Explanation of P articulate Inheritance 157 



organism ? It will not be difficult to convince us that the 

 possibility of this phenomenon will be fully provided for 

 by the same hypothesis of the structure of the germ sub- 

 stance which has served to explain for us the same 

 phenomenon in so far as it is due to sexual reproduction. 



Let us imagine, for example, two germinal substances 

 constituted by two series of specific anlagen, which are 

 qualitatively alike, but in one of which a certain entire 

 group of these anlagen is furnished with a little less 

 potential energy than in the other. We do not need to 

 suppose, even though we could, that this certain group of 

 specific anlagen is of such a nature that its activation in 

 the above mentioned common zone from which formative 

 stimuli are given out should determine preferably or exclu- 

 sively just that part of the organism which shows itself 

 capable of independent variation, such as for example the 

 dimple in front of the ear of which Weismann speaks. 

 Instead we could very well suppose that this group, 

 either by itself or in combination with others, brings 

 about definite ontogenetic modifications not only in this 

 one part but also in many other parts, perhaps even in 

 all the cells of the organism without exception. But 

 the epigenetic nature which we attribute to the process 

 of development implies the idea that the activation at 

 a given stage of ontogeny of a definite specific anlage 

 must exert very different influences not only qualitatively 

 but quantitatively upon the individual parts of the soma 

 that are already formed. It is thus conceivable that 

 a very small amount of potential energy in a given 

 group of specific germinal anlagen might exert inappre- 

 ciable effects or indeed no effect at all on a definite or 

 even great part of the organism, but yet exert quite an 

 appreciable or even considerable effect upon another very 



