs 

 from the corresponding series of vibrations in the other 

 phonograph only through a single vibration or through 

 a very inconsiderable group of these specific vibrations. 



From the explanation which centroepigenesis gives of 

 the inheritance of acquired characters there follows also 

 at once a very important consequence. If we mean by 

 functional stimulus not so much the external influence as 

 rather the immediate modification induced by it in the 

 vital process, then the functional stimulus according to 

 the centroepigenetic hypothesis is of quite the same 

 nature as the ontogenetic stimulus. And this appears to 

 be indicated also by the best demonstrated facts. 



We regard it as absolutely necessary to understand 

 first clearly this distinction between external physical 

 actions and functional stimulus. For the former do not 

 themselves constitute the true and proper functional 



