22 
Dr. Pearson's Experiments and Observations 
no milkiness could be induced. If carbonate of soda was added, 
in place of the caustic soda, the mixture could not be made clear. 
3. Lime water was rendered turbid by this solution, but I 
neglected to examine the precipitated matter. 
4. A little of the solution, with the addition of a few drops of 
concentrated nitric acid, being evaporated to dryness, sometimes 
a pink, and at other times a blood-red, or rose-coloured matter 
was left ; which, by further application of fire, became black. 
5. Carbonic acid, digested and shook with this solution, did 
not render it turbid. 
6. To the whole of the remaining solution was added diluted 
sulphuric acid, to saturate the alkali. On standing, a copious 
precipitate took place, from a clear liquid ; which precipitate, 
being washed and dried, was a mass of very light, mica-like, 
: 7 v/ / whitish crystals, amounting to 123 grains. It was estimated 
that the solution used in the Experiments 1. — 5. would have 
O ' r ; . ' - produced 12 grains, and that the 30 grains of soap-like matter, 
( b , ) not decompounded, would have yielded about 1 4 grains more. 
( e ) The precipitate, ( d , 6 .) 
1. Had no taste, nor smell, and did not dissolve in the mouth. 
2. About one part of it only dissolved in 800 parts of boil- 
ing water; which solution did not redden paper stained with 
turnsole* nor the solution and tincture of this test; neither did it 
change turnsole paper, reddened by acid, to a blue colour. On 
cooling, the greatest part of what had been dissolved was de- 
posited, in a crystallized state, equally on the sides and bottom 
of the vessel. This crystallized matter had the properties 
abovementioned {d.). Boiling water was found to dissolve a 
much greater proportion of urinary stone, and also of gravel , 
than of this precipitate. 
