284: DIGESTION. 



It Will not be necessary to discuss the opinions of the 

 earlier experimenters upon the influence of section of the 

 pneumogastric nerves in the neck on stomach-digestion ; as 

 their experiments were made in ignorance of the fact that 

 division of these nerves paralyzes the oesophagus, and ren- 

 ders the deglutition of most of the articles of food impossible. 

 After section of the nerves in the neck, acts of deglutition are 

 apparently performed, but the food collects in and distends 

 the paralyzed oesophagus, and does not pass to the stomach. 1 

 It is not surprising, therefore, that the first experiments upon 

 the influence of the pneumogastrics on digestion should have 

 been contradictory, some contending that section of the nerves 

 arrested stomach-digestion, while others maintained that the 

 nerves had little or no influence upon the stomach. It is 

 evident that without an appreciation of the effects of section 

 of the pneumogastrics upon deglutition, observations on the 

 influence of their section upon stomach-digestion would be 

 of little value. 



The recent experiments of Longet seem to show that 

 while section of the pneumogastrics in the neck undoubtedly 

 diminishes the secretion of gastric juice, the production of 

 this fluid is not entirely arrested. He states that in dogs, 

 one or two days after section of the nerves, he found the 

 lacteals filled with chyle after milk had been passed into the 

 stomach ; but it is now well known that chyle is in great part, 

 if not entirely, formed in the intestinal canal, without the inter- 

 vention of the stomach. Another experiment, howev er, is more 

 interesting. After section of the pneumogastrics, having ex- 



1 This observation, first made by Bouchardat and Sandras, in 184Y, has since 

 been confirmed by many experimenters. Bernard, after dividing the pneumo- 

 gastrics in the middle region of the neck in a dog which had a large gastric fistula, 

 gave the animal soup and sugared milk, which he ate with difficulty, and made 

 many efforts to swallow ; but the matters did not pass into the stomach, and 

 were soon regurgitated by the mouth (Legons sur la Physiologic et la Pathologie 

 du Systeme Nerveux, Paris, 1858, tome ii., p. 422). This was one of many experi- 

 ments made by Bernard with the same results (Lemons de Physiologie Experi- 

 mentale, Paris, 1856, p. 435). 



