THE SCOPE OF BIOLOGY. 103 



aspects of tlie phenomena. Recognizing the general facts of 

 multiplication without reference to their modes or immediate 

 causes, it concerns itself simply with the different rates of 

 multipHcation in different kinds of organisms, and difl'erent 

 individuals of the same kind. Generalizing the numerous 

 contrasts and variations of fertility, it seeks a rationale of 

 them in their relations to other organic phenomena. 



§ 42. Such appears to be the natural arrangement of 

 divisions and sub-divisions which Biology presents, when re- 

 garded from the highest point of view, as the Science of 

 Life — the science which has for its subject-matter, the cor- 

 respondence of organic relations, with the relations amid 

 which organisms exist. This, however, is a classification of 

 the parts of Biology when fully developed ; rather than a 

 classification of the parts of Biology as it now stands. 

 Several of the sub-divisions above named have no recognized 

 existence ; and sundry of the others are in quite rudimentary 

 states. It is therefore impossible now to fill in, even in the 

 roughest way, more than a part of the outlines here 

 sketched. 



Our course of inquiry being thus in great measure de- 

 termined by the present state of knowledge, we are com- 

 pelled to follow an order widely different from this ideal one. 

 It will be necessary first to give an account of those empiri- 

 cal generalizations which naturalists and physiologists have 

 established : arranging them rather with a view to facility 

 of comprehension than to logical sequence ; and append- 

 ing to those which admit of it, such deductive interpreta- 

 tions as First Principles furnish us with. Having done this, 

 we shall be the better prepared for dealing with the lead- 

 ing truths of Biology, in connexion with the doctrine of 

 Evolution. 



