Cantharides.—Spanish fly, or blistering beetle, is the basis of most of the blistering preparations. It is sometimes taken as an abortifacient or given as an aphrodisiac, but whether it has any such action is open to question. It acts as an irritant to the kidneys and bladder, and sometimes produces haÆmaturia and a good deal of temporary discomfort.

Symptoms.—Burning sensation in the throat and stomach, with salivation, pain and difficulty in swallowing. Vomiting of mucus mixed with blood. Tenesmus, diarrhoea, the motions containing blood and mucus. Dysuria, with passage of small amounts of albuminous and bloody urine. Peritonitis, high temperature, quick pulse, headache, loss of sensibility, and convulsions.

Post-Mortem.—Gastro-intestinal mucous membrane inflamed, with gangrenous patches. Genito-urinary tract inflamed. Acute nephritis.

Treatment.—An emetic of apomorphine; demulcent drinks, such as barley-water, white of egg and water, linseed-tea and gruel (but not oils), with a hypodermic injection of morphine to allay pain.

Tests.—The vomited matter often contains shining particles of the powder. The urine will probably be albuminous.