BACTERIAL METABOLISM WITHIN THE BODY 697 



tyramin. The bacteria which can form amins by the decarboxylization 

 of the aromatic amins are not thoroughly studied. Berthelot and Ber- 

 trand have described Bacillus aminophilus, a member of the Mucosus 

 cap^ulatus group, but according to Koessler and Hanke, Harai, Yoshimura, 

 Guggenheim, Einis, and Berthelot, it is probable that a number of in- 

 testinal bacteria can decarboxylize these compounds. 



The amounts of the putrefactive derivatives of the aromatic amino 

 acids found in the urine of normal adults under normal dietary conditions 

 arc not large in proportion to the amount of protein ingested. The 

 figures for indican and phenolic bodies, chiefly phenol and paracresol, 

 are the best known because these substances give color reactions which 

 are quantitative, or approximately so; consequently, fairly accurate 

 measurements are possible. About 10 milligrams of indican and about 

 0.3 gram phenolic bodies are usually found (Folin and Denis). The 

 fecal content of indol and phenols under these conditions is unknown, 

 although a variable amount of each must escape absorption. 



At times, particularly in purulent infections incited by Staphylococci, 

 and to a lesser extent by Bacillus coli and Bacillus proteus, some indican 

 may properly be of parenteral origin, it being well known that these or- 

 ganisms form indol and phenols from the degradation of tissue and blood 

 proteins. This is not the usual source of the urinary putrefaction prod- 

 ucts, however; as a rule they are derived solely from bacterial activity 

 in the intestinal tract. 



Obstruction of the lower levels of the small intestine, intestinal stasis, 

 and, in general, any factor which leads to an upward extension of the 

 habitat of Bacillus coli and related forms, is a potent factor for in- 

 creased protein putrefaction. 



It should be noted that the relative desiccation of the intestinal con- 

 tents at the lower levels of the large intestine, together with the accumu- 

 lation of products of bacterial proliferation carried down from higher 

 levels, restricts materially the intensity of growth and activity of the 

 intestinal flora from the transverse colon to the rectum. On the other 

 hand, the relative emptiness of the upper small intestine, particularly the 

 duodenum, in interdigestive periods, has been emphasized by Escherich, 

 Tissier, and the author and is correlated with a periodic diminution of bac- 

 teria, most of which are carried downward mechanically with the food. 

 The net result is a large fluctuation in the numbers of bacteria in the 

 duodenum, corresponding approximately with the ebb and flow of the 

 duodenal content of food, and a gradual increase in numbers and decrease 

 in fluctuation, as the ileum is reached, where an intestinal residuum is 

 almost constantly present. 



At the rectum, the number of living microbes is very greatly reduced, 

 although the corpses of bacteria [which appear to be insoluble in the 

 digestive juices] are present in enormous numbers. It has been estimated 



