288 CONCOCTION. [Lesson xxxvn 



T- ' ' ' = f = 



sorts of liquors. It receives two kinds of bile 

 the one, thick, yellow, and extremely bitter, from 

 the gall-bladder; the other, scarcely bitter, or yel- 

 low, but in a much larger quantity, from the liver. 

 The third liquor that falls here upon the food, 

 issues plentifully from a large glandular substance, 

 called the Pancreas or sweet-bread, and is a limpid 

 mild fluid, like the saliva, which serves to dilute 

 and sweeten what may be too thick and acrimo- 

 nious. The two saponaceous biles resolve and 

 attenuate viscid substances; incorporate oily fluids 

 with aqueous ones, making the whole mixture 

 homogeneous ; and by their penetrating and deter- 

 gent qualities render the chyle fit to enter the 

 lacteal veins, into which it is conveyed, partly by 

 their absorbent nature, and partly by the peristaltic 

 motion of the intestines. 



If we now consider the change which our ali- 

 ment has undergone, in the mouth, gullet, and 

 stomach, together with the large quantity of bile, 

 and pancreatic juice poured upon it in the intes- 

 tines : and if we reflect also on the incessant ac- 

 tion of the muscles, blending, churning, and 

 incorporating the whole, we shall readily perceive 

 that their united agency must alter the flavours 

 and properties of the different kinds of food, in 

 such a manner as to bring the chyle nearer in its 

 nature to our animal juices, than to the original 

 substances from which it was formed. Our food, 

 thus changed into chyle, constitutes the first stage 

 of Concoction; and we shsll find the same assi- 

 milation carried on through the second. 



Th 



