PIGME XT. I TION OF PATHOLOGICAL URLNES. 629 
than normal amount. I have also frequently observed thai urochrome itself 
takes a share in the increased pigmentation of febrile urine. 
Urobilin is found in large amount when extensive haemolysis, or large 
internal haBinorrhages, 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 l> and F is usually visible. It is common 
for free urobilin to lie present in diabetes. An increase of uroerythrin is 
seen in many forms of hepatic disorder. Hsematoporphyrin dues nut 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 haeniatoporphyrin, 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, ami 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 foimd in the deposit. Some specimens of urine preserve 
the integrity of the corpuscle- very completely, ami in slight cases of hematuria, 
while no pigment may lie found in solution, the deposit obtained by centrifuging 
will show a red layer of corpuscles. In hcemoglobinuria 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 oxyhaemoglohin, 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 bilirubin, when the urine is saffron-coloured ; but occasionally 
partly as biliverdin, 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 Hos}). Hej)., London, 1893, vol. 1. p. 363 ; Garrod and Hopkins, "The 
unity of Urobilin," Juian. Physiol., Cambridge and London, 1890, vol. xx. p. 130.. 
