CHAPTER I. 



PRELIMINARY. 



§ 109. In the foregoing Part, we have contemplated the 

 most important of the generalizations to which biologists 

 have been led by observation of organisms; as well as some 

 others which contemplation of the facts has suggested to me. 

 These Inductions of Biology have also been severally glanced 

 at on their deductive sides; for the purpose of noting the 

 harmony existing between them and those primordial truths 

 set forth in First Principles. Having thus studied the lead- 

 ing phenomena of life separately, we are prepared for study- 

 ing them as an aggregate, with the view of arriving at the 

 most general interpretation of them. 



There is an ensemble of vital phenomena presented by each 

 organism in the course of its growth, development, and decay ; 

 and there is an ensemble of vital phenomena presented by the 

 organic world as a whole. IS'either of these can be properly 

 dealt with apart from the other. But the last of them may 

 be separately treated more conveniently than the first. What 

 interpretation we put on the facts of structure and function 

 in each living body, depends entirely on our conception of .the 

 mode in which living bodies in general have originated, To 

 form some conclusion respecting this mode — a provisional if 

 not a permanent conclusion — must therefore be our first 

 step. 



We have to choose between two hypotheses — the hypo- 

 thesis of Special Creation and the hypothesis of Evolution. 



415 



