Jamque fere mediam cæli nox humida metam Equate fpirant auræ, datur bora quieti : Pone caput, feffofque oculos furare labori. Ecce Deus ramum, Lethæo rore madentem Vique foporatum Stygia, fuper utraque quaffat Tempora, cunilantique natantia lumina folvit. Vix primos inopina quies laxaverat artus Et fuper incumbens, cum puppis perte revulsa Cumque gubernaculo liquidas projecit in undas Præcipitem, ac focios, nequicquam, fæpe vo cantem. Now half the Night through Heav'n had roll'd away, The Sailors ftretch'd along their Benches lay, When thro' the parting Vapour swiftly flies The God of Slumbers, from th' ætherial Skies; To thee poor Palinure he came, and shed • Behold the Fleet, my Friend, fecurely fails, Steer'd by the Floods and wafted by the • Gales! guide A-while the Veffel o'er the floating Tide.' To whom the careful Palinure replies, While scarce he rais'd his heavy closing Eyes: Me would't thou urge in Sleep to fink 6 away, And fondly credit fuch a flatt'ring Sea? 'Too well, my Friend, I know the treach'rous Main, Too well to tempt the Monster's Smiles ⚫ again! • Too oft deceiv'd by fuch a Calm before, I truft my Master to the Winds no more.' This faid, he grafp'd the Helm, and fix'd his Eyes On ev'ry guiding Star that gilds the Skies: Then o'er his Temples fhook the wrathfulGod A Branch, deep-drench'd in Lethe's filent Flood; The potent Charm in Dews of Slumber steep, And foon weigh down his fwimming Eyes to Sleep; Scarce yet his languid Limbs had funk away, When o'er the Wretch the God incumbent lay, And, with a shatter'd Fragment of the Ship, Bore down the Helm and Pilot to the Deep; Headlong he tumbles in the plashing Main, And calls for Succour to his Friends in vain. It is from this State of the Mufcles that proceeds the Impoffibility of fleeping ftanding. The fpinal Column is fupported by the conjunct Action of fo many Mufcles, that on the Ceffation of this Action, whether wholly, or in Part, the Trunk of the Body collapfes. This Confideration is not to be closed without admiring the wonderful Wifdom of Providence in the Relaxation of the Mufcles during Sleep; the firft which drops is appointed as a Safeguard to one of our most important Organs, and that which is moft exposed to Danger, I mean the Eye; we no fooner are inclined, or difpofe ourselves to sleep, than the Eye-lid closes of itself, and serves as a Fence to the Eye, till we awake. On the other Hand fome Muscles are more strongly contracted, as the Relaxation of them would be both uneafy and dangerous; fuch are thofe of the Bladder and Rectum, whofe Sphincters redouble their Contraction. This Diversity of Mechanism, in fimilar Parts, plainly indicates the Ends which the great Former of our Bodies propofed in them. I now proceed to a third Change which Sleep occafions in our Machine; it diminishes and, as we have seen, deadens the animal Functions, but it augments and invigorates the vital. This, in B 5 deed, deed, is Matter of Difpute, and very skilful Physicians adduce ftrong Reasons on both Sides of the Queftion: Hippocrates, Epid. VI. N. 4, 5, fays, that in Sleep the internal Parts are warmer; it is an Aphorifm of Sanctorius, Somno animales, vigilia vitales et naturales languefcunt. In Sleep the ⚫ animal Functions flacken, in Vigilance the • vital and natural.' But, without accumulating Authorities, it fuffices, to give this Opinion at once all the Weight it can derive from the Reputation of its Affertors, to fay, that it has been espoused by the celebrated Boerhaave; his principal Reasons are, the Heat of Perfons fleeping, the Force of their Refpiration, the Increase of their Perfpiration, and the Strength of their Pulfe. On computing the Beats of a Child's Pulse whilft awake, and afterwards when he is afleep, they are, indeed, found to be lefs frequent in Sleep, but more equable, fuller, and stronger; and, by this Sign only, it may be known, whether a Child be afleep, without feeing him. In a Frenzy, when the Patient becomes inclined to fleep, the Strength of his Distemper may be determined by his Pulfe; ifftronger than when he is awake, the Sleep will be lafting, and do him Good; if quicker, but more faint, his Sleep will be foon at an End, and produce no Amendment; according to this Hypothefis, a deep Sleep is an abfolute Apoplexy. An apoplectic Perfon is seen, a little before his Death, to be poffeffed of an Increase of vital Strength, even beyond what he enjoyed in all the Vigour of Health. Likewife in a Perfon fast asleep there is an Augmentation of Heat and Rednefs, in Proportion to the Soundness of his Sleep; confequently the Force of the Heart, the Arteries, and Veins is then increased. Another Refemblance betwixt Apoplexy and Sleep is the Strength of the Refpiration; a Perfon, whilst asleep, is heard to breathe, which is far from being the Cafe in us, whilst awake, unless under fome extraordinary Agitation of Nature. In the firft State the Diaphragma is strongly compreffed, the Ribs rife, fo that there is a proper Respiration; but, on an Increase of it, the Perfon is heard to fnore, and this Snoring very much resembles the fatal Rattling which is the fure Prognoftic of Death, and especially in apoplectic Subjects. From all these Obfervations the illuftrious Boerhaave concludes, That the vital Functions are performed with greater Energy during Sleep, and that all the Operations of Nature, as the Coction of the Ventricle, the peristaltic Motions of the Inteftines, the Secretion of the inteftinal Liquid, of the Bile, the pancreatic B 6 Juice, |