KURTIIKIl STIIDIES ON OREINE. 533 



if tlic filtrate obtained is colorloss or nearly so, we raay concliulo that the 

 luixture of ureinc -i- iirea contaiued 0,ß gr. iirea and 1,8 gr. uroine. But 

 Ict us sujjpose tliat tlio filtrat(! still lias a permauganate color. In that case 

 wc can easily asccrtaiu liow mucli ['ormaiiganatf lias remained unclianged: 

 We prépare a standard solution of 1/) gr. K^Mn^Og dissolved in 100 cbcm. 

 water, so that eacli ciibic centimeter reprosonts 0,01 Permanganate; with 

 the aid of tliis standard solution we eau easily find out liow much Potassium 

 Permanganate is requircd to imjjart to 500 cbcm. water the color of the 

 filtrate. If in our e.xample tlie iiltrate has the color of a Permanganate solu- 

 tion of 0,1 gr. in 500 cbcm. watei-, we kuow that the mixture of urcîinc 

 -H urea lias decomposed in 24 liours only 1,1 KaMiuO^, but not 1,2 gr., 

 so that the amount of iircine jjreseut was 1,5 X 1,1 = 1,65 gr., leaving for 

 urea 0,75 gr. (2,4—1,65 = 0,75). 



In the following I sliall give the results of a few analyses whicli I hâve 

 made accordiiig to the niethod just described: 



1) Ureiiie -+- urea 2,275 gr. (in 100 cbcm. urine). 



Ureine 1,5»/, 

 Urea 0,775%. 



2) Ureine -i- urea 2,71 gr. 



Ureine 2,01 gr. 

 Urea 0,7 gr. 



3) Ureine -+- uroa 2,5 gr. 



Ureine 1,875% 

 Urea 0,G25%. 



4) Ureine -+■ urea 3,0 gr. 



Ureine 2,175% 

 Urea 0,825%. 



As to the complète isolation of meine, it will be understood from 

 what we hâve said before, that neither oxalic acid nor Mercury Nitrate can 

 be used to separate urea from ureine. Judging from ray mimerons attempts in 

 this direction tliis can be effected only hi/ the use о f absolute alcohol mul of 

 cold. The following is our method to obtain ureine in sufficiently large 

 quantities tor physiological and cliemical imrposes: We collect the urine of 

 several weil fed persons between 5 — 8 o'clock in the cvening; it is advis- 

 able to use only such urine, whose specific gravity is not less thau 1030, 

 and to take at least 1 — 2 liter. The urine is evaporated at 45 — 50" C. 

 until a half-solid, jellylike residue remaius, wliich cannot be poured from 

 one récipient into auother. After the residue has cooled oft" sufficiently it is 

 thoroughly mixed with cold, absolute alcohol, — 200 cbcm. of absolute al- 



Фп.-Ыат. стр. 135. 5 3g 



