CHAPTEE VI. 



THE CAT'S ALIMENTARY SYSTEM. 



1. IN the first chapter of this work it was pointed out that the 

 great function of sustentation * was in part brought ahout by the 

 process of alimentation and in part by secretion. 



ALIMENTATION is effected by the reception of new elements into the 

 very ultimate substance, or parenchyma, of the body. This process 

 is called assimilation, and consists in the transformation of what is 

 immediately external to the parenchyma into the parenchyma itself 

 the change of the flesh and blood of other creatures into cat-flesh 

 and cat-blood. As to this process, science can only say that it is 

 performed, the ultimate " how " of the transformation is an altogether 

 insoluble problem. 



Nevertheless certain physical properties and conditions, to be 

 adverted to shortly, help us to understand various digestive and 

 other processes which serve and lead up to the final act of assimila- 

 tion. Assimilation is always effected from a fluid medium derived 

 from the food ; but in order that the food should be able to supply 

 the body with such a medium, it must, sooner or later after its 

 reception, undergo a certain process of preparation. Thus the 

 whole process of nourishing the body by food the process of 

 alimentation is made up of three subordinate processes : (1) the 

 reception of the food, (2) its preparation, and (3) its assimilation. 



But that the life of the cat may be maintained, nutriment is by 

 no means the only requisite. It is also necessary that a certain tem- 

 perature should be maintained by a constant process of oxygenation 

 of the body's substance, which temperature may be greatly above or 

 somewhat below that of the surrounding air. Thus two classes of 

 supply are called for: (1) matter for the nutrition of the tissues,, 

 (2) matter to serve for the production of warmth. Both these 

 matters together constitute what is known as "food." 



2. As to the kinds of FOOD required by the animal we are 

 considering, it must evidently be supplied with what contains the 

 requisite materials for forming all its tissues, since all of them, even 

 the very bones, are being slowly changed and renewed piecemeal 



* See ante, p. TO. 



