Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/276

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POLYGONATUM, Salmon's feal, in botany, the name of a genus of plants, the characters of which are, that tile flower confifts of one leaf, formed in the ftiape of a bell ; but hav- ing a long tube, having no cup, and being divided into feve- ral figments at the end. From the bottom of this flower rifes a pift.il, which ripens into a foft roundim fruit, which contains a great number of roundifh feeds. T here are a great many fpecies of this plant r. The com- mon broad-leaved one. 2. The red (talked broad-leaved one. 3. The great broad leaved one. 4. The white helle- bore-leaved one. 5. The red-ftalked white hellebore-leaved one. 6. The large fweet-fiowered one. 7. The double- flowered fweet broad-leaved one. 8. The little broad-leaved one, with large flowers. 9. The low Englifh fingle-ftalked kind. 10. The narrow-leaved fingle-ftalked kind. 11. The narrow-leaved blanched kind. And, 12. The climbing American kind. Taurn. Inft. p. 78.

1 he root of Solomon' 's feal is a vulnerary of the very firft rank ; it is famous in bruifes for taking away the marks, and for healing up frefti wounds ; in both which cafes, it is applied in form of a pultice. It has alfo been greatly celebrated in the cure of hernias, and for aiufting in forming a callus in broken bones.

POLYGONUM, knot graf, in botany, the name of a genus of plants, the characlers of which are thefe: the flower is of the apetalous kind, being compofed only of a number of ftamina arifing from a funnel-fhapcd cup, divided into many fegments at the edge. The piftil finally becomes a triangular feed, which is covered by a capfule that was originally the cup of the flower. To this it is to be added, that the floweis grow in the ala: of the leaves, and that the roots are fibrous.

The fpecies of tnetgrafe, enumerated by Mr. Tourncfort, are thefe : r. The common broad leaved knltgrafs. 1. The white-flowered broad-leaved hwtgtafs. 3. The long and nar- row-leaved knotgrajs. 4. The fhort and nanow-leaved knot- grafi. 5. The llone-kn-tgrafs. 6. The great knltgrafs, with long (talks and long leaves. 7. The broad-leaved ki-knotgrafs. 8. The broad-leaved white flowered Ua-knotgraji. 9. The Spanifti Cei-inetgra/s, with very long ftalks, and white flower- cups. 10 .The broad-leaved fbxub Cez-inotgrafs. is. The round-leaved creeping Portugal ka-knotgrajs. 12. The little hoary, fcz-knotgrafs. Town. Inft p. 510. The antients as well as moderns have defcribed the common kinds of kmtgraf under the name polygonmn ; but as they have alfo given the fame appellation to another plant, much error has arifen by mifiaking thefe fynonyms. Pliny began the miftake, and others have fince in great numbers fallen into it, and thought Pliny's example a fufficient excufe. The word polygonum being formed of the Greek woAvf, many, and 5-ot, joint, or knot, fignified properly any plant that had feveral joints or knots. It was originally given to the kmt- graf very properly, fcarce any plant having more joints; but it was afterwards given alfo to a kind of equifetum or horfe- tail.

The defcription of this was, that the ftalks were hollow; the branches long, (lender, and refembling rufhes, or the twigs of the broom, but without any leaves ; and that they were {a brittle, that they could not be ufed as wyths, to bind things with, which feems to have been a ufe the common imtgrafs was very frequently put to, and for which it was found very proper, becaufe of the toughnefs of its branches. This kind of polygonum of the antients is faid to grow in woods, at the roots of trees, as the horfe-tails of feveral kinds do at this time ; and tho' the defcriptions of this and the other polygonum are fo extremely different, this having no leaves, and the other being defcribed by all to have fmall, oval, and pointed leaves, yet Pliny has confounded the two plants together, becaufe both called by the fame name ; and has formed out of the de fcription of different authors of thefe different plants, one ge- neral account, which he gives under the head of polygonum, and which can ferve no plant at all. He fays, it grows at the roots of trees, and climbs up them ; and that it has long, rufti- like, and brittle ftalks, befet with fmall oval leaves" He even compares the branches to the hairs of a horfe's tail, and yet did not find out at the time, that he was blending the de- fcription of the hippuris, or horfe-tail, called by Tome the female polygonum, with "the common knotgrafs, or polygonum originally fo called ; a plant as different from it as one plant can well be from another. Pliny, 1. 26. c. 13. The common great knotgrajs is eftecmed a very powerful aftringent. It is generally ufed in infufion, and is faid to have great virtue in Hopping haemorrhages of all kinds. Date Pharm.

POLYGRAM, in geometry, a figure confiding of many lines.

POLYIIEDROUS^F^n-, in geometry, a ("olid contained under, or confining of many fides. See Polyhedron, Cycl.

POIA HiSI OR, is ufed for a perion of great and various erudi- tion. SeePoLYMrtTHIA, Cycl.

POLYMORPHQS, varioufly fiiaped, an epithet often given to

the os fphenoides. POLYNOMIAL (Cycl.) -To raife a polynomial to any given

power, may he done by Sir Ifaac Newton's binomial theorem. Among other methods of demonflrating this, we have one by Signior Caftillioni in the philqfo.ph.ical tranfactions, numb. 464.

POLYOSTEON, a name given by authors to that part of the foot which confifts" of a great many bones.

POLYPE, orPotYpus, in zoology, a fmall frefll water infect, which, when cut into a number of feparate pieces, becomes in a day or two fo many diftindr and feparate animals; each piece having the furpi izing property of producing a head and tail, and the other organs neceflary for life, and all the animal functions. See Tab. of microfcopical Objects, Oafs 1. The firft difcoveryof this animal was owing to Mr. Leuwen- hoek, who, in the year 170 /, prefented to the royal fociety of London, a defcription of it, and an account of its uncom- mon way of producing its young: but the difcovery of its amazing property of reproducing the feveral organs from its various pieces, was not made till the year 173c by Mr. Trembley, at the Hague.

The produaion of its young is, indeed, different from the common courfe of nature in other animals ; for the youno- one iflues out from the fide of its parent, in form of a ("mail pimple or protuberance, which lengthening and enlarging every hour, becomes, in about two days, a^ perfect animal and drops from off its parent to fhift for itfelf: b^t before it does this, it has often another growing from its fide ; and fometimes a third from it, even before the firft is fepara- ted from its parent. They breed quicker in hot than in cold

- weather; and what is very extraordinary is, that there never has yet been difcovered among them any difiinction of fex, or appearance of copulation ; every individual of the whole fpe- cies being prolific, and that as much if kept feparate, as if fuffered to live among others.

If the method of this little animal's producing its young be very amazing, its reproduction of the feveral p~arts, when cut off, is much more fo. The difcovery of this was perfectly ac- cidental ; for Mr. Trembley, who had often met with the creature in the water, and from its fixed relidence in one place, and fome other observations, not being able to determine whether it" were an animal or a vegetable, made the trial by cutting it afunder, when, to his amazement, he found, that in a few days each of thefe pieces was become a perfect ani- mal, the head part having Ihot forth a tail, and the tail a head. A thoufand other trials, by cutting the animal in different manners, firft by Mr. Trembley, and afterwards, at his re- queft, by Monf. Reaumur at Paris, and Mr. Folkes Mr. Baker, and the other naturalifts in England, were the refult of this; and all fucceeded in the fame manner, by whoever they were tried.

It is not eafy to fay what is the fize of this creature ; for it can contract or extend its body at pleafure from the Ien<nh of an inch or more, and the thicknefs of a hog's brittle, to the fhprtnefs of a (ingle line, with a proportionable increafe of thicknefs. Its body is round and tubular, at one end of which is the head, furrounded with fix, eight, ten or more arms, with which it catches its prey; and at the other the anus and tail, by which it fixes itfelf to any thing it pleafes.

There have been many different fpecies of it difcovered, the mod elegant of which, the polype aparmaeht, or plumed polype, of Mr. Trembley, feems much to refemble the wheel-ani- mal (fo called from having the appearance of two wheels in its head) which Mr. Leuwenhoek difcovered living in a fheath or cafe, and affixed to the roots of duckweed. All the fpecies are found in clear and {lowly running waters, adhering by the tail to flicks, ftones, and water-plants, and live on fmall infects. They are eafily kept alive a long time in glafles, often changing the water, keeping the glaffes clean, and feeding them with a fmall red worm, common in the mud of the Thames, or with other fmall infects. The creature has its name from the Greek snAiit, many, and was, a foot, fignifying an animal with many feet; but a more appolite one might ealily have been invented, fince it has in reality no feet at all. What were originally taken for feet, are what have fince been called its horns, and of late more properly its arms, their office being to catch its prey. The feveral ftrange properties recorded of this animal, tho' very furprifing, are, however, none of them peculiar to it alone. The Surinam toad is well known to produce its young not in the ordinary way, but in cells upon its back. Mr. Sherwood has very lately difcovered the fmall eels in four pafteto be each, without exception, full of living young ones. And as to the moft amazing of all its properties, the repro- duction of its parts, we know the crab and lobfter, if a leg be broken off, always produce a new one : and Mr. Bonet, Air. Lyonet, Monf de Reaumur, and Mr. Folkes, have all found on experiment, that feveral earth and water worms have the fame property, fome of them even when cut into thirty pieces. The urtica marina, or fea-nettle, has been alfo found to have the fame : and the fea-ftar-fifh, of which the pilpe is truly a fpecies, tho' it had long cfcaped the fearches of the naturalifts, was always well known by the fifhermen to have it alfo.

Clujler