590 GASTRO-INTESTINAL "AUTOINTOXICATION" 



observed in the feces and urine of persons with cystinuria. The stools in cholera 

 also seem to contain these ptomains frequently. Their etiological; relation to the 

 cystinuria is no longer accepted, however, and their toxicity is slight. They are 

 probably derived from the diamino-acids of the protein molecule, putrescine being 

 closely related to ornithine,^^ and is probably formed from it as follows: 



NH2 NH2 NH2 NH2 



i ' I ■ 



CH2-CH2-CH2-CH-COOH = CH2-CH2-CH2-CH2 + CO2 



(ornithine) (putrescine) 



while cadaverine is probably formed from, lysine, 

 NH2 NH2 NH2 NH2 



CH2-(CH2)3-CH-COOH = CH2-(CH2)3-CH2 + CO2 



(lysine) (cadaverine) 



/NH2 

 Ethvlidendiamine, CH3 — CH<C ^^„ which is somewhat toxic, has also been 



\NH2 



detected in the contents of the gastro-intestinal tract. 



Apparently these substances are absent from normal feces, but this does not 

 exclude the possibility of their normal formation, absorption and destruction. 

 There is no evidence that they ever cause symptoms or pathological alterations. 



(3) Substances Arising from the Sulphur-Containing 

 Radical of Proteins 



Most if not all of the sulphur in the protein molecule seems to be contained in 

 the amino-acid, cystine, which has the following composition: 



S - CH2 - CHNH2 - COOH 



I 



S -CH2 -CHNH2 -COOH. 



From this is formed the hydrogen sulphide of the intestinal gases, of which about 

 0.058-0.066 gram is present in each one hundred grams of normal colon contents. 

 Although Senator has described a case in which an intoxication with US of in- 

 testinal origin occurred, this gas seems not to be a frequent cause of intoxication, 

 and Senator's case stands almost alone. Under normal conditions H2S does not 

 appear in the urine, any that may be absorbed probably being oxidized to SO4. If 

 enough H2S should enter the blood so that it was not completely destroyed, it 

 might well cause harm, for it is decidedly toxic, particularly affecting the nervous 

 system; but we have no evidence that this often happens. Van der Bergh'^ has 

 observed cases of intestinal obstruction in which the presence of sulphernoglobin in 

 the patient's blood was demonstrated. 



Methyl mercaptan, CH3SH, has also been found in the feces, although it seems 

 not to be abundantly or constantly present, according to Herter,^^ who found 

 also that mixed bacteria from normal feces rarely produce mercaptan in cultures. 

 However, bacteria from the feces of persons suffering with various diseases often 

 produce mercaptan. Ethyl mercaptan, C2H5SH, and ethyl stdphide, C2H5-S-C2H6, 

 have also been described as fecal constituents. It is not known that the mercap- 

 tans are a cause of intoxication. 



Cystine and Cystinuria^s 



Cystine has been observed in the urine in a number of cases, and 



when present at all it is usually found in considerable quantities. 



*' Ornithine forms part of the arginine molecule, which is the most universally 

 present (in proteins) of all the amino-acids, ornithine being formed when urea 

 is split from arginine. 



" Dent. Arch. klin. Med., 1905 (83), 8G. 



" Jour. Biol. Chem., 1906 (1), 421. 



88 Literature concerning cystine given by Friedmann, Ergebnisse der Physiol., 

 1002 (I. Abt. 1), 15; and l)y Mann, "Chemistry of the Frotoins," ])p. 56-61. Cys- 

 tinuria reviewed l)y Bodtker, Zcit. ])hysiol. Cliein., 1905 (15), 39;?; CJarnxl, "Inborn 

 Errors of Metabolism," and Lancet, July, 190S; Kretsclimer, Urol, and Cut. Rev., 

 1916 (20), No. 1. 



