Page:Cyclopaedia, Chambers - Supplement, Volume 1.djvu/859

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the left auricle were joined and cemented together, and left only a very fmall aperture formed in the middle of the plane made by their re-union ; the blood coming from the iungs in- to this auricle, could not without a very great and unnatural difficulty, pafs thence into the ventricle ; and the auricle compelled by this to extend it'felf to contain a large quantity of blood, was become much larger than it ought to have been in its natural ftate. In different parts of the united valves there appeared feveral little points where an oflification was begun. The woman died phthifical, nor could it be other- wife, fince the lungs could not but be affe&ed by the diffi- culty with which the blood entered into the left ventricle of the Heart. And the gentleman who gave the account ob- ferved, that this was no fmgle initancc of a cafe of this kind, but that he had met with feveral fuch, particularly one in the right auricle of the Heart of a girl of fourteen. Another in- ftance of a remarkable diftemperature of the Hearty is given by Mr. Du Fay of the fame academy : A man who had lived to thirty-four in very good health, became at that age very fubject to the vapours, but the complaint encreafed to no particularly violent degree for the fpace of eighteen years, but at this time he perceived a palpitation of the Heart to join with the other fymptoms, and this held him to the time of his death, which was two years afterwards. Mem. Acad. Scien. Paris, 1 735,

Thefe palpitations, which were flight at firft, became after- wards fo ftrong, that they communicated their motion to the fides, and might be feen through the patient's cloaths even when he was drefied. If the hand were applied to the region of the Heart, it was perceived to move very forcibly, and the arteries all partook of the diforder, while the veins were all confiderably fwelled in the upper parts. In the latter part of his life he became dropfical, his legs fwelling violently. On opening his body, the cavities of the breaft and belly were found to be full of water, the lungs were found, but confi- derably wafted j the liver and fpleen fomewhat larger than ordinary, and the pancreas very large, and very hard and fcirrhous. The Heart weighed above two pounds, and was fo large that it threw the left lobe of the lungs toward the upper part of the bread. It mcafured fifteen inches round at the bafe, and the two ventricles were full of blood ; the right was nearly of its natural fize, but the left, which ought to be fmaller than that, was fo dilated as to be vaftly larger, tho' its fides had not at all loft their thicknefs. The pericardium was fomewhat thicker than ordinary, and was nicely applied to the Heart, but had on one fide a tumor of the fize of an egg, full of blood ; the aorta was oflified at the place where it goes out of the left ventricle. Mr. Du Fay cfteems this cafe to have been an extraordinary aneurifm of the left ventricle of the Heart ; a cafe feldom heard of.

Another fcarce Iefs memorable inftance there is in the me- moirs of the fame academy, which proves that wounds of the Heart are not always fo immediately mortal as is generally fuppofed. The cafe was this; a foldier was brought into one of the hofpitals with a wound made by a fword in the upper part of the left breaft ; he feemed very well for three days, but on the fourth he was taken with a fever and difficulty of refpiration, and in fine died on the tenth day. On openin" the body it was found that the fword had pierced the pericar- dium, traverfed the right ventricle of the Heart in its lower part, and near the point, and pierced the pericardium on the oppofite fide, and gone through the diaphragm, and an inch deep into the liver ; there was much blood found in the pe- ricardium, a little clot of congealed blood in the wound in the Heart, and a quantity of purulent water on each fide of the breaft.

We have an account of a child which lived feveral days, yet upon dhTedtion its Heart was found without a pericardium, and turned upfide-down, fo that its bafis, with all the vefTels, had fallen down as low as the navel, and its apex frill on the left fide, lay hid between the two lungs. See Phil. Tranf N° 4 6i. Sea. 7.

Mr. Boyle tells us of a kind of fifh on the coaft of Ireland, about the fire of mackerel, the Heart of which was inver- ted, the bafis lying towards the taii, with the mucro pointing to the head, and adhering to the aorta. Works abrid"-. Vol. 1. p. 27.

Some creatures are known to live a confiderable time after their Hearts are taken out: Mr. Boyle mentions fro^s fwim- ing in this condition, and living above an hour; and the Heart of an animal often gives figns of life after exfection. The fame author mentions the Heart of a chicken unhatched, but perfectly formed, which continued to beat above an hour after the head and breafl-bone were clipped off to difclofe it. And when the Heart was dead to appearance, it might be excited to frefh motion by puncture. The motion was alfo again excited by placing the part in the fleam of warm wa- ter; and thus the Heart was kept beating for two hours and an half. See Boyle's Works abridg. Vol. 1. p. 28. Hearts of Fiji}. The Heart in fifhes is fituated a little below the gills. It is ufually contained in an extremely thin mem- brane by way of pericardium, and placed in a large cavity. The Heart in the feveral kinds of fifhes is of many different figures : j. In fome it is quadrilateral ; of this wc fee inftances in molt ©f the common fifh, 2. la fome it is of a femicircular figure. Sum.. Vol. I.

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but a little flatted, as in the cyprini. 3. Its fituation is gene- rally tranfverfe with refpedt to the head, but not always Co. In the cetaceous fifties the Heart has two ventricles, as in land animals : but in all other fifhes, that isj in all that have gills and not lungs, it has only one cavity. The Heart in all fifh has only one auricle ; this is very large, and is always placed on the left fide of the Heart: At the place of the infer- tion of this auricle, there are two valves, the one an upper* the other a lower one. The auricle in its lower part contains the receptacle of the veins, and this has alfo, at its infertion into the auricle, two valves.

The aorta, or great artery in fifhes, adheres to the upper part or bafe of the Heart by a ginglymus. Its firft part, or that next the Heart, is fmall, and contains two figmoide valves. Soon after this it is dilated into a large cavity, which is whitifh on the outfide, and within is fupported by feveral carneous fibres, forming a fort of columns. From this part the artery is formed into a fort of cave, and thence is carried to the gills ; it gives one great branch to the hollow of each gill, that is four to each fide ; and each of thefe large branches is again, a little beyond its infertion into the hollow part of the bow of each gill, divided into four other branches:, which running along the bafe of the lamellae, are divided finally into as many branches as there are lamella?, each receiving one ; thefe are carried to the extremity of the lamella?, and there loll ; but the blood returns by as many veins, and is thence diftributed throughout the whole body. In the margin of every lamina in the leaves of the branchiae, or gills, there is a vein which difcharges the blood it receives from the arteries of thefe parts into a trunk, which runs over the furface of every arch or bow of the gills ; and in fine, every vein com- ing from all the bony circles of the gills, are by degrees, fome higher and fome lower, inferted into one common trunk. This grand trunk of the vein runs along the fpine, and per- forms the office of the defcending trunk of the aorta in land animals, and diftributes the blood to every part of the body of the fifh. The trunks of the lower part of each bony circle take this courfe, but thofe of the upper part are carried up to the brain and organs of fenfation, and are returned thence by other branches, which join thefe lower trunks. Thefe veins when thus join'd, are carried to the origin of the gills, and there are dilcharged into another trunk lying upon the aorta$ which is opened into the receptacle of du Vcrney. This re- ceptacle is no other than a venofe trunk formed by the meet- ing of feveral veins coming from the fpine, from the liver, and other parts, and terminating in the auricle. Thus is the circulation in fifh carried on in a very different manner from that in land animals ; and the gills ferve to offices little thought of by many authors. Artcdi Ichthyolog. Hearts ofinfeEls. It is eafy to difcover that many infects have a true and regular Heart ; nor is this any where more beautifully diftinguifhable than in the clafs of flies ; the fmall ones, and thofe of tranfparent bodies, are to be chofen indeed for this examination, the larger and more opake being wholly improper for it. None is more eligible on this occafion than the little fly produced of the puceron eater ; this is a very pale yellowifh fly of a flat body, and fo perfectly tranfparent, that examined in a proper manner, its internal parts are feen as clearly as if they were in a white glafs vefTel. One of thefe little flies is to be taken foftly by the head be- tween the fingers ; the wings are to be bent backward, and held with the head, the body inverted and held up againft a ftrong light, and the belly then examined with the help of a magnifying glafs. This examination will convince any one that flies have a real Heart ; they have not a long vcffel only, in the place of one running lengthway down the back, as Malpighi thinks is the cafe in caterpillars and butterflies ; but toward the middle of the fecond ring, and fomctimes in the third, counting from thecorcelet, one plain- ly difcovers a part which can be taken for no other than a real Heart. The figure of the Heart in thefe animals varies however much more than in any others that we are acquainted with. Sometimes this Heart is of the figure of a kidney placed tranfverfely, and with its hollowed part toward the corcelet, with a long veflel running ftrait from this hollowed part up the corcelet. At other times the hollow of the Heart difap- pears, it lengthens itfelf, and acquires the figure of a bottle, with the veflel before described placed as its neck. Sometimes it is more, and fometimes lefs inflated and diftended ; fome- times the tranfverfe diameter furpaffes the longitudinal, and at others the longitudinal diameter exceeds the other. At all times, however, one may fee a regular alternative contraction and dilatation of the Heart j and to the contraction there conftantly fucceeds a jet of liquor thrown into the long vefTel as if by a fyringe ; but what is very angular is, that after four or five of thefe jets, one always fees the liquor before thrown up defcending into the Heart again out of the corcelet, by the fame veflel by which it was received from the Heart, Reaumur's Hift. Inf. Vol. 4, p.-»6i.

We art -burn, a difeafe properly called by medical writers foda« See the article Soda.

He art -Jhells, Concha cordiformeSj in natural hiftory, the name

of a genus of fhells, by fome authors referred to the pe£tun-

culus or cockle kind, but by later writers juftly diftinguifhed

into a feparate genus. The characters are thefe : It is a bi-

13 F valv«