tions of the two feet, which were almost as lively as thofe in the first experiment.

At the end of thirty minutes, the motions of the two feet were feebler, but alike in both.

At the end of forty minutes, the feet scarcely contracted; but their distinct muscles were clearly seen to contract, when the crural nerves were ftimulated; and the motions of these muscles were equally lively in each foot.

At the end of fifty minutes the motions were very small, but alike in both fides.

At the end of eighty minutes there was no longer any motion to be obferved in feveral of the frogs, in whatever way I ftimulated either their crural nerves that were medicated, or thofe that were not so.

I can conceive, adds FONTANA, nothing more decifive and more certain, than from this series of experiments, that the action of OPIUM is not directly on the nerves, and when I related thefe experiments to Sir John PRINGLE, he very frankly told me, that for his part " he had never too great a belief in the explanation given

of NERVOUS DISEASES, and that for the future "he fhould have lefs faith in the doctrine than ever.'

In order to make this point still clearer, I wished to fee, whether opium, when injected into the veffels, caufes death, and whether it produces the fame derangements in the animal œconomy, when introduced into the circulation of the blood, as it does when swallowed, or injected into the different organs and viscera.

I injected about eighteen drops of the aqueous folution of opium into the jugular vein of a large rabbit. It was scarcely injected when the animal felt drowsy, could no longer fupport itself, and fell down. It, however, recovered in a few hours, and became perfectly well.

I next injected a tea-fpoonful of the fame aqueous folution into the vein of another rabbit, and it died inftantly.

I repeated this experiment on a third rabbit, with the fame quantity of solution, and it died also at the moment of injection.

Thus then opium, injected into the veins, produces heaviness, and even death itself. Wine or alcohol produces, as I found, pretty nearly the fame effects.

I conceive it to be altogether fuperfluous to relate a greater number of experiments on opium, injected into

the

the jugular vein, and introduced into the circulation, without its touching any of the wounded folids. When once it is received into the veffels, I do not fee how it can communicate itself in an immediate way to any of the nerves, fince all-prying anatomy affures us that the coats of the blood-veffels are not furnished with any nerves, and we have a further confirmation of this point from an experiment made by the celebrated profeffor of anatomy at Edinburgh. I found, fays Dr. MONRO, when I poured a folution of opiuin under the fkin of the thigh and leg of a living frog, not only the leg itself was very foon affected, but the affection was communicated to the most diftant part of the body: but if, previous to the application of opium, I cut out the heart, or cut acrofs the femoral blood-veffels, the effects of the opium were not communicated from that limb to distant parts,-which seems to prove how much the circulation of the blood, and the fluid of the machine, is the vehicle for opium, and that without this fluid it would have no action on the living body.

Another argument to prove, that the action of opium is on the irritable fibre through the medium of the fluids,

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is fhewn from its power over vegetable productions *, and those parts of the body which are irritable, and have been separated from its communication with the brain. Having cut out the heart of a young kitten, fays Dr. James JOHNSON, it notwithstanding continued its natural movements in a very lively and regular manner. In that flate I put it into a tea-cup containing fome laudanum in a moment the pulfations of the heart ceafed, and could not be removed by any kind of ftimulus.

Having divided the heart of another kitten into two pieces, out of the body, one of them was thrown into laudanum, a little diluted with water, and it foon loft its pulfatory motions, and stimuli had no power or effect in restoring them: but the other half of the heart, lying at the fame time upon the table, contracted very brifkly whenever it was touched with the point of a needle or a knife, and that long after the part steeped in diluted laudanum remained immoveable.

The fame events happened to a piece of inteftine, cut out, when dipped in laudanum : the peristaltic motions,

*The analogy betwixt these two kingdoms of nature have never been sufficiently fcrutinized. This fubject has of late engaged the attention of Drs. GIRTANNER, GAHAGEN, INGENHOUZE, THORNTON, &C. Vide Vol. III. P. 411.

which were brifk before, ceafed inftantly, and could not be removed by ftimuli: yet another piece of the finall gut, cut out, lying on the table, continued to move and twift itself with great vivacity when it was ftimulated.

Does not OPIUM then act upon the mufcular fibres through the medium of the blood? Does not the motion and power of these fibres, depend upon their union with OXYGEN, chiefly taken into the body by refpiration, and diffused by the circulation of the blood? And does not its action confift in difuniting the OXYGEN from thefe fibres fo rapidly, by changing the law of ELECTIVE ATTRACTION *, as to extinguish their vitality, before they can have a fresh and adequate fupply of VITAL AIR?-The fudden extinction of life, and the ftate of the body after death, entitled the ingenious Dr. BEDDOES to make thefe fuggeftions; and start an opinion, which an enlightened and reformed fyftem of phyfic will foon, perhaps, fatisfactorily elucidate.

Mr. Y―, of the age of fifty years, took by mistake, at bed-time, about ten drachms of laudanum: he had a fit of the gout at the time. No alarm was given till about four o'clock next morning, when exceffive

*The nature of the LAWS OF AFFINITY, or ATTRACTION, has been before explained, Vol. I. p. 13, and Vol. II. p. 225. drow finefs

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