INTRODUCTION. 7 



what we have said, it follows, that life can be enjoyed by organized bodies 

 only. 



Organization, then, results from a great variety of arrangements, which 

 are all conditions of life ; and it is easy to conceive, that if its effect be to 

 alter either of these conditions, so as to arrest even one of the partial mo- 

 tions of which it is composed, the general movement of life must cease. 



Every organized body, independently of the qualities common to its tis- 

 sue, has a form peculiar to itself, not merely general and external, but ex- 

 tending to the detail of the structure of each of its parts ; and it is upon 

 this form, which determines the particular direction of each of the partial 

 movements that take place in it, that depends the complication of the ge- 

 neral movement of its life — it constitutes its species and renders it what it 

 is. Each part co-operates in this general movement by a peculiar action, 

 and experiences from it particular effects, so that in every being life is a 

 whole, resulting from the mutual action and re-action of all its parts. 



Life, then, in general, pre-supposes organization in general, and the life 

 proper to each individual being pre-supposes an organization peculiar to 

 that being, just as the movement of a clock pre-supposes the clock; and 

 accordingly we behold life only in beings that are organized and formed to 

 enjoy it, and all the efforts of philosophy have never been able to discover 

 matter in the act of organization, neither per se, nor by any external 

 cause. In fact, life exercising upon the elements which at every moment 

 form part of the living body, and upon those which it attracts to it, an ac- 

 tion contrary to that which, without it, would be produced by the usual che- 

 mical afl&nities, it seems impossible that it can be produced by these affini- 

 ties, and yet we know of no other power in nature capable of re-uniting 

 previously separated molecules. 



The birth of organized beings is, therefore, the greatest mystery of the 

 organic economy and of all nature : we see them developed, but never be- 

 ing formed; nay more, all those whose origin we can trace, have at first 

 been attached to a body similar in form to their own, but which was deve- 

 loped before them — in a word, to a parent. So long as the offspring has 

 no independent existence, but participates in that of its parent, it is called 

 a germ. 



The place to which the germ is attached, and the cause which detaches 

 it, and gives it an independent life, vary ; but this primitive adhesion to a 

 similar being is a rule without exception. The separation of the germ is 

 called generation. 



Every organized being reproduces others that are similar to itself, other- 

 wise, death being a necessary consequence of life, the species would be- 

 come extinct. 



Organized beings have even the faculty of reproducing, in degrees vary- 



