300 
DR. HASSALL ON THE FREQUENT PRESENCE 
these quickly subsided and left a clear supernatant liquid of a deep wine-red colour; 
above the deposit of earthy phosphates, collected at the bottom of the vessel, the 
colouring- matter formed a thin stratum composed of dirty bluish-green flocculi. 
The bottle was corked and set aside for ten days, at the end of that time the bluish- 
green precipitate had entirely disappeared, but on removing the cork and allowing 
free access of atmospheric air for some days, the coloured deposit was again 
produced. While in this state the liquid was filtered and the precipitate washed 
with water, then drenched with weak hydrochloric acid, and finally dried. By this 
means a rich blue precipitate was obtained possessing the following characters, 
chemical and general. 
a. It exhibited a coppery lustre on being rubbed with the nail. 
(3. It presented an amorphous, granular and fragmentary appearance under the 
microscope. 
y. It was not soluble in water, dilute acids, ether, alcohol, or turpentine ; nor was it 
affected by spirits of wine in which there was a little free acid. 
($. It was not attacked by liquor potassee at ordinary temperatures, but when 
heated therewith, it was converted into a dirty, yellowish-brown solution. 
g. It was freely dissolved by strong sulphuric acid, and produced a deep blue 
liquid miscible with water, and which chlorine had the power of bleaching. 
£ When heated with fuming nitric acid, it yielded a greenish-yellow solution, which 
became of a brilliant yellow with liq. potassse. 
/I . On diffusing it through water and boiling with lime and grape-sugar, it furnished 
a wine-red fluid, which on being filtered and then neutralized with hydrochloric acid, 
gave a greenish-blue precipitate. Another portion of the liquor was exposed to the 
air for a few hours, and it reacquired its blue colour. 
0. When heated in a test-tube it evolved vapours of a rich violet- red colour, and 
produced the characteristic odour of sublimed indigo. 
The urine that was filtered off from the above precipitate was allowed to evaporate 
spontaneously, by which means it yielded an additional quantity of indigo, which 
adhered in the form of very small flakes to the sides of the dish. It also gave a 
rather large proportion of a deliquescent brown colouring matter, and a number of 
large rhombic plates of ammoniacal phosphate of soda and potash. These crystals 
were removed from the vessel by means of a needle, and the brown residue was 
treated first with alcohol and then with water. The alcohol acquired a deep brownish- 
red colour, and the water a dark brownish-green. Both of these solutions were 
evaporated at a temperature of 160 c Fahr. 
The alcoholic solution furnished a rich brown extractive, which was soluble in 
water, but not in dilute acids ; and nitric acid did not produce that play of colours 
which is characteristic of bile pigment, nor did the precipitate formed with basic 
acetate oflead furnish a purple liquid with alcohol and free acid. A strong solution 
of potash dissolved the extractive and yielded a deep blood -red fluid, which was 
