428 OF FOOD, AND THE DIGESTIVE PROCESS. 



tion, into the bloodvessels of the walls of the stomach ( 462) : and in part to 

 the successive escape of the reduced portions through the pyloric orifice ( 429). 

 The importance of the previous state of minute division and incorporation with 

 aqueous fluid, in promoting the action of the gastric solvent, has been already 

 dwelt on ( 424). 



452. Although the Chyme, or product of gastric digestion, which escapes 

 through the pyloric orifice into the duodenum, contains much azotized matter 

 in a state of actual solution, a considerable proportion of it is still only reduced 

 and mechanically suspended; and the solution of the latter is continued in the 

 intestinal tube. In the farinaceous part of the food, moreover, no great amount 

 of change has hitherto been effected; and the sugar which has been generated 

 by the agency of the salivary ferment, is probably absorbed into the bloodves- 

 sels nearly as fast as it is formed. In the condition of the fatty matters, no 

 important change is perceptible, except such as results from the solution of the 

 membranes, &c., that enclosed them. Hence we see that the process of Diges- 

 tion, so far from being completed in the stomach, has only been carried one 

 stage further. Soon after its entrance into the Duodenum, the chyme is sub- 

 jected to the ac^ns of the bile, the pancreatic fluid, and that secretion from 

 the glandules in the walls of the intestine itself (probably proceeding chiefly, 

 however, from the glands of Brunner, 235), which is known under the name 

 of the "succus entericus." Of these, the Pancreatic fluid will be first noticed. 

 The structure of the Pancreas closely resembles that of the Salivary glands 

 ( 436) ; for it consists of racemose clusters of secreting follicles, which form 

 the terminations of the ramifying divisions of the duct; each cluster with its 

 bloodvessels, lymphatics, nerves, and connecting tissue, forming a lobule ; and 

 the separate lobules being held together by areolar tissue, as well as by the 

 vessels and ducts. Like the salivary glands, moreover, its development com- 

 mences by a sort of budding-forth of the alimentary canal at a particular spot, 

 upon which a mass of cells has previously accumulated. The secretion of this 

 gland strongly resembles saliva in its general appearance, being clear and color- 

 less, slightly viscid, and alkaline in its reaction; it contains, however, a larger 

 proportion of solid matter, its specific gravity being 1008 or 1009; and the 

 nature of its animal principle is not precisely the same. The following is Prof. 

 Frerichs' analysis of the pancreatic fluid of the Ass. 



Water 986.40 



Solids 13.60 



Fat . . . -W i . . s ? .*, .*;-...,' ;',- v 0.26 



Alcohol-Extract. . v ..; ,..;.>::, r .-, \ <...* *,?..<.; n 0.15 



Water-Extract, albuminous k - ,,, ; rf . . + ..,; y, 3.09 



(Chlorides ) 



Phosphates I . ' . "* . . 8.90 

 Sulphates ) 

 Carbonate and phosphate of lime and magnesia . . . .1.20 



1000.00 13.60 



The albuminous "ferment" is not perfectly coagulable by heat, and when pre- 

 cipitated by alcohol it redissolves readily in water; it is precipitated by sul- 

 phuric, nitric, and concentrated hydrochloric acid, and by the metallic salts ; 

 and when thrown down by these, or by heat, it is redissolved by alkalies. It 

 is also precipitated by acetic acid; but it slowly redissolves in an excess of the 

 reagent, and on the application of heat ; and from this solution it is precipitated 

 by ferrocyanide of potassium. When boiled with ammonia, it assumes an in- 

 tense yellow color. The readiness with which this substance undergoes change 

 is indicated by the rapidity with which the pancreatic fluid passes into decom- 



