674 CANTHARIDES 



is hot, tender, or inflamed. In applying blisters to inflamed 

 joints or bursse, it is sometimes desirable to place them, 

 not immediately upon, but somewhat above or below, the 

 affected spot. Where continued effects are desired, mercury 

 biniodide ointment is alternated with cantharides, or sub- 

 stituted for it, or the actual cautery is used instead of 

 blisters. 



Owing to its liability to become absorbed and irritate the 

 kidneys, it is an unsuitable counter-irritant in inflammation 

 of the urinary organs. In common with all other causes 

 of irritation, it must be avoided in tetanus. Unless on a 

 very limited surface, and freely diluted, cantharides must 

 not be used in weakly, exhausted subjects. In dogs, special 

 caution is required, as they are apt to rub the blistered 

 parts. Cantharides sometimes acts with unexpected violence 

 on the skin of well-bred horses, and for such subjects strong 

 blisters are not advisable, and their application over a con- 

 siderable surface should be avoided. No horse should have 

 all four legs blistered at one time. In some excitable 

 subjects even a moderate blister causes much constitutional 

 disturbance. 



DOSES, etc. For horses, grs. iv. to grs. xx. ; for cattle, 

 grs. xxx. to 3J- ; for sheep and swine, grs. ij. to grs. viij. ; 

 for dogs, gr. ss. to grs. ij., repeated once or twice a day, 

 usually given with aromatics and bitters, in the form of 

 bolus or tincture ; administration suspended if urinary 

 irritation or any untoward effects occur. 



Cantharides is used externally in the form of powder 

 tincture, vinegar, ointment, liniment, and plaster. 



Powdered cantharides is principally used for maintaining 

 irritation, and for scattering over mustard poultices and 

 other stimulant applications to increase their activity. 



Tinctures of cantharides are made of varying strength. 

 The B.P. tincture (1 in 80), and other alcoholic prepara- 

 tions, used in human medicine are too weak for most 

 veterinary purposes. One ounce of coarsely-powdered 

 flies, macerated for seven days with fifteen or twenty ounces 

 of alcohol, 60 per cent., forms a useful tincture of medium 

 strength. The activity is augmented by addition of liquor 

 ammoniae, or oil of turpentine. The tinctures in common 



