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powerfully influenced by the vital principle, that in the prefent ftate of our knowledge, we can scarcely proceed farther than to affert, that the effects are really produced by an application of the MOST SUBLIME CHEMISTRY: but thefe difficulties ought rather to encourage than deprefs our attempts to arrive at a more intimate knowledge of the powers of nature.

In the healthy living body the balance of principles is constantly kept up, by the furface discharging the superabundant AZOT and the useless AQUEOUS FLUID (hydrogen and oxygen), AMMONIACAL SALTS (azot and hydrogen), and PHOSPHORIC ACID (phosphorous and oxygen);—

where the four juices of a. CRAB, by paffing through the chemical apparatufes of the engrafted part, is made to produce the most delicious FRUITS. So in the animal world, the fpur of a cock being taken off by JOHN HUNTER, and engrafted (if I may be allowed the expreffion) in the forehead of another bird, the juices of the latter, by pervading it, gave it life and growth.

Are we staggered, that a few principles, differently modified by chemical proceffes, fhould produce such an immenfe variety? Here let me remind the young ftudent in philosophy, that I part oXYGEN, with 4 parts AzoT, loosely combined and fufpended by CALORIC, is atmospheric air, and that 4 parts OXYGEN and I part Azor, in a state of combination, which may be easily effected, by passing the electric fluid repeatedly through a jar containing thefe proportions of the two airs, fufpended by CALORIC, is nitrous air ;—that the former, blended with WATER, is the beverage of common life, the element defigned for fish-whereas the latter, combined with WATER, is aquaFORTIS, which corrodes and destroys every thing; fo much do the nature of things depend on the proportions and combinations of the FIRST ELEMENTS.

Vide note, page 385.

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by the lungs throwing off CARBON and HYDROGEN, and the blood in the lungs and the absorbents of the skin taking into the system VITAL AIR (oxygen and caloric), while the lacteals of the inteftines imbibe all THESE SEVERAL PRINCIPLES. The just balance of these principles in the body conftitutes HEALTH and LIFE, or, more properly speaking, is the condition necessary for the maintenance of LIFE.

When the balance gets broken, a loss of HEALTH or DEATH enfues.

We are now to investigate, as far as we are able, "the condition of the body when deprived of the IRRITA"BLE PRINCIPLE, by the venom of the viper, opium,”

&c.

The diminution of irritability in the muscular fibres, in those animals bitten by the VIPER, is occafioned without doubt by the destruction of the right balance of the principles in the fystem.

The blood partly dissolved, and partly coagulated,-from being red becomes black or brown,—from being a bland fluid contained within numerous veffels, it becomes a perfect cauftic, which diffolves the texture of the containing veffels, paffes through their coats, and sheds itself in the adipose membrane, corrupting and decompofing whatever it meets with.

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The part in which the wound has been inflicted paffes,

in the shortest time, into the ftrongest putrefaction, and prefents a perfect gangrene and spacelation.

The skin is speedily corroded and livid, and the muscles become black and fœtid.

I have known a rabbit die in less than three hours, with the muscles of the leg already gangrened throughout their whole fubftance; they were black and offenfive, and were divided by a knife without any resistance. After death the flesh was foftened fo much as to crumble at the least touch, and even without violence fell from the bones. Upon opening its body I found the blood in all the cavities of the heart black, and often coagulated*; but the most remarkable change was in the lungs, which was filled with black blood, and exhibited every where livid fpots.

This black appearance of the blood, especially in the lungs, would lead one to fuppofe, that the OXYGEN of the blood, which we have before fhewn gives it its crimfon colour, had entered into fome new state of combination, and with it the irritable principle itself was fled.

We will now fee how it affects the blood when drawn from an animal.

* In this cafe the irritable principle in the blood was not wholly deftroyed, for when that is the cafe it is fluid. See page 392, line 3.

I let

I let fall, fays FONTANA, into a small conical glass, three drops of the venom of the viper, and twenty drops of the blood that flowed from the neck of a fowl, into which I had made an incifion. I reclined the glass, and fhook it circularly for ten feconds, that the venom and blood might mix well together.

At the fame time I let fall into a fimilar glass, twenty drops of the blood of the fame fowl, in the fame state as the last. I shook the glass, as I had done on the preceding occafion, that, the venom excepted, all circumftances might be alike.

At the end of two minutes, the blood unmixea with the venom COAGULATED, and was of a FINE VERMI

LION COLOUR.

On the contrary, the blood united to the venom was BLACK and FLUID.

I repeated this experiment next on the blood of a Guinea pig. The venomed blood at the end of twentyfour hours was ftill BLACK and DISSOLVED, whilst the other COAGULATED in less than two minutes, and continued to preserve its BRIGHT RED COLOUR.

The venomed blood did not harden, but it dried by degrees, and split into fcales, and preferved its BLACK COLOUR till the laft; inftead of which, the blood in its

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natural ftate ftill continued RED, even after it had dried

and fplit.

It is the fame with VEGETABLE POSONS. We find that the flesh of animals which has been cut with a knife dipped in the juice of napel, inftantly becomes more tender, and fitter for culinary purposes. Travellers inform us that in both INDIES, as well as in AFRICA, the inhabitants usually hunt with poisoned arrows, and that in the space of fix minutes, or more or lefs, according to the degree of the poison's activity, these arrows kill the largest animals, such as lions, tygers, and even elephants. They likewise observe that the flesh of these animals immediately foftens, and becomes tender; an unequivocal proof that all these poisons equally dispose the flesh to a Speedy putrefaction, by a destruction of the proper balance or adjustment of the constituent principles.

I procured, fays FONTANA, by favour of Dr. HEBERDEN, the poison with which the Americans fatalize their arrows, called TICUNAS.

I put into the syringe, for the first experiment, four drops of an aqueous folution, which scarcely contained half a grain of the dried poifon. Having introduced the point of the syringe into the jugular vein of a large rabbit, I perceived the liquor to flow back on the moment

of

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