NUTRITION. 233 



and in the dried-up AnguilluHdae^ of Baker and 

 Spallanzani, in the encysted colpoda^ that a drop of 

 warm water will revive, in the animals exposed by 

 E, Yung and Pictet to a cold of more than a 

 100" C. below zero, are due to the general arrest of 

 the two forms of assimilation, or to the arrest of the 

 manufacture and utilization of reserve-stuff alone, or 

 finally, to the arrest of protoplasmic assimilation 

 alone. The latter, which is already very restricted 

 in beings in a normal condition whose growth is 

 terminated, may fall to the lowest degree in the 

 being which, having no functional activity, is assimi- 

 lating nothing. So that, to cut the question short, 

 the experimenter who measures the value of the 

 exchanges between the being and the medium has 

 seldom to do more than decide between little and 

 nothing. Hence his perplexity. But if experiment 

 hesitates, theory affirms : it admits a priori that the 

 movement of protoplasmic assimilation, an essential 

 sign of vitality, is neither checked nor renewed, but 

 proceeds continuously. 



Is Nutrition^ the Assimilating Synthesis, inter- 

 rupted? — Nevertheless, there are many reasons for 

 suspending all judgment as to this interpretatioh. 

 It is questioned by most biologists. According to 

 A. Gautier, the preserved grain of corn and the dried 

 up rotifera are not really alive ; they are like clocks 

 in working order, ready to tell the time, but awaiting 

 in absolute repose the first vibration which will set 

 them going. As for the grain, it is the air, heat, and 



^ Minute thread worms, known as paste-eels and vinegar- 

 eels.— Tr. 



"^ Genus of Infusoria. Colpodea cucullils is found in infusions 

 of hay — Tr. 



