METHODS 59 



substance in chemical repose ; the living substance mani- 

 fests itself to us only in uninterrupted activity, an activity 

 that is assimilative or destructive according to the con- 

 ditions. But with many other species, on the contrary, 

 we can get the living substance in the state of chemical 

 repose just as we get in chemists' bottles sulphate of soda 

 or antipyrine. 



These little morsels of living substance in chemical repose 

 go by the name of spores. The spores of bacteria or of 

 mushrooms are capable of remaining very long in chemical 

 repose in a dry spot without loss of their elementary life, 

 or at least losing it by very slow destructive reactions. 

 But does not the same thing often happen to ordinary 

 chemical substances preserved in a chemist's bottle ? 

 Duclaux was able to bring about germination in spores con- 

 tained in air-dust filtered by Pasteur on dry cotton thirty 

 years before, when he was experimenting with spontaneous 

 generation. 



With the higher animals we do not generally come across 

 the living substance in chemical repose ; we find the tissues 

 always under way of assimilation or destruction. Yet 

 rotifers, little worms fairly advanced in organization, can 

 be dried and, like spores, will keep for a long time the faculty 

 of coming to life when furnished with water. 



At the beginning of this chapter it was remarked that 

 the definition of elementary life, as a chemical property 

 deduced from the verification of quantitative chemical 

 results, could have no direct reference to structural mani- 

 festations, of which no account had been taken in drawing 

 up the definition. We might guess from the start that, 

 elementary life being common to all living beings, it is 

 likely that the existence of such a chemical property is 

 related to the structural manifestations which are alsq 



