ance on his master. In two confumptive patients, I am able to induce fleep almost at pleasure by the HYDROCARBONIC AIR *. In a great majority of such cases, it is well known that the nights are exceedingly disturbed in spite of opium freely administered. The foporific virtue of HYDRO-CARBONATE feems however, from the experience I have had, by no means confined to confumption,

The analogy which obtains between sleep and the ftate of torpor, is so striking, and at the fame time so applicable to the present fubject, that it seems to deferve more attention than has yet been bestowed upon

it.

The clafs of dormant animals, says the celebrated natural hiftorian, M. de BUFFON, are not, as vulgarly imagined, in a state of abfolute fleep, for the respiration is scarce perceptible, and the blood is cold, or scarcely exceeds

the temperature of the outward air.

There is little rea

fon then to wonder why thefe animals, fo inferior com- . paratively to others in point of heat, fhould become torpid, as foon as their own fmall portion of internal heat ceases to be affifted by the external warmth of the air: a circumstance which naturally happens when

A mixture of fixed and inflammable airs.

the

the thermometer is not more than 10 or 11 degrees above congelation. The fame extends to all torpid animals during the winter. Alike are its effects on the dormouse, the hedge-hog, and the bat. Of this clafs the marmot is the most remarkable, which delights in the regions of ice and snow, and is never found but on the highest mountains: it, nevertheless, of all others is the most liable to be rendered torpid by cold.

This animal, though extremely active in fummer, lays up no provifion for the winter, because fuch a precaution would be useless* during its dormant state. But when he perceives the first approaches of the season, in which his vital motions are to continue in a great meafure fufpended, HE CLOSES UP THE APERTURES OF

HIS SUBTERRANEOUS DWELLING WITH SUCH SOLIDITY, THAT IT IS MORE EASY TO OPEN THE EARTH ANY WHERE ELSE, THAN WHERE HE HAS CLOSED IT. When their retreat is discovered, they are found, each rolled into a ball, and apparently lifeless. In this ftate, they may be dragged roughly along the ground, or even killed, without teftifying any fenfe of pain.

*The bees, which were transported to BARBADOES, and other weftern iflands, ceased to lay up honey after the first year, and are become very trou→ blefome; but those in JAMAICA continue to make honey, as the cold north winds, or rainy feasons of that ifland, confine them at home for feveral weeks together.Dr. DARWIN.

By a mild and gradual heat alone, are they to be recovered from this torpor, and if brought fuddenly before

a fire, they perish. A few degrees above the tenth or eleventh degree are fufficient to re-animate them; and if they are kept in a warm place during the winter, they do not become torpid, but continue as lively as at any other time. If the marmot remains longer torpid than the dormouse, it is probably because the weather of the climate is longer cold.

It is curious, adds M. de BUFFON, to obferve this animal, when he is prematurely forced to pass from the torpid to an active ftate. He firft yawns, fetches a deep figh, and utters broken inarticulate founds like a drunken man. His limbs become less rigid, he stretches out his legs, fetches another still deeper figh, opens his eyes, and at length recovers. Such are the uneasy senfations he vifibly undergoes, from a fudden and forced re-animation; which is probably performed in a more gentle and imperceptible way by the vernal warmth, when left in his cell. But what is fingular, HE

NEVER BECOMES TORPID, THOUGH EXPOSED TO A DEGREE OF COLD EQUAL TO THAT OF FREEZING,

PROVIDED HE IS KEPT IN THE open air INSTEAD

OF A CLOSE PLACE.

From

From the circumftance of these animals excluding all communication with the external atmosphere, may not the ftagnant air of the cell, contaminated by their respiration, and faturated with carbonic gas, add confiderably to the fedative effects of cold in bringing on torpor * ?

It is curious to obferve how the animal and vegetable tribes mutually fupport each other, through their whole existence! Vegetables, by emitting vital air during the day, purify the atmosphere for the use of animals; while the fixed air expired by animals affords nourishment to vegetables. But at the time when this diffufive ftimulus is lefs wanted, sleep being desirable, the vegetable race then pours forth azotic air †.

* From the account of Mr. Wildman, and other people of nice obfervation, it appears, that during the very severe part of the winter season bees are torpid, and do not confume any of their provifion. As the death of our hives of bees arife frequently from the cold not being fufficiently great to render them torpid, at which time they require the provision that has been taken from them, I directed, fays Dr. DARWIN, two hives to be placed in a confined cellar, and obferved, during all that time, they did not confume any of their stock of provifion, for their weight did not decrease, as it had done when they were kept in the open air. Might not a direct experiment with factitious air turn out, with regard to bees, of twofold advantage ?

+ Vide Part I. p. 29.

With

1

With what ADMIRABLE OECONOMY has the SUPREME ARCHITECT then eftablifhed this reciprocal intercourfe between the animal and vegetable kingdoms! By what ELEGANT SIMPLICITY OF DESIGN are the different parts of nature thus rendered at once fubfervient to the mutual fupport of each other respectively, and to the general well-being and harmony of the whole * !

* From Dr. FOTHERGILL'S Effay on the Sufpenfion of Vital Action, whofe able deductions, ftrong reasoning, and ingenious queries, we shall have frequent occafion to notice.

SECT.