WATER, AN EXCITANT OF GA8TRIC SECRETION. 95 



the vagi nerves, which suppresses all psychic influence upon the 

 gastric glands, does not in the least prevent the stimulating effect 

 of water upon them; nor could the secretory fibres of the sympa- 

 thetic, whose existence is almost certain, take the place of the vagi in 

 transmitting the psychic impulses. We have, therefore, before us the 

 interesting fact, that secretory fibres which course in different nerves 

 have in all probability different physiological duties to perform. But 

 why does water act as an exciter ? The fluid needs no digestive juice. 

 The chief reason, I believe, lies in this : that in cases where, for example, 

 no psychic juice is present, the impulse to the secretory work of the 

 stomach may be given by means of water. Water is very widely 

 distributed in nature, and the instinct for it thirst is even more 

 pressing and persistent than the desire for solid food. If a dry meal 

 be eaten without appetite, thirst will compel one to drink water after- 

 wards, and this fluid suffices to ensure the beginning and continuation 

 of the secretory work of the glands. That the .secreted juice at times, 

 when water alone is drunk, remains without finding a use, is of no 

 consequence, and cannot weigh as a serious objection against our 

 explanation. For, in the fiivt place, as we have already seen, the secre- 

 tion caused by water is not of itself important ; and secondly, even the 

 free flow of psychic juice may at times be secreted when there is no 

 use for it for example, when, with an empty stomach, we have a 

 keen desire for eating, but are unable to do so for some reason or 

 other. But this does not make us doubt the great physiological import- 

 ance of the psychic juice. 



The stimulating influence of water must be kept in view when we are 

 testing the effect of any other substance upon the gastric glands. We 

 must always compare the results produced by a watery solution of the 

 given substance with the effects of a like quantity of water alone. 



After water, a number of different inorganic substances, which 

 are constituents of the food or are employed in the practice of medicine, 

 were also tested. Thus, the constituents of meat ash, chloride 

 and bicarbonate of sodium, and hydrochloric acid were repeatedly 

 brought under investigation (Dr. Chigin), till we were fully satisfied 

 of the certainty and accuracy of the results. It appeared that not one 

 of these substances, with the exception of bicarbonate of sodium, exer- 

 cised the least influence on the secretory work of the stomach that is 

 to say, their watery solutions had precisely the same effect as water 

 itself. To sodium bicarbonate an inhibitory influence must be ascribed. 

 Not one of the soda solutions (varying from 0*05 to 1 per cent, strength), 

 when brought in quantities of 1 50 c.c. into the large stomach, were able 

 to expel even a single drop of juice from the small cavity. At most 

 a little mucus escaped. Hence the presence of sodium bicarbonate 



