DIGESTION IN THE SMALL INTESTINE. 403 



production of acid albumen. Dilute acetic, lactic, and phosphoric acids 

 are without apparent action on pancreatic juice, but it is precipitated by 

 metallic salts, tannic acid, iodine, and chlorine- and bromine-water. The 

 pancreatic secretion obtained from a temporary fistula in a sheep is a 

 clear, tenacious fluid, which may be drawn out in threads like the white 

 of an egg. The first portions secreted are claimed to have a slightly 

 acid reaction, which soon becomes converted into an alkaline reaction. 

 The pancreatic juices of the horse, the rabbit, the chicken, and pigeon 

 behave in a similar manner, although the pancreatic secretion of the 

 rabbit only becomes turbid when heated, and does not form a firm eoagu- 

 lum, like that of the dog. 



The pancreatic secretion differs from the other digestive fluids in 

 the large amount of solids, principally proteid in nature, which it con- 

 tains. Its specific gravity as obtained from temporary fistulae may be 

 placed at 1030 ; obtained from permanent fistulae in the dog, the pancreatic 

 secretion is a thin, watery fluid, with a specific gravity only of about 1010 

 or 1011; the lower specific gravity, of course, being clue to the smaller 

 amount of solids. In the fluid from permanent fistulae the solids amount 

 to 2 to 5 per cent., while in that obtained from temporary fistula? they 

 may rise to 10 per cent. Otherwise the fluid from permanent fistulae 

 agrees in most respects with that from temporary fistulae, it is clear and 

 colorless, alkaline in reaction, and of a sickly, saltish taste. When 

 heated it becomes turbid and may even coagulate, while it may also be 

 precipitated by alcohol, the precipitate being soluble in water. When 

 cooled down to the freezing point, it is said to deposit transparent mu- 

 cus-like coagnli. The pancreatic secretion, in contradistinction to that 

 of the gastric glands, is readily decomposed; it then acquires a faecal 

 odor and colors chlorine-water red. After standing for some time, it 

 acquires an offensive, putrefactive odor and now no longer gives a red 

 with chlorine, but with nitric acid a bright-red color is produced. This 

 reaction is evidently due to iudol. 



The pancreatic secretion contains serum-albumen, alkali albuminate, 

 fat, soaps, and sodium salts, and is thus very closely allied to blood-serum 

 in composition; but it differs from it in containing four ferments, — 

 an amylolytic, a proteolytic, one which splits fats into glycerin and fatty 

 acids, and the milk-curdling ferment. The first three of these ferments 

 are precipitated by alcohol and are found in the pancreatic secretion of 

 both carnivora and herbivora. The existence of the milk-curdling fer- 

 ment is not entirely beyond question. Pancreatic juice is also stated to 

 contain peptones, leucin, and tyrosin, but it seems probable that these 

 elements are not found in perfectly fresh juice, with the exception, may 

 he, of a trace of leucin, but are formed through the digestion of the 

 albumen in the pancreatic juice by one of its own ferments. 



