266 HAND-BOOK OF PHYSIOLOGY. 



An extract of pancreas made from the gland, which has been removed 

 from an animal killed during digestion, possesses the active properties of 

 pancreatic secretion. It is made by first dehydrating the gland, which 

 has been cut up into small pieces, by keeping it for some days in absolute 

 alcohol, and then, after the entire removal of the alcohol, placing it in 

 strong glycerin.- A glycerin extract is thus obtained. It is a remarkable 

 fact, however, that the amount of the ferment trypsin greatly increases 

 if the gland be exposed to the air for twenty-four hours before placing in 

 alcohol; indeed, a glycerin extract made from the gland immediately 

 upon removal from the body often appears to contain none of that fer- 

 ment. This seems to indicate that the conversion of zymogen in the 

 gland into the ferment only takes place during the act of secretion, and 

 that the gland, although it always contains in its cells the materials (tryp- 

 sinogen) out of which trypsin is formed, yet the conversion of the one 

 into the other only takes place by degrees. Dilute acid appears to assist 

 and accelerate the conversion, and if a recent pancreas be rubbed up with 

 dilute acid before dehydration, a glycerin extract made afterward, even 

 though the gland may have been only recently removed from the body, is 

 very active. 



Properties. Pancreatic juice is colorless, transparent, and slightly 

 viscid, alkaline in reaction. It varies in specific gravity from 1010 to 

 1015, according to whether it is obtained from a permanent fistula then 

 more watery or from a newly-opened duct. The solids vary in a tempo- 

 rary^ fistula from 80 to 100 parts per thousand, and in a permanent one 

 from 16 to 50 per thousand. 



CHEMICAL COMPOSITION OF THE PANCREATIC SECRETION. 



From a permanent fistula. (Bernstein.) 



Water . . . 975 



Solids Ferments : 



Proteids, including Serum Albumin, Casein, ) -, -, 



Leucin and Tyrosin, Fats and Soaps . j 

 Inorganic residue, especially Sodium Carbonate . 8 



25 



1000 



Functions. (1.) It converts proteids into peptones, the intermediate 

 product being not akin to syntonin or acid-albumin, as in gastric diges- 

 tion, but to alkali-albumin. Kiiline believes that the intermediate pro- 

 ducts, both in the peptic and pancreatic digestion of proteids, are two, 

 viz., antialbumose and hemialbumose, and that the peptones formed cor- 

 respond to these, viz., antipeptone and hemipeptone. The hemipeptone 

 is capable of being converted by the action of the pancreatic ferment 



