Explanation of Particulate 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 
