CHEMICAL MECHANISMS OP SECRETION 299 



a discharge of correspondingly different efferent stimuli to the 

 gland cells, as also to the variation in amount and kind of psychical 

 stimulation by the variation to sight and smell of different sorts 

 of food. 



This explanation was given, however, before the days of Bayliss 

 and Starling's discovery of the chemical excitants to secretion, 

 and the question now remains an open one whether the nervous 

 system has anything, and if so how much, to do with the adapta- 

 tion of secretion to food, and with the characteristic variations 

 above described of rate and progress of secretion with the nature 

 of the food. 



In the light of our new knowledge the whole subject of secretion 

 stands ripe for investigation, and is rich in promise of new addi- 

 tions to our knowledge of the highest value to physiology and to 

 medicine. 



