RESPONSE OF DIGESTIVE ORGANS 



345 



applied at intervals of one minute. The responsive variation 

 took place by the induced galvanometric negativity of the 

 excited area. Under long-continued stimulation fatigue was 

 found to be induced, the responses becoming diminished 

 and even tending to a reversal from the normal to 

 positive. 



In order to show that the inner mucous surface is 

 relatively more excitable than the muscular coat, I next 

 subjected the two to simultaneous excitation by equi-alter- 

 nating electrical shocks. And for the sake of establishing a 



FIG. 210. Photographic 

 Record of Normal 

 Negative Responses 

 of Frog's Stomach to 

 Mechanical Stimula- 

 tion 



FIG. 211. Photographic Record 

 of Normal Negative Re- 

 sponses of Stomach of Tor- 

 toise to Stimulus of Equi- 

 alternating Electric Shocks 

 applied at Intervals of One 

 Minute 



generalisation as to the reaction of the stomach, I now took 

 a different specimen namely, the stomach of tortoise. The 

 responses in the figure (fig. 211) showed relative galvano- 

 metric negativity of the inside of the stomach. 



We have seen that fresh vegetable stomach responds by 

 normal negativity, but that, under continuous stimulation, 

 a phasic change is induced, by which response is reversed to 

 positive (cf. fig. 208). I shall next demonstrate the corre- 

 sponding effect in the animal stomach. Taking a preparation 

 of the stomach of gecko, I obtained normal responses, whose 

 direction was from the glandular internal to the muscular 



