AROMATIC DERIVATIVES OF PROTEIDS 473 



demonstrated that indol, skatol, and methyl mercaptan cause 

 muscles to react to stimuli like fatigued muscles. Normal urine 

 contains but about 12 milligrams of indican per day, which 

 amount is so insignificant in proportion to the above-mentioned 

 doses that were found necessary to produce symptoms, that we 

 may well doubt the occurrence of noticeable intoxication from 

 this substance under ordinary conditions. Nesbitt 1 states that 

 twenty times as much indol or skatol as are excreted daily by 

 an adult man may be injected into the jugular vein of a dog 

 of four kilos without causing appreciable effects. Richards 

 and Rowland, however, have recently demonstrated the possi- 

 bility that defective oxidation of substances of this group may 

 permit of intoxication. 2 



Other Aromatic Compounds. Skatol seems to accom- 

 pany indol in small amounts, but apparently in no constant 

 quantitative relation. Although formed in larger quantities in 

 the intestines, it is but slightly absorbed. 



Indol-acetic acid appears in the normal urine in extremely 

 minute quantities, and is increased in the same conditions as are 

 indol and skatol. 



Phenol appears in the urine normally in very minute quan- 

 tities from 0.005 to 0.07 grams per day, according to various 

 observers. Much more is undoubtedly formed in the intestines, 

 for but a small fraction of phenol given by mouth (2 to 3 per 

 cent., according to Munk) appears in the urine as a sulphuric- 

 acid compound ; part of the rest is oxidized to hydrochinon and 

 pyrocatechin, C 6 H 4 (OH) 2 , and eliminated as ethereal sulphates. 

 The largest quantities are found in the same conditions as indican, 

 except, of course, in " carbolic-acid " poisoning, when the amounts 

 may be so great that practically all the sulphuric acid in the 

 urine is in this organic combination, much of the phenol under 

 these conditions being also combined with glycuronic acid. 3 



Cresol (chiefly paracresol), para-oxyphenyl acetic acid, and 

 para-oxyphenyl propionic acid appear under similar conditions, 

 except that the two oxy-acids are possibly also formed within 

 the body through cellular metabolism, as they have been found 

 present in the urine independent of intestinal putrefaction. 

 Probably part of the benzoic acid that appears in the urine 

 combined with glycocoll, as hippuric acid, is derived from 

 intestinal putrefaction. 4 



1 Jour. Exper. Med., 1899 (4), 5. 2 See note in Science, 1906 (24), 979. 



3 See the observations of Wohlgemuth and of Blumenthal (Biochem. Zeit- 

 schrift, 1906 (1), 134), on the detoxication of lysol and similar poisons. 



4 See Prager, Med. News, 1905 (86), 1025; Magnus-Levy, Munch, med. 

 Woch., 1905 (52), 2168. 



