PROTEOSES AND PEPTONES 575 



I. The consdtuents of the digestive secretions, including the Inlc salts and 

 pigments, pepsin, and trypsin. 



II. Products of normal digestion: 



(a) From proteins — proteoses, peptones, amino-acids. 



(b) From fats — fatty acids and glycerol. 



III. Products of putrefaction and fermentation: 



(a) From proteins: 



(1) From the aromatic radicals (tyrosine, phenylalanine, trypto- 

 phane) — indole, skatole, skatole-carbonic (or indole-acctic) acid, 

 phenol, crcsol, dioxyphenols, and the pressor bases. 



(2) From the fatty acid radicals — fatty acids (especially butyric and 

 acetic), acetone, ammonia, amino-acids, carbon dioxide, hydro- 

 gen, marsh-gas. Also ptomains; cadaverine, putrescine, ethyli- 

 dendiamine, isoamylamine. 



(3) From the sulphur-containing radicals — H2S, methyl mercaptan, 

 ethyl mercaptan, ethyl sulphid. 



(6) From carbohydrates: 



Fatty acids, the following having been detected — formic, acetic, 

 propionic, butyric, valerianic, lactic, oxybutyric, and succinic; 

 also acetone, CO2, CH4, H2. 



(c) From fats: 



Higher fatty acids, as well as butyric acid ; also glycerol. From 

 lecithin — choline, neurine, and muscarine-like bodies. 



IV. Synthetic products of bacterial activity (e. q., botulismus) which cannot 

 properly be considered as causing "autointoxication." 



I. THE CONSTITUENTS OF THE DIGESTIVE FLUIDS 



These call for but brief consideration, for, although many of them 

 are known to be toxic, yet there is no evidence that they cause auto- 

 intoxication, either in health or disease. Both pepsin and trypsin, 

 especially the latter, are decidedly toxic when injected experimentally 

 into the blood (see Enzymes), but they do not appear ever to pass 

 through the intestinal wall in sufficient quantity to cause harm, al- 

 though minute traces may appear in the urine; this harmlessness 

 probably depends largely on the known inhibiting action of the blood 

 upon enzymes. 



The bile salts are also toxic, especially hemolytic, but those that are 

 reabsorbed from the intestines are taken back into the liver and re- 

 excreted. This protective arrangement seems to be sufficient for all 

 emergencies. The bile-pigments become converted into urobilinogen 

 through reduction, and this is largely absorbed and eliminated as 

 urobilin. Icterus and cholemia do not seem ever to be produced by 

 absorption of bile-pigments and bile salts from the intestines. 



II. PRODUCTS OF NORMAL DIGESTION 



Proteoses and Peptones. — Under normal conditions, these are 

 broken up in the intestinal wall into the amino-acids, through the 

 agency of erepsin, and do not appear in the blood in appreciable 

 quantities. To be sure, certain authors claim to have found albumose 

 in normal blood, but if present the amounts are extremely minute. 

 In conditions in which ulceration or other lesions are present in the 

 gastro-intestinal tract it is possible to find small amounts of proteoses 

 in the urine, probably absorbed through the abnormal areas, but 

 not in quantities sufficient to account for any appreciable intoxication, 



