Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/303

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ment he carefully tried, not only on coral but on many other of the ftony plants, and found all of them yielded the fame principles with vegetables. All of them yielded on this trial, a phlegm, a volatile urinous fpirit, with always more or lei, of a fea-water fmell, and a thick reddifh black foetid oil ; and the remainder in the retort being calcined, always yielded a fixt alkaline fait like that of plants.

The fea productions all afforded more or lefs of every one of thefe principles ; but thofe of which ever kind that had been kept a long time after they were taken out of the fea, afforded always much lefs fluid matter than thofe which were frefh. Mr. 'Geoffrey was very defirous of following the Count in thefe refearches ; and as he had no opportunity of procuring any frefh coral from the fea, he put into a retort a pound of the common red coral, fold by the druggifts, which is what wants the outer bark, and has ufually been a long time out of the fea. This yielded two drams and fix grains of a reddifh volatile urinous fpirit, and two or three grains of a fcetid oil, and the remainder in the retort by the common treatment, yielded afterwards near two drams of a lixivial fait of a fa- line tafte : the matter remaining after the Hxiviation appeared a fort of lime.

The fpirit appeared to Mr. Geoffroy to be wholly the fame with that which the Count had himfelf fent to the academy under the title of the fpirit of old coral ; and it appeared fcarce at all different from fpirit of hartfhorn. It turned (y- rup of violets green, and made a white coagulation with ihe folution of corrofive fublimate. Tho' this was much the fame with the Count's fpirit, the falts drawn from the caput mor- tuum were, however, different ; that made by Mr. Geoffroy making a white coagulation with a folution of corrofive fub- limate, and that of Count Matfigli having no fuch effefl ; both the falts, however, turned the fyrup of violets green, and Mr. Geoffroy judged the difference in the other trial to be only from the Count's fait having been lefs carefully made, and containing fome quantity of earth which weakened its power and prevailed this effect from it. It follows from all this, that the corals and all the other fea produBims of that clafs are properly plants, tho' of the hardnefs of ftones: and in the internal u(a of coral it may be proper to confider it not as a mere abforbent, but as a fubftance which contains alfo a volatile fpirit and oil, which may well be fuppofed to pof- fefs virtues above thofe of mere abforbent earth ; and that there is great difference between the virtues of fuch coral as has been long kept, and fuch as is newly taken up from the fea. The Count, after analyfing coral in this manner, tried the fame procefs on feveral parts of the rocks on which the coral ffrew ; but he found this to yield none of thefe active principles ; fo that altho' the hardnefs of corals and of ftones teems the fame, there is great difference between them in their principles, their nature, and effects. There is yet one queftion remaining to he determined in this point, which is, what is the nature of this milky juice con tained in the tubercles or flowers, and perhaps not lefs in the other parts of coral. The Count has faid nothing as to its qualities, but Boccone fays it is hot, acrid, and almoft cau- ftic ; whence perhaps it is the natural fap of the plant, and is analogous to the milky juice of the fpurges and fome other plants. It w*re to be wifhed that this liquor could be tried with acids and alkalies, and in other ways, and its analyfis known : this perhaps would make our knowledge of the nature of this ftony vegetable perfect. Mem. Acad. Par. 1708. PROEDRI, Ileoefyoi, among the Athenians, magnates whofe hufinefs it was to propofe to the people the things they were to deliberate upon and determine at every affembly, after which their offices expired. Potter, Archeeol. Grsc. 1. i.e. 17. T. 1. p. 93.

They were fo called from the privilege they enjoyed, of al- ways having the firft feats at aflcmbUes. PROEROSIA, n,M f «i«, in antiquity, the fame with prerofia

See Prerosia. PROFUNDUS, in anatomy, a name given by Albinus, Hu- naud, and others, to a mufcle of the wrift, generally known by the name of the perforam. Thefe authors called, in the fame manner, the perfbratw of others the fublimis. PROGALL-INSECT, an animal nearly approaching to the gall-infect clafs, but differing from it in fome refpects, and called by this name from its refemblance to thofe creatures ; as the creatures fomewhat approaching to tie fcarab or beetle clafs, but not regularly of it, are called profcarabs. This clafs of animals pafs a great part of their lives in the fame manner with the gal-infects, faftened to the bark of a tree, and there remaining motionlefs ; fome of them alfo in the manner of the gall-infects cover their young brood with their bodies ; but they are eafily diftinguifhable as animals, in all the ftages of their lives, and in that they differ from the others. The annular depreffions of their bodies may in all their Hates be diftinguifhed, efpecially with the help of a mag- nifying glafs ; whereas thofe of the gall-infects all difappear as they grow towards their utmof: bulk.

If the gall-infects are worthy of obfervation on account of the great value of one fpecies of them, the kermes ; the progall- infeSts are at leafl equally fo on the fame account, fince the cochineal belongs to this clafs. Suppl. Vol. II.

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The moft common and obfervable fpecies of the progatt-ififefl clafs, is that of the elm, and a defcription of that alone may give a fufKcient light into the hiftory of the whole clafs, and ihew what characters are to be found in the infects properly reducible to it.

This infect is principally found in the fori-ied branches of the elm, and commonly in thofe of one, or at the utmoft <<f two. years growth; it is fometimes found in other parts of the branches and twigs, but that is much lefs frequently. It is in the months of June and July that this infect is at its full growth ; at this time, however, it appears to the naked eve only as a fmall oval convex mafs, of a dirty brownifh red co- lour, furrounded with a fmall downy white thread. This reddifh oval mafs is the back of the animal, and by the help of glafies we may fee the annular ridges and depreffions that characterize the infect clafs. This is all that gives an idea of its being an animal ; for it is at this time in a ftate of per- fect immobility, and fhews neither head, legs, or any other part that might give a proof of what it is ; all thefe parts are enveloped and hid by the cottony band that furrounds it, which fufFers no part but the convex furface of the back to be feen.

It is giving but a very imperfect idea of this downy rim, to call it only a border or pad laid round the body of the ani- mal. This matter, in reality, makes a kind of neft in form of a bafket, in which the body of the infect is in a great meafure lodged. Its belly, which is placed on this neft, is feparated by it from the bark of the tree, and lodged on a fort of downy bed ; the threads of this down are fomewhat thick and itrong. The principal ufe this bed or neft feems deftined for, is, the reception of the young, which are pro- duced in the end of June or in July, if the animal be re- moved from its bed at this feafon, a vaft number of fmall living animals are found in the bottom and fides of the neft. Thefe are of a yellowifh white, and have two fmall horns; their fhape much refembles that of the young gall-infects ; their hinder part is more {harp than their fore part, and they run about very fwiftly on fix very fhort legs. At whatever time however the progaliirifeci is removed from its neft, there are never found any eggs ; the creature is vivipa- rous, and the young animal feems to be born with its head foremoft, which is contrary to the manner of the pucerons and fome other fmall animals.

If the body of the parent prcgaU-infetl be crufhed in the month of June, a great number of fmall oblong bodies are always protruded ; thefe are probably the embryo animals, tho' all that the niceft attention can in this ftate difcover in them, is, two fmall black fpecks, which afterwards prove to be the eyes. The nefts of thefe infects are feldom fou ;d fo full of young ones as might be expected ; but that is probably owing to the length of time taken up in bringing forth fo great a number, probably eight or ten days, and the young ones in a day or two are perhaps fit to efcape aqd run away ; fo Chat one finds only the laft born there.

The branches of the elm examined with the help of glafTe3 at this feafon, ihew us multitudes of the young progall-infeSis running about them ; thefe, however, continue in this ftate but a little while, they foon choofe their place for fixing for life, and there remain without motion afterward.;. They do not lofe the power of moving, however, till the month of April following; for till that time, if the branch on which they are be cut off, when it becomes dry, and furnifhes them no more juces, they will leave it and go in fearch of another; but after April, if the branch be cut off, they die upon the place when it dries, being no longer able to remove themfelves. Thefe infects, like the gall-infeCts, do not grow much till af- ter the winter is over : toward the end of April they have ufually arrived at their deftined bignefs ; their bodies in the beginning of this month, and in fume part of March, are fomewhat reddifh ; but this colour is the left to be diftinguifh- ed, as the rings are all bordered with fhort grey hairs. Thefe hairs are considerably thick, but the animal is found abfolute- ly without them again, when it has its cottony bed under it, having then divefted itfelf of them in quitting its fkin, which it changes for one whofe pores are more proper to give paftage to the matter of which that bed is to be made. At all feafons their belly is of a redder colour than their back; and that is in a great meafure owing to the belly being always free from thofe grey hairs. The legs are very fmall and flen- der, in proportion to the fize of the animal ; they are fix in number. Its trunk or fucker is not eafily difcovered, but is placed however in the fame manner with that of the gall-in- fect, and is like it in fhape.

The cottony matter forming itfelf by tranfpiration from the feveral parts of the animal, forms by degrees the neft, and as this increafes, the animal itfelf increafes alfo in bulk, and be- comes gradually more and more red. No obfervation has yet been able to determine the manner of the fecundation of thefe infects ; they are never fcen to couple one with another, and moft probably the male of this clafs, as of the gatl-infeds, is a fmall fly. Reaumur's Hift. of Infects, Tom. 4. p. 83. Progall-insect, otherwife called Cochineal. There have been many conjectures about cochineal; but the moft probable feems to be, that it is an animal of the progall-infecl clafs.

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