246 NERVOUS SYSTEM. 



the pneumogastrics upon the stomach and intestines, under 

 the following heads : 



1. The effects of galvanization of the nerves. 



2. The effects of section of the nerves upon the move- 

 ments of the stomach in digestion. 



3. The effects of section of the nerves upon the secre- 

 tion of the gastric juice and the chemical processes of di- 

 gestion. 



4. The influence of the nerves upon the small intestine. 



Effects of Galvanization. Bichat, in the first edition of 

 his great work on general anatomy, published in 1801, states 

 distinctly that irritation of the pneumogastrics produces con- 

 traction of the muscular coat of the stomach : "I remark 

 nevertheless that irritation of one of the vagus nerves, or of 

 both, immediately causes the stomach to contract, as occurs 

 in a voluntary muscle the nerve of which is irritated. It is 

 necessary, in performing this experiment, to open the abdo- 

 men of the living animal, and then to irritate the eighth 

 pair in the cervical region, in order to have under the eyes 

 the organ that is made to contract." 1 This fact was con- 

 firmed by Tiedemann and Gmelin, 2 and many others, but 

 was denied by M tiller. 3 In more recent experiments, the 

 effects of galvanization of the pneumogastrics upon the 

 movements of the stomach are unquestionable. Longet 

 shows that the stomach contracts as a consequence of irrita- 

 tion of the nerves, not instantly, but after the lapse of five 

 or six seconds. He explains some of the contradictory re- 

 sults obtained by other observers by the fact that these con- 

 tractions are very marked during stomach-digestion, while 

 they are wanting " when the stomach is entirely empty, 



1 BICHAT, Anatomic generale, appligitee d la physiologic et d la pathologic, 

 Paris, 1801, seconde partie, tome iii., p. 360. 



2 TIEDEMANN ET GMELIN, Recherches experimentalcs, physiologiques et chimiques, 

 Mir la digestion, Paris, 1827, premiere partie, p. 374. 



8 MULLER, Elements of Physiology, London, 1840, vol. i., p. 530. 



