As far as you have had an opportunity of visiting patients, do you know it to be a painful complaint?—It produces cramp, which is painful, and it certainly produces pain in the stomach and bowels by its violent action.
Do you apprehend that a purgative medicine would be a proper medicine for a person in that situation, supposing it to have been Cholera Morbus?—There were no symptoms of Cholera Morbus when I saw Mrs. Downing; but from what I heard of her complaint, I imagined that there was something offensive either in the stomach or bowels, which ought to be evacuated.
Were ten drops of laudanum a proper thing to give her?—It is sometimes given to allay the irritation of those parts.
Might not a powerful administration of laudanum be of use in Cholera Morbus?—Seldom, I think, in large quantities, but is given in small doses frequently, if the case be urgent.
I think you have stated, that the result of your chemical experiment was not the production of any gross arsenic, or arsenic in substance?—Not arsenic in substance.
And you judged from the application of chemical tests?—Yes, Sir.
Be so good as to state what the chemical tests were which you used?—The first was with the sulphate of copper, which is the common blue vitriol. If you put a little carbonate of potash into water containing a solution of arsenic, and then add the sulphate of copper in solution, a green precipitate will be produced; whereas, if no arsenic be present, a blue precipitate would be formed: that was the first test which I used.
What was the second test?—The second test was with the nitrate of silver, or common lunar caustic, (these are the same in substance, but the lunar caustic is the more common term). Put a little carbonate of potash into water containing arsenic in solution, and dip the end of a cylindrical piece of lunar caustic into the water, a yellow precipitate will be produced; whereas if no arsenic be present, a white precipitate would be formed. Those were the chief tests which I used; but in order to ascertain whether any thing which had been taken into the stomach, or was naturally contained in it, would alter the appearances produced by the tests, so as to make the result uncertain, I tried other experiments. I concluded that bile formed part of the contents of the stomach; I therefore procured some and mixed it with water, and subjected it to the same tests in the same manner, and I found that the appearance of the precipitate was not the same as if arsenic were present; I therefore inferred that bile, in the quantity in which it may occasionally be found in the stomach, would not alter the conclusion I had drawn from the result of my first experiments.—I was informed that Mrs. Downing had eaten onions; I boiled some in water in the usual way, and after pouring off the water in which they were boiled, I poured some boiling water on them, and let them stand for some hours; I then ascertained what effect this water would produce on the tests, and was satisfied that it would not, when the experiment was carefully made, produce the appearance of arsenic.—I also understood that some tartarized antimony had been given; I tried the tests with a solution of that substance, and the precipitate had not the appearance which arsenic, if present, would put on.
Do you happen to know who was the first person who discovered these tests?—I believe Mr. Hume discovered that with nitrate of silver.
Do you know Dr. Marcett?—Yes, I know him from his writings, to be a clever man.