cesophagus, and will suffer much distress from being prevented from vomiting, even supposing the substance not to be poisonous; and accordingly we find M. Orfila himself admitting that some animals, on whom the operation was merely performed without any poison being administered, died sooner than others who got poison at the same time. From our own experiments, we are satisfied, that, by much the best method of ascertaining the poisonous nature of any substance, and of tracing its effects upon the system, is, to apply it to a slight wound in some unimportant part, reaching to the subcutaneous cellular membrane. We are thus able to distinguish accurately between its local and general effects; and it is astonishing how small a quantity of a really poisonous substance, applied in this way, will produce death. The method has not been altogether neglected by M. Orfila, but only not carried to the extent it deserves. Another mode of experimenting used by M. Orfila, was, the direct injection of the suspected substance into the circulating system, by throwing it into the jugular vein. The results are undoubtedly interesting, but they are not conclusive as to the poisonous nature of any substance, for they may kill in other ways; for example, by chemical action coagulating the blood, and yet be perfectly innocent, taken into the stomach, or inserted into a wound. We may also here notice an error into which M. Orfila has sometimes fallen, in concluding that because a substance, injected into a vein, produces different and much more violent symptoms than when taken into the stomach, it does act by absorption. But surely there is a very wide difference between the action of a substance rudely thrown into the circulating mass, and one gradually taken and insensibly blended with it. Besides, the substance may not be absorbed entire, and unchanged; and yet we are warranted, in common language, to say, that it acts by absorption, if the essential constituent by which it acts on the constitution be absorbed.

We therefore consider Dr. Lafort's proof against the absorption of corrosive sublimate, as being totally unfounded; nor do we acquiesce in Mr. Brodie's, that, when it destroys the inner membrane of the stomach, the idea of absorption is precluded. That it may, and occasionally does kill, by disorganizing the stomach, and the violent impression it makes

upon it, independently of absorption, just as a child is sometimes killed by a large draught of boiling water, we admit; but there are abundance of facts, which prove that it may be absorbed even when the part to which it is applied is disorganized. M. Orfila also seems to adopt Mr. Brodie's opinion, in regard to the immediate cause of death from corrosive sublimate; that it was not in the stomach, because its functions may be suspended for days, without death being produced, but that it was in both the brain and the heart. We doubt much, however, whether we are yet so far advanced in physiological science, as to adopt his conclusions, or admit the validity of his arguments. But this subject would require a very long discussion. We therefore postpone it to another opportunity, and return to M. Orfila, and the immediate effects of the various poisons he has examined.

The modes of action of corrosive sublimate, may be summed up in the following theses:

1. Corrosive sublimate acts instantaneously, as a chemical agent, on the part to which it is applied, corroding or disorganizing it. This action may be so intense, as to produce almost instantaneous death, (Sproegel, Experiment 4.) Where the animal survives the first impression, its death is the consequence of the inflammation produced, and is seldom very speedy.

2. Corrosive sublimate, and, indeed, every mercurial, is apt to produce a specific excitement of the system, of which salivation is a peculiar symptom; and this action may also be so excessive as to produce death.

The action of arsenic is much more obscure; but we know that it acts in a totally different manner, and upon different principles from corrosive sublimate. It is not a chemical caustic, and ought to be removed from among the corrosive or escharotic poisons, with which it has hitherto been classed by all systematic writers, even by M. Orfila, in whose description of the organic lesions produced by it, the bad effects of this error are evident. The primary action of arsenious acid, we think, may be summed up in the following theses, chiefly the result of a great variety of experiments, made by the late ingenious Dr. Campbell, at most of which we assisted:

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1. It does not act chemically on animal matter, living or dead.

2. Its chief effect is to produce a disease somewhat analogous to cholera morbus, whether it be taken directly into the stomach itself, or inserted into the subcutaneous cellular membrane of a remote part, or applied to a delicate membrane. In some few cases, where the action of the poison is most intense, death occurs from the sickness or fainting, without vomiting or purging.

3. Frequently a considerable interval intervenes between its being received, even in solution, into the stomach, and its action.

4. Neither paralysis of the voluntary muscles, nor convulsions, nor delirium, nor coma, nor disordered respiration or circulation, are ordinary symptoms of the disease produced by arsenic.

5. After death, we were frequently unable to discover any organic lesion, and we generally found that the inflammation was less, in proportion as the arsenic was more speedily fatal.

Copper. M. Orfila has repeatedly had opportunities of giving verdigris and acetate of copper to dogs of different size, and he has constantly remarked, that, when the dose of the latter exceeded twelve or fifteen grains, the animals perished in less than three quarters of an hour. The symptoms which preceded death, were abundant vomitings of a bluish matter, evidently coloured by the metallic salt; fruitless retchings, after he had emptied his stomach of its contents; plaintive cries; great difficulty of respiration; irregularity and quickness of pulse; frequently general insensibility; the animal couched as if dead; almost always he was convulsed; and some moments before death, general rigidity, tetanic struggles, and a great deal of foam at the mouth, were observed. On examining the body immediately after death, no contractility remained in the muscles; the mucous membrane of the stomach was covered with a bluish layer, containing a portion of the ingesta, (matière ingerée,) which layer was hard, as if horny, and when scraped, the mucous membrane below was of a rose colour. The trachea and bronchiæ were filled with white froth; the lungs crepitated, and exhibited some red points, upon a pale ground. The heart had ceased to beat.

The injection into the jugular, of a grain of acetate of copper in half an ounce of water, commonly causes death in ten or twelve minutes. The animal at first performs the motions of mastication and deglutition, and afterwards vomits with violent efforts; he respires with great difficulty, and is very violently convulsed; he lies down,-suddenly becomes insensible,-the rattle comes on, and he dies. On opening him, nothing remarkable is perceived in the primæ viæ; the irritability of the muscles seems extinguished; there is no change in the lungs, and the heart is without action.

Tin. Three-fourths of a grain of muriate of tin, in solution, injected in small quantity into the jugular vein, produced paralysis and insensibility; two grains tetanus; and six grains speedy death after vertigo. On dissection, the lungs were more or less shrivelled, and partially gorged with blood; the blood itself was dark coloured, and there was a slight redness of the mucous membrane of the stomach and duodenum. Muriate of tin, introduced into the stomach, excited violent vomiting, great depression, and death without paralysis or convulsions. On dissection, the stomach was indurated, and as if tanned; ulcerated in various parts, and of a dark red colour; and the intestinal canal contained much black thick ropy bile. The lungs were sound.

Silver. A very small quantity of nitrate of silver in solution, injected into the jugular, produced difficulty of breathing, threatening suffocation, retching, pain, convulsions, and death. On dissection, the lungs were found gorged with blood, and the heart distended with black blood. A dog took into the stomach twenty grains, dissolved in seven drachms of water, which only produced uneasiness and depression; in two days, it got thirtytwo grains more, which excited frequent vomiting, from which it speedily recovered. On the fifth day, thirty-six grains were thrown into the stomach, through a hole in the œsophagus, which was immediately tied to prevent vomiting; the animal instantly suffered excruciating pain, which ceased in three hours, and died on the night of the following day. The whole mucous membrane of the stomach was dissolved into a pulp, but the lungs were healthy.

Zinc. A contracted solution of zinc, injected into the jugular

vein, produced retching, coma, and death. On dissection, no morbid alteration was discovered. Taken in large quantities into the stomach, it only acted as an emetic, accompanied with temporary uneasiness and depression; but when the vomiting was prevented, by putting a ligature on the œsophagus, the animal died, and the stomach was everywhere of a dark red colour; and the lungs were a little darker than usual.

Gold. The muriate in solution, injected into the jugular, killed, apparently by inducing suffocation; it also excited vomiting. The lungs were gorged with blood, so as to sink in water, and the heart was full of black blood. Taken into the stomach, muriate of gold proves fatal in consequence of the inflammation it excites.

Bismuth. The supernitrate injected into the jugular vein, produced retching, plaintive cries, convulsions of the limbs, palpitation, difficulty of breathing, and general depression; or vertigo, and intoxication, according to the quantity. The lungs were dark coloured, but turgid only in small portions, or wrinkled, and the left ventricle and arteries contained only a little black blood. The subnitrate of bismuth, introduced into the stomach, produced nausea, and vomiting of white ropy matter, difficult, noisy, and deep respiration, trembling of the limbs, and death. The mucous membrane of the stomach was universally inflamed or destroyed, and portions of the lungs gorged with blood, so as to resemble liver.

Acids. The sulphuric, nitric, muriatic, and phosphoric acids, when injected into the jugular vein, caused death by coagulating the blood; when introduced into the stomach, they killed by the inflammation and disorganization of that organ; and when applied to the skin, by the burn which they produced, or the suppuration which was the consequence of it. The nitrous, fluoric, sulphurous, phosphorous, oxalic, and tartaric acids, acted in the same manner.

Alkalis. Potass, soda, and ammonia, and their subcarbonates, act also in the same way. They coagulate the blood when injected into the jugular, and they corrode the stomach; but ammonia also produces tetanus and violent convulsions.

Barytes, pure or carbonated, introduced into the stomach, caused vomiting, hiccup, insensibility, convulsions, and death.