160 THE WORK OF THE DIGESTIVE GLANDS. 



only just begun. The application of the usual tests for ferment action 

 namely, destruction by boiling, activity in very small quantities, and 

 so on convinced us that in this case we were dealing in point of fact 

 with a ferment. We had, therefore, discovered a ferment, not for this 

 or that constituent of the food, but a FERMENT OF OTHER FERMENTS. I 

 propose to give it the name of Enterokinase to distinguish it from 

 other possible ferments of a similar kind. 



I may renmrk that the activity of the fat-splitting and amylolytic 

 ferments of the pancreatic juice is promoted equally well, both by the 

 secretion of the duodenum and by that of other portions of the small 

 intestine. The proteid ferment, on the contrary, is most increased by 

 the duodenal secretion. Our preliminary experiments therefore afforded 

 ground for hoping that in the study of the chemical action of the three 

 united fluids, namely, the pancreatic juice, the bile and the succus 

 entericus, a wide field was open to us in which we could study the most 

 subtle problems of adaptation on the part of these combined fluids to 

 the substances undergoing digestion. 



The secretion of the succus entericus seems also to follow laws of its 

 own, in so far that it is a purely local secretion. A flow follows only 

 in that segment of the alimentary canal which is immediately stimulated. 

 This fact has obviously a rational significance. Since the food mass, 

 especially in some cases, moves very slowly forwards along the digestive 

 canal, a secretion of succus entericus would be unnecessary at a place 

 where the food could only arrive some minutes or even some hours 

 later. 



Why the mechanical stimulus should here prove to be efficient, 

 was a puzzling question which long troubled us. From cur previous 

 experience the fact appeared quite extraordinary. Wherein lay the 

 specific nature of the stimulus ? A review of all the facts, of everything 

 that we had learned in connection with the other secretions, taught us 

 to steadfastly believe in this specific character, and the belief has not 

 deceived us. Indeed, the two fundamental features of digestive activity, 

 namely, adaptivity and response to a specific stimulus, stood out more 

 prominently in connection with the succus entericus than with any 

 other fluid. Thus, it was found (experiments of Dr. Sawilsch) that 

 when a tube was introduced into the fistula, and the succus entericus 

 afterwards collected in separate portions, the amount of kinase in the 

 secretion became steadily less and less ; obviously the tube excited a 

 secretion mainly of water and not of kinase. For the latter, a specific 

 stimulus had to be sought, and this stimulus was ultimately 

 discovered in the ferment constituents of the pancreatic juice. 

 When the secretion produced in an isolated loop of intestine under the 

 stimulus of the cannula is studied for several consecutive hours, and 



