SKATOL, OTHER ORGANIC CONSTITUENTS. 489 



agitated with ether, the latter then evaporated, and the residue dissolved in 

 water, it will yield a red color with Millon's reagent. This is the reaction of the 

 aromatic oxyacids. 



Baumann has named the following list of substances that result from tyrosin 

 by decomposition and oxidation, of which most members develop both as a 

 result of the putrefaction of proteids in the intestine, and pass thence into the 

 urine. 



Tyrosin, C ft H u NO 3 -fH 2 = C 9 H 10 O 3 (hydroparacumaric acid) +NH 3 . 



C 9 H 10 O 3 = C 8 H 10 O (parethylphenol, not yet demonstrated) +CO . 



C 8 H in O+O 3 = C 8 H 8 O 3 (paraoxyphenylacetic acid) +H 2 O. 



C 8 H 8 3 = C 7 'H 8 (parakresol)+CO 2 . 



C 7 H 8 O+O 3 = C 7 H 6 O 3 (paraoxybenzoic acid, not yet demonstrated) +H 2 O. 



C 7 H 6 O 3 = C 6 H 6 O (phenol) +CO 2 . 



Potassium sulphocyanate or sodium sulphocyanate is present in the 

 urine in the proportion of from 0.02 to 0.08 gram to the liter, in larger 

 amount in the urine of smokers. It is derived from the saliva and can 

 be recognized by the ferric-chlorid test after acidulation with hydro- 

 chloric acid. 



Succinic acid, C 4 H 6 P 4 , occurs particularly after the ingestion of 

 meat and fat, and in infinitesimal amounts after the taking of vegetable 

 food. It occurs in considerable amount as a product of the decom- 

 position of asparagin, after the eating of asparagus. Also, as a product 

 of alcoholic fermentation, it finds its way into the urine through in- 

 gestion of spirit; or, administered internally, it passes undecomposed 

 into the urine. 



Lactic acid, C 3 H 6 O 3 , is a constant constituent of the urine. Fermen- 

 tation lactic acid has been found principally in cases of diabetes, sarco- 

 lactic acid in cases of phosphorus-poisoning and of trichinosis. 



Traces of volatile fatty acids are inconstant. They occur par- 

 ticularly in connection with destructive diseases of the liver. 



Ferments. Diastatic, peptic, and rennet-like ferments have been found by 

 Griitzner principally in urine of high specific gravity. Fat-splitting ferment is 

 not present normally. Trypsin is much attenuated. 



Traces of grape-sugar occur up to between o.oi and 0.05 per cent. 

 After the ingestion of milk-sugar, cane-sugar, or grape-sugar (50 grams 

 and more), these varieties of sugar appear unchanged in the urine in 

 small amounts. Baisch found some isomaltose. 



Reducing substances (yielding Trommer's reaction) are always present in the 

 urine. Normal human urine effects reduction almost like a 0.3 or 0.4 per cent. 

 solution of grape-sugar, in larger measure in the presence of fever. Almost five- 

 sixths of these substances are probably combinations of glycuronic acid, while 

 one-sixth "consists of uric acid and kreatinin. There is present a dextrin-like 

 carbohydrate and one soluble in alcohol, as well as some animal gum. Bechamp's 

 nephrozymose consists principally of gum. This substance is prepared by pre- 

 cipitating the urine with thrice its amount of 90 per cent, alcohol. It is not a 

 simple body, and it transforms starch into sugar at a temperature of between 60 

 and 70 C. 



Acetone, C 3 H 6 O, appears after an exclusive diet of meat and fat, according 

 to v. Noorden only on digestion of the flesh of the body. As soon as carbohydrates 

 are taken, it is no longer observed. Also the digestion of the muscle and fat 

 of the body occasions its appearance. Vicarelli found it in pregnant women with 

 dead fetuses. 



Demonstration. One-half liter of urine is acidulated with hydrochloric acid 

 and is distilled. On addition of tincture of iodin and ammonia, iodoform appears 

 in the distillate as a cloudiness and is recognizable by its peculiar odor. 



Optically inactive urine that becomes discolored brown or black on exposure 

 to the air after addition of alkali, with the taking up of oxygen and a powerful 

 reducing activity, contains alkapton, homogentisic acid, which occurs but rarely, 



