ii.] THE PLANT AND THE ANIMAL 117 



say that the plant must have been greatly benefited, in 

 its turn, by a new division, analogous to that between 

 plants and animals. While the primitive vegetable 

 cell had to fix by itself both its carbon and its nitrogen, 

 it became able almost to give up the second of these two 

 functions as soon as microscopic vegetables came forward 

 which leaned in this direction exclusively, and even special- 

 ized diversely in this still complicated business. The 

 microbes that fix the nitrogen of the air and those which 

 convert the ammoniacal compounds into nitrous ones, 

 and these again into nitrates, have, by the same splitting 

 up of a tendency primitively one, rendered to the whole 

 vegetable world the same kind of service as the vegetables 

 in general have rendered to animals. If a special kingdom 

 were to be made for these microscopic vegetables, it might 

 be said that in the microbes of the soil, the vegetables 

 and the animals, we have before us the analysis, carried 

 out by the matter that life found at its disposal on our 

 planet, of all that life contained, at the outset, in a state 

 of reciprocal implication. Is this, properly speaking, a 

 "division of labor"? These words do not give the exact 

 idea of evolution, such as we conceive it. Wherever there 

 is division of labor, there is association and also convergence 

 of effort. Now, the evolution we are speaking of is never 

 achieved by means of association, but by dissociation; it 

 never tends toward convergence, but toward divergence of 

 efforts. The harmony between terms that are mutually 

 complementary in certain points is not, in our opinion, 

 produced, in course of progress, by a reciprocal adapta- 

 tion; on the contrary, it is complete only at the start. 

 It arises from an original identity, from the fact that the 

 evolutionary process, splaying out like a sheaf, sunders, 

 in proportion to their simultaneous growth, terms which 

 at first completed each other so well that they coalesced. 



