UNORGANISED FERMENTS 269 



alkalies have a powerful destructive action upon it, even 

 in very small quantities, and carbonate of sodium, calcined 

 magnesia, etc., act the same, though in a lesser degree. 

 Heat readily destroys chymosin, especially if acid. 



4. The Ferments of the Pancreas. — Pancreatic juice is a more 

 or less viscid liquid, invariably alkaline and readily putrefy- 

 ing. Alcohol causes an abundant precipitate, which carries 

 down the ferments it contains. These are at least three : 



1. A proteolytic ferment acting in neutral or alkaline 

 solutions. 



2. A diastatic ferment, similar to that in the saliva. 



3. A fat - decomposing ferment which emulsifies and 

 decomposes fats into glycerine and fat acids. 



The proteolytic ferment (trypsin) does not exist in the 

 perfectly fresh pancreas, but is formed in an hour or two's 

 time. It may be extracted by digesting with water, pre- 

 cipitating with alcohol, re-dissolving, re-precipitating, and 

 digesting in absolute alcohol. The precipitate is treated 

 with water, acetic acid added, filtered, sodium hydrate 

 added to slight alkalinity, filtered, concentrated at 40° C, 

 filtered, and precipitated with alcohol. If necessary, it is 

 purified by dialysis. 



Trypsin acts most readily in a solution containing about 

 1 per cent, of NajCO,, that being the strength of the juice. 

 It acts in neutral and in very slightly acid solutions, but 

 contact with warm acid fluids gradually decomposes it. 



The diastatic ferment is obtained by treating the pancreas 

 by extracting with glycerine, chloroform-water, solution of 

 borax with boracic acid, brine, etc. By these methods 

 solutions of the two ferments are obtained, which may be 

 precipitated by alcohol. The ferment acts most readily on 

 starch at from 30° to 40° C. One part of the diastase is 

 said to be able to convert 40,000 parts of starch into sugar 

 and dextrin. 



