OCCUBRHNOE OF INDIGO-BLUE IN URINE. 24? 



when the amount of indigo-blue formed was very small I 

 always found that 16 fluid ounces of urine yielded an appre- 

 ciable quantity of it. 



The urine of forty different individuals, all of whom were 

 apparently in a good state of health, yielded, with one excep- 

 tion only, more or less indigo-blue, when examined in the 

 manner just described. These individuals belonged to both 

 sexes, and they were of ages varying from 7 to 55. The ma- 

 jority were persons of the working classes. The largest quan- 

 tity of indigo-blue was obtained from the urine of a man above 

 the age of 50, a publican by trade. The urine of a young man, 

 aged 32, a servant in my employment, yielded almost as large 

 a quantity. Among the rest, the urine of a young man, aged 

 25, an engraver, that of a clerk, aged 23, and that of a girl, 

 aged 12, who had been a cripple from infancy, were alone 

 remarkable for the amount of indigo-blue which they yielded, 

 In all these cases the indigo-blue was accompanied by the 

 substance imparting to alcohol a purple colour, and which I 

 suppose to be indirubine. The other specimens afforded much 

 less, sometimes mere traces. In all cases however in which 

 the urine of the same individual was examined at different 

 times, the amount of indigo-blue obtained from it was found 

 to vary exceedingly, it being sometimes considerable and occa- 

 sionally dwindling down to a mere trace. It was only very 

 rarely however that none was found. In the case of the 

 individual first referred to, the urine gave on one occasion not 

 a trace, and this took place when he was engaged in perform- 

 ing labour, unusual for him both in its nature and amount. 

 In my own case, as well as that of my assistant, the amount 

 varied most capriciously from a tolerable quantity to a mere 

 trace, occasionally even none at all being obtained. 



I performed several experiments with different kinds of diet 

 in order to ascertain the effect on the amount of indigo-blue 

 yielded by the urine. Only one experiment, however, led tQ 

 any decisive result. Having selected an occasion, when the 



