658 URINE. 



solution which contains an ammonium salt (MACLEOD and HASKINS). Carbamic 

 acid is also produced by the action of potassium permanganate on protein and 

 several other nitrogenous organic bodies. 



The occurrence of carbamic acid in human and animal urines has already 

 been considered in connection with the formation of urea. The calcium salt, 

 which is soluble in water and ammonia but insoluble in alcohol, is the most impor- 

 tant in the detection of this acid. The solution of the calcium salt in water 

 becomes cloudy on standing, but much more quickly on boiling, and calcium car- 

 bonate separates. NOLF, MACLEOD and HASKINS have made experiments as to 

 the method of formation of carbamic acid. The latter have indicated a new 

 method for the quantitative estimation of carbamates. 1 



Carbamic-acid ethylester (urethane), as shown by JAFFE, 2 may pass, by the 

 mutual action of alcohol and urea, into the alcoholic extract of urine when one 

 is working with large quantities. 



FOLIN 3 claims that all human urine contains a body which is probably methylurea* 



NH - CO 



Creatinine, C^yNsO, or NH : C^ | , is generally considered as 



>N(CH 3 ).CH 2 



the anhydride of creatine (see page 546) found in the muscles. It occurs 

 in human urine and in that of certain mammalia. It has also been 

 found in ox-blood, milk, though in very small amounts, and in the flesh 

 of certain fishes. 



JOHNSON'S statement that the creatinine of the urine is different from that 

 produced by the action of acids on creatine is incorrect according to TOPPELIUS 



and POMMEREHNE, WOERNER and THELEN. 4 



The quantity of creatinine in human urine is, in a grown man voiding 

 a normal quantity of urine in the course of a day, 0.6-1.3 grams (NEU- 

 BAUER), or on an average 1 gram. JOHNSON 5 found 1.7-2.1 grams per 

 day, and similar results have been obtained by v. HOOGENHUYZE and VER- 

 PLOEGH. 6 The quantity of creatinine with a diet free from meat is, 

 FOLIN 7 says, variable for different individuals, but is constant for the 

 same person. He never found the quantity below 1 gram and often 

 between 1.3 and 1.7 grams. Nurslings also eliminate creatinine, although 

 the quantity is small (v. HOOGENHUYZE and VERPLOEGH). The quantity 

 of creatinine nitrogen in per cent of the total nitrogen varies under 

 different conditions, but is on an average about 4.5-6 per cent, as 

 determined by several experimenters. 



As the two bodies, creatine and creatinine, can easily be transformed 



1 Nolf, Zeitschr. f. physiol. Chem., 23; Macleod and Haskins, Amer. Journ. of 

 Physiol., 12, and Journ. of biol. Chem., 1. 



2 Zeitschr. f . phygi^i 6&em., 14. 



4 S.^-cording to WiecH. Roy. Soc., 42, 43; Chem. News, 55; Toppelius and Pom- 

 merehne,*, in urine tharm., 234; Woerner, Arch. f. (Anat. u.) Physiol., 1898. 



5 Huppeitein, Zeauer, Harnanalyse, 10. Aufl., 387. 



6 Zeitschr. i36hysiol. Chem., 46. 



7 Amer. Journ. of Physiol. 13; v. Klercker, Hofmeister's Beitrage, 8. 



