LECTURE V. 



PERIOD OF OCCURRENCE AND IMPORTANCE OF THE 

 PSYCHIC OR APPETITE JUICE IN THE SECRETORY 

 WORK OF THE STOMACHTHE INEFFICIENCY OF 

 MECHANICAL STIMULATION OF THE NERVOUS 

 APPARATUS OF THE GASTRIC GLANDS. 



The psychic secretion is the normal commencement, in the majority of 

 cases, of secretory activity on the part of the gastric glands. If the 

 meal be subdivided and administered at intervals, the psychic juice 

 appears each time Demonstration of "appetite juice" in a dog with an 

 isolated gastric cul-de-sac. The work of the gastric glands if appetite 

 juice be avoided by introducing food through a gastric fistula unper- 

 ceived by the animal Digestion of flesh by the stomach with and without 

 sham feeding Duration of the secretory influence of sham feeding After 

 the cessation of the psychic effect, how is the secretory work of the stomach 

 maintained? Experiments to prove the ineffectiveness of mechanical stimu- 

 lation : excitation of the mucous membrane by means of a glass rod, a 

 feather, a puff of sand, and by rhythmic dilatation of an india-rubber ball 

 Contact between the food and the stomach-wall may indirectly call the 

 activity of the glands into play by awakening or increasing the desire for 

 food. 



GENTLEMEN, On the last occasion we made ourselves acquainted with 

 the first normal impulse which, in the natural course of events, calls into 

 activity the innervation apparatus of the gastric glands. This impulse 

 is a mental one, and consists in a passionate longing for food, that 

 which in everyday life, and in the practice of the physician, is called 

 "appetite," and which everybody, both medical and lay, endeavours care- 

 fully to promote. We may now venture to say explicitly, APPETITE is 

 JUICE, a fact which at once displays the pre-eminent importance of the 

 sensation. Medical science endeavours to assist the debilitated stomach 

 by introducing the active constituent of gastric juice pepsin from 

 without, or by prescribing other remedies believed to promote its 

 secretion. It is, however, of interest to follow our experimental 

 investigation still farther. What position is to be assigned to the 



