their death. (See Plutarch's Lives.) The celebrated poisonous tree of Java, called in the Malayan tongue Bohun Upas," by giving out this deftructive principle in the gafeous ftate, may prove fatal to vegetation,

or to animals which come too near it. Although I believe the terrible accounts of this tree have been much exaggerated by travellers (See a paper in the Batavian Society at Rotterdam, by Dr. Holft; wherein he endeavours to confute a very curious account of the Bohun Upas, by Foerch); yet this is in fome degree the effect of poisonous plants (with which we are better acquainted) not only preventing vegetation, but proving fatal to animals which happen to fall asleep under their fhade. The fenfitive plant feems evidently affected when brought near fome of these plants, as alfo with the fumes of tobacco, and the volatile alkali, The juice of the Upas ferves, when infpiflated, to poifon the arrows of the natives where it grows: but it is a moft melancholy inftrument in the hands of their tyrannic princes.

That fome vegetables do not contain azote in their compofition is certain; but it is very evident in others, as in many of the genus of Tytradinamia of Linnæus. This may be felt by their very pungent quality, as well as from their entering fo eafily into a state of putrefactive fermentation, and giving out large quantities of azote, either by itself or united with hydrogene in the gafeous form, as may be felt by eyes and nose. In the vegetable form we ufe azote daily, either through pleasure or from neceffity. In cold climates tobacco is now univerfal, either taken into the ftomach, or applied to the olfactory

nerves. Opium is very general in the warm countries of the eaft: the Turks take it, to the quantity of two drams at a time, without any inconvenience: the porters at Surat (fee Grofe) take it to the quantity of an ounce at a time; and they find it increases their ftrength, and af fifts them in going through more labour: it is allowed plentifully to the foldiery, and is faid to infpire them with a furious and undaunted courage. But to thofe who accuftom themfelves to take it (first perhaps through pleafure; for, as if by fome heavenly magic, it is found to lull the fenfes into a moft pleafing forgetfulness of all our cares, and to affuage the moft excruciating pains which affect the human body, and here it is a blefling to mankind) for any length of time, they are fure to experience its baneful effects: from time to time they are feized with a moft dejected languor both of body and mind, until the ufual and welcome dofe is repeated: their conftitutions become emaciated, and have every appearance of a premature and decrepit old age, and too often fink under the firft fhock of difeafe. We fee the azote daily used as a frimulus in cafes of fufpended animation: it is applied in a concrete form to the nofe, in the form of fmoke to the inteftines, and finapifms to the foles of the fect, &c. It is found to act differently on different conftitutions; and, in the fame conftitution, when in health and when under difeafe. I have feen a child thrown into most violent convulfions by taking only two drops of laudanum; and a man, after one grain of digitalis, has fearcely recovered. This difference in the operation of poifons may depend on the different degrees of

irri

irritability in the different conftitutions. From the difficulty of difcovering the conftituent principles of animal and vegetable poifons by chemical decompofition, the foregoing hypothefis may be found erroneous; yet, from the uniformity of nature, from the analogy in the action of thefe fubftances on the human body when taken into the circulating fyftem, and from the analogy the action of these fubftances bear with the azote in the pureft and moft fimple ftate the chemift can prepare it, we may venture to conclude that it is the deftroying principle in all thofe poifons which deftroy the animal life, by throwing it into convulfions; and that the existence of this principle in fubftances where it cannot be afcertained by chemical analyfis, may in a great meafure be determined by their operation on the animal conftitution. From the violent elevation and depreffion of the ribs in perfons who are juft hung, and from the fame taking place in the diaphragm in dogs, as if nature was ftruggling to throw off fomething which is noxious to the conftitution, it feems by its ftimulus to be the remote caufe of refpiration. That the atmofpheric air is a ftimulus itself, even when taken into the ftomach, is proved by Mr. Goffe's experiments above quoted. Quare, May not this be the caufe of the difference which is found in the recovery of perfons after drowning, whether their lungs were inflated during the time they were under water? or if they had a fenfe of their danger?

When the atmospheric air enters the lungs, it is foon deprived of its oxygene or vital principle, and is rendered thereby noxious to ani

mals, and unfit to fupport flame; it not only becomes a ftimulus, but puts on the form of a moft deadly poifon. Melancholy procfs of this have happened where numbers have been crowded into the holds of fhips, and clofed from the circulation of fresh air. In the Black Hole at Calcutta there was a striking inftance of this. The effects of the wind called the Sirroc, feems to be owing to a diminution of the empyrcal air in the atmofphere. In fome parts of Sicily the inhabitants are confined to their houses for four or five days together, to avoid a contact with this wind. Thofe Europeans who have felt it, defcribe it as bringing on fuch a languor and dejection of fpirits as is almoft infupportable. (See Bry, done's Tour.)

The fatal effects which daily occur to perfons from going into vaults, caverns, wells, &c. which have been long fhut up, proceeds from the fame principle. The famous Lago del Cani, fo often defcribed by travellers, is furely na more than throwing the animal into it; which, by the fudden fhock it gives, roufes nature to throw off the effects of this air which it had taken into its conftitution in the cave; and I make no doubt but one of our English lakes would do as well, had we an equal opportunity of applying it.

The violent pains which take place in the beginning of fever, the fpafinodic contraction over the whole body, and the great fenfation of cold fucceeded by a burning heat, feems to indicate this fubftance for a primary cause. We find the plague too often arifing in thofe warm countries, and where the rivers, after fubfiding, leave vaft quantities

ture, which, by combining with or decompofing this fubftance in whatever flate or combination it fhould find it in, would thereby render it lefs deftructive to life. We know that vinegar taken into the ftomach after opium, in a great measure deftrovs its effects: the vitriolic acid mixed with the poifon of ferpents renders it much lets dangerous (fee Fontana): the thieves vinegar was found infallible in preventing the plague to certain perfons who used it at Marfeilles, and thereby were enabled to go about and plunder the houfes of the inhabitants; but were pardoned on difcovering by what means they avoided the infection: it was therefore called Thieves Vinegar.

Vinegar is found to be a preventative to the infection in all fevers; and is much ufed in hofpitals and the holds of fhips, where there is danger of the infection fpreading. When the habit is emaciated, after long voyages, bad food, or breathing confined air, vegetable acids are found the only certain remedy we know of; and a very few days on fhore, after a long voyage, never fails to reftore the fhip's crew to their priftine vigour. Acids themfelves, as a topical application, may be employed where perfons have been ftung by venomous animals. It is common in the country for perfons who have been ftung by bees, wafps, or even nettles, to rub the parts immediately with the leaves of forrel or other acid vegetable; and I have known vinegar applied to gonorrhea and chancres with good effect. In the hot countries, where people are daily bit by ferpents and other poifonous infects, they rub the part immediately with fome acid vegetables; but

the most effectual remedy feems to be fucking the part with their mouths, as the poifon only is dangerous when carried into the circulating fyftem: the Marii and Pfylli, brought to Rome from Africa, were famous for this kind of remedy.

It is a curious remark, that ferpents infpire, but are not feen to expire; perhaps the phiogift'icated air which fhould be thrown out by the trahea, ferves in them to form the poifon in those which are mortal from the bite; and may ferve to form that horrible fater in thofe which are not poisonous by the bite: and to this we may afcribe that fafcinating power fo curioufly defcribed by travellers, and which ferves the animal to take its prey, or to defend itself. The devoted animal, as affected by fome convulfive ftupor, unable to extricate itself, grows weaker and weaker, till it at laft drops into the extended jaws of its deftroyer. Putrefaction is the immediate and common effect of the bite of the more dreadful ferpents: the perfon dies in moft violent convulfions, fucceeded by a total lofs of irritability. Mr. Williams, in a very ingenious paper in the Afiatic Refearches, recommends (as in cafes of fufpended animation before mentioned) every ftimulus that can roufe nature to ftruggle with the disease; and that volatile alkali was a most efficacious application. According to Wolfe and Mead, it helps to throw off the effects of laurel water, and is efficacious even in hydrophobia.

Mr. Bruce and Savary, in their accounts of Egypt, defcribe a common practice of charming ferpent, which is by rubbing their naked arms and bofoms with fome fort of vegetable; and, to the aftonifh

ment