APPENDIX. 533 



Chloride of sodium was altogether absent ; the other salts were 

 diminished in nearly similar proportions. 



Death occurred the same evening, about six o' clock. Shortly 

 before that event, nearly two ounces of urine were removed by 

 the catheter. The secretion had lost its previous colour, and 

 was of a deep citron- yellow tint ; it was turbid, and deposited 

 a perfectly white sediment, composed of all the previous ingre- 

 dients with the exception of uroglaucin. It was acid, and re- 

 mained so for twenty-four hours, although exposed during part 

 of that time to the sun's rays. Its specific gravity was 1012. 



From the examination of the urine it seems clear that the 

 uroglaucin and urrhodin are products of oxidation of the peculiar 

 yellow pigment uroxanthin. For the f native ' urine was in- 

 tensely yellow, and did not contain, either in solution or in the 

 sediment, a trace of either uroglaucin or urrhodin. On the addi- 

 tion of nitric acid there was a white precipitate of albumen, 

 which gradually assumed a violet tint, and after standing for 

 some time became of a deep blue colour. On the addition of 

 this acid the urine became first of a carmine tint, then of a 

 violet colour, and ultimately of a rich blue ; and during these 

 changes it deposited uroglaucin presenting the appearance of 

 bright powdered ultramarine, but under the microscope exhi- 

 biting a crystalline form. On the surface of this urine there 

 was formed the same coppery film that was noticed on the 

 blue urine, and the microscope detected crystals of uroglaucin 

 in it. Cold spirit, when added to the sediment, took up ur- 

 rhodin, assuming a brilliant carmine tint. 



Hence it seems to follow that the acid urine, which was of 

 a pure yellow colour, contained uroxanthin, and that this uro- 

 xanthin, under the oxydizing influence of nitric acid, yielded 

 uroglaucin and urrhodin in the same manner that it had spon- 

 taneously done in the case of the bluish-green specimens. To 

 confirm this opinion a portion of the yellow urine was ex- 

 posed for a length of time to the action of the atmosphere. The 

 same products were slowly developed which had been rapidly 

 produced by nitric acid. The same red metallic film was 

 produced, the same blue tint gradually developed, and, subse- 

 quently, the same blue sediment yielding uroglaucin and ur- 

 rhodin, while the supernatant fluid became pale. 



