Royal Society. 301 



consistence of the food in some animals, and thus shows a dependence 

 of this physical process on a previous one. 



A solitary experiment is adduced to show that, as in the healthy 

 movement, so also in vomiting, no backward or antiperistaltic con- 

 traction necessarily occurs. 



A conjecture concerning regurgitation of fluid from the stomach 

 concludes this part of the paper. 



II. On the Physiology of Intestinal Obstructions. — In the preceding 

 part of the paper it has been stated, that two currents probably ob- 

 tain in the liquid contents of the stomach. Many of the conditions 

 of the intestinal tube approximate to those of the stomach ; and if 

 disease or experiment add to these occlusion and distension, the ana- 

 logy of the two organs is rendered tolerably complete, and the results 

 will hence probably be referrible to the same general principle. 



The most remarkable and constant symptom of this state of ob- 

 struction is the occurrence of faecal vomiting. 



The author briefly states the theory of an antiperistalsis by which 

 this phenomenon is ordinarily explained : and from an inquiiy into its 

 experimental basis he deduces this general result, that an antiperi- 

 staltic movement has never yet been observed in any part of the ali- 

 mentary canal. He regards the irregular actions seen on laying 

 open the bellies of healthy animals recently killed, as not definedly 

 peristaltic or the reverse, but as dependent on the irritation pro- 

 duced by the admitted air. So also, in the case of the occluded in- 

 testine, an inverted movement likewise fails to be recognized. In 

 general, the vermicular actions are more energetic, and more peri- 

 staltic, than in the healthy bowel. 



He next adduces the following arguments :— 



1 . The antiperistalsis is usually attributed to irritation ; but 

 irritation is present in almost every disease of the tube, while faecal 

 vomiting is limited to cases of obstruction. This renders it pro- 

 bable that the latter is the cause, and that the process of causation 

 is, like the cause, physical. 



2. The starting-point of the supposed inverted movement is the 

 fullest part of the bowel, while the place towards which it has set is 

 the emptiest. This condition is inconsistent with the supposition 

 of an antiperistalsis, yet perfectly consistent with a forward move- 

 ment, and analogous to the obstructions of other tubes conveying 

 fluids. 



3. Intus-susception is often the cause of obstruction. But, both 

 from experiment and argument, it appears probable, that an anti- 

 peristalsis would at once remove this condition, and would there- 

 fore be incompatible with it. 



4. The supposed inverted movement is continuous, while the 

 vomiting is occasional. Hence a theory which showed the essential 

 independency of the return of faecal matters to the stomach, and 

 their ejection thence, would be, so far, preferable. 



5. Experiment and observation agree in showing that the ordi- 

 nary peristalsis obtains immediately below the strangulation. And 

 it is difficult to imagine how or why the same irritation should pro- 

 duce two opposite movements in reversed directions. 



