334 BACTERIAL FERMENTATION IN THE INTESTINES. 



small amount of indol is formed. If, on the other hand, with a lesser 

 degree of absorption, the putrefactive process can exert a profound effect 

 chiefly upon the products of pancreatic digestion still present in large 

 amount, considerable indol will be formed, and much indican subse- 

 quently appears in the urine. 



Thus Jaffe found an abundance of indican in the urine in the presence of in- 

 carcerated hernia and obstruction of the bowel. After transfusion with hetero- 

 geneous blood, in connection with which the walls of the intestine are often the seat 

 of extravasation of blood and thrombosis, and paralytic conditions of the intes- 

 tinal vessels and musculature itself are not rarely encountered, the author has 

 often found the amount of indican contained in the urine to be large. 



Test for indol: The fluid to be tested is acidulated with considerable hydrochlo- 

 ric acid and is well shaken after addition of a few drops of oleoresin of turpentine. 

 If an intense red color results, the pigment is removed by agitation with ether. 

 The pigment resulting from fibrin in the process of tryptic digestion, and becom- 

 ing violet with bromin-water, can be isolated by agitation with chloroform. In 

 addition to the latter pigment, there is still a second pigment that passes over 

 in the process of distillation, and can be extracted from the distillate by ether. 

 Both appear to belong to the indigo-group. 



A. v. Bayer was able to produce indigo-blue artificially from orthonitrophenol- 

 propionic acid by boiling with dilute sodium hydrate and after addition of some 

 grape-sugar. From indigo-blue he obtained skatol, in addition to indol. G. 

 Hoppe-Seyler observed an abundance of indican in the urine after feeding rabbits 

 upon sodium orthonitrophenol-propionate. 



Further, some phenol (C 6 H 6 O) is formed in the intestine by the putre- 

 factive process. Baumann observed the same substance as a result of 

 the putrefaction of fibrin with pancreas outside of the body, and Brieger 

 found it constantly in the feces. It appears to undergo an increase under 

 conditions analogous to those attending an increase in the amount of 

 indol, as an increase in the amount of indican in the urine is accompanied 

 by an increase in the amount of phenyl-sulphuric acid. 



Amidophenyl-propionic acid also can be obtained from putrefying meat and 

 fibrin as a product of the decomposition of tyrosin. Part of this is changed by 

 putrefactive ferments into phenylpropionic acid (hydrocinnamic acid) , which is com- 

 pletely oxidized in the organism to benzoic acid, and appears in the urine as 

 hippuric acid. In this way is explained the formation of hippuric acid when a 

 pure proteid diet is taken. 



Skatol (C 9 H 9 N, methylindol), a constant constituent of human feces, 

 has been prepared artificially by Nencki and Secretan by protracted 

 putrefaction of egg-albumin under water. In this way results skatol- 

 carbonic acid, which, when heated, readily decomposes into skatol and 

 carbon dioxid. Skatol also appears in the urine in combination with 

 sulphuric acid. 



Milk inhibits the decomposition of albumin and intestinal putrefaction through 

 the presence of casein and thus also diminishes the amount of ethereal sulphates 

 in the urine. 



According to the brothers Salkowski, both skatol and indol result from a 

 common substance preformed in albumin, which, when decomposed, at one time 

 yields a larger amount of indol, and at another time a larger amount of skatol, 

 accordingly as to whether the hypothetical indol-bacterium or the skatol-bac- 

 terium active under such conditions prevails in the development. 



It is of great importance in the process of putrefactive fermentation whether 

 this takes place with the exclusion of oxygen or not. In the former case reduc- 

 tion occurs: oxy-acids are reduced to fatty acids, and there are developed, 

 especially hydrogen, but also marsh-gas and hydrogen sulphid; the hydrogen, 

 in turn, may cause further reduction. If, however, oxygen is still present, the 

 nascent hydrogen divides the molecule of ordinary free oxygen into two atoms 

 of active oxygen; there forms, thus, on the one hand, water, and on the other hand, 

 the second atom of oxygen brings about active oxidation. 



