38 Society for Experimental Biology and Medicine. 



character. But frequently at the end of an antiperistalsis, after 

 only a short interval, the wave returns and runs from the small gut 

 towards the colon ; in other words, the antiperistalsis is often fol- 

 lowed by a peristaltic wave. The constriction is preceded by a bulg- 

 ing which is more marked than the former. The degree of the con- 

 striction (and bulging) is variable. Weaker waves sometimes do not 

 finish the course. A complete course of a wave in one direction lasts 

 from thirty to fifty seconds. The average rate of the movements 

 is about one per minute, but the rhythm is far from being regular. 



Some influences suppress cecal peristalsis. Ether applied 

 through the nose stops the movements but they return in about a 

 minute after the ether is removed. Pain, struggle and fright stop the 

 movements ; but they soon return again. The most striking effect, 

 however, is the one caused by opening the abdomen : the peristaltic 

 movements as a rule disappear completely and permanently. 



What is the cause of this complete abolition of the movements ? 

 We thought it might be due to the strong and perhaps continued 

 pain which the laparotomy causes, and tested this theory in the 

 following way. The dorsal cord of a rabbit which showed well 

 defined peristalsis of the cecum was cut at about the third vertebra. 

 As a rule, in such experiments, the peristalsis was stopped for an 

 hour and longer. After the peristalsis had been completely rees- 

 tablished the abdomen was opened. The laparotomy could now 

 cause no pain ; nevertheless it completely abolished the peristalsis, 

 as in a normal animal. 



In the course of the latter series of experiments we made the 

 observation that it was not necessary to open the peritoneal cavity 

 to inhibit the movements. Cutting through the skin in the linea 

 alba (in an animal with a cut cord) and dissecting it extensively 

 from the muscles below was sufficient to abolish all cecal peristal- 

 sis. Furthermore, the movements returned as soon as the muscles 

 were again covered by the skin, the cut edges of which were held 

 together by clamps. It looked as if the cooling and drying due 

 to the impact of the air upon the muscles above the cecum might 

 have caused the suppression of the movements. But suspending 

 the skin flaps and filling up the cavity above the muscles with 

 warm physiological salt solution did not restore the cecal peris- 

 talsis. Furthermore extensive dissection of the skin of the lower 



