Scientific Proceedings. 



39 



extremities also suppressed these movements. Finally immersion 

 of the lower half of the animal in a warm saline bath inhibited the 

 movements for twenty minutes and longer. When the peristalsis 

 was reestablished it could then again be inhibited by taking the 

 animal from the bath. All the various conditions referred to could 

 affect the cecum only reflexly and not directly. 



These experiments led to the inevitable conclusion that the 

 warm or cool bath, and the dissections of the skin over the abdomen 

 and the lower extremities, were various forms of more or less effec- 

 tive stimuli which caused reflex inhibition of the cecal movements. 

 The path of these reflexes could run only through the dorsal cord 

 below the cut. This conclusion was then tested by the effect 

 which the complete destruction of that part of the cord would have 

 upon the inhibitory reflexes. Cecal peristalsis is frequently abol- 

 ished by such an operation, but reappears sooner or later, and then 

 is often more marked than before the destruction. It was found 

 that after the destruction of the cord the peristalsis of the cecum 

 could not be inhibited by baths, dissections, etc. It was thus 

 established that the cecum is under the control of inhibitory influ- 

 ences invested in the cord, which can be called into action by vari- 

 ous peripheral stimulations. Such a stimulus is also exposure to 

 the air of a part of the body which is usually more or less covered. 



Under these circumstances we had reason to assume that the 

 inhibitory influence of a laparotomy might be due also to such a 

 stimulation and that it is in the nature of a reflex inhibition. But 

 after further experimenting we found that opening of the abdomen, 

 whether within a saline bath or not, unlike the other peripheral 

 stimulations, inhibits greatly the cecal peristalsis : even after the 

 destruction of the cord, only a few incomplete cecal waves appear 

 after a laparotomy. We must then conclude that direct stimula- 

 tion of the cecum caused by its exposure to abnormal conditions is 

 capable of inhibiting its movements also directly. Laparotomy 

 therefore abolishes the movements of the cecum by direct inhibition 

 assisted probably also by reflex inhibition. 



As to the cause of the movements of the cecum we found that 

 the peristalsis ceased after cutting both vagi. Furthermore stimu- 

 lation of the peripheral end of one vagus causes a tetanic contrac- 

 tion of the entire cecum, especially after destruction of the cord. 



