B L I 



B L I 



The pTaftcr of cantharides feldom fails to produce a large 

 liUfter, in ten or twelve hours ; but its operation continues 

 fomctimes longer, fo that it may be conveniently fuffered 

 to rtma'!n for twenty-four hours, the large cuticular bags 

 being punctured to let out the fluid. When the plafter is 

 taken off, and the ferum moftly difcharged, the bliftered 

 part fliould be dreOcd with fperraaceti, or fomc other 

 mild ointment, uulefs it be intended to keep up tlie ferous 

 dilchaige by ftimulating applications. 



The pain produced by the aftion of cantharides varies 

 preatly, according to the part affected, the thicknefs of the 

 !kin, and the general irritability of the conftitution, and in 

 particular of the furfacc of the body. Mod frequently the 

 pain is very flight, often ?,ir;ounting to no more than a fenfe 

 of iieat on the part. When very acute, it is of great fervice 

 to remove the plalter, when it has been on about two 

 hours, to arioint the part with oil or cream ; and about an 

 hour or two after, to replace the bliftering plafter, which will 

 then often, proceed to veficate without much further irrita- 

 tion. 



The operation of cantharides is much affefted by the 

 thicknefs of the Ikin beneatli ; and hence the fcalp refills 

 "vefication more than the fofter &in of the abdomen ; and 

 partic'.ilarlv by the heat of the body, fo that the plafter 

 fhoald be ftrougcr, and its confiftence fofter, when applied 

 to an unufualiy cold furface. 



Sometimes, though rarely, the fymptoms of ftrangttry 

 produced by this aftive medicine, follow even its external 

 application. 



A more active veficatory is fuppofed to be made, by add- 

 ing other ftimulating fubllances to the cantharides plafter. 

 In the Paris Pharmacoparia, euphorbium (the m.oll acrid of 

 all the medicinal gums) is added in equal quantity with the 

 cantharides: in the Edinburgii, verdigris, niuftard, and black 

 pepper are ufed. 



It is often of advantage to keep up a difcharge from a 

 bliftered part for a confiderable time. It then becomes 

 gradually puiulent. For this pui-pofe, a milder form of 

 canthari'lts !■= highly ufeful, and a fofter confiftence is given 

 tn it. This may be done by mixing a fmall portion of the 

 flies in powder, with any finnple ointment ; but this is hablc 

 to act unequ.-.Uy, and the entire particles of the fly fome- 

 timcs create trouble, by lodging upon the tender cutis. To 

 remedy th'S, tl;e London college ufe a watery infufion of 

 cantharides, mixed with a. ftimulating refin ointment, melted, 

 and continued over a flow fire, till all the water is evaporated, 

 leaving a fmall portion of extractive matter of the flies, 

 equally difFiiftd through the ointment, and ftrongly in- 

 cieafing its ftimulating power. 



A few other fubftances have been occafionally ufed to 

 produce vefication. One of thefe is the inner bark of the 

 3Iezercon, (Daphke ATezercum) and of another plant of the 

 fame ger^us, the Thhiielsa Laureola, or Spurge Laurel, 

 (Daphne I^aureola) both flirubby plants, well known in 

 gardens. The ufe of the latter (which will equally apply 

 to the mezereon) is thus directed in the Paris Pharmacopseia. 

 Small twigs ol the plant, about the fize of a pen, and 

 fmooth, are ftlcdted, and cut tranfverfely into portions of 

 the requifite length. Thefe are fteeped in milk-warm 

 water, or in vinegar, for about half an hour, to loofen the 

 bark, which is then peeled off v.'ith a pen-knife, and the wood 

 is thrown away. This bark is applied to the fkin to be 

 bliftered, prev:oufly rubbed with vinegar. 



In twenty -four hours a perfect vefication is produced, 

 with little pain, and without the poffibility of thofe fymptoms 

 of ilrangurj-, which now and then attend the ufe of can- 

 tharides. 



BLISTERED, bullalus, in Botany, is applied to the 

 Vol. IV. 



furface of a leaf, which rifes high above the veins, fo as to 

 appear like blifters. 



BLISTERING ofhorfes, in the VeUrhiary Art, a remedy 

 much in ufe for promoting the removal of a great variety 

 of diforders ; more efpecially, however, in reducing morbid 

 enlargements of bone, or morbid thickenings of any of the 

 fofter parts, where its utility is principally obvious. 



The vefication of the fkin of the horfes is attended with 

 feme remarkable circumftances, in which it differs from the 

 human, efpecially in the greater irritability of the fldn ; for 

 the cuticle of the horfe is raifed by a bliiler of kfs ftrength, 

 than is required in raifing the human cuticle ; v^'hencc, per- 

 haps, it may be inferred, that its fenfation alfo is more 

 acute. It is probable that the fl:ins of animals covered 

 with hair are, in general, more irritable than naked flcinned 

 animals ; the fpirits of turpentine producing a moft painful 

 irritation, both in the horfe and the dog, when apphcd to 

 the fKin, but not fo in the human. 



Irritants, howes-er, of the ft<in, without any bliftering, or 

 vefication, may be had recourfe to with very great advantage, 

 in the veterinary art, as they can, without injur)- to the 

 parts, be very frequently renewed, and with the happicft 

 effefts. 



The mildeft applications of this dcfcription, are the 

 animal and vegetable oils ; as hog's-lard, and the oil ex- 

 preffed from linfecd, or olives : where more irritation is 

 thought requifite, the addition of the effentiil oil of ori- 

 ganum, or the fpirits of turpentine, will readily afford it. 



Lard alone, rubbed on the ftvin of the horfe, we have 

 often oblerved to produce a fenfible irritation and increafed 

 warmth in the part, fo fufceptiblc is this part in thefe ani- 

 mals ; and may ferve as a bafis from which we may proceed 

 to the higher degrees of ftimulus, firing the (kin with the 

 actual cautery, in lines more or Icfs clofe, being the higheft; 

 degree of initation to which we can or ought to pro- 

 ceed. 



That initation v.'hich is produced by the cantharides, 

 is, of all others, we believe, the moft ufeful in its effects. 

 It fhouldbe applied, mixed with lard, or olive-oil ; to which 

 it is ufual to add t:ie dried juice of the euphorbium ; as, 

 however, it is ever defnable to avoid unneceffary compli- 

 cation in the remedieD we prefcribe, by wliich our effects arc 

 rendered more certain, and the indu&ions more eafy and clear, 

 fo we propofed to try this medicine by itfeSf, to afcertain 

 its precife cffefls ; and being mixed with olive-oil, it was 

 applied to the flcin of the leg of the horfe : no diftinct 

 vefication of the part followed, but it produced a con- 

 iiderable heat, and formed a brown fcab, with very little dif- 

 cjtarge of ferum ; but, on the contrary, was particularly drr 

 ai)d irritating to the horfe. We have fince omitted it in the 

 blifter, and, v/e beUeve, without the fmalleft detriment to 

 its operation ; for the cantharides, when they aft properly, 

 and are not applied too ftrong, produce a plentiful veficaticn, 

 and a copious difcharge of thick ferum, almoft of the con. 

 fiftcnce of honey. 



We have found alfo the pyro-ligneous acid, or the ac'd 

 obtained by the diftillation of wood, in clofe veftels, and 

 properly concentrated, a cutaneous irritant, of veiy ufeful 

 qualities. After the. fkin has been fimply wetted with it, 

 it flightly inflames it ; and the cuticle, after two or three 

 days, comes away dry, bringing with it any fonlnefs of the 

 (kin, for the removal of which it is moft 'particularly fervice- 

 able. 



We have known fome, from motives of economy, omit 

 the cantharides in their blifter, and ufe, inftead of it, vitriolic 

 acid. It, in general, as far as we have feen, forms a dry, 

 black fcab, and is by no means fo agreeable in its effects as 

 the former. 



+ 1 It 



