LIFE AND THE COSMOS 297 



possibly insurmountable) have put forth other 

 chemical elements, which would then have had 

 to be associated or dissociated by entirely dif- 

 ferent physical means. And if the element 

 characteristic of the substances that supply 

 energy to the organism had been other than 

 carbon, the element characteristic of the 

 plastic substances would probably have been 

 other than nitrogen, and the chemistry of 

 living bodies would then have been radically 

 different from what it is. The result would 

 have been living forms without any analogy 

 to those we know, whose anatomy would have 

 been different, whose physiology also would 

 have been different. Alone, the sensori-motor 

 function would have been preserved, if not its 

 mechanism, at least in its effects. It is there- 

 fore probable that life goes on in other planets, 

 in other solar systems also, under forms of 

 which we have no idea, in physical conditions 

 to which it seems to us, from the point of 

 view of our physiology, to be absolutely op- 

 posed. If its essential aim is to catch up 

 usable energy in order to expend it in explo- 

 sive actions, it probably chooses, in each 

 solar system and on each planet, as it does 

 on the earth, the fittest means to get this 

 result in the circumstances with which it is 

 confronted. That is at least what reasoning 



