CORRELATIVE VEGETABLE AND ANIMAL PROCESSES. 65 



character. Feeling that every phase of life deserves our attentive 

 examination, I am far from insensible to the advantages attending 

 the study of its most elementary forms. But this study cannot, 

 I maintain, teach us the whole truth. There are principles ol 

 the highest importance which can only be learned by having 

 regard to the directions in which animal and vegetable life re- 

 spectively tend by comparing with another the highly differen- 

 tiated forms of animal and vegetable life, not in their minute 

 details, but in their broad general features. In my next lecture, 

 then, we shall have to consider more especially what is the nature 

 of the force exerted in the characteristic actions of vegetable and 

 animal life whether we have to do with some peculiar internal 

 vital force, or only with the ordinary external forces of nature, 

 working in a manner strictly parallel to that in which they are 

 habitually exerted in the inorganic world. 



