PHYSIOI.OGICAL lNT.liGKA.lJON IN PLANTS. 281 



direct action of the moist earth, must conduce to an increased 

 current of the liquid evaporated from the one and supplied 

 by the other — must serve, therefore, to aid the formation of 

 sap-channels in the ways already described ; that is — must 

 serve to develop the structures through which mutual aid of 

 the parts is given : the additional differentiation tends imme- 

 diately to bring about the additional integration. Con- 

 trariwise, it is obvious that an interdependence such as we 

 see between tte secretion of honey and the fertilization of 

 germs, or between the deposit of albumen in the cotyledons 

 of an embryo- plant and the subsequent striking root, is a kind 

 of integration in the actions of the individual or of the 

 species, which no differentiation has a direct tendency to 

 initiate. Hence we must regard the total results as due to a 

 plexus of influences acting simultaneously on the individual 

 and on the species : some chiefly affecting the one and some 

 chiefly affecting the other. 



