300 Explanation of Inheritance 



special cases of this reversibility, and all find their im- 

 mediate explanation in this very simple hypothesis. 



In resume : By this hypothesis of a nervous accumu- 

 lator formed and deposited by the same specific current 

 which it can afterward restore, the first of the two sub- 

 conditions, included in the third condition, necessary and 

 sufficient to account for the inheritance of acquired char- 

 acters, are fulfilled. On the other side the localization of 

 the germinal substance in the central zone, which con- 

 stitutes the point of departure and the foundation for the 

 hypothesis of centroepigenesis, has already satisfied com- 

 pletely the second of these sub-conditions. As to the two 

 other conditions, the first has already been satisfied by 

 considering the nervous current with its numerous differ- 

 ent specificities as the common denominator or as the 

 basis of vital phenomena of the most diverse kinds which 

 are in activity at each instant in the most varied points of 

 the soma; the second was satisfied by assuming a con- 

 tinuous action on the part of the germinal substance 

 throughout the whole of ontogeny, by means of the 

 steady activation of new specific potential elements pour- 

 ing their discharges into the general circulatory system. 

 It follows from this that centroepigenesis is able singly 

 and alone to explain the inheritance of acquired char- 

 acters, because it fulfills these conditions which we rightly 

 regarded not only as necessary, but also as sufficient. 



For greater clearness, nevertheless, it will be worth 

 while to institute, as w r e have indicated above, a compar- 

 ison between this ontogenetic development, as it would be 

 constituted according to the hypothesis of centro- 

 epigenesis, and a very characteristic phenomenon, in some 

 respects analogous, which is presented by the inorganic 

 world. The reproduction of a sentence by a phonograph 



