172 LIFE AND DEATH. 



now understand what is the life, and at the same 

 time what is the death, of a complex being. The 

 life of the complex animal, of the metazoon, is of two 

 degrees ; at the foundation, the activity proper to 

 each cell, elementary life, cellular life ; above, the 

 forms of activity resulting from the association of the 

 cells, the life of the whole, the sum or rather the 

 complex of elementary partial lives. There is a 

 solidarity between them produced by the nervous 

 system, by the community of the general circulatory, 

 respiratory apparatus, etc., and by the free com- 

 munication and mixture of the liquids which con- 

 stitute the media of culture for each cell. We shall 

 have an opportunity of recurring to current ideas as 

 to the morphological constitution of organisms. 



