374 PHYSIOLOGICAL CHEMISTRY. 



Volatile fatty acids, such as formic acid, acetic acid, and perhaps also 

 butyric acid, occur under normal conditions in human urine (v. JAKSCH), also 

 in that of dogs and herbivora (SCHOTTEN). The acids poorest in carbon, 

 formic acid, and acetic acid are more constant in the body than those richer in 

 carbon, and therefore the relatively greater part pass unchanged into the urine 

 (SCHOTTEN). Normal human urine contains besides these bodies others which 

 yield acetic acid when oxidized by potassium dichromate and sulphuric acid 

 (V. JAKSCH). The quantity of volatile fatty acids in normal urine is, according 

 to v. JAKSCH, 0.008-0.009 grm. per 24 hours, and according to v. ROBITANSKY, 

 0.054 grm. The quantity is increased by exclusive farinaceous food, also in 

 fever and in certain diseases of the liver (v. JAKSCH). It is also increased in 

 leucaemia and in many cases of diabetes (v. JAKSCH). Large amounts of 

 volatile fatty acids are produced in alkaline fermentation of the urine, and the 

 quantity is 15-16 times as large as in normal urine (SALKOWSKI). 



Paralactic Acid. It is claimed that this acid occurs in the urine of healthy 

 persons after very fatiguing marches (COLASANTI and MOSCATELLI). It is 

 found in larger amounts in the urine in acute phosphorus poisoning or acute 

 yellow atrophy of the liver (Scnui/rzEN and RIESS), also in osteomalacia 

 (MoRS and MUCK). After the extirpation of the liver of birds it is found in 

 large quantities in their urine (MINKOWSKI). Glycero-pJiosphoric acid occurs as 

 traces in the urine, and it is probably a decomposition product of lecithin. The 

 occurrence of succinic acid in normal urine is the subject of discussion. 



Carbohydrates and Reducing Substances in the Urine. The 

 occurrence of grape-sugar as traces in normal urine is highly prob- 

 able, as the investigations of BRUCKE, ABELES and v. UDRANSZKI 

 show. The last has also shown the habitual occurrence of carbo- 

 hydrates in the urine, and their presence has been positively proved 

 by the investigations of BAUMANN and WEDENSKI. Besides this, 

 the urine contains traces of a carbohydrate similar to dextrin 

 (animal gum) (LANDWEHR, WEDESTSKI). Besides traces of sugar 

 and the previously-mentioned reducing substances, uric acid and 

 creatinin, the urine contains still other reducing substances. These 

 last are probably (FLUCKIGER) coupled combinations of glycuronic 

 acid, C 6 H 10 7 , which closely resembles sugar. The reducing power 

 of normal urine corresponds according to FLUCKIGER to 1.5-2.5 

 p. m. grape-sugar, according to SALKOWSKI 4.08, according to 

 MUNK an average of 3.0, and according to WORM MULLER about 

 4.0 p. m. 



Glycuronic Acid, C 6 H 10 7 or CHO.(CH.OH),.COOH. This 

 acid may be converted into saccharic acid, C 6 H 10 8 , by the action of 

 bromine (THIERFELDER), and it seems to occupy an intermediate 

 position between this acid and gluconic acid, C 6 H 12 7 , obtained by 

 the oxidation of glucose or cane-sugar with chlorine or bromine. 

 Glycuronic acid probably only occurs normally in very small quanti- 



