382 HANDBOOK OF PHYSIOLOGY. 



CHEMICAL COMPOSITION OF PANCREATIC JUICE (C. SCHMIDT). 



From a dog. Recent fistula. Permanent fistula. 



Water 900.76 080.45 



Solids 1)9.24 19.55 



Organic substances . . . . .00.44 12.71 



Ash 8.80 6.84 



Sodium carbonate 0.58 3.31 



Sodium chloride 7.35 2.50 



Calcium, magnesium, and sodium phosphates 0.53 0.08 



Functions. ('.) By the aid of its proteolytic or proteid-splitting 

 enzyme, trypsin, it converts proteids into prcteoses and peptones, but the 

 process is both more rapid and more complete than in gastric digestion, 

 so that, in the final result, the peptones are greatly in excess of the pro- 

 teoses. The proteids pass through the same preliminary stages as in 

 gastric digestion, being split at first into alkali-albumin, then into 

 primary proteoses, both proto-proteose and hetero-proteose, and then 

 into deutero-proteose; but the first stages are so transient that it is 

 difficult to detect either the alkali-albumin or primary proteose. For 

 this reason some investigators deny the existence of either alkali-albumin 

 or primary proteose in pancreatic digestion. The deutero-albumoses 

 are easily demonstrated in the earlier stages, but become very scanty 

 later. Anti-albumid is found as a side product in artificial digestion, 

 but is not present in normal digestion. Trypsiu also has the power of 

 splitting a certain proportion of peptones into simpler bodies, such as 

 leu tin* or amido-caproic acid, tyrosin or paroxyphenyl-amido-propionic 

 acid, lysin, lysatinin, tryptophan, and some other bodies. Leucin and 

 tyrosiu have been found in the intestinal contents, so that this destruc- 

 tion of hemipeptone must take place to a certain extent within the body 

 as well as in artificial tryptic digestion. 



In laboratory experiments only about one-half of the peptones can 

 be changed in this way. The more stable portion which cannot be 

 changed is usually known as antipeptone, though it is as yet undecided 

 whether this term represents a single chemical substance or a complex of 

 various bodies; recent experiments, however, tend to show that it repre- 

 sents a mixture of much simpler substances than peptone. There are 

 several theories as to the reason or use of this change into leucin, tyrosin, 

 etc. One of the most plausible is that it saves the body from needless 

 work when too much proteid food has been taken ; the breaking down in 

 the intestine of bodies only slightly removed from urea relieves the liver 

 and other glandular organs from the strain of converting an excess of ab- 

 sorbed proteid material into a form in which it can be excreted. Another 

 theory is that leuciu, tyrosin, etc., are essential for the physiological 



