20 Dr Barclay-Smith, Extreme Visceral Dislocation. 



commencement of the transverse colon are usually much more 

 conspicuous objects when the abdominal cavity is opened than the 

 descending colon, which is more often than not contracted up to a 

 cord-like consistency. The cause of this distension is fairly obvious; 

 gas is the distending agent, and the gas is the result of decompo- 

 sition affecting the intestinal contents. Further, there can be 

 little doubt that this gaseous decomposition is due to bacteria. 

 A definite segment of the gut therefore presents definite anatomical 

 features w T hich are the result of microbic activity. It is obvious 

 that there must be some peculiar conditions whereby the microbic 

 activity with the resulting gaseous decomposition should prefer- 

 entially take place in one segment of the gut on which it leaves 

 such an indelible mark. 



These peculiar conditions are open to the conceptions that this 

 segment of the gut usually contains material suitable for bacterial 

 decomposition, that by some means the stay of this material is 

 prolonged and that the bacterial activity is to a certain extent 

 localised, or at any rate, that indefinite bacterial invasion of the 

 proximal part of the gut is prohibited. 



The first condition is fulfilled by the nature of the intestinal 

 contents which pass from the small intestine into the large through 

 the ileocolic valve, and it is conceivable that if this material has 

 not undergone sufficient change under the influence of the digestive 

 fluids present in the small intestine, i.e. is in a more or less un- 

 digested condition, it will afford a more suitable medium for 

 microbic activity, will favour a microbic increase and at the same 

 time will provide a more abundant and a more suitable material 

 for undergoing gaseous decomposition, thus bringing about con- 

 ditions favouring undue distension of this part of the gut. 



A stay of certain duration is essential in order that time may 

 be afforded for the production of this gaseous decomposition. That 

 there is a tendency to accumulation in the caecum, whether in 

 man or in any other animal provided with this appendage to the 

 gut 1 , is a well established fact, but as far as I know, no completely 

 satisfactory explanation as to its causation has been adduced. 

 The key to the matter is probably to be found in the results 

 of a remarkable series of experiments made by W. B. Cannon, who 

 directly studied the movements of the intestine in the cat by means 

 of the Rontgen rays, the outlines of the intestine being brought 

 into view by mixing subnitrate of bismuth with the food 2 . Cannon 

 found that the movements of the proximal part of the large gut, 



1 In connection with this vide an interesting paper entitled "On some remark- 

 able Digestive Adaptations in Diprodont Marsupials" by Dr Einar Lonnberg. Pro- 

 ceedings of the Zoological Society of London, 1902, Vol. i., Part i., p. 12. 



2 W. B. Cannon, " The movements of the intestines studied by means of the 

 Rontgen rays," The American Journal of Physiology , Vol. vi., No. v., p. 251. 



