428 URINE. 



uroxanthin and urrhpdin is still doubtful ; the one whose exist- 

 ence is most clearly established, and which admits of the most 

 accurate examination, is the crystallisable uroglaucin, which has also 

 been artificially obtained by Alois Martin* and by Scherer, by the 

 action of nitric acid. This uroglaucin may possibly be contained 

 in the blue., violet, and black urine of the earlier observers, and is 

 probably identical with the pigment named cyanurin. Heller's 

 assertion that the urine in Bright's disease and in cholera very 

 often assumes a blue colour on the addition of very concentrated 

 nitric acid, may be very easily put to the test ; as far as my own 

 experience goes, it is only when ureemic symptoms have mani- 

 fested themselves that this peculiarity of the urine is generally 

 observable. 



The presence of the biliary acids in the urine is by no means 

 so rare as has generally b.een supposed. Pettenkofer himself once 

 detected them, by means of his own test, in the urine in a case of 

 pneumonia ; it is worthy of notice, that they are often present in 

 only very small quantity, or are altogether absent, in well marked 

 cases of icturus, even when the urine abounds in bile-pigment, 

 while a urine which contains very little pigment is often found, on 

 a careful investigation, to be comparatively rich in the biliary 

 resinous acids. Cholic acid is, however, by no means invariably 

 present in the urine in cases of pneumonia ; indeed, it is compara- 

 tively seldom found in that disease. I have not been able to 

 discover these substances in the urine in any other disorder, unless 

 (as is often the case with pneumonia of the right side) there was a 

 decided affection of the liver. 



We have nothing to add to the observations already made (in 

 vol. i., p. 316) regarding the occurrence of bile-pigment in the urine, 



We must similarly refer our readers to vol. i., pp. 169 and 177> 

 for all that need be stated regarding those comparatively rare sub- 

 stances, ocanthine and cystine. 



We have already noticed the pathological conditions under 

 which carbonate of ammonia may occur in the urine. 



Sulphuretted hydrogen, although in most cases formed in the 

 same manner as carbonate of ammonia, has been occasionally found 

 in the urine in cases of tuberculosis and rubeola by Chevallier,t 

 Hoflet, and Heller. 



* Arch. f. Chem. u. Mikros. Bd. 4, S. 191 19G. 



t Journ. de Chim. meM. T. 1, p. 179. 



I Medic. Ann. Bd. 11, S. 415. 



Arch. f. Chem. u. Mikros. Bd. 3, S. 24. 



