THE PIGMENTS OF THE URINE. 295 



solution is treated with an excess of sodium hydrate solution, and 

 will then give the spectrum of haemochromogen. 



Haematin. Haematin is very rarely found in the urine. Its 

 presence as such can be determined only by spectroscopic examina- 

 tion. Like hemoglobin and methaemoglobin, it gives Heller's 

 reaction. 



Haematoporphyrin. According to Garrod, traces of haematopor- 

 phyrin may be found in every urine. Larger quantities are 

 observed in a number of diseases, but even in these the amount 

 is usually so small that its presence will scarcely be suspected 

 from simple inspection. Typical ha3matoporphyrinuria, on the 

 other hand, may be observed following the prolonged administra- 

 tion of sulphonal, trional, and tetronal, or in cases of poisoning with 

 the substances in question. The urine then appears dark red in 

 color, and on standing may turn almost black. As Hammarsten 

 has pointed out, this change in color is only in part due to haemato- 

 porphyrin, and is largely referable to other red and reddish-brown 

 pigments of unknown character. Whether or not different haemato- 

 porphyrins exist has not been definitely determined, but is probable. 

 In freshly voided urines hsematoporphyrin probably exists in com- 

 bination with some other, still unknown body, with which it forms 

 a colorless chromogen. From this the free pigment then develops 

 on exposure to the air. 



Like the common blood-pigments and haematin, haematoporphyrin 

 also reacts with Heller's test. To prove its presence, however, as 

 such, a spectroscopic examination is necessary. To this end, the 

 urine is precipitated with barium hydrate and barium chloride. 

 The precipitate is washed and allowed to stand in contact with 

 acidulated alcohol, which extracts the pigment. After filtering, 

 the solution is examined with the spectroscope ; if subsequently 

 the solution is rendered alkaline with ammonia, the spectrum of 

 haematoporphyrin in alkaline solution is obtained. To isolate the 

 substance as such, the acid solution is mixed with a little chloro- 

 form and diluted with water. On gentle agitation the chloroform 

 takes up the greater portion of the haematoporphyrin, while a 

 small fraction and other pigments remain in the diluted alcoholic 

 solution. On evaporating the chloroform extract the substance is 

 obtained in comparatively pure form. 



Neumeister states that besides haematoporphyrin another deriva- 

 tive of the blood-pigment may be observed in cases of poisoning 

 with sulphonal, which, in contradistinction to the first, contains iron. 

 This does not react with Heller's test, however, while the color 

 of the urine is the same as in typical haematoporphyrinuria. The 

 pigment is precipitated by an alkaline barium chloride solution, 

 and can be subsequently dissolved in acid alcohol. This solution 

 presents a reddish-violet color, and shows one broad band of absorp- 

 tion in the blue portion of the spectrum immediately bordering on 

 the green. 



