62 MEMOIRS OF 



conclusion, " that no ])ody exists which has not 

 once formed part of a body similar to itself, 

 from which it has been detached ; or, that all 

 bodies have shared the life of another body, be- 

 fore they themselves exercise vital motion ; and 

 it is even by the effect of the vital force, to 

 which they then belonged, that they have be- 

 come sufficiently developed to support an isolated 

 life." From this conclusion may be deduced 

 the axiom, " that life springs from life, and no 

 other life exists than that which has been trans- 

 mitted from one living body to another, in 

 uninterrupted succession." '* Being- 

 unable to go back to the first origin of living 

 bodies, we have no resource," says M. Cuvier, 

 " but to seek information concerning tlie true 

 nature of the forces which animate them, in an 

 examination of their composition ; that is to say, 

 of their substance, and the combination of ele- 

 ments which composes this substance or tissue. 

 For although this tissue, and this combination, 

 are in some measure the results of the action 

 of tlie vital principles which gave them being, 

 and continue to preserve tliem, it is evident that 

 these principles can only have in them their 

 source and their foundation. Thus, if the first 

 assemblage of these mechanical and chemical 



