132 CONTENTS OF THE INTESTINAL CANAL. 



sulphuretted hydrogen always occurs in the gases of the large 

 intestine in far less quantity than we should have expected from 

 the odour. It is hardly necessary to indicate the reasons why the 

 development of gas is always more considerable in the large than 

 in the small intestine; for although the decomposition of the 

 remains of the food may have begun in the ileum, it proceeds 

 with greater rapidity in the colon, since there the feecal mass no 

 longer meets with any free acid to impede its further decompo- 

 sition. Should, however, the contents of the large intestine be 

 acid, this, as we have already shown, must depend on a butyric 

 fermentation, which indeed is accompanied by a copious de- 

 velopment of gas. We need not trouble the rational physician 

 with a detailed notice of all those morbid conditions which lead to 

 large accumulations of air in the caecum and the colon ; it is suf- 

 ficient for us simply to mention that these accumulations of gas, 

 which we are accustomed to term meteorism or flatulence, 

 may either be a consequence of suppressed or perverse secre- 

 tion of the intestinal juices, or of diminished contractility of 

 the muscular coat of the intestine, of strictures and other ana- 

 tomical changes of the colon, of pressure exerted by morbid 

 tumours on the lower parts of the intestine, &c. Substances 

 stagnating in the different parts of the colon, undergo complete 

 putrefaction, and their products, gaseous as well as solid, are 

 precisely the same as we observe out of the animal body. Thus, 

 in the examination of such masses, Frerichs found substances 

 precisely similar to those which Bopp has obtained from putrefy- 

 ing protein-bodies. 



The early physicians believed in a secretion of gas from the 

 walls of the intestine ; to those who are at all acquainted with the 

 law of the metamorphosis of the animal tissues and with the 

 chemical processes of putrefaction, such an assumption is altogether 

 unnecessary for the explanation of considerable accumulations of 

 gas ; and further, from what is known on the subject, it is very 

 improbable that gases, such as hydrogen, carburetted hydrogen, 

 and sulphuretted hydrogen (which latter we do not find in the 

 blood), should pass from the general juices of the body into the 

 intestinal canal. Magendie and Girardin* have, however, made 

 an observation which has also been confirmed by Frerichs,t which, 

 at all events, proves the possibility of a secretion of gas from the 

 blood into the intestine ; for if a loop of intestine in dogs, after 

 being perfectly emptied of its contents, were tied at both ends, it 



* Recherches physiol. sur les Gaz. intestin. Paris, 1824, p. 24. ^ 

 t Op, cit. p. 86G. 



