In your judgment, is that test an infallible test of arsenic being present in solution?—By no means.
Have you heard of the other test which he tried, namely, that by means of the nitrate of silver, or the lunar caustic?—I have.
What is your judgment of that species of test as to arsenic?—That it is equally fallible.
Now as to the test with bile?—No [meaning, that test is not infallible]: from the presence of phosphoric acid, the same yellow-coloured precipitate will be thrown down, if some lunar caustic be put into a solution of phosphate of soda.
What do you esteem to be a complete test of arsenic being held in solution in any complicated body?—I don't conceive that there is any complete test, but the evaporating of the solution, and reproducing the arsenic in its metallic state.
Have you made any experiment upon any mixture, through the medium of nitrate of silver, or the lunar caustic, in which onions have been infused?—Yes, with a decoction of onions.
Be so good as to state particularly what that experiment was which you made?—I made it within the last five days; I made a decoction of onions, and added the carbonate of potash together with the lunar caustic, and a pale yellow cloud was produced; the liquor became opaque, and a cloud, of a colour between white and yellow, or opal, or precious stone colour, was produced.
(By Mr. Justice Abbott.) Through the whole body?—Yes, my Lord; I then varied the experiment and added to it the phosphate of soda.
(By Mr. Sergt. Pell.) After this opaline cloud had been produced, what other effect had it?—It precipitated gradually; there was a precipitation.
(By Mr. Justice Abbott.) This dark shade, or yellowish white cloud, precipitated to the bottom?—Yes, my Lord.
