By the process of diftillation, the HYDROGEN is feparated in a great measure from the oXYGEN and CARBON, and we obtain what is called alkohol or brandy.

Alkohol itself contains fome oxygen, but by combuftion, it takes to itself still more from the atmospheric air: and thus by experience it is found, that 16 ounces of alkohol, by combuftion produces 18 ounces of pure water.

The combuftion here is nothing elfe but the combination or chemical union of HYDROGEN with OXYGEN, from which results a third substance water, whilst the HEAT which was before in combination with oxygen efcapes.

PILATRE DE ROZIER has frequently amufed his friends by inhaling a large quantity of HYDROGEN AIR; which may be taken into the lungs without fear of injury, and then, applying his mouth to a tube, he blew out the air unmixed with atmospheric air, and fired it at the end of a tube, fo that he appeared to breathe flame. By this operation water was produced, which afcended in the form of vapour.

In order to give a distinct idea of the quantity of heat arifing from the combustion of HYDROGEN AIR, I shall

only mention that one pound of this melted 295 lb. of

ice,

ice, whereas in fimilar circumstances wax candles* weighing one pound melted only 133 lb.

Thefe obfervations I have prefented to the ftudent, in order to give him a clear and diftinct idea of the subftances which I have had occafion to mention; and by which he will see the strong affinity and chemical attraction between HYDROGEN and OXYGEN, the latter of which, as I have stated, is by the lungs derived from the atmosphere, whilst the former is conveyed into the system by the affistance of the ftomach, and is most readily obtained from æther, alcohol, and wine.

So much for what has been discovered by the chemist with his retorts. But it is time that we should return to the living retort, and confider by what laws the proportions are established between the OXYGEN to be derived by inspiration from the atmosphere, and the HYDROGEN to be conveyed into the system by the action of the ftomach.

The reader, no doubt, calls to mind the memorable experiments of Mr. SPALDING, who obferved that in proportion to the quantity of food received into the ftomach, if it abounded with HYDROGEN, the fyftem

* These form fixed air (carbon and oxygen).

coveted

Coveted OXYGEN, taking up a greater quantity of it by refpiration from the atmosphere, as his diving-bell clearly demonftrated, and he will also remember having met with this remark in the case of bilious autumnal fever, "The attentive obferver will take notice, that there is a

certain proportion between the VITAL AIR received "into the lungs, and THE QUANTITY OF FOOD "which can be digefted in the ftomach *.”

When I made the laft obfervation I was not aware that the fame had occurred to any one before me. But I have the pleasure to see the fame idea had also occurred to Dr. THORNTON, as appears in his Thefis, and to Dr. BEDDOES, as is seen in his Letter to Dr. DARWIN. He had been breathing air, fuch as contained almost equal parts of OXYGEN and AZOTIC AIR. "His fpirits were in confequence elated; his appetite great; and he eat one "third or one fourth more than before, without feeling his 66 ftomach loaded +."

From these premises I trust it will be clear, why, in cafes of fufpended animation, we must not be contented merely with conveying VITAL AIR into the lungs, but

* Vide PART II. VOL. I. page 89.

+ Vide PART III. VOL. II. page 256, where this memorable experiment is related at length.

muft

muft at the fame time convey HYDROGEN into the ftomach, which powerfully attracts this fubftance fo ef fential to vitality.-From the Rev. Mr. TOWNSEND'S Guide to Health.]

This

[In time of health, cordials, on being received into the ftomach, presently manifeft their enlivening effects: even before they can have time to enter the lacteals, their stimulus is diffufed through the remoteft parts of the fyftem. In order, therefore, to restore the motion of the heart, through the medium of the ftomach, some active cordial ought to be early administered. having been confidered by the faculty as unfafe, if not wholly impracticable, until the power of fwallowing fhould be restored, it has hitherto on that account been very rarely attempted. Fortunately, however, we can now with confidence affert, that instead of waiting for the return of deglutition, an event which may never happen, fluids may at the beginning be immediately conveyed into the stomach, without occafioning the smallest hazard of fuffocation.

Amongst the class of internal stimulants, fpirituous liquors, as rum, brandy, or ufquebaugh, are well adapted, as being speedy in their operation: but

the

the exhaufting effect which fucceeds the action of these, and all other potent ftimuli, tends to limit their use, and demands no finall circumfpection.

Good wine, where it can be had, though lefs active, affords a more generous cordial, and feems to deferve the preference; for during vital suspension, irritability must be confiderably accumulated. Hence the neceffity of artificial ftimuli to compenfate for the defect of the natural ones in carrying off the redundancy. But if these are too powerful they may prove equally destructive, by totally exhaufting the moving fibres. Thus may the falutary efforts of nature be overpowered by the officioufnefs of art, a circumftance which fometimes we have had occafion to obferve with regret.-Dr. FOTHERGILL.]

PROP. V.

While these things are going on, viz. the INFLATION of the lungs and STIMULATION of the heart, an affiftant fhould carefully heat the bed-clothes. I confider heat as congenial to the living principle. But from obfervations and experiments it appears to be A LAW OF NATURE in animal bodies, that the degree of external beat should bear proportion to the quantity of life; as it VOL. III. 4 F

is