COUNTER-IRRITANTS. 615 



It is usual to apply blisters in all cases of some standing, when organic changes 

 in the parts involved are suspected. Before a blister is applied, the hair should be 

 clipped from the part, which, if dirty, ought to be washed, and when dry, the blister 

 applied with smart friction for about ten minutes. To obtain the full effect of 

 a blister, a quantity of ointment is to be thickly laid on after the rubbing in is 

 completed.' 



The best agent is cantharides, in the form of acetate, tincture, or ointment, to 

 the limbs, the ointment in preference ; one part of cantharides to twelve parts of' 

 lard or palm-oil. If prepared with a temperature equal to the boiling point of water 

 (213°); it will be sufficiently strong and will never blemish. It is a mistake to think 

 that the powdered flies should be mixed with the vehicle when it is nearly cold. An 

 ointment so prepared Will require three times the quantity of cantharides. The heat 

 melts the cantharidine. 



Hints upon Blistering Generally. — No more than two legs are to be blistered at one 

 time, and three weeks at least must be allowed to elapse before the others are blis- 

 tered, and between each re-application. It is a bad practice to blister extensively in 

 very hot weather ; and it is a mistake to suppose that blisters to the loins and back 

 are more apt to irritate the urinary organs than when applied to any other part of 

 the body, provided that it be carefully and properly done. - » 



The evil results of blistering are: 1st. The production of strangury, by the ab- 

 sorbed cantharidine irritating the urinary passages. This is a very rare occurrence, 

 provided the blister has been applied to a moderate extent of surface ; but if four 

 legs, or even two, be extensively blistered at one time, the occurrence of such may 

 be laid down to the indiscretion of the practitioner. In some cases, however, very 

 moderate blistering may be followed by strangury-, and when it does occur, it is best 

 treated thus : First wash the blistered surface with warm water, in which a little 

 alkali has been dissolved; dress it with oil, give the animal demulcents to drink, 

 such as cold linseed tea, and administer a few doses of opium and bicarbonate of 

 soda. 



2d. The production of a considerable amount of nervous irritability, fidgeti- 

 ness, quickened pulse, and injected mucous membranes, with loss of appetite. 

 These symptoms are due to a nervous temperament ; and if not very severe, had bet- 

 ter not be interfered with. Should they become alarming, the animal must be treated 

 as in the first instance ; the fomentations being continued for a longer period to the 

 legs) It may be here mentioned that fomentations should not be hot, but soothingly 

 warm. ' ' 



' Sometimes blisters, no matter how carefully applied, produce excessive swell- 

 ings of the limb or limbs, with a tendency to suppuration and sloughing of the skin. 

 These results are generally due to the animal's being in bad health, and in a condi- 

 tion tending to anasarca or to erysipelatous disease. The treatment must consist Of 

 purgatives or diuretics, as the case may be ; fomentations, astringent lotions, and 

 gentle exercise, as soon as the pain is sufficiently subsided to admit of the animal's be- 

 ing moved about. In many cases the swellings' involve the sheath of the penis, and 

 the under surface of the abdomen. Punctures are very useful in such parts, by al- 

 lowing the escape of the contained fluid. I have seen tetanus arise from a very 

 .limited blister to one fore leg. 



If the effects are not sufficiently apparent in about thirty hours after the blis- 

 ter has been applied, a very little more, or what is remaining on the skin, which 

 may be sufficient, should be gently rubbed in ; and in about forty-eight hours after 

 the application the part is to be washed, and every trace of the blister removed ; 



