The Only New Thing in the Hypothesis 299 



counts for the fact that a small stimulus as cause may 

 often result in an extraordinarily great reaction, just as 

 a grain of gunpowder kindled by a small spark may 

 provoke the explosion of a great mass." 218 



We have opened this parenthesis on nuclear somatiza- 

 tion and cited these passages from the two investigators 

 in order to set in clear relief the fact that in the definition 

 given above of the specific potential elements, both the 

 conception of accumulators of nervous energy in tension, 

 and that of accumulators of a specific nervous energy con- 

 stituting their special irritability, are ordinary conceptions 

 very generally employed which are expressed here in 

 words at most only a little different from the ordinary. 

 The only new thing which the above definition includes 

 is the hypothesis that the substance which is thus capable 

 of giving as a discharge a given nervous current was pro- 

 duced and deposited only by a nervous current of the 

 same specificity, but in the inverse direction, and could 

 have been produced and deposited only by such a current. 

 But in this hypothesis, quite simple as it is, lies every- 

 thing; for it is just it which alone can explain completely 

 the fundamental law of the reversibility of the relation 

 between action and reaction, between stimulus and im- 

 pression, which governs all organic life. The inheritance 

 of acquired characters, the psycho-mnemonic phenomenon 

 proper, the process of specialization and somatization of 

 the cells in consequence of which they react in their 

 habitual manner to accidental stimuli unusual to them, 

 even the vital phenomenon itself in all its generality, all 

 of these, as we have seen and shall see, are only so many 



S18 0scar Hertwig : Die Zelle und die Gewebe I, P. 77. 



