200 PHYSIOLOGY OF ALIMENTATION., 



greatest when meat is fed (0.56 percent HC1) and lowest 

 when bread is given (0.46 percent HC1). A milk diet gives 

 an intermediate figure. 



3. The Relation of the Nervous System to Gastric Secre- 

 tion. The relation of the nervous system to the secretion 

 of the gastric juice by the stomach has for many years been 

 the subject of debate. Against the well-known clinical 

 fact that emotional states, injuries of various kinds, etc., 

 profoundly alter the activity of the stomach stood the 

 observations of a score of experimenters who were able to 

 prove no direct connection between the central nervous 

 system and the digestive organ. In 1852 BIDDER and 

 SCHMIDT published the fact that the mere sight of food 

 will call forth a secretion of gastric juice in the dog, and 

 in 1878 RICHET demonstrated on a patient gastrotomized 

 for an incurable stricture of the oesophagus that a secre- 

 tion of gastric juice occurred whenever the patient took 

 certain articles of food into the mouth. The efforts, how-} 

 ever, to show the paths of nervous connection in these cases 

 were singularly unsuccessful. In recent years, however, 

 PAWLOW and his coworkers SCHUMOW-SIMANOWSKI, JUR- 

 GENS, and SSANOZKI, in a series of beautiful experiments, 

 have been more fortunate, and, thanks to their researches, 

 we are now familiar with the cause of failure in the older 

 experiments, and may look upon the connection between 

 central nervous system and stomach as experimentally 

 proved and the nervous paths constituting this connection 

 as fundamentally established. 



The following experiment ^shows that the effect of feeding 

 is transmitted to the gastric glands through nervous channels 

 and that one of these channels is the vagus nerve. 1 A dog, 

 possessing an ordinary gastric fistula and cesophagotomized 

 as described above, 2 so that the mouth is entirely cut off 



1 PAWLOW : Work of the Digestive Glands. Translated by THOMP- 

 SON, London, 1902, p. 50. 

 * See p. 191. 



