62 HORSE-BACK RIDING. 



cles, etc., how can we refuse to admit that the red 

 globules — these other anatomical elements which are 

 in most favorable conditions for nutrition— also feed 

 and assimilate, and if in certain cases their number is 

 insufficient for the needs of the system, that new 

 ones are formed and their proportion increased ? 



We have already had occasion to refer to the role 

 filled by the hydro-carbonaceous elements of the 

 food, as well as the saccharine and fatty matter ; 

 those which in no way serve for the support or repa- 

 ration of the tissues of which they form a constituent 

 part are burned by the oxygen, in order to produce 

 heat and movement. If these aliments are in excess, 

 this excess is retained in the system, and the cellular 

 tissue is fixed upon whenever it is found as the place 

 of deposit, and thus adipose tissue is formed ; the 

 saccharine as well as fatty matters taking part in 

 its formation. But this tissue has not its own proper 

 life ; when once formed, it remains as it is, is not 

 assimilated, nor does it disintegrate ; it increases or 

 diminishes by juxtaposition or consumption, according 

 to circumstances ; it is a sort of reserve which is 

 drawn upon to supply insufficient alimentation and to 

 establish a kind of balance between the phenomena 

 of nutrition and waste. It is easy to conceive the 

 variable influence which horse-back riding might 

 exert upon the production of this tissue, according to 

 the expenditure of force which it might require and 



