132 ASSIMILATION AND ITS ORGANS. 



CHAPTER III. 



ASSIMILATION AND ITS ORGANS. 



Organized beings grow from, and subsist upon, matter which is 

 extraneous to themselves, and the fitting of this matter for the pur- 

 poses flf their lives, constitutes the process of digestion in a wide 

 sense. In the human body, the immediate end of digestion is the 

 blood, which is the fountain or beginning of the whole solid fabric. 

 The food, on the other hand, is the matter to be digested — to be 

 converted into blood. Looking, then, at the food as the one end, 

 and at the blood as the other, and noting the marked difference be- 

 tween the two, it may be anticipated that a long chain of means is 

 necessary before the one can become the other. Where the diver- 

 sity is great between any two things, their assimilation must be 

 proportionately gradual, and their reconcilement gently successive; 

 and the passage which either of them describes on its way to the 

 other, will probably have many joints, and lead about through 

 strange turnings to an unexpected union. Such is the case with 

 the food itself, and especially with the portions of it that are intro- 

 duced as chyle into the sanguineous current. Digestion, therefore, 

 and its organs, present us with a new element in our studies of or- 

 ganization; with the element of a series pervading the body; in 

 this case, a series terminating in the blood, and recommencing 

 from the blood ; and, as a consequence of the powers of series or 

 gradualness, with the notion of assimilation, or the likening of 

 one thing to another through a succession of changes occurring 

 in a certain order, and exhibiting a play of harmonious differences 

 and increasing likenesses running without a break through the 

 whole. Let us, then, bear in mind, for the present, that successive 

 series, and successive assimilation, are the meaning of the digestive 

 act, and that these apply to the digestive organs, as well as to the 

 digestive objects or the alimentary substances which we consume. 



