THE PANCREATIC JUICE 793 



to fresh pancreatic juice, the calcium being in such a quantity as 

 to suffice to combine with, all the carbonate present in the juice, 

 complete activation of the juice occurs within a couple of days, no 

 further increase in its digestive powers being obtained on subsequent 

 addition of enterokinase. It has been suggested that the action of 

 calcium is in some way to assist in the production of an enterokinase 

 from some precursor of this body akeady present in the juice. There 

 is no doubt, however, that the two kinds of activation of the juice 

 are entirely independent. Enterokinase will activate the juice in 

 the entire absence of any lime salts, e.g. in the presence of excess of 

 sodium fluoride or of ammonium oxalate. After lime salts have 

 activated a juice no enterokinase can be found in the activated juice, 

 i.e. it has no power of activating fresh portions of pancreatic juice. 

 The mode in which calcium salts act is not at present understood. 

 If they have once been removed from the pancreatic juice it is not 

 possible to reinduce activation by the subsequent addition of excess 

 of lime salts. We must therefore conclude that the lime salts are 

 present in some form of combination which is destroyed by decalci- 

 fication, the change involved in the destruction being irreversible, 

 so that the original condition cannot be restored by the subsequent 

 addition of lime salts. It is not likely that this calcium activation 

 plays any part in the normal processes of digestion. For its com- 

 pletion it needs twelve to sixteen hours, whereas the enterokinase 

 present in the succus entericus will effect the activation of the juice 

 within a few minutes. The action of calcium salts at present must 

 be regarded as merely of theoretical significance. 



THE ACTION OF PANCREATIC JUICE ON MILK 



On the addition of pancreatic juice to milk a clot is produced 

 which speedily redissolves. If re-solution takes place too rapidly 

 the production of a formed clot may be missed. In every case, 

 however, on heating the milk a few minutes after the addition of 

 the trypsin a clot is obtained. How far this action is to be ascribed 

 to the proteolytic ferment trypsin, or how far it is due to the 

 presence of a free rennet -like ferment in the juice, is not yet definitely 

 settled. Since the rennet action is parallel to the proteolytic activity 

 of the juice, it is probable that we must regard the clotting of milk 

 as the first stage in its proteolysis. 



THE ACTION OF PANCREATIC JUICE ON 

 CARBOHYDRATES 



The pancreatic juice, as well as fresh extracts of the pancreas 

 itself, contains a strong amylolytic ferment, diastase, amylase, or 

 amylopsin. If a few drops of pancreatic juice be added to a 1 per 



