Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/492

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It may be propagated either by fowing the feeds, or by plant- ing the flips and off-fets, but the firft is much the belt me- thod. It fliould be fowed on a moift rich foil, in the be- ginning of February ; in April the young plants will come up, when they mutt be cleared of weeds, and houghed up to three inches afunder ; and about a month afterwards they muft be thinned a fecond time, leaving them only fix inches diftant. After this they muft be carefully kept clear from weeds, and when their leaves are decayed, they fhould be taken up for ufe; but this thould only be done as they are wanted, for they fpoil with lying out of the ground. The leaves decay in October, and from that time till the middle of March the roots are in feafon ; after this the roots become good for little. Miller's Gard. Diet. SKITTISH, in the manege. A horfe is faid to be fiittijli, in French ecouteux, or retenu, that leaps inftead of go- ing forward ; that does not fet out, or part from the hand freely, nor employ himfelf as he ought to do. SKOUT, in zoology, a name given by the people of York- fhire to the lomwia, called in many places the kiddaw, and in Scotland the auk., or razor-bill, another of the webfooted water-fowl. Ray's Ornitholog. p. 244. See the articles Alka and Lomwia. SKRABBA, in ichthyology, a name given by fome to a fifh called by Jonfton and Schoneveldt the fcorpius marinus, but wholly different from the fcorpcena of other authors. It is a fpecies of cottus, and is diftinguifhed by Artedi by the name of the emus without fcales, with feveral prickles upon , its head, and with the upper jaw fomewhat lower than the other. See the article Cottus. SKULL (Cvr/.)— It is not uncommon to find in fome human Jkulls a different ftructure and conformation from that which nature has given to others, or to the generality of the fpecies.

Frequently there are met with heads, the fagittal future of which is prolonged to. the root of the nofe, and divides the coronal bone into two parts : and there have been anato- mifts, who have judged this fort of conftrufiion of the /hull peculiar to one fex, rather than common to both. To find the true caufe of this, we are to have recourfe to the ftate of the fiull in the infancy. This bone is, at that time, always found divided into two lateral portions; fo the fame feparation, which is found between the two fides, is found alfo between the two pieces, which afterwards compofe the coronal bone. The two pieces of this coronal bone unite one with another, by means of their indented edges, and thefe afterwards coalefce fo perfectly, that the future is obliterated ; and this coalefcence, which thus in proper time takes place in the coronal bone, fometimes extends itfelf, alfo, to almoft all the other bones of the fiull i but this only happens in old age. But if, on the contrary, the two pieces, of which the coronal bone is compofed, acquire their full thicknefs and hardnefs, before this coalefcence is brought about, the future remains, and is not obliterated, except in extreme old age. This reflexion may be alfo carried much farther.

In the Jkulls of a great number of infants, the coronal and the two fides fo perfectly unite, as not to leave the leaft trace of their original feparation. It feems as if the bones, hav- ing expanded and grown in thefe early ftages too fall: for the brain, have been united to one another while yet foft and tender : but when the brain, on the other hand, grows too faft for the bones of the fiull, thefe bones, prefied more from within outwards than any other way, have little dif- pofrtion to unite with one another ; and thus acquiring their thicknefs and hardnefs before their coalefcence, they become much lefs inclined to coalefce than before. From thefe confiderations we may conclude, that in thofe infants, in which the growth of the brain is flow, and that of the bones of the fiull quick, the future, which is betweei the two portions of the coronal bone, is very quickly ob literated ; and, on the contrary, when the encreafe of th, brain is quick, and the growth of the bones is flow, the fu- ture, which divides the coronal bone into two pieces, is found to a great age.

That which is the fiull in the more advanced ftate of the infant, is originally no other than a membrane, which is af- terwards to oflify : not unfrequently the offification is im- peded, in different parts of this membrane ; and in the fiulls of young fubjefls it is common to fee thefe diftinft parts, which remain membranous while the reft of the fiull has ac- quired its proper bony hardnefs. If the caufe, which im- peded the progrefs of the offification, fubfifts fo long, as till the other parts of the fiull are hardened into bone, and have their full growth and hardnefs, then will that, which mould have been naturally only one bone, form two. This is the origin of the Angular and unnatural futures found in fome human fiulls, and called by fome Jupernume'- rary futures. Sometimes there are, from this caufe, fuch fu- pernumcrary futures in almoft all the bones of the fiull. The os planum frequently is found thus divided into two; and from the fame principle in nature it is, that a fmall future is fometimes found in the maxillary bone, below the orbit, along the canal, which forms the lower orbitary cavity ■ the

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place where this little future is found has happened to remai a long time membranous, and the offification at laft takin place on the two edges of the remaining membrane, there has been found a future.

In other bones of the fiull we alfo frequently meet with larger or fmaller fpaces, which have continued membranous •

and there are inftances, in which the offification

lay be

plainly perceived juft begun in the center of the membranous fpots.

It might be fuppofed that the brain was little liable to an unnatural growth, or expanfion, when we confider that the brain is no other than a vaft alfemblage of pipes, or tubes of a molt extreme finenefs, and that the particles, which compofe thefe tubes, have but a very weak band of union one with another, indeed we know very well, that when an injection has penetrated to the cortical fubftance of the brain, if that fubftance he macerated a little in water, its parts detach themfelves from one another, the velfels become wholly deftroyed, and there remains nothing but a number of extremely fine filaments of the matter of the injection which has found its way into thefe veffels, and been formed into their fhape by cooling in their cavities. As there are found, however, a great number of Jkulls, which have a An- gular and odd configuration, it cannot but be, that the brain muft be expanded into the fame form. We are in- formed, that the people of fome nations prefs the forepart of the heads of their children, as foon as born, with confider- able violence, and continue this, in order to reduce the forehead to a flatnefs ; but thefe fiulls are always found to get in length behind what they want before. Sometimes there has been obferved, in the fiulls of perfons of an advanced age, in the middle of the fagittal future, a deep impreffion, or finking in, which had remained there from infancy ; but nature, in this cafe, fupplies the cavity with two protuberances of bone from the fides of the adjoin- ing parts ; and fome Jkulls are found very narrow, and of a remarkable length, nature giving one way the room (he de- nied the other. Many other fmgular conftructions of the fiull have been obferved by anatomifts ; and prohably in the perfons, to whom they have belonged, the brain has been able to perform its functions but badly. Be that as it will it is certain that the brain has expanded, and formed itfelf to the ftiape of the fiull in all thefe its unnatural figures; and neceffarily the partSj of which the brain in fuch cafes is compofed, have taken a very different figure and arrange- ment from what nature intended : and in this cafe it cannot be, but that fome portions of the brain have extended them- felves farther than they naturally fhould have done, and others much lefs than was allotted to them. Mem. Acad. Scienc. Par. 1740. Bones of the Skull. The eight principal bones of the fiull are ordinarily divided into common and proper. By proper bones anatomifts mean thofe, which are wholly employed in forming the globe of the fiull, and of thefe they reckon fix; the os frontis, the two parietal bones, the occipital bone, and the offa temporum : the common bones are thofe which contribute to form the face, as well as the fiull, viz. the os ethmoides, and the os fphenoides. But this divifion is not juft, for the os frontis, and offa temporum, deferve as much to be called common, as the two that are ufually reckoned fo ; and thus, inftead of fix, there would be only three proper bones, the offa parietalia, and os occipitis ; and inftead of two, there would be five common ones-, the os frontis, offa temporum, os ethmoides, and os fphenoides. IVinJlow's, Anatomy, p. 21.

The adhefion of the pericranium to the fiull, has been thought a fure fign of the bones being entire, but this is a miftake ; and the feparation of the cranium from the fiull, is as uncertain a fign of the cranium's being broken. Mem. 'de l'Acad. de Chirurg. Tom. 1.

We have fome very particular obfervations on the bones of thehuman./fe//, by Mr. Hunauld, in the Memoires del' Acad. Royale des Sciences, An. 1730. Concealed injuries of the Skull. When a blunt inftrument ij the occafion of an injury on the cranium, if the injured part does not fufficiently appear of itfelf, great induftry is to be ufed to difcover it. Where the common integuments ap- pear tumid and foft, they are in this cafe to be divided to the bone; but in making the incifion, great care muft be taken not to lay too much ftrefs upon the knife, left fplinters of the fraftured cranium fhould by that means be forced in upon the brain. The belt way to make this incifion is in form of the letter X, and about an inch and half in length ; lifting up the fkin at each angle, and leaving the bone bare. The blood that is fpilt is to be taken up with a fpuno-e, and dry lint fluffed between the lkin and the cranium ; and having thus found out the injured part of the cranium, the trepan is to be applied, if it be found neceffary. If fplinters .of the bone are now found, they muft be removed either with the fingers or the forceps, or, when they hang to the pericranium, with fciffors; but when they adhere pretty firmly to the neighbouring parts of the cranium, it is more advifeable to replace them, than to endeavour to remove them by violence. Heijler's Surgery, p. 85.

Fijfurts