454 DRUGS OF ANIMAL ORIGIN 



parts. Cantharides acts more powerfully on the skin of horses and dogs, 

 than on that of cattle and swine. If applied over an extensive surface, 

 absorption and poisoning may occur. 



Action Internal. — Cantharides affects mainly the digestive and 

 genito-urinary tracts. It is a violent gastro-intestinal irritant. Toxic 

 doses cause vomiting, in animals capable of the act, at first bilious (and 

 containing greenish specks of the wings and wing cases), then mucous, 

 and finally bloody. There is purging in all associated with great pain 

 and straining, of a mucous, fibrinous,, and often hemorrhagic character. 

 There are salivation, swelling and pain in the salivary glands. The 

 gastro-enteritis is accompanied by general prostration, and feeble, rapid 

 pulse. A few hours after the occurrence of the preceding symptoms 

 there is enough absorption of cantharidin to induce lumbar pain, followed 

 by frequent, scanty and painful micturition (strangury). The urine is 

 albuminous and often bloody. Cantharides is eliminated chiefly by the 

 kidneys, but also to some extent by the other excretory organs, including 

 the skin. Sexual excitement may be present in poisoning. It is more 

 common with small than large toxic doses. There are erections and great 

 heat in the penis, and even inflammation and sloughing of the organ. 

 Abortion is precipitated in the pregnant, and "heat" is hastened in the 

 non-pregnant female. Stupor, coma, and collapse close the scene after 

 lethal doses. Twenty grains of cantharides have killed a man; forty, 

 a dog; one dram has destroyed a horse. 



The treatment includes the use of emetics or the stomach tube; 

 opium, to relieve pain and strangury ; albuminous, mucilaginous drinks ; 

 and, in collapse, external heat, alcoholic stimulants, camphor, digitalone, 

 strychnine and atropine under the skin. Oils and fats dissolve can- 

 tharidin and must not be given in poisoning as demulcents. 



Post-Mortem Appearances. — Swelling, congestion, ecchymoses, and 

 erosion of the gastro-intestinal mucous membrane are observed after 

 death by cantharides. There are, moreover, lesions of acute nephritis and 

 cystitis, with inflammation of the whole genito-urinary mucous membrane. 

 Hyperemia of the brain and spinal cord have also been reported. 



Uses External. — Cantharides is employed more frequently than any 

 other counter-irritant, to cause blistering, in veterinary practice. The 

 reader is referred to the section on counter-irritants (p. 491) for an 

 account of their actions. The action of cantharides is too tardy and 

 irritating, and there is too much danger of absorption and poisoning to 

 recommend it for the production of counter-irritation over an extensive 

 area (chest and abdomen) in acute pulmonary congestion, pneumonia, 

 bronchitis, colic, enteritis and peritonitis. Mustard, turpentine, and ex- 

 ternal heat are generally preferable in these disorders. 



A blister of cantharides is serviceable in pericarditis and pleuritis 

 with effusion, and, applied over the throat in severe, acute laryngitis, 

 may obviate the necessity of tracheotomy. Again, blisters are useful on 

 the poll in inflammation of the brain and its membranes; and over the 

 spine in myelitis and meningitis; over the lumbar region in paraplegia. 



A cantharidal application is often efficacious in muscular or joint 



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