294 Explanation of Inheritance 



is likewise proportional to the mass of the substance of 

 the accumulator, (because it is proportional to its nervo- 

 motive force, which also is in its turn proportional to this 

 mass, according to the preliminary hypothesis), then the 

 quantity of work required to effect the change under con- 

 sideration, must be regarded as equivalent to a resistance 

 R, which opposes the discharge. 



If now we assume that in nearly all cases, which come 

 into consideration here, the quantity of work, requisite 

 for effecting a given change in the dynamic equilibrium 

 of the whole circulatory system, is proportionately 

 greater the more considerable (if we may be pardoned 

 for this much too indefinite expression) in quantity and 

 quality this change is, it becomes at once conceivable why 

 each specific potential element of the central zone can 

 becomes activated only when the embryo has reached 

 the ontogenetic stage, corresponding to the particular 

 phylogenetic stage at which this element was acquired by 

 the germinal substance. For then first will the change 

 which the dynamic system of the embryo undergoes, as 

 a result of the activation of this specific potential element, 

 be the very least possible, and therefore usually also the 

 only one whose resistance can be surmounted by the very 

 weak nervo-motor force of this specific potential element. 

 The following general rule can thus be established : 

 The smaller the mass and therefore the nervo-motor 

 force of a specific accumulator, so much the more 

 closely is its discharge dependent upon the condition 

 that the whole dynamic system, above all and very 

 especially in the immediate neighborhood of the ac- 

 cumulator, find itself again in exactly the same state in 

 which it was when the accumulator was formed. Con- 

 versely, the greater the mass of the accumulator, the 



