THE PANCREATIC JUICE. 339 



[In making experiments upon the pancreatic secretion, it is important to remem- 

 ber, that the number of pancreatic ducts varies in different animals. In man 

 there is just one duct opening along with the common bile-duct at Vater's 

 ampulla, at the junction of the middle and lower thirds of the duodenum. The 

 rabbit has two ducts, the larger opening separately about 16 inches below the 

 entrance of the bile-duct. The dog and cat have each two ducts opening 

 separately.] 



In a gland which has been exposed for some time, leucin, butalanin, tyrosin, 

 often xanthin and guanin are found ; lactic and fatty acids seem to be formed 

 from chemical decompositions taking place. 



169. The Pancreatic Juice. 



Method of obtaining the pancreatic juice. Regner de Graaf (1664) tied a 

 cannula in the pancreatic duct of a dog, and collected the juice in a small bag 

 placed in the abdomen. Other experimenters brought the tube through the abdo- 

 minal wall, and made a temporary fistula, which after some days became inflamed 

 so that the cannula fell out. To make a permanent fistula, a duodenal fistula 

 (like a gastric fistula) is made, and Wirsung's duct is catheretised with a fine tube ; 

 or the abdomen is opened (dog), and the pancreatic duct is pulled forward and 

 stitched to the abdominal wall, with which in certain cases it unites. 



The secretion obtained from a permanent fistula is a copious, slightly 

 active, watery secretion containing much sodium carbonate ; while the 

 thick fluid obtained from the fistula before inflammation sets in acts 

 far more energetically. This thick secretion, which is small in 

 amount, is the normal secretion. The copious watery secretion is per- 

 haps caused by the increased transudation from the dilated blood- 

 vessels (possibly in consequence of the paralysis of the vaso-motor 

 nerves). It is, therefore, in a certain sense, a " paralytic secretion " 

 (p. 288). The quantity varies much, according as the fluid is thick 

 or thin. 



During digestion, a large dog secretes 1-1*5 grammes of a thick 

 secretion (Cl. Bernard). Bidder and Schmidt obtained in 24 hours 

 35-117 grammes of a watery secretion per kilo, of a dog. 



When the gland is not secreting, and is at rest, it is soft, and of a 

 pale yellowish-red colour, but during secretion it is red and turgid 

 with blood, owing to the dilatation of the blood-vessels. 



The normal secretion is transparent, colourless, odourless, saltish to 

 the taste, and has a strong alkaline reaction, owing to the presence of 

 sodium carbonate, so that when an acid is added, C0 2 is given off. It 

 contains albumin and alkali-albuminate ; like thin white of egg it is 

 sticky, somewhat viscid, flows with difficulty, and is coagulated by heat 

 into a white mass. In the cold, there separates a jelly-like albuminous 

 coagulum. Nitric, hydrochloric, and sulphuric acids cause a pre- 

 cipitate; while the precipitate caused by alcohol is redissolved by 

 water. Cl. Bernard found in the pancreatic juice of a dog 8 -2 p.c. of 



