200 PHYSIOLOGICAL CHEMISTRY. 



more correctly, three zymogens, which will be described later. We 

 also find in this gland nuclei n, leucin (butalanin), tyrosin (not in 

 the perfectly fresh gland), xanthin, 1-8 p. m., hypoxanthin, 3-4 

 p. m., guanin, 2-7.5 p. m. (all figures are calculated for the dried 

 substance, KOSSEL), adenin, inosit, lactic acid, volatile fatty acids, 

 fats, and mineral substances. According to the investigations of 

 OIDTMAN, the human pancreas contains 750-760 p. m. water, 240- 

 250 p. m. organic and 3.7-9.5 p. m. inorganic substances. 



Pancreatic Juice. This secretion may be obtained by adjusting 

 a fistula in the excretory duct, according to the methods suggested 

 by BERNARD, LUDWIG, and HEIDE^HAIN. If the operation is 

 performed with sufficient rapidity and dexterity on an animal which 

 has been well fed a few hours before, there is obtained from the 

 fistula, as a rule, immediately after the operation (temporary 

 fistula) a secretion rich in solids, viscid, very active, and which may 

 be considered as normal pancreatic juice. Ordinarily, however, the 

 gland becomes diseased in a few hours or days after the operation, 

 and the secretion which then flows out of the fistula (permanent 

 fistula) is more liquid, deficient in solids, and in certain other 

 respects different from the secretion obtained immediately after the 

 operation. Still a permanent fistula may also sometimes yield a 

 normal secretion for a long time (HEIDENHAIK), while the tem- 

 porary fistula in careless operations may give no secretion or only 

 an abnormal juice. 



In herbivora, such as rabbits, whose digestion is uninterrupted, 

 the secretion of the pancreatic juice is continuous. In carnivora it 

 seems, on the contrary, to be intermittent and dependent on the 

 digestion. During starvation the secretion almost stops, but com- 

 mences again after partaking of food. Food seems to act in a two- 

 fold manner. First, it may, with the more abundant flow of blood 

 during the digestion, which is seen by the red color of the gland, 

 convey a larger quantity of nutritive material to the gland, and 

 thereby cause the secretion of a juice rich in solid nutritive bodies. 

 In another way the food may also, by the irritation which it pro- 

 duces on the mucous coat of the stomach and the duodenum, cause 

 an increased secretion. That the food indeed acts in these two 

 ways follows from the fact that other substances, such as ether, 

 may also cause a secretion of pancreatic juice, but by this means 



