Z METAMORPHOSES OF MAN 



wliicli the corresponding weights were placed will be 

 depressed. From this result we are forced to con- 

 clude that, in every moment of their lives, plants, 

 animals, and even man himself, lose a portion of their 

 substance. In order to preserve life, these constant 

 losses must be incessantly repaired; and hence it 

 results that the beings included in the two kingdoms 

 must be supplied with food. Animals and plants, 

 then, borrow from the external world certain materials, 

 which, when properly elaborated, fill up the gap that 

 is being constantly made. During the early life of 

 all organized beings, and during the entire life of a 

 certain number of them, the quantity of matter fixed 

 by the organism exceeds to some extent that which 

 is rejected, and from this the growth of the individual 

 results. In the adult these quantities are usually 

 exactly equal : hence his stationary condition. In 

 the aged, finally, the force of decomposition gains the 

 upper hand. But whether the loss and gain balance 

 each other, or whether the one or the other is in 

 excess, the double movement of arrival and departure 

 never ceases. 



Here a very important problem presents itself, 

 which it is difficult enough to solve. Does the vital 

 stream (to employ the appropriate expression) hold 

 the entire organism under its control, or are there 

 certain portions beyond its sphere of government ? 



This latter hypothesis has been, and is still, perhaps 

 that of some physiologists who have urged to its 

 greatest lengths, the comparison between living bodies 

 and the apparatus used in our laboratories, and for in- 

 dustrial purposes. According to them, even the human 

 body is something like a locomotive. The solid parts 



