ITS CONSTITUENTS. 113 



secreted when the gland has become inflamed in consequence of 

 the injury attendant on the operation; but since, immediately 

 after the operation, a very thin secretion is poured forth, poor 

 in coagulable matter, Bernard's explanation cannot hold good, and 

 the extreme fluidity of the juice can scarcely be referred to a 

 diseased condition of the gland in question. 



In order to obtain the pancreatic fluid, we must previously give 

 a meal to the animal to be employed, and then make an incision 

 two or three inches in length into the linea alba, for the purpose of 

 seeking the duodenum after the abdominal cavity has been opened; 

 the descending portion must then (according to Frerichs) be laid 

 open, and the mouth of Wirsung's duct sought. If, as in the 

 human subject, the bile-duct opens at the same spot as the pan- 

 creatic duct, the former, as a matter of precaution, should be tied, 

 while a small silver canula should be introduced from the intestine 

 into the latter, in order to obtain this fluid in a state of purity. 



Bernard attempted to obtain the pancreatic juice by establishing 

 a fistulous opening from Wirsung's duct ; with this view, he cut 

 through the duct near the point where it enters into the duodenum, 

 and drew the cut end towards the abdominal walls, to which he 

 attached it by sutures. 



The principal constituent of the pancreatic juice is a substance 

 resembling albumen or casein, but which is not perfectly identical 

 with albuminate of soda, with casein, or with ptyalin. It coagu- 

 lates only imperfectly when heated (probably from its containing an 

 alkali), is precipitated by acetic acid, but redissolves slowly in an 

 excess of the acid } and especially if heat be applied ; it is precipi- 

 tated from its acetic-acid solution by ferrocyanide of potassium ; 

 it is precipitated by nitric acid, and if it be then boiled, especially 

 if ammonia has been added, it assumes a deep yellow colour; on 

 the addition of chlorine-water it separates in greyish flakes ; it is 

 thrown down by alcohol, but, according to Bernard, redissolves 

 readily in water. Frerichs found 0'309f of this substance in the 

 pancreatic juice of an ass. It is to this substance that the pan- 

 creatic fluid especially owes its principal chemical and physiological 

 properties. 



Bernard found a considerable quantity, and Frerichs a smaller 

 amount (0'026-g-), of a butter-like fat. 



The organic matters soluble in alcohol only amounted to 0'015^ 

 in the pancreatic juice of the ass. 



Neither Frerichs nor Bernard could detect the presence of 

 sulpho cyanides. 



VOL. II. * 



