PIGMENTATION OF PATHOLOGICAL URINES. 629 



than normal amount. I have also frequently observed that urochrome itself 

 takes a share in the increased pigmentation of febrile urine. 



Urobilin is found in large amount when extensive haemolysis, or large 

 internal haemorrhages, have occurred ; it is also greatly increased in certain 

 cases of hepatic cirrhosis. The high colour of the urine of pernicious anaemia 

 is in part due to urobilin ; other pigments may take a large share in the increase 

 in colour, but it is characteristic of this disease for free urobilin to be present 

 instead of the chromogen, for even in pale specimens, which are sometimes 

 passed, an absorption-band between b and F is usually visible. It is common 

 for free urobilin to be present in diabetes. An increase of uroerythrin is 

 seen in many forms of hepatic disorder. Haematoporphyrin does not appear to 

 depend upon haemolysis for increased excretion. After excessive use of drugs 

 of the sulphonal type, the urine may exhibit a deep port-wine colour ; part, 

 but not the whole, of this pigmentation is due to an enormously increased 

 excretion of haematoporphyrin, which may be quite unassociated with any 

 decrease in the haemoglobin of the blood. Increase of this pigment, but of 

 much slighter degree, occurs also in plumbism and in certain other diseased 

 conditions. 



The so-called pathological urobilin. Several observers have made a 

 distinction between normal urobilin and a pathological form of the pigment. 

 The differences found have been mainly those of spectroscopic appearances ; the 

 pathological form showing a proportionately broader band between b and F, 

 and additional bands elsewhere. The various descriptions of the pathological 

 pigment are in no sense consistent one with the other. Evidence has recently 

 been brought forward to show that the points of distinction may be all 

 explained as the result of impurities, and that urobilin is one and the same 

 substance wherever found. 1 



Special pathological pigments Blood pigments. In hcematuria, due 

 to whatever cause, the urine usually contains unaltered haemoglobin. In 

 general the pigment may be recognised in solution spectroscopically, while red 

 blood corpuscles are found in the deposit. Some specimens of urine preserve 

 the integrity of the corpuscles very completely, and in slight cases of haematuria, 

 while no pigment may be found in solution, the deposit obtained by.centrifuging 

 will show a red layer of corpuscles. In hwmoglobinuria the pigment is passed 

 wholly in solution, and no corpuscles are found. Not infrequently methcemo- 

 globin is present in place of or in addition to oxyhaemoglobin, even when 

 the urine is first passed. Specimens which are spoken of as " smoky " usually 

 contain this latter form of pigment. 



If the quantity of pigment is too small to show a recognisable spectrum 

 direct, the urine may be heated with caustic alkali, filtered, and a few 

 drops of ammonium sulphide added. The more powerful absorption-bands 

 of haemochromogen will then be generally visible. Or, the urine may be 

 boiled with caustic alkali, when, in the presence of blood, a greenish tint is 

 produced, and the phosphates are precipitated with a brownish-red colour, due 

 to haematin (Heller). The blue colour produced by the addition of guaiacum 

 tincture and an ethereal solution of hydrogen peroxide, is a delicate but not 

 wholly conclusive test when applied to urine. 



Bile pigments appear in the urine in most cases of jaundice, generally in 

 the form of bilimbin, when the urine is saffron-coloured ; but occasionally 

 partly as biiiverdin, when a greenish tint predominates. When present in 

 large amount, there is no difficulty in the recognition of these pigments. 

 Gmelin's reaction is obtained by allowing the urine to run gently on to the 

 surface of some fuming nitric acid contained in a test tube. The test is made 

 more delicate if the urine be first repeatedly filtered through a clean white 



1 Hopkins, Guy's Hoy}. Rep., London, 1893, vol. 1. p. 363 ; Garrod and Hopkins, "The 

 unity of Urobilin," Journ. Physiol., Cambridge and London, 1896, vol. xx. p. 130. 



