THE ACTIVATION OF PANCREATIC JUICE

I. There are two different kinds of activation of pancreatic juice: ( a ) the formation of trypsin by the action of the ferment enterokinase; ( b ) activation in the absence of enterokinase, in which calcium is intimately concerned, and which is, as far as one can tell, a chemical process. II. It is conclusively proved by the temperature method that spontaneous activation may occur when no enterokinase or ferment of any kind is present; and that the activation of the juice is really spontaneous in so far that it is caused by the juice, or some of its constituents only, and not by any external agent. III. The spontaneous activation of the juice is dependent on the presence of calcium salts in the juice, as well as on some other factor which is destroyed by decalcification. Hence it is not possible, after decalcification, to activate by further addition of calcium salts. Excess of calcium salts, on the other hand, may inhibit activation. IV. ( a ) The spontaneous activation of juice is very much accelerated by heat. ( b ) The calcium reaction of juice is in no way affected by change of temperature, within broad limits, e.g. under 40°C. ( c ) Activation of the juice by enterokinase is very much retarded by raising the temperature to 350°C., on account of the destruction of this ferment by the heat in an alkaline medium. On the other hand, in a neutral medium the action of enterokinase, like that of all other ferments, is quickened by rise of temperature.