BLISTERING. 589 



light ; others persist there is no virtue in hot iron unless it 

 burns very deep. The operation consists in having irons of 

 some substance made red hot, and then drawing them 

 mechanically along, or twisting them about upon the skin. 

 The figures are various, so is the depth of the incision. Both 

 must be decided by the taste, judgment, or heartlessness of 

 the operator. 



BLISTERING. 



This is"^n operation of very great utility, and is, perhaps, 

 compared with its benefits and importance, the safest that 

 is performed. When a vesicatory becomes absorbed through 

 the pores of the skin, it inflames the sensible cutis under- 

 neath ; the consequence of which is an effusion of serum 

 through the part, which, in the human, elevates the cuticle 

 into a bladder equal to the surface inflamed ; but in the 

 horse, from the greater tenacity of the cuticular connexions, 

 it becomes separated in the form of small distinct vesicles 

 only. If the irritating cause be quickly removed, the serum 

 may be reabsorbed, and the surface restored by a slight 

 effort of adhesive inflammation. If the irritant act in a still 

 minor degree, it simply irritates the vessels of the cutis to 

 an infiltration of fluid through the sensible pores, but pro- 

 duces no desquamation of cuticle : such has been called, 

 a sweating blister. But wdien by continued irritation, the 

 cutis is exposed, suppuration succeeds, and the part is fully 

 blistered. The salutary action of blisters is exerted in 

 several w^ays ; in promoting absorption ; in combating deep- 

 seated inflammations, and in aiding others. As a stitimlus 

 to the absorbents, they act beneficially in the removal of 

 injurious deposits, as the coagula remaining after inflam- 

 matory lesions. But it is to be remarked, that when any 

 existing deposit is of long continuance, or is osseous, 

 it requires that the action of the vesicatory be kept up. 

 Mercurial blisters have been thought to have a superior 

 influence in accelerating absorption. Mercurials, 7'ubhed in 

 some weeks or days previously to blistering, are certainly great 

 assistants, and should always be employed in the treatment 

 of obstinate osseous or ligamentary enlargements. Blisters 

 are very important aids, in inflammatory affections, as 

 counter-irritants, derived from a law in the animal economy, 



