CHAPTER VII. 



THE ADRENAL SYSTEM, THE GENERAL MOTOR 



SYSTEM, AND THE PNEUMO- 



GASTRIC NERVE. 



THE OXIDIZING SUBSTANCE AND THE DUAL NERVOUS 

 SUPPLY OF THE ORGANS OF DIGESTION. 



THE oxidizing substance has already shown its ability to 

 subserve the physiological needs of several sets of organs; we 

 will now find it to assume similar functions in the stomach, 

 liver, heart, lungs, etc., notwithstanding the dissimilarity of 

 the functions of these organs. Here, however, the uncompli- 

 cated nervous mechanism we have described all apparently 

 carried on, as far as efferent impulses are concerned, through 

 the agency of the single cerebro-spinal motor system does not 

 suffice. A new and separate nervous supply seems to demand 

 recognition: i.e., that represented by the pneumogastric nerves. 



THE STOMACH AND ITS PHYSICO-CHEMICAL FUNCTIONS. 

 In an able review of the relationship between the nervous 

 system and the production of gastric secretion Howell 1 intro- 

 duces the following remarks: "It has been very difficult to 

 obtain direct evidence of the existence of extrinsic secretory 

 nerves to the gastric glands. In the hands of most experi- 

 menters stimulation of the vagi and of the sympathetics has 

 given negative results, and, on the other hand, section of these 

 nerves does not seem to prevent entirely the formation of the 

 gastric secretion. There are on record, however, a number of 

 observations that point to a direct influence of the central 

 nervous system on the secretion. Thus, Bidder and Schmidt 

 found that in a hungry dog with a gastric fistula the mere 

 sight of food caused a flow of gastric juice, and Richet reports 

 a case of a man in whom the oesophagus was completely oc- 

 cluded and in whom a gastric fistula was established by sur- 

 gical operation: It was then found that savory foods chewed 



1 Howell: "American Text-book of Physiology," second edition, 1900. 



(296) 



