328 



under the microscope, he frequently observed in the field of vision 

 particles of a deep blue colour ; so often did this occur, that he 

 could not even then help suspecting that their presence was not ac- 

 cidental; however, no analj^sis of the blue colouring matter was 

 made at that time, and the circumstance was in a fair way of being 

 forgotten, until the recollection of it was revived by another oc- 

 currence. 



In June 1852, a sample of urine, freely exposed to the air in an 

 open vessel, was observed after four or five days' exposure, gradually 

 to change colour ; the pellicle or scum which had formed upon the 

 surface of the urine became first slate- coloured, and at length deep 

 blue, with here and there a rusty-red tint. The urine also under- 

 went at the same time some remarkable changes ; it became thick 

 and turbid, deep brown, greenish, bluish-green, and finally of a 

 faded yellowish-green colour ; a considerable sediment was found 

 at the bottom of the glass ; this was deep brovvu, intermixed with a 

 little blue colouring matter, and it had a medicinal smell resembling 

 somewhat that of Valerian. In this state, without undergoing any 

 further material changes, the urine remained for many days. 



Examined with the microscope, the scum or pellicle on the sur- 

 face was found to consist of vibriones, innumerable animalcules, and 

 crystals of triple phosphate, with a great many fragments and gra- 

 nules of a deep and bright blue colour. 



A second sample of the same urine was therefore procured, taking 

 every precaution to avoid fallacy. Gradually the same changes en- 

 sued as in the first sample, and this likewise became blue. Having 

 thus ascertained that the changes observed were due to something 

 contained in the urine itself, the author next proceeded to set aside 

 in open vessels, a series of urines all from the same patient, noting 

 the alterations which occurred from day to day; these samples 

 underwent nearly similar changes ; but the quantity of blue colour- 

 ing matter and brown extractive gradually diminished, until at length 

 they were present in such small amount as to be visible only under 

 the microscope, and at last they entirely disappeared. 



The results obtained from an examination of the urine, the Hue 

 colouring ^natter and the brown extractive, are then given by the 

 author ; they are as follow :— - 



The urine. — The urine of the second sample at the time of analysis, 

 when shaken, had a dark, greenish-brown colour ; but on standing 

 at rest for some time, the colouring matter fell to the bottom, form- 

 ing bluish-green flocculi, while the supernatant liquid was of a 

 deep wine -red colour. The bottle was set aside corked, for ten days, 

 at the end of which time the bluish- green precipitate had entirely 

 disappeared ; but on removing the cork, and allowing free access of 

 air for some time, the coloured deposit was again produced. This 

 was washed with water;, drenched with hydrochloric acid, and finally 

 dried ; by this means was obtained a rich blue powder possessing all 

 the chemical characters and properties of indigo. 



The urine that was filtered oflr from the above precipitate was 

 allowed to evaporate spontaneously, by which means it yielded an 



