THE REGULATION OF GASTRIC SECRETION. 201 



from communication with the stomach, is used. In addi- 

 tion the right vagus nerve is divided below the recurrent 

 laryngeal and cardiac branches, at the time that the 

 gastric fistula is made. No* juice flows from the gastric 

 fistula in such a dog. If now sham feeding is indulged 

 in, that is to say if the dog is fed food which it swallows 

 but which never reaches the stomach, because the swallowed 

 masses drop out of the oesophageal opening in the neck, 

 a stream of gastric juice, which steadily increases in volume, 

 appears at the gastric opening within five minutes after 

 the dog is given its first food. As long as the dog is fed, 

 which may be two or more hours, often even five or six, 

 the gastric juice continues to pour out of the fistula. In 

 this way several hundred cubic centimeters of juice may 

 be collected. 



How is this effect of feeding carried from the mouth to the 

 stomach? If the food is taken away from the dog in the 

 experiment just described, the secretion of gastric juice con- 

 tinues for several hours, gradually becoming less in quantity. 

 The right vagotomy threw out of function only the pulmon- 

 ary and abdominal branches on the side operated upon while 

 the laryngeal and cardiac fibres were left intact. If now the 

 left vagus nerve, which has been laid free in the neck by 

 operation some three hours before the sham feeding is to be 

 indulged in, be carefully drawn out of the wound and divided 

 with a snip of the scissors, the pulmonary and abdominal 

 branches of both vagi are paralyzed. The preservation of 

 the laryngeal and cardiac fibres on the right side, however, 

 prevents the symptoms of cardiac and laryngeal distress 

 which follow division higher in the neck. If food be now 

 given this dog a second time, it eats greedily as before, but, in 

 sharp contrast to the preceding sham feeding, not a single 

 drop of gastric juice flows from the stomach. Indeed, never 

 again in such a double vagotomized dog, even if it lives for 

 months afterward, as some of them do, does a sham feeding 

 call forth a secretion of gastric juice. 



