176 INFLUENCE OF THE 



sham feeding was found never to give rise to a secretion, although 

 often tested. 



In addition to demonstrating that the vagus is at any rate 

 the most important efferent channel for reflex stimulation of the 

 gastric secretion, these experiments clearly demonstrate that the 

 profound and fatal effects of double cervical vagotomy carried 

 out at one operation are due to the sudden shock of complete 

 removal of vagal control from the heart, respiratory, and alimentary 

 systems, and that compensation can occur and prevent the fatal 

 result, if the operation be carried out piecemeal. 



Although sham feeding calls forth reflexly no flow of secretion 

 after the vagal fibres have been completely severed, it must not, 

 however, be hastily assumed that no secretion can occur under 

 any circumstances after the vagal fibres have been so thrown otit of 

 action, for both Pawlow and other observers, as already mentioned, 

 have observed secretion under such conditions. Whether such 

 secretion is due to stimulation through other nervous channels 

 such as the sympathetic fibres, or to absorption of chemical sub- 

 stances which cause direct chemical stimulation of the gland cells, 

 is still doubtful, but recent work goes to show that such direct 

 chemical action upon the cells is a very probable cause of secretion. 



Effects on Gastric Secretion of Stimulation of the Peripheral End 

 of the Severed Cervical Vagus. The experiment of vagus stimulation 

 yields results entirely confirmatory of those obtained by section 

 of the nerve, but similar preliminary precautions are necessary. 



After gastrotomy and cesophagotomy have been previously 

 carried out as before described, one vagus (the right) is cut through 

 as before below the cardiac and laryngeal branches, then the other 

 vagus is cut through in the neck, and after a length has been dis- 

 sected out and attached to a ligature it is left in situ, and the wound 

 closed up for a period of three to four days. The stitches are then 

 carefully removed, exposing the nerve for stimulation, and this 

 is stimulated with slow rhythmic induction shocks at intervals 

 of one to two seconds. A secretion of juice is invariably obtained 

 from the empty stomach as a result of such, stimulation. The 

 object of waiting for three or four days after section of the vagus 

 is to allow time for the cardiac fibres to degenerate, which process 

 appears to occur earlier than the degeneration of the secretory 

 fibres to the stomach. 



After obtaining positive results regarding the efferent function 



