Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/429

 S C A

S C A

call it la portion pojlerimre du fecond fcalene ; a name given it by Window.

SCALLION, or Escallion, a fort of onion which never forms any bulb at the root, but is ufed green in fpring, be- fore the other forts fown in July are large enough. This is however very fcarce in London, the gardiners ufually felling in its place the moots of fuch decayed common oni- ons, as have fprouted in the houfe. Thefe they plant in a bed early in the fpring, and they foon grow large enough for ufe, when they pull them out ; and taking oft" all the old outer coat of the roots, they lay them in bunches, and fell them at market for fcallions.

The true fcallion is eafily propagated by parting the roots in autumn, and planting them three or four together in a hole, at fix inches diftance. Thefe will grow in any foil or fitu- ation, and will multiply very quickly, and in a very great abundance ; and their being hardy enough to endure the fe- vereft winter, and fit for ufe fo early in fpring, makes them worthy a place in all kitchin gardens. Miller's Gardner's Dictionary.

SCALLOP. The anatomy of this fifh lets us greatly into the knowledge of the ftrudture of the parts of other bivalve fticll fifh.

The fcallop is compofed of two fhells, which, as in man) others, are one concave, and the other plane or flat. The cardo, or hinge, is lightly bent from the concave fhell, and thence carried over a part of the plane fhell, and all the way between it is firmly connected to a cartilage. In the middle of the length of the cardo there is placed another fliort, black, and very ftrong cardo.

It is eafy to fee, from hence, to what is owing that remark- ably ftrong power, which this creature has of fhutting and opening its fhell ; and it is very poflible, that by means of fo ftrong an apparatus of tendons or ligaments as it has in this part, it may be able to move the plane fhell in fo fwift and regular, as well as forcible and eafy a manner, that it may ufe it in moving from place to place; and poflibly it may make a fort of wing of it, to beat againft the water, as the pinion of a bird does againft the air ; and what the an- tients have fo frequently faid of its moving about in a very fwift manner, from place to place, may be true, though we have been wanting in later obfervations to fee it. When the two fhells are opened, the following particulars offer themfelves to the view. Firft, the mouth : this is co- vered with a fort of membranous hood, as in the .oifter ; it does not ftand on the center of the head, but toward the right hand, and the covering is only an elongation of the branchiae, or gills of the fifh : thefe are of a membranous nature, and furround the whole body from the mouth to the anus, which ftands toward the left hand from the mouth, where they are connected again.

That branchia of the exterior pair, to which the flat or plane fhell adheres, is fixed in its center to an immenfcly ftrong mufcle, which grows from the fhell, and is fixed into the body of the fifh at right angles : this branchia is fixed to the upper limb of that mufcle, and the other branchia is, in like manner, connected to the lower limb of the fame ftrong mufcle. Thefe two exterior, or fpurious branchiae, from this mufcle to a confiderable extent, are formed only of a thin and pellucid membrane, and being carried to the middle of the valves on each fide, they are there fixed down in fuch a manner, that they cannot be removed by any means, without injuring or deftroying them. The ufe of thefe is to defend the body of the animal from the injuries of the water, and other fubftances let in with it, on the opening of the fhell. From the place of this adhefion there is propagated a ftrong and thick mufcle, of a truly wonderful ftructurej this is a fort of limb, or verge to the animal. It is contracted inward when the animal is dead, but while it is alive it is expanded, at the creature's pleafure, a great way out beyond the edges of the fhell, and is jagged, and variegated with lines and ftreaks, in an amaz- ing and elegant manner.

The ufe of this part feems eafily guefled, it being, when expanded out at the mouth of the fhell, a fort of netj for the catching whatever the creature chufes to feed upon. It is, at the pleafure of the animal, either laid flat on the fur- face of the mud or rock, or arched into a part of a circle : when in any of thefe politions, any thing comes in its way which is proper food for .the creature, it immediately ga- thers up like a net round about it, and withdrawing itfelf into the fhell, takes in the prey with it. In this cafe, the ufe of its being cut or fringed, is alfo plainly feen ; for it can, by means of this ftrucfure, let out the water taken in with the prey through the jags, and yet retain the prey it- felf. Philof. Tranf. N°22g. p. 567.

The ufe of this admirable mufcle, is not only the ferving as a net for the taking the food, and afterwards as a ftrainer for the feparating the water from it, but its mufcular force is fo great, that it alfo ferves as a weapon of death to the little animal it has feized, by compreffing it to pieces if ne- ceflary, at leaft by fqucezing it till no life remains. This is a very necefl'ary article in the preying of an animal, which can neither follow or refift an animal in motion ; but this is

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not all. When the prey is brought into the fhell, it might there remain, where firft laid down, without being of any ufe to the fcallop, who cannot turn about her mouth to come to it : in this cafe the fame wonderful mufcle, by its undulatory motion, ferves to convey the prey to a part of the fhell nearer the mouth of the animal ; and when there., taking it up between the jags of the fringe, it holds it to the opening of the mouth ; in this laft office ferving in the place of a hand. Thefe are the many and neceflary ufes of this part.

But to come to the branchiae, or gills, properly fo called; The true branchiae are four in number j they are of a yel- lowifh colour, and are fringed in a very elegant manner : thefe every way furround the great central mufcle, and ferve as a covering to the uterus of the animal, or its ovary ; certainly, however, to the parts of generation, by whatever name they may be called.

The lower part of the body of the fcallop is yellow, and its upper part white, and near its mouth there is very plainly to be difcovered a procefs with a double aperture. It feems probable, from all obfervation, that the fcallop is an herma- phrodite animal, and contains the parts of generation of both fexes in each individual ; and it appears that the female part of generation is, on occafion, pufhed out from one of thefe apertures, and the penis, or male part, from the other. The mouth of the fcallop is furnifhed with reddifh lips, re- fembling the branchiae, or gills, in their ftruflure, but very fhort and fmall; and near the hinge there are two large circular cavities, refembling the eyes of the turbot. Near the head there is a large mafs of blackifh mat- ter toward the left hand, and under that, or rather behind it, is fituated the creature's heart. The pericar- dium is pellucid, and is of fo fine a ftruflure, that the heart is eafily feen through it : it is of a reddifh colour, and its aorta, or large artery, is divided into a great num- ber of branches, which are fent every way round to the gills.

It is fome doubt, however, whether this their membrane, before defcribed, ferves alone in the capacity of a pericar- dium; or whether all this black matter, that lies about it in a fort of rhombic form, does not alfo, in fome degree, fup- ply that office. The lower part of this gives place to the urinary bladder, and the ftrait gut arifes from the hafe of this black fubftance, and is thence carried ftrait over the pe- ricardium ; whence it runs on to the branchiae, and is at length affixed to the great central mufcle. This central mufcle is of a rounded figure, vety fmooth, and white, and even in the greater part of its bulk, where it is connected to the fhell ; but on the left it is divided, and forms another white and lacerated mufcle, which runs along a part of the fhell, and ftrengthens the connection of the body of the fifh with this part of the plane valve. Philof. Tranf. N° 229. p. 569. •

SCALMUS, among the Romans, a block or round piece of wood in a boat, to which the oars were tied with a thong of leather called Jlrappus. See the article Strappus. Scalmui was alfo ufed to denote the boat, a part being taken for the whole. Pitifc. in voc.

SCALPRA dentalia, inftruments ufed by the furgeons to take off thofe black, livid, or yellow crufts, which infeft the teeth, and not only loofen and deftroy them, but taint the breath.

According to the varieties of the occafion, the furgeon has thefe inftruments of various fhapes and fizes ; fome are pointed,, and narrow at the end, others are broader pointed, and have edges, others are hooked, or falciform, but thefe are ufually, for convenience of carriage, all adapted to one handle.

The manner of ufing them is to begin near the gums, fup- porting the blade with the left hand, and fcraping all along the tooth, till the cruft is taken off, taking care not to wound the gums, or difplace the teeth. Heijler's Surgery, p. 456. _

SCAMlVIA, Sxafifia,- among the Greeks, the mark m leaping,. or throwing quoits; fo called, from its being made by dig- ging up the earth. Potter, Tom. I. p. 442.

SCAMMATHA, in the Jewifh cuftoms, a kind of excom- munication, and the moft terrible of all in ufe among that people. See the article Niddui.

SCAMMONY {Cycl.}— Scammonia Monfpeliaca, Montpclier fcammonf, a name given by fome botanical writers to a fpecies of periploca, diftinguifhed by Mr. Tournefort by the name of periploca Monfpeliaca foliis rotund'wribuu

SCAMPIUSA, in botany, a name ufed by Myrepfus and others for a plant, which they greatly recommend in the itch, and other cutaneous diforders.

Fuchfius confeffes himfelf at a lofs to guefs what plant was meant by this name ; but a little knowledge of the cu- ftoms of the later Greeks, in adopting the Roman names for things, would have explained this to him. We find, by familiar inftances without number, that in the words they adopted from the Latin, they ufually changed the into b„ and the Roman b into mp. If we look upon the word

I [campiifa in this light, fuppofe it formed from a Roman

' word*