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term comprehends nothing but :Obfervations upon animals, commonly what regards its living in both air
called amphibious by authors. Pre- and water at discretion; however, Jented by Dr. Parfen, F. R. S, fince the word amphibious is a.
si dopted by the writers of the his. T HE following remarks, tory of animals, let us retain it
1 which I have the honour to ftili, and examine some of this lay before this learned - society, class, and, by considering their were occasioned by a conversation, natural economy respectively, enthat passed between me and a gen. deavour to range them, according tleman well acquainted with natu. to that standard, in the following ral history, however mistaken in manner. They are fuch as,
the subject before us. His opinion - 1. Enjoy their chief fonctions .: was, that amphibious animals liv. by land, but occasionally go into : ed more in the water than on the the water. .. .
land: but I believe the contrary ... 2. Such as chiefly inhabit the will appear by the sequel of this water, but occasionally go ashore, treatise.
Of the latter, there are but very If we consider the words are Q. few species. And although none and Bios, from which the term am- of the winged tribe are to be rang. phibious is derived; we should ed under this class, yet as many understand that animals, having of them semain long upon the this title, should be capable of water in search of their proper living as well by land or in the food, we fall enumerate some air, as by water, or of dwelling in peculiar advantages, which have : either constantly at will; but it been allowed to several of them will be difficult to find any animal by the bountiful wisdom of the
that can fulfil this definition, as creator, in order to render them .. being equally qualified for either; the more able to obtain it; and
and in clasling creatures of this this will make one curious part kind, authors are much divided, of my present purpose, not gene. and sometimes mistaken.
sally known. : Now if any natural historian The dispute mentioned between
should deduce his distinction of my friend and me, turned upon this class, from the structure or the class of the phocæ, which con. characteristic of any part of the lists of a very numerous tribe of animal, I think he would be a different species: I shall therefore little out of the way ; because the endeavour to thew that none of
them can live chiefly in the wa. or total expiration of the air in ters, but that their chief enjoy. breathing; for in the former care ment of the functions of life is on the inflation compresses the return.. shore.
ing veins, and in the latter, by These animals are really qua. the collapsion of the lungs, these drupeds; but, as their chief food veins are interrupted also, fo that is fi in, they are under a neceffity it is onty between these two vio. of going out to sea to hunt their lent actions that the blood can prey, and to great distances from pass; and hence it is that the lives Thore; taking care that, however of animals are shortened, and "great the distances, rocks or small their health impaired, when they iflands are at hand, as refting are subjected to frequent violent places when they are tired, or "respiration; and thus it is that in their bodies become too much ma. animals who have once breathed, cerated in the water; and they they must continue to refpire ever
return to the places of their usual after; for life is at an end wher * resort to feep, copulate, and that ceases, bring forth their young, for the There are three necessary and
following reasons ; viz. It is well principal uses of refpiration in all : known that the only effential dif. land animals, and in these kinds
ference (as to the general ftruc. that are counted amphibious ; the ture of the heart) between amphi. first is that of promoting the cir. bious and mere land animals, or culation of the blood through the ! such as never go into the water, is,' whole body and extremities : ia.
that in the former the oval hole re. real fishes, the force of the heart "mains always open. Now, in such is alone capable of sending the
as are without this hole, if they blood to every part, as they are were to be immersed in water for “not furnished with limbs or ex. but a little time, respiration would tremities; but in the others men. cease, and the animal moft die; tioned, being all furnished with becaufe a great part of the mass of extremities, respiration is an afa blood paffes from the heart, by fiftant force to the arteries in fenda. the pulmonary artery, through the ing blood to the extremities, lungs, and by the pulmonary which, being so remote from the veins returns to the heart; while heart, have need of such aslistance ; the aorta is carrying the greater otherwise the circulation would be part of the mass to the head and very languid in these parts; thus extremities, &c,
we see, that in persons subject to Now the blood passes through afthmatic complaints, the cir.' the lungs in a continual uninter. culation grows languid, the legs rupted it ream, while respiration is grow cold and edematous, and gentle and moderate ; but when it other parts suffer by the defect in is violent, then the circulation is respiration. interrupted, for inspiration and ex." A second use of breathing is, piration are now carried to their that, in inspiration, the variety of exteni; and in this state the blood particles, of different qualities, cannot pass through the langs which float always in the air, either during the total infpiration 'might be draws into the lungs,
to be infinuated into the mass of as I have explained it above, and blood, being highly necessary to he is rendered fit for his next contemperate and cool the agi- cruize: for action waftes the most tated mass, and to contribute re-exalted fluids of the body, more fined pabulum to the finer parts of or less, according to its duration it, which, meeting with the daily and violence; and the restorative supply of chyle, ferves to aslimi. rest must continue a longer or Jate and more intimately mix the shorter time, according to the mass, and 'render its constitution quantity of the previous fatigue. the fitter for supporting the life of Let us now examine by what the animal. Therefore it is, that power these animals are capable of valetudinarians, by changing foul remaining longer under water than or unwholesome air for a frec, good, land animals. open air, often recover from ling- . All these have the oval hole open ering diseases.
between the right and left auricles And a third principal use of re. of the heart, and, in many, the spiration is, to promote the ex. canalis arteriosus also: and while .hibition of a voice in animals; the phocă remains under water, which all those that live on the which he may continue an hour or land do according to their specific two, more or less, his respiration natures.
is stopped, and the blood, not From these confiderations ir ap- finding the passage through the pears, beyond contradiction, that pulmonary artery free, rushes. the phoce of every kind arc un. through the hole from the right der an absolute necessity of mak- to the left auricle, and partly ing the land their principal resis through the arterial canal, being dence ; but there is another very a short passage to the aorta, and convincing argument why they re. thence to every part of the body, fide on more the greatest part of maintaining the circulation: but, their time, and that is, that the upon rising to come ashore, the flesh of these creatures is analo. blood finds its passage again
gous to that of other land ani. through the lungs the moment he 'mals ; and therefore, by over. respires long maceration, added to the Thus the fætus ip Otero, during fatigue of their chacing their prey, his confinement, having the lungs they would suffer such a relaxation compressed, and consequently the as would destroy them. It is well pulmonary arteries and veins im. known that animals, which have pervious,'has the circulation of lain 'long under water, are reduced the blood carried on through the to a very lax and even putrid state; 'oval hole and the arterial canal; and the phoca must balk in the air now so far the phoca in the water on Thore; for while the folids are and the fætus in utero are analo. at reft, they acquire their former gous; but they differ in ocher degree of tension, and the vigour material circumstances; one is, of the animal is restored ; and that the fætus, having never rewhile he has an uninterrupted spired, remains sufficiently nou. placid respiration, his blood is re- rished by the maternal blood cis. freshed by the new supply of air, culating through him, and conti.
nues to grow till the time of his shore; I shot him, and saved the fish birth, without any want of refpi- whole. Now, as all fætuses have ration during nine months con. these passages open, if a whelp of a finement; the phoca, having re- true water-spaniel, was, inmedi. spired the moment of his birth, ately after its birth, served as the ' cannot live very long without it, phoca does her cubs, immersed in for the reasons given before ; and water, to stop respiration for a little this hole and canal would be time every day, I make no douba clofed in them, as it is in land but the hole and canal would be animals, if the dam did not, very kept open, and the dog be made foon after the birth of the cub, capable of remaining as long under carry him into the water to teach water as the phoca.. him, so very frequently ; by which Frogs, how capable foever of: practice these passages are kept remaining in the water, yet can. open during life; otherwise they not avoid living on land, for they would not be capable of attaining respire; and if, as I have often the food designed for them by pro- done, a frog be thrown into a vidence.
r iver, he makes to the shore as fast Another difference is, that the as he can. phoca, as I said before, would be The lizard kind, such as may relaxed by maceration in remain- be called water lizards, or lacer. ing too long in the water ; where- tz aquaticæ, all are obliged to as the fætus in utero suffers no in- come to land and deposit their eggs, jury from continuing its full num. reft, and sleep ; even the crocober of months in the fuid he diles, who dwell much in rivers, swims in the reason is, that leep and lay their eggs on shore; water is a powerful solvent, and and, while in the water, are com. penetrates the pores of the skins pelled to rise to the surface to of land animals, and in time can breathe'; yet, from the texture of diffolve them: whereas the liquor his scaly covering, he is capable of amnii is an insipid soft fluid, im- remaining in the water longer by pregnated with particles more or far than any species of the phocæ, less mucilaginous, and utterly in whose skin is analogous to that of a capable of making the least altera- horfe or cow, tion in the cutis of the fætus. . The hippopotamus, who wades
Oiters, beavers, and some kinds into the lakes or rivers, is a qua. of rats, go occasionally into the druped, and remains under the warers for their prey, but can. water a confiderable time ; yet his not remain very long under wa. chief relidence is upon land, and ter; I have often gone to thoot op. he must come on thore for refpi. ters, and watched all their mo. ration. tions; I have seen one of them go The testudo, or sea-tortoise, tho' foftly from a bank into the he goes out to sea, and is often river; and dive down, and in found far from land; yet, being about two minutes rise, at ten or a respiring animal, cannot re* fifteen yards from the place he main long under water. He has went in, with a middling lalmon in indeed a power of rendering him. his mouth, which he brought on self specifically heavier or lighter
trian the water, and therefore can the eel and serpent kinds, can live i lechimself down to avoid an enemy a considerable time on land, and
or a storm ; yet he is under a ne. the vertical and horizontal kinds ceffity of rising frequently to die almost immediately when taken. breathe, for reasons given before, out of the water: and, in this re.. and his mod usual situation, while search, we shall come to know what at sea, is upon the surface of the analogy there is between land ani. water, feeding upon the various mals and those of the waters. All substances that foat in great a. land animals have lungs, and can: bundance every where about him; live no longer than while these are these animals sleep securely upon inflated by the ambient air, and als the surface, but not under water, ternately compressed for its exand can remain longer at sea than pulfion; that is, while respiration any others of this clars, except the is duly carried on, by a regular in. crocodile, because, as it is with spiration and expiration of air. . the latter, his covering is not in . In like manner, the fish in genedanger of being too much mace. ral have, instead of lungs, gills, rated ; yet they must go on shore or branchiæ, and, as in land aoi. to copulate, and lay their eggs. mals, the lungs have a large por
The confideration of these is tion of the mass of blood circu. sufficient to inform us of the na. lating through them, which muft. ture of the first order of the class be stopped if the air has not a free of amphibious animals; let us now, ingress and egress into and from see what is to be said of the second them; fo, in fin, there is a great in our , division of them, which share of blood-vefsels that pass are such as chiefly inhabit the through the branchiæ, and a great waters, but occasionally go on portion of their blood circulates Thore.
through them, which muft in like These are but of two kinds; manner be totally itopped, if the the eel, and water serpents, or branchiæ are not kept perpetually snakes of every kind. It is their wet with water; so that, as the form that qualifies them for loco. air is to the lungs, in land animotion on land, and they know mals, a conftant affiftant to the their way back to the water at circulation, so is the water to the will ; for by their structure they branchiæ of those of the rivers and have a strong peristallic motion, by feas ; for-when these are out of which they can go forward at a the water, the branchiæ very soon pretiy good rate, whereas all o. grow crisp and dry, the blood vet. ther kinds of fith, whether vet. els are shrunk, and the blood is tical or horizontal, are incapable of obftructed in its paffage; so, when a voluntary loco-motion on shore; the former are immersed in water, and therefore, as soon as fuch fish or otherwise prevented having reare brought out of the water, fpiration, the circulation ceaics, alier having flounced a while, and the animal dies. they lie motionless, and foon Again, as land animals would die..
be destroyed by too much macera. Let us now examine into the tion' in water, fo fithes would, reason why, these vermicular fith, on the other hand, be ruined by