170 THE NATURE AND ORIGIN OF LIFE 



suits. Current observation proves that as long as phenomena 

 of assimilation have the better of destructive phenomena, that 

 is, just so long as life persists, the protoplasmic form of the 

 animal remains recognizable. Now we have the means of 

 suppressing whenever we wish all phenomena of assimila- 

 tion without changing any of the conditions of the medium 

 this means is the suppression of the nucleus. Here we have 

 one of the most certain results of experiments in merotomy. 



Merotomy 



Experiments in merotomy consist in cutting the body of 

 a living being in two or in several pieces ; we then see if the 

 pieces remain living and verify what is going on in such living 

 pieces. 



When the body under experiment is that of a unicellular 

 being (Fig. 11) it is easy to observe that fragments deprived 

 of nucleus immediately cease assimilating ; fragments con- 

 taining the nucleus or a piece of nucleus, on the contrary, go 

 on assimilating. The important result of the experiment is 

 that the nucleated fragments which continue assimilating, 

 after a short time, no matter how they may have been 

 truncated, recover the normal form of their species. Cyto- 

 plasm and nucleus regain that form of equilibrium which 

 they have in an ordinary individual that has not been sub- 

 jected to merotomy. 



On the contrary, fragments of cytoplasm deprived of nu- 

 cleus, or fragments of nucleus deprived of cytoplasm, are 

 susceptible only of destructive phenomena and are destroyed 

 without resuming their specific form. 



Except in the case of a rigid skeleton that hinders, these 

 two results taken together prove that the specific form of 

 equilibrium under normal conditions is a sign that phenom- 

 ena of assimilation are going on in the being possessed of the 



