PHYSIOLOGY CHAP. 



We have already referred to a remarkable case of anus 

 jjreternaturalis in the upper part of the small intestine in a 

 woman. Busch, who described this case, was able to produce con- 

 siderable improvement in nutrition and increase of body weight, 

 by introducing food through the intestinal fistula where neither 

 bile nor pancreatic juice could penetrate. This case was cited by 

 Herzen in support of Schifi" s theory, which endowed the succus 

 entericus with the power of digesting natural proteins. Now that 

 the impossibility of this assumption has been established, Busch's 

 observations are of still greater importance, because they show 

 that in the early stages of the putrefactive process the intestinal 

 bacteria are able to convert proteins into proteoses and peptones, 

 on which the digestive ferment, crepsin, can then act. Vizioli 

 repeated and confirmed the observations of Busch on another case 

 of fistula of the small intestine. 



No less interesting are the studies of Macfadyen, Nencki and 

 Sieber, on another woman with a fistula in the lower part of the 

 small intestine. They showed that the bacteria confine them- 

 selves in this region to the decomposition of carbohydrates, and 

 that putrid decomposition of protein does not take place, or only 

 to a very limited extent. In fact, it was found impossible to 

 extract even the primary products of the putrid decomposition of 

 protein, leucine, and tyrosine from the contents of the small 

 intestine, probably because they are absorbed as fast as formed. 

 On the other hand, the acid reaction of the contents does show the 

 presence of organic acids derived from decomposition of carbo- 

 hydrates. Jakowski, on examining two other cases of intestinal 

 fistula in man, obtained fresh confirmation of these conclusions. 



That the intestinal bacterial processes differ essentially from 

 those of ordinary putrefaction outside the body, may also be 

 concluded from the fact that normally, according to Brieger, 

 Baumann and Udransky, ptomaines are not found in the intestinal 

 contents, even when extracted some days after death. It is 

 possibly the bile acids that make the intestines unsuited to the 

 development of the ptomaines. 



Generally speaking, the presence of aromatic products (phenol, 

 indole, scatole) may be taken as the sign of putrefactive processes in 

 the intestine. Part of these products are absorbed and partially 

 oxidised : the indole is converted into indoxyl, the scatole into 

 scatoxyl, and they are for the most part coupled with sulphuric 

 acid, reappearing in the urine as indoxyl and scatoxyl sulphuric 

 acid. The classical proof that the origin of these aromatic 

 substances depends exclusively on the life of the intestinal 

 bacteria is the fact of their invariable absence from the contents 

 of the foetal intestine and the meconium excreted by the 

 new-born. 



V. In order the better to appreciate the functional importance 



