Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/693

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fluid in feme adjoining part where there is feme obftruflion. I he air, which is naturally mixed with all the fluids in the human body, always remains in them while they continue in their fluidity, and ill their natural motions; but when they are amafled together in any particular part, and their fluidity and motion become impaired, the air that was in them be- comes immediately in a ftate of difengaging itfelf from them ; and it dually does (o difengage itfelf. The membranes of the part where this collection of the fluids is made, are relaxed by it, and their pores confequently enlarged, and the air which has difingaged itfelf, efcapes eafily by thefe pores, while the fluids are much too thick to be able to follow it, fo that it efcapes alone.

'i he air, thus feparated, runs under fome other adjoining membrane, which it immediately elevates and diftends. As the liquors amafled in the other place are not yet fo far altered, but that part of them are continually received again into the road of circulation, and confequently more frefh fluids left in their place : thefe frefh fluids contain more air, which is, by degrees, feparated from them, as from the others, and finds its way, in the fame manner, to the place where the reft of the air is ; and hence is the continual increafe of the Turners ; and it is very evident, that when a Tumor is once formed in this manner, it cannot go down, even though the firft cxtra- vafat.on, which occafioned it, fhould wholly difappcar, and all the fluids be again received into their veffels again ; but, in fine, the air included in the Tumor may dilate the membrane, which enclofes it, fo far, that its pores may be fuflkiently opened to let it efcape ; this, however, wholly depends on its quantity, and on the defer or laxer texture of the mem- brane.

Thofe acute pains which we call flitches in the fide, and Which are principally felt on the fides, and about the region of the breait, may poffibly be fometimes occafioned by acrid humours, which prick the nervous fibres ; and the pain, in this cafe, is fometimes very acute, and even attended with a fliarp fever; but very often this pain is occafioned only by air included between the fibres, where it occafions a violent ten- fion and pain ; but often the relief from this is hidden, the natural elafticity of the parts reftoring all to their priftine ftate, and the air being condenfed again almoft as foon as dilated. Very often the natural fpring'of the parts either entirely fends off the air, or elfe drives it to another place ; and this is the reafon why pains of this kind are often found to fljift about and change place fo fuddenly.

But of all the effects of air in the body, none is fo great as that found in the bodies of thofe who have died by lofs of blood, whether that has been occafioned by wounds or natural he- morrhages. There may, in this cafe, often be perceived, through the coats of fome of the veins, little bubbles of air floating on the furface of the blood contained in them ; and this is no way to be wondered at, fince as a great part of the blood has been loft out of the body by the hemorrhage, the remainder has been by this much injured in its power of mo- tion, as well by lofs of quantity to impel it, as of animal (pi- nts to enliven it ; and by the want of ftrength in the arteries to perform their pulfations, in order to the keeping it in mo- tion ; the confequences of thefe joint caufes, according to the principles before laid down, muft be, that the air muff efcape out of the blood, and appear freed as we fee it. If we perceive this only in the veins, the reafon is plain, fince there is no blood any where but in the veins of perfons who have died in this manner, the arteries having been already drained ; whereas, in other bodies there always remains fome blood, though but little, in the arteries. Another confe- quence of dying by an hemorrhage is, that the ventricles of the heart are always found empty of blood ; which is not the cafe in thofe who have died by other means. The caufe of this is, that the force with which the veins drive up the blood from their extremities toward their larger trunks, and thence to the heart, is much weaker than that by which the arteries throw the blood they contain toward the extremities. This being allowed, a great lofs of blood cannot but diminifh the force of the arteries and veins both ; but its eft'eft will cer- tainly be greater on the veins ; fo that they may wholly lofe their force before the arteries have loft theirs ; and thefe laft making at length one general contraflion, may throw off all their contents into the veins, while they, having already loft all their Dower, can no longer move it forwards ° fo that, in this cafe, it all remains there, and confequently what blood remains in the body, muft, on opening it, be found lodged in the veins.

ft is fometimes obferved in bodies which have died of hemor- rhages, that the fmaller veflels, at confiderable diftances from the heart, have been all full and diftended with wind ; in this ftate it is not impoflible that they may have been fometimes miftaken for lymphatic veffels ; but in tracing them up to their trunks, they foon dlfcover what they really are. After a large quantity of blood has been loft, it is plain that there can be but little in the lungs, while the quantity of air is al- ways equal there ; and as the air always eafily difen<rages it- felf from the blood, when it is lefs fluid, and in fmallei Quan- tity than before, the air may, in this cafe, pars from the lungs to the heart with the blood, without beino- fo intimately PUPPL. yea. II. °

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mixed with it as at other times ; when the arteries have, aftef this, not power enough to impel the blood into the veins, their power may yet be fumeicnt to drive this wind into them, t being much lighter, and mote fufceptible of motion ; and this alone Teems a very natural and eafy Colution of this phe- nomenon. 1 ins fuppofes, indeed, that the motion of the Wood being flopped, death comes on, as well by this means, as by the ftoppage of refpiration. Mem. Acad. Par. 1 7 14.

'™ 01!s. 'ftbe Teftides. See the article Testicles. 1 j 1 '" botan y> thc name b y which fome authors have cal- led the opmti.a, the Indian fig, or ficus India, as it is ufually called. Jo„J. Dendr. p. 57. '

TUNALLUS, in ichthyology, a name given by Albettus, and iome others, to that fpecics of the corcgoni called by the gene- rality of authors the tbymalhu, by us the grayling, or um- ber. Artedi dlftlnguifhes it by the name of the arcgonus, with the upper jaw longeft, and with twenty-three rays in the

TTTNTr. ■" SeC the art ' Cle COREOONUS.

JUNG, in natural hiftory, the name given by the Indians to a little infect, called by the Spaniards Piqui, which is very common, and very troublefome in feme parts of the Eaft and Weft Indies.

It is of thefizeofafmall flea; its place of laying its eggs is within the flan of the human body, and it diligently fearehes' opportunities of doing this, and often fuccceds in the attempt, to the great pain and trouble of the pctfon who fuffers it. 1 he creature, knowing that it ihall be foon crufhed to death under the fkm, generally makes its way cither under the nails, or where there is fome callus on the furface ; there it eats its way along, and, in fine, lays its eggs, which hatch into fo many young ones, and fprcad themfelves between the Hem and flan all over the finger and hand, if not prevented by taking out the old one in time.

I he perfon often does not perceive the creature's getting in, ie enters fo gradually and eafily ; but he is foon advertifed of the place where it is by a violent gnawing pain, the creature really eating its way as it goes along. The only remedy in this cafe is, to enlarge the orifice at which it enteied, and take it ■ out whole ; thc wound foon heals up, and there is an end of the matter. This may often be done with the point of a needle ; but if not, it is much better to fubmit to the opening it with a lancet, than to the ill confequences which otherwife

■rntjT ' Knd *' ° hfav - fur '« Coutumes de l'Afie. p. 184.

1 UMCA {Cyd.) Tunica Jlhuginea, the name of the mem- brane that covers the body of the tefticles. It is of the fains fubftance with others of the thicker membranes of the body, and is fupplied with proper veflels for its nourifhment ; but un- der this thebodyofthetefticle is, on a Arid examination, found to be only a congeries of veflels rolled up in regular and even folds, without any intermediate fubftance of whatever kind. It is neceffary to have rccourfe to the ufe of glaffes to fee this ftru- cture ; and there is one caution neceffary to the perfons who would make the experiment, which is, that as thefe veffels all contain a liquor, which being fomewhat thick and whitifb, foon dries when expofed to the air, and, in drying, acquires fomewhat of the appearance of flefh, it is very apt to deceive the infpedlor into an opinion, that there is really a flefhy mat- ter in the fubftance of the tefticle, diftinfl from the veflels : What will fct this right, will be the obfetving, that the ob- ject, when newly cut, and immediately viewed, has none of this flefh-like matter about it ; but only a mucous humour may be feen ouzing from the mouths of the rolls or folds of the veffels where cut ; and that afterwards, when the fiefh- hke matter becomes vifible, it is only feen about the ends and edges of the piece of the tefticle that is examined, and only in thofe places where it was before feen ouzing out in form of a fluid from the apertures of the veflels.

Thefe veflels, of which the fubftances of the teftes are.com- pofed, are extremely tender and fine ; yet, while the fubjeil is frefh, they may, by a delicate hand, be drawn out, and will fometimes be extended to half a yard long without break- ing. The fingle veffel, when thus extended, has much the appearance of the external coat of the epididymis, and its cor- rugations. Thefe tubes receive their contents in fome fort from the arteries, and have a communication with them, info- much that on injecting a coloured matter into the arteria pre- faram, and afterwards opening the tefticle, this matter will be found to have made its way into feveral of the tubes com- pofing the rolls or folds of the fubftance of the tefticle. It might be fuppofed, that this colouring of the tubes was only external, and that the matter of the injection had only fpread itfelf on their furface, or penetrated into the plexus of veffels that cover them ; but, on trying to wafh off the colour with fpirit of wine, it proves fo permanent as not to give way to that ; and, on curioufly examining a part of a fingle tube pricked with a fine needle, the coloured matter of the injection may be diflinef ly feen ouzing out of the puncture. The glands in general are no other than the teftes ; and the pancreas, and many other parts of the body, have no parenchyma or inter- mediate flefhy fubftance between the veflels, but are made up of veflels or tubes filled with peculiar liquors, and generally owe their colour to that of the liquor they contain. No re- puted gland is any other thing than a mere congeries of veffejs, through which peculiar juices come and go ; and the very 5 A coatj*