A PECULIAR PHENOMENON, THE PROLAPSUS OF THE ESOPHAGUS-STOMACH, OBSERVED IN THE VOMITING OF THE FROG

Abstract

(1) When in frogs, Rana nigromaculata and Rana catesbeiana, the mucosa close to the aditus laryngis as well as to the esophageal opening was gently stroked with a piece of absorbent cotton, there occurred abrupt and powerful contractions of the abdominal muscles, being accompanied with the prolapsus of both esophagus and stomach into the mouth wide open. As regard to the gastric motility neither augmentation nor inhibition was to be seen.
The mechanism of the prolapsus may be as follows: At first the contractions of the abdominal muscles produce a sudden rise of the abdominal pressure and this then forces the stomach upwards into the esophagus, until both esophagus and stomach are turned inside out.
From the results described above, it may be concluded that in the frog the abdominal muscles play a major role in the vomiting, whereas the stomach has no active concern with it.
(2) When 0.5 ml (Rana nigromaculata) or 5 ml (Rana catesbeiana) of the tartar emetic-Ringer solution whose concentration of the emetic was 0.05 g/ml were introduced into the stomach, not only the prolapsus but also the excitation of the movements of the stomach was elicited. The latter phenomenon should be attributed to the drug action upon the neuro-muscular apparatus of the stomach, because upon the stomach of the pithed frog the drug also exerted the excitatory action similar to that observed in the intact frog.