398 Dr. A. E. Garrod. A Contribution to the Sludy [Apr. 



extracted from the highly- coloured urine of febrile patients, but 

 neither case does he consider that the quantity present suffices 

 materially affect the colour of the urine when diluted to the 01 

 bulk. 



He adds : " I am disposed to regard the colour of urine as beii 

 due to the presence of a yellow body which, for the present, may 

 called urochrome, and, without positively denying the presence 

 traces of urobilin in normal urine, I consider that the amount \\liic 

 occui-s in ordinary specimens is far too minute to affect the colot 

 whilst even in febrile urine the colour is only modified a little by 

 presence of urobilin." 



The present writer waa led to approach this difficult problem 

 the study of the coloration of uric acid sediments in urine, in whic 

 it became obvious that the yellow pigment played an important pat 

 Attempts were therefore made to extract this pigment for purposes 

 further investigation, by a process which should differ from 

 hitherto employed in the following important respects : 



1. That, if possible, the recognised urinary pigments, and especi 



urobilin should be got rid of at the outset. 



2. That the employment of powerful reagents, and especially 



mineral acids, should be, as far as possible, avoided. 



3. That the colouring matter should not be precipitated by lew 



acetate or other metallic compounds, and afterwards extracts 

 from the precipitate. 



After many attempts and repeated failures, a method was devise* 

 which, to a great extent, fulfils the above conditions, the essentia 

 parts of the process being as follows : 



1. Saturation of the urine with pure ammonium sulphate and tiltra 



tion. 



2. Extraction, from the filtrate, with ethylic alcohol, which sepi 



rates out from the saturated liquid, and carries most of tb 

 colouring matter with it. 



3. Evaporation, and solution of the residue in absolute alcohol. 



4. Precipitation of the pigment from its alcoholic solution by exces 



of ether. 



For purposes of more detailed description, it will be convenient b 

 divide the process into the above four stages. 



Stage I. A pint or two of concentrated normal urine is saturate* 

 with pure ammonium sulphate, solution being aided by gentle warmth 

 and is then passed through a filter. 



The filtrate is clear and has a pure golden colour, somewhat pale 

 than that of the original urine. 



The precipitate, which varies in tint from brown to pink, cont 





