252 ZOOLOGICAL PHILOSOPHY 



established by these two orders of things are always combined in living 

 bodies, though not in the same parts at the same time, and since they 

 follow each other in turn as a result of the incessant changes wrought by 

 the vital movements, there does exist in these bodies throughout Hfe a 

 perpetual struggle between those conditions which make the vital 

 force synthetic, and those others, always being renewed, which make it 

 analytic. 



Before developing this doctrine, let us consider several principles 

 which should not be lost sight of. 



If all the activities of hfe, and all the organic phenomena, without 

 exception, are merely the result of the relations existing between the 

 containing parts in an appropriate state and the contained fluids 

 set in movement by a stimulating cause, the effects named below must 

 necessarily ensue from the existence of this order and state of things 

 in a body. 



In point of fact as a result of these relations and of the movements, 

 actions and reactions produced by the stimulating cause, there do 

 incessantly occur the following events in all bodies possessing an active 

 life: 



1. Changes in the state of the containing parts of this body 

 (especially the most supple), and in that of its contained fluids ; 



2. Keal losses in these containing parts and contained fluids, caused 

 by the changes wrought in their state or nature ; losses which give 

 rise to deposits, dissipations, evacuations and secretions of substances, 

 some of which can be no more utilised, while others may be turned 

 to various purposes ; 



3. The constant need for making good the losses undergone ; a 

 need which perpetually requires the introduction of new and suitable 

 substances into the body, and which is actually assuaged by food in 

 animals, and by absorptions in plants ; 



4. Lastly, various kinds of combinations, which the conditions 

 and results of the various activities of hfe are alone able to bring 

 about ; combinations which, but for these results and conditions, 

 would never have occurred. 



Thus throughout hfe in a body, combinations are incessantly formed 

 which are as heavily loaded with principles as the organisation of the 

 body is adapted for ; and among them also, decompositions are always 

 taking place, and ultimately destructions which perpetually give rise 

 to the losses experienced. 



This is the main positive fact, that is always confirmed by a close 

 observation of vital phenomena. 



Let us now return to the study of the two important principles of 

 which I spoke above, and which furnish us to some extent with the key 



