188 ZOOLOGICAL PHILOSOPHY 



observed on its surface, and of all the transformations incessantly- 

 undergone by the remains of these bodies. 



If we neglect this important principle, we become involved in an 

 inextricable confusion, and the general cause of observed facts and 

 objects cannot be perceived ; our knowledge of this subject then 

 remains without value, coherence or progress, so that instead of com- 

 prehensible truths we shall continue to set up those phantoms of our 

 imagination and that love of the marvellous, in which the human 

 mind takes so much deHght. 



If, on the other hand, we pay to this proposition all the attention to 

 which its importance entitles it, we shall then see that there naturally 

 flow from it a number of subordinate laws which furnish an explanation 

 of all the weU-known facts concerning existence, nature, and the various 

 faculties ; and, lastly, concerning the transformations of Uving bodies, 

 and the other more or less complex bodies that exist. 



As to the constant but variable movements of the fluids that I am 

 about to discuss, it seems quite clear that they are permanently main- 

 tained on our earth by the influence of the sunhght. SunUght is 

 incessantly causing modifications and displacements of great masses 

 of these fluids in certain regions of the earth, and forcing them to 

 xmdergo a kind of circulation and various sorts of movements, so 

 that they are able to produce all the observed phenomena. 



To establish the accuracy of this statement, I shall merely have to 

 introduce order into my citation of the facts and their relations, and 

 into the application of these principles to observed phenomena. 



In the first place it is necessary to distinguish the visible fluids, 

 which are contained in living bodies and there undergo constant 

 change and movement, from certain other subtle fluids which are always 

 invisible but which animate these bodies and are indispensable to the 

 existence of life. 



Next, when considering the effects of the activity of the invisible 

 fluids, to which I refer, on the solid, fluid and visible parts of Uving 

 bodies, we shall easily discern that the organisation of these different 

 bodies and all their movements and modifications are entirely due 

 to the movements of the various fluids occurring in these bodies ; 

 that the fluids in question have by their movements organised these 

 bodies, modified them in various ways and modified themselves also, 

 so as gradually to have produced the state of things now observed. 



In short, if we give sustained attention to the various phenomena 

 presented by organisation, and especially to those concerned with the 

 development of that organisation mainly in the most imperfect 

 animals, we shall reach the following convictions : 



1. That the entire work of nature in her spontaneous creations 



