8 IIORSE-BACK RIDING. 



phenomena of his species ; and from the reciprocal 

 and harmonious reaction of mind and matter re- 

 sults his perfect development. 



For a long time physiologists have considered the 

 various phenomena, which are the manifestations of 

 organic life, to be produced by some hidden forces. 

 These forces have received various names, the most 

 prominent among them being bone (Van Helmont), 

 soul (Stahl), and vital principles (Bartles). A very 

 slight consideration of the meaning to be attached to 

 the terms vital force and vital principle will convince 

 us that they both mean one and the same thing, and 

 that under these two names modern physiologists 

 designate that force residing in the individual upon 

 which depend the phenomena or attributes by 

 means of which life manifests itself. This is the 

 force which, Avhen acting upon matter, vivifying it, as 

 we may say, causes it to take a particular form, which 

 presides over the function of nutrition, which per- 

 petuates the various races, which forces organized 

 matter to take on a predetermined specific form. 



The principle of life is not a question for us now to 

 discuss. The arguments on that point, though always 

 in the mouths of men, are yet very far from being 

 settled. Two conflicting opinions stand confronting 

 each other. The first, held by Zenon, Epicureus, 

 Cabanis, Broussais, etc., represents matter active in 

 and of itself, sole cause of all the phenomena of 

 nature ; and to these philosophers life is but an effect 



