329 whole Blood doth not fo often circulate through the Lungs, as it doth through the reft of the Body. This manner of Breathing is fufficient to maintain in them that Degree of Heat which is fuitable to their Nature and Manner of Living. For to our Touch they are always cold even in Summer-time, and therefore fome will then put Snakes into their Bofom to cool them.

3. Fishes, which were to live and converfe always in a cold Element, the Water; and therefore were to have a Temper not excelling in Heat, because otherwife the constant immediate Contract of the Water (unless some extraordinary Provision were made) could not have been fupported by them; that they might not be neceffitated, continually to be coming up to the Top of the Water to draw in the Air, and for many other Reasons that might be alledged, perform their Refpiration under Water by the Gills, by which they can receive no more Air than is difperfed in the Pores of the Water, which is fufficient to preserve their Bodies in that Temper of Heat that is fuitable to their Nature, and the Place wherein they live. Thefe alfo have but one Ventricle in their Hearts.

But now, though this be thus, the great and moft wife God, as it were purposely to demonftrate, that He is not by any Condition or Quality of Place neceffarily determined to one Manner of Refpiration, or one Temper of

Body

Part II. Body in Fishes; He hath endued the Bodiesof fome of that Tribe of Aquatick Creatures with Lungs like viviparous Quadrupeds, and two Ventricles of the Heart, and an Ability of Breathing like them, by drawing in and letting out the open Air; fo contriving their Bodies, as to maintain, in the midst of the cold Water, a Degree of Heat answerable to that of the forementioned Quadrupeds.

We

Another remarkable thing relating to Refpiration, is the keeping the Hole or Paffage between the Arteria venofa and Vena cava, called Foramen ovale, open in fome amphibious Quadrupeds, viz. the Phoca or Vitulus marinus, called in the English, Sea-Calf and Seal and, as is generally held, the Beaver too. have already given the Reafon of the twofold Communication of the great Blood Veffels in the Fatus or Young, fo long as it continues in the Womb: The one between the two Veins entring the Heart, by a Hole or Window; the other between the two Arteries, by an Arterial Channel, extended from the Pulmonary Artery to the Aorta, or great Artery; which was, in brief, to divert the Blood from the Lungs. The fame Reafon for keeping open this Foramen ovale, there is, in thefe amphibious Creatures; For, 1. The Lungs proba-. bly being not extended, but emptied of Air when they abide long under Water, and flacid, it is not eafy for the whole Blood every Circulation to make its way through them. 2. To maintain that Degree of Heat and Motion in

the

the Blood, as is fufficient for them while they are under Water, there is not fo much Air required, as is when they are above: The Blood then moving but gently, as doth that of the Fatus in the Womb.

Farther, in reference to Refpiration, it is ob ferved by the Parifian Academifts, that fome amphibious Quadrupeds, particularly the SeaCalf or Seal, hath his Epiglottis extraordinarily large in proportion to other Animals, it extending half an Inch in Length beyond the "Glottis to cover it. I believe the Beaver hath the like Epiglottis, exactly clofing the Larynx or Glottis, and hindring all Influx of Water; because in one diffected by Wepferus, that suffocated itself in the Water, there was not a drop of Water found in the Lungs. It is probable fay they) that this is done more exactly to clofe the Entrance of the Afpera Arteria, or Wind-Pipe, when the Animal eats his Prey at the Bottom of the Sea, and to hinder the Water from running into his Lungs. An Elephant (as is obferved by Dr. Moulins, I think, in the Anatomy of that Creature) hath no Epiglottis at all, there being no danger of any thing falling into their Lungs from eating or drinking, feeing there is no Communication between the OEfophagus and it. For he thus defcribes the OEfophagus or Gullet: The Tongue of this Creature (faith be) had this peculiar in it, that the Paffage to the Ventricle was through it; for there was a Hole near the Root of it, and exactly in the middle of that

Part;

Part; which Hole was the Beginning of the OEfophagus. There was no Communication between this and the Paffage into the Lungs, contrary to what we may obferve in Men, in all Quadrupeds and Fowl, that ever I had opportunity to diffect. For the membrana pituitaria anterior reached to the very Root of the Tongue below the OEfophagus, and fo quite ftopped the Paffage of the Air into the Mouth. But though there be no danger of Meat or Drink falling into the Lungs; yet were they not fufficiently fecured from fmall Animals creeping in there: For though, to fupply in fome measure the Want of an Epiglottis by lef fening the Glottis, there grew to the Outfide of the Cartilages, called Arytenoides, another capable of Motion up and down, by the help of fome Muscles that were implanted in it, strong on both fides of the afpera Arteria, but on the Under-fide, oppofite to that of the OEfophagus, very limber, wanting about two Inches and a half of coming round the aforefaid Cartilages on the Upper-fide, or the next to the OEfophagus: Yet did not this Cartilage fo fhut up the way against them, but that even a Mouse creeping up his Probofcis might get into his Lungs, and fo ftifle him. Whence we may guess at the Reafon, why the Elephant is afraid of a Mouse: And, therefore, to avoid this Danger, this Creature [the Elephant, which this Author defcribed] was obferved always when he slept, to keep his Trunk [Probofcis] fo close to the Ground, that nothing but Air could get in be

tween

tween them. This is a strange Sagacity and Providence in this Animal, or else an admirable Instinct.

Again, The Parifian Academifts obferve of the Sea-Tortoife, that the Cleft of the Glottis was ftrait and clofe. Which exact Enclosure, I do rather believe, is to prevent the Water from entring into the Wind-Pipe, when the Tortoises are under Water, than to affift the Effect of the Compreffion of the Air in the Lungs, as they would have it. For they make the main Reason of Refpiration, and Use of the Lungs in this Creature, to be, to take in and retain Air; by the Compreffion and Dilatation whereof, made by the Muscles, it can raise or fink itself in the Water, as need requires; though I do not exclude this. But if this be the main Ufe of the Lungs and Refpiration in this Animal, what is it in Land-Animals, which have alike Conformation of Lungs, and Manner of Refpiration; as the Chamaleon, Serpents, and Lizards?

But before I difmifs the Tortoife, I fhall add two notable Obfervations concerning him, borrowed of the faid French Academifts, which feem to argue fomething of Reafon in him, and more than a bare Inftinct. The firft is in the Land-Tortoife; and it is his manner of turning himself, and getting upon his Feet again when he is caft upon his Back, which they defcribe in thefe Words: At the great Aperture of the Shell before, there was at the Top a raised Border, to grant more Liberty to the Neck

and