Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/525

 S P I

S P I

cured art oil highly rectified, and pellucid as water, which will dry away as foon as touched on any thing. The great difadvantage attending the nil of fpike adulterated with fpirit of wine, is, that it will not readily mix with all the iorts of varnifh.

Having gone through the properties of oil of fpike, in regard to varnifh, it remains to enquire into them in regard to its other great ufe in enamel, and to confider the effects of the two ufual methods of adulterating it in this work. The oil of fpike which wants body, is not at all fit for ena- melling, becaufe it dries too fuddenly, and does not at all aflift the natural drynefs of the enamel, which is only a fort of powder of glafs ; and the particles of this powder, with a fluid of too little body, are not manageable by the artifts, fo that the colour nsver is brought to a due confift- ence : and when the oil has too much body, the mixture becomes too tenacious, and is as unmanageable in that ex- treme as in the other ; and this fault is attended with an- other very great mifchief, which is, that the fume railed by this oil, when heated, is often fo grofs, as to deftroy the beauty of the colours. In fhort, thick oil of turpentine is always deftructive of enamels by its fmoak. The true compofition for enamelling is oil of fpike mixed with fpirit of wine, but the proportions muff be nicely regulated from repeated trials : for if the quantity of the fpirit be too large, it is apt to feparate iifelf from the oil and colour in the drying, and this always fpoils the glofs and beauty of the work. Artificers obferve, that ail of fpike does heft for their purpofes, after it has been kept two or three years. But this is only owing to the oil's being adulterated with fpirit of wine, and ufually containing too large a proportion of the fpirit when firft fent over, it be- comes better for ufe when a part of that fpirit has had time to evaporate in the keeping. It would be a better way for thefe curious works, to procure the oil pure, and then occa- iionally mix it with fuch a proportion of fpirit of wine, as experience fhews to be the moft proper. Mem. Acad. Par. 1716.

SPIKENARD, in botany. See the article Nardus.

Ointment of Spikenard. See Nardinum unguentum.

SPIKES, or, as the feamen call them, Speeks, in a fhip, are large long iron nails with fiat heads. They are of divers lengths, fome a foot, or two long, and fome are jagged, fo that they cannot be drawn out again. They are ufed to faften the planks and timbers. They call alfo a kind of fmall fidd, which ferves them to open and fplice fmall ropes, a marling fpike.

SPINA (Cycl.) — Spina bifida, in anatomy, a parting of the fpinal proceffes into two rows. The existence of fuch a cafe is doubted. See Spine.

Spina burgi, in botany, a name ufed by fome authors for the alaternm, or ever-green privet, a garden fhrub, the fruit of which is a mild aftringent. Park. Theatr. p. 1445.

Spina ventofa, is properly a fpecies of corruption of the bones, which takes its rife in their internal parts, and by degrees enlarges the bone, and raifes it into a tumor. The antients were ffrangers to this name for this diforder, and called it fideraUo^ gangr&na, or cancer ojfis, and fome- times expreffed it by the word teredo. Some among the French call it alfo an exoflofis, though this is a term more properly denoting certain eminences, or preternatural acu- minated excrefcences in the bones, which happen after fracture, or other accident, and are fome. imes attended with a caries.

The name of the diforder feems to have been borrowed from fpina, a thorn, from the refemblance the eminences of the bone in this cafe bear to thorns, continually pricking the flefh, and producing the moft grievous pains; and the epithet ventofa is added, becaufe the tumor feems, to the touch, to be filled with air, though this is very rarely the cafe. This feems to have been the origin of the name fpina ventofa, which fome after-writers barbaroufly difforted into fpina ventofitas. When this diforder happens to children, Severinus, and many others, call it padarthrocacei. In the fp'ma ventofa the caries, or erofion of the bone, is occafioned by a depravity of the contained fluids, and ge- nerally arifes fpontaneoufly, or without any external caufe, and does not begin upon the furface of the bone, but be- tween its lamella, or elfe in its internal cavity j from whence extending itfelf by degrees to the external parts, it at length either affects the whole bone, or a greater or fmaller part of it, expanding itfelf to different widths, and rifing to a tumor, which is fometimes hard, and without pain, and at others feels as if it were filled with wind, and is attended with a greater or lefier degree of pain, pricking and fhooting, and at laft grows red, and is attended with other bad fymptoms, till the difordered bone being by de- grees corroded, the common integuments, and other fofter parts that lay over it, remaining at firft entire, but at laft partaking of the diforder, foul ulcers of a very terrible fort break out. When tumors of the bone are hard, and the foft parts about them not inflated, and arc free from rednefs, inflammation, and pain, as is very frequently the cafe in ricketty diforders, the bad fymptoms juff defcribed fddom

come oh. This is properly the predarthrocaces, but the painful, red, inflated tumors happening equally to children; and to adults, are properly the fpina ventofa. It differs from a caries by being attended with a tumor, and from the rickets by its being accompanied with pain and erofion. It generally begins about the heads, or epiphyfes of the larger bones, where they are moft tender and fpungy, and where the noxious matter may not only have fufflcient room to lodge in the cellular fubftance, hut where it will alfo meet with the leaft refiftance in foftening and expand- ing the parts. Sometimes, however, it alfo arifes in the middle of the bones, between their lamella;, efpecially in the tibia. The os frontis is alfo fubject to diforders of this kind in venereal cafes, and it is frequently fituated in the bones of the face, neck and breaft ; though thofe of the arms, legs, fingers, carpus, meta-carpus, tarfus, and meta-tarfusj are more frequently the fubjects of it.

Though this diforder ufually arifes from internal, yet it is fometimes found to be owing to external caufes; efpe- cially in perfons conftitutionally addicted to a diforder of this kind, when the vefiels between the lamella? of the bone, or in the medulla itfelf, are by a blow, fall, or other ex- ternal violence, injured, or torn, and their fluids extrava- fated, and by degrees putrefy, corrupt, and deftroy the me- dulla, and foften the very fubftance of the bone, and corrode it ; whence proceed pain, tumors, ulcers, and fiftulas of the bone, and adjacent parts, and all the fame train of mifchiefs which attend thefe diforders, when begun fpon- taneoufly from internal caufes.

The proximate caufe of this diforder is a collection, or con- geftion, either of a vifcid and thick, or of an acrimonious and corroding humor, or an inflammation arifing in the medulla, or in the cellular fubftance of the bone, degene- rating into an abfeefs, and forming matter, or ichor. As thefe ftagnating fluids can find no difcharge from the bones, efpecially from their cavities, they continue confined there till they putrefy, and become acrimonious, and corrode and deftroy the neighbouring parts, converting them, particu- larly the medulla, into a kind of fanies ; and at length they attack the bone and deftroy it. The collection of vifcid and pituitous humors, and the expanfion of the bones, fome- times happens without pain, as in ricketty cafes, but the erofion of the parts can never happen without the moft acute pains.

When the internal parts of the bonqf only are affected by this diforder, the pain does not encreafe upon external pref- fure ; when the pain encreafes upon external preffure, the) external parts are brought into confent; and when this hap- pens, the periofteum, and parts which furround it, with the fubftance of the bone and tunica cellularis, enlarge, from whence a fenfation frequently arifes, as if the parts were filled with air, or wind. But when the tumor 19 opened, either fpontaneoufly, or by the knife, the bone, if it lies bare, is found full of fmall erofions, refembhng a fpunge or pumice-ftone.

Of this terrible diforder there are properly three degrees: the firft is, when the patient complains of a continual grievous pain in the bone, which feems to him to proceed from the marrow, and torments him fo, that he can have no fleep, and all this while there is no external pain or tu- mor ; in this cafe the difeafe is confined to the internal part of the bone. The fecond degree is when a tumor appears to be arifen on the furface of the bone, and is attended with external pain, more or Iefs. The third degree is when, after the former fymptoms, an ulcer is formed in the tumor, which difcharges a fetid ichor, or purulent matter, fmelling like rank butter or lard.

There are two methods of treating this diforder, one fuited to the milder, the other to the more violent ftate of it, in which the bones, and the parts furrounding them, are en- tirely corroded and deftroyed. In the milder ftages, the acrimony of the blood muff be endeavoured to be corrected by large draughts of the decoctions of the woods, with the China and farfaparilla roots. The parts affected fhould alfo be fumigated with the fleam of decoctions of aromatic herbs, and twice a day, in the intermediate times, the part may be rubbed over with a mercurial ointment, and afterwards covered with the common mercurial plafter. Mercurial me- dicines fhould alfo be given internally, according to the ftrength of the patient, and fometimes a falivation is ne- ceflary.

Mercurial remedies feem indeed fo peculiarly appropriated to this cafe, that nothing is to be done without them ; and it hence looks very fufpicious, that fomething venereal is always in the cafe, or elfe that the diforder is of itfelf very much akin to that difeafe. By diligently purfuing this me- thod for fome weeks, the firft and fecond ftages of this dif- eafe may be cured even where there are bony tumors formed ; and the tumors may either be reduced, or at leaft brought to that ftate, that they will remain as they are without farther encreafe, or without pain, or any farther inconveniency. But when thefe tumors are fo far advanced, as to be out of the reach of the remedies, the pain and tumors encreaf- ing, and abfcefl.es forming ; as there is great reafon to fear

the