676 CANTHARIDES 



the surface may be simply anointed. Swelling and vesicles 

 appear usually within a few hours ; the vesicles are as large 

 as pigeons' eggs ; but by the second day inflammation 

 subsides, and blemishing does not occur. 



In cattle practice, counter-irritation is generally produced 

 with mustard paste or blister, but some powder, or strong 

 ointment, of cantharides, mixed with the mustard, greatly 

 increases its effects. For dogs, a convenient ointment is 

 made with an ounce each of powdered cantharides and oil 

 of turpentine, and twelve to twenty ounces of lard. 



To ensure full vesication, the hair should be removed, 

 the skin washed with soap and water and dried, and the 

 ointment then well rubbed in. The extent of surface to 

 be covered must obviously depend upon the nature, seat, 

 and extent of the malady. To prevent the blister, when 

 liberally applied, from spreading beyond the desired limits, 

 the blistered area may be surrounded with an edging of 

 resin ointment. The blister, while acting, often causes 

 considerable irritation, and the animal, if permitted, will 

 rub or bite the blistered part. In the horse this should be 

 prevented by securing the head to the rack, putting on a 

 cradle, or, when required, tying up the tail ; in the dog, by 

 the use of the muzzle. On the next, second, or third day, 

 the blistered part should be dressed with zinc oxide oint- 

 ment, oil, lard, vaseline, or Carron oil. If sufficient effect 

 has not been produced, a little more of the blister may then 

 be applied. 



Liniments of cantharides are merely liquefied ointments, 

 and, in respect of activity, usually occupy a place between 

 ointments and tinctures. They generally consist of one pai 

 of cantharides and six to ten parts of rape or linseed oil. 

 Oil of turpentine is sometimes added. The B.P. Liquor 

 epispasticus is made with ten of cantharides and twenty of 

 acetic ether. 



Plasters of cantharides are made in the same manner 

 ointments, but rendered more strongly adhesive by th( 

 addition of yellow wax, soap plaster, and resin or pitch. 

 To prevent displacement they are usually applied in th< 

 melted state, immediately covered by a little tow or teasec 

 lint, and enveloped in a suitable bandage. 



