Dr. Neale also stated that he thought nothing short of the re-production of metallic arsenic could be satisfactory. Dr. Neale's experiments were as follow:

1st. To a solution of sulphate of copper a small quantity of decoction of onions was added; a solution of phosphate of soda dropped into this mixture, produced a green precipitate very much resembling the Scheele's green.

2d. To a solution of phosphate of soda was added some decoction of onions: on applying the nitrate of silver, a yellow precipitate took place, resembling that when a solu tion of arsenic is used.

There is one circumstance connected with the case of the deceased which greatly adds to the merit and applicability of these experiments, and that is, the deceased had dined on rabbit and onion-sauce a few hours before her death; and, as many of the animal fluids contain phosphate of soda, we readily perceive the source of each substance from which the analogy was taken.

A few days after reading the account of this interesting trial, I went over the experiments of Dr. Neale, and repeated them before three medical friends of this town, the results of which, with some observations, I shall now state.

In Dr. Neale's first experiment, I found the green preci pitate so exactly resembling that from a solution of arsenic, that I was induced afterwards to repeat it on a larger scale, so as to obtain a small lump of it in a dried state, and then the resemblance to the Scheele's green was remarkably striking. In his second experiment the result is so much like that made with arsenic, that it would puzzle most people to distinguish them; if there be any difference, it is that, when the phosphate of soda is employed, the precipitate is of a more beautiful sulphur colour than when arsenic is used. It may be proper to mention, that, in this experi ment, the decoction of onions is not at all necessary, its addition or omission making no difference in the colour of the precipitate; but, in the first experiment it is indispensable, the peculiar green precipitate not taking place till it be added.

As a further elucidation of the subject, I took the lump of green precipitate before mentioned, and laid it on a red hot iron, holding over it a plate of polished copper: it soon be came a black cinder, without at all affecting the copper, On substituting a lump of arsenite of copper, or Scheele's green, white fumes are exhaled, and the copper plate is immediately covered with a white coat, in the same manner as when white arsenic is employed.

The conclusions to be drawn from these experiments appear to me to be of considerable importance to the

public in general. We now see two experiments, which, though not considered quite conclusive, were thought to be strongly corroborative, rendered completely nugatory. In your Journal for December, 1815, is a paper by Mr. Crowfoot, in which, after trying the two experiments made by Dr. Edwards, and that with the copper plates, the writer says, "From the whole, therefore, though every experiment produced conviction of the fact, it may be useful to state that the weakest proof was that by the action of heat, and the strongest and most decisive by the admirable test of Mr. Hume." Yet who will place confidence in this test in future? I hope this will not be understood as any censure of Mr. Crowfoot. So far from any intention of that kind, I take this opportunity of stating that I read Mr. Crowfoot's communication at the time with great pleasure, and had not the least doubt of its accuracy. What surprises me is, that Mr. Hume and other excellent chemists should not have been acquainted with the fact that phosphate of soda pro duces with the nitrate of silver the same beautiful yellow precipitate that arsenite of potash does. In searching for Information on this subject, I found, in your Journal for 1816, under the head of Medical and Physical Intelligence, that an ingenious student at Guy's Hospital" had suggested this fact to Dr. Marcet; but, what is very curious, he goes on to say, "Yet in juridical cases other tests may be requisite to be assured of the presence of arsenic. The addition of sulphate of copper and potash, and the formation of Scheele's green, affords a very satisfactory confirmation." After the first experiment of Dr. Neale, I am inclined to think this ingenious student" will have his confidence shaken in this test as well as in the other. In consulting the celebrated work of M. Orfila on Toxicology, I cannot find that he was acquainted with either of these facts. In a note to page 115 of vol. i. part i. he says, "It may readily be conceived that the nitrate of silver lately proposed by Mr. Home (Hume) for discovering the arsenious acid, ought to be a very uncertain test in a great number of cases. In fact, if the quantity of arsenious acid mixed with the aliments is, very small, and these contain muriates, there ought to be formed, at the same time, a small quantity of arsenite of silver of a yellow colour, and a great deal of muriate of silver of a white; in such manner that the precipitate would appear of this last colour, whilst it ought properly to be yellow." Here it is evident that, had M. Orfila known that phosphate of soda would produce the same yellow precipitate, he would have mentioned it. Nor can I find any mention of a green precipitate produced in any way, but by the help of arsenious acid, or white arsenic.

I have thus endeavoured to shew how much obligation we are under to Dr. Neale; for, although previous mention was made of the yellow precipitate, I believe he was the first to inform us that an apple-green precipitate resembling the arsenite of copper or Scheele's green could be produced without the existence of arsenic.

I

Great Yarmouth;

June 12, 1817.

For the London Medical and Physical Journal.

On the Trial of Mr. Donnell; by AMINICUS.

BEG leave to transmit to you a few remarks on your Report of the Trial of Mr. Donnell, which has also appeared at length in the London newspapers. It is not only very surprising, but much to be regretted, that, in a case wherein the life of an individual was at issue, as well as the interests of humanity deeply involved, every possible means of elucidation which the present advanced state of chemistry could furnish was not had recourse to; for it is well known to chemists that even a single grain of the white oxyd of arsenic will (when properly treated) exhibit such metallic appearance as to leave no doubt of its presence. Humid analysis is liable to deceptive appearances from adventitious causes, and therefore ought never to be solely relied on when life is at stake. How the presence of arsenic could be so clearly evinced in a fluid state as to leave "not the slightest doubt of its being the cause of Mrs. Dunning's death," when it could not be reduced to a metallic state, (simple as the process is known to be,) I am at a loss to conjecture.

Reflecting on this trial, I have been led to contrast the conduct of Dr. Edwards with that of the late John Hunter, in the memorable case of Captain Donnellan, who was executed for poisoning Sir Theodosius Boughton by laurel, water. The judicious remarks and extreme care manifested by him while under examination in court, were such as bespoke the character so justly given of that great man. I think his remarks on experiments are worth recording in your valuable Journal.

He says, "I apprehend a great deal depends upon the mode of experiment. There is no man fit to make an experiment (under such circumstances) but those who have made many, and with a considerable attention to all the circumstances that relate to experiment. It is a common experiment, which I believe seldom fails, and is in the mouth of every-body, that a little brandy will kill a cat: I have made the experiment, and have killed several cats; but it is a

false

false experiment, for, in all those cases where it kills the cat, it has got into the lungs, and not the stomach-if you convey it into the stomach so as not to affect the lungs, the cat will not die," &c. &c.

I have been induced to turn to the evidence given in court of the effects of laurel-water on the stomach in the case of Sir T. Boughton, from the instance of sudden death reported in a monthly periodical work (probably copied from some newspaper) of Mr. Middleton's housekeeper, occasioned by her drinking a quantity of that deleterious article by mistake. This statement, I find, by communication with Mr. M. is very incorrect, and ought, therefore, to be rectified. The case was briefly this:-Mr. M.'s housekeeper was ordered to prepare a quantity of boiled custard, to be ready for company expected on the succeeding day. Four or five laurel-leaves had been employed, as usual, to give it a fla vour; and, a small portion of the custard remaining in the pan, after the requisite quantity had been poured out, the housekeeper was induced to taste it, inviting also another female servant to partake with her, which she did. The housekeeper died before medical assistance could well be administered; and the other servant was only saved by the best possible attention being paid to her, she having, it was supposed, taken less of the custard. It is very remarkable that this servant exhibited all the symptoms of drowsiness, inaction of the stomach, &c. which usually succeed the taking a fatal portion of Tincture Opii, for the judicious and welldirected efforts of those around her were scarcely sufficient to prevent her sinking into sleep.

This appears a very remarkable circumstance, inasmuch as it was not manifest, either from the numerous experi ments of the late John Hunter, instituted on different animals previous to the trial of Captain Donnellan, or from the effects of laurel-water on the stomach of Sir T. Boughton, that any thing like drowsiness or inaction of the stomach was apparent. On the contrary, he complained to Lady Boughton repeatedly that his medicine occasioned so much sickness that he was afraid of being unable to retain it on his stomach, &c. I am quite at a loss to account for this discordancy of symptoms; but, perhaps, some of your numerous medical contributors, more conversant with the subject, may think it worth while to oblige your readers with their sentiments.

Doncaster; May 13, 1817.

This gentleman has favoured us with his name, but delicacy induces him to decline its publication.-EDIT.

For

97

For the London Medical and Physical Journal. Further Remarks on Phthisis Pulmonalis; by ISAAC BUXTON, M.D.

N Dr. Sutton's reply to my letter, published in your

late to me individually. As the personal dispute of two combatants can be very little interesting to the public at large, I shall endeavour to reply to that part of his letter as briefly as possible.

Dr. S. informs me, that he has no personal enmity towards myself. Judging of his feelings towards me by my own towards him, I never imagined that any such motive influenced either his heart or his pen.

He conceives that I am displeased with him for calling my opinions in question. In this I beg to assure him that he is' mistaken. A writer who publishes his opinions is like a man who gives a general challenge; and any one, or every one, has the privilege of entering the lists with him.

Dr. S. asserts his full liberty of "communicating any thing further on pulmonary consumption that would interfere with my opinions.". Without doubt, he, or any other individual, is perfectly at liberty to do this. But it did appear to me, and still does appear, rather extraordinary, that, in his communication in March 1816, p. 182, he should express a wish that the discussion between us might cease, and, either in the same paper, or in a paper published some months afterwards, should bring forward fresh matter, which was professedly intended to bear on the questions at issue between us, and to diminish the force of the evidence which I had produced. This must demand a reply; and, consequently, the wish and the procedure appear inconsistent with each other.

In your Journal for May last, p. 362, in replying to Dr. Sutton's observations respecting Sicily and Malta, I mentioned I had before shewn, that, in quoting Irvine on the Diseases of Sicily, Dr. Sutton's "supposed proof depends entirely on his separating particular passages; and, by detaching them from their situation, giving them a force, which, in their connexion, they do not possess." To this Dr. S. answers, p. 462, "I really believe he (Dr. Buxton) thinks so; but, if the reader of this note can confide in my assertion, I will assure him, that I have not employed myself in any such inferior work. I have laid always more stress upon absolute facts in the writings I have alluded to, than on