(Spanish Flies.)

Origin. - Cantharis vesicatoria De Geer, a beetle indigenous to Southern and Central Europe, and found eastward as far as Western Asia. It should be thoroughly dried at a temperature not exceeding 400 C. (1040 F.).

Description and Properties. - About 1 inch (25 Mm.) long and 1/4 inch (6 Mm.) broad; flattish-cylindrical, with filiform antennae, black in the upper part, and with long wing-cases and ample, membranous, transparent, brownish wings, elsewhere of a shining, coppery-green color. The powder is grayish-brown, and contains green shining particles. Odor strong and disagreeable; taste slight, afterward acrid.

Cantharides contains a fatty crystallizable body, cantharidin, supposedly related to benzol, which is the active principle, a volatile oil also possessing vesicatory properties, and a green oil closely allied to chlorophyl. Cantharidin is found in a number of beetles.

Used externally.

Dose. - 1/2 grain (0.03 Gm.), U. S. P.

Official Preparations

Ceratum Cantharidis - Cerati Cantharidis - Cantharides Cerate. - Cantharides, 320; yellow wax, 180; resin, 180; lard, 170; liquid petrolatum, 150. Used externally.

Collodium Cantharidatum - Collodii Cantharidati (60 per cent.) -Cantharidal Collodion (Blistering Collodion). - Used externally.

Tinctura Cantharidis - Tincturae Cantharidis (10 per cent.) - Tincture of Cantharides. - Dose, 1-5 minims (0.06-0.3 Cc.) [5 minims (0.3 Cc), U. S. P.].

The cantharides cerate is an ingredient of Emplastrum Picis Cantharidatum.

Physiological Action. - Externally and Locally. - Cantharides is a slow though very powerful irritant. When the drug is applied to the skin or mucous membrane it excites a tingling, burning pain, with marked redness of the cuticle. In the course of three or four hours after the application of cantharides there are formed numerous vesicles which soon coalesce, forming one large bleb full of clear serum.

The drug not only causes vascular dilatation of the part to which it is applied, but reflexly dilates the blood-vessels of the deep-seated organs underneath, thus acting as a counterirritant.

The active principle of cantharides may be absorbed through the skin, producing its constitutional effects.

Internally. - Digestive System. - Moderate doses of cantharides produce a sensation of heat in the stomach, and may even occasion gastrodynia. Large amounts occasion severe gastro-intestinal irritation. There is a sense of constriction in the esophagus, a burning heat in the throat, ptyalism, intense gastric pain, nausea, and vomiting of glairy mucus often containing blood. There is great tenderness over the abdomen, fibrinous and sometimes bloody stools, attended by griping pain and tenesmus.

Circulatory System. - Full medicinal doses excite the heart, increasing the force and rapidity of its action, and elevate arterial tension. Under large doses the pulse and arterial pressure fall, and there is great depression of the entire circulatory system.

Nervous System. - Small doses have no influence on the nervous system other than would be produced by stimulation of the circulation. Excessive amounts have produced marked cerebral effects, consisting of partial or general convulsions, coma, and insensibility.

Respiratory System. - No effect follows medicinal doses; toxic amounts accelerate and weaken the respiration.

Absorption and Elimination. - The active principle of cantharides is rapidly absorbed; as it is eliminated, produces marked irritation of the genito-urinary organs. There is at first increase of urine, which is soon greatly diminished in amount, and which may be albuminous or bloody. There is strangury and frequent desire to micturate, and severe pain in the loins and bladder. The local irritation is apt to occasion priapism, with frequently erotic excitement and seminal emissions. There may also be swelling and inflammation of the external genitals. In women cantharides may also occasion increased sexual desire, cause abortion, or induce menstruation. Yet amatory desire does not always follow the ingestion of cantharides, even in large doses. Indeed, the aphrodisiac effect of the drug is usually more manifest under small or full medicinal doses than from the ingestion of immoderate amounts. The drug is principally eliminated by the kidneys.

Temperature. - The temperature is at first elevated by excessive amounts, but declines together with the depression of the circulatory system.

Uterus. - The uterus and female genital organs are stimulated by the drug, as has been previously described.

Untoward Action. - The untoward manifestations do not differ from the symptoms produced by excessive amounts, as described under the different systems. These various untoward effects vary in intensity according to the individuality of the patient.

Poisoning. - Toxic amounts of cantharides produce violent gastrointestinal and genito-urinary inflammation. The general symptoms are great pain in the throat, stomach, and bowels, excessive thirst, vomiting of bloody mucus, frequent stools which may contain blood, burning pain in the kidneys, strangury, scanty, albuminous, and bloody urine, painful erections of the penis, seminal emissions, swelling and inflammation of the external genitals, a rapid, small, and weak pulse, accelerated respiration, skin hot and dry, congestion of the face, pain in the head, delirium, trembling, partial or general convulsions, and coma. The postmortem appearances are swelling, ecchymoses, and sometimes gangrene of the mucous membrane of the alimentary canal. The kidneys are enlarged and engorged, and are in a condition of parenchymatous and desquamative nephritis.

Treatment of Poisoning. - The stomach should be emptied, and demulcents, stimulants, and opiates given as necessary. Oils and fats should be avoided, as they increase the solubility and favor the absorption of cantharidin.

Therapeutics. - Externally and Locally. - A cantharidal blister is frequently of service as a revulsive when there is a local tendency to congestion. The drug is applied to the chest in the second stage of pneumonia and in pleurisy, and "flying" blisters are beneficial in hydrothorax and chronic pleurisy.

The cure of boils and carbuncles has been hastened by applying a cantharidal blister to the indurated spot.

The drug is also of service to stimulate indolent ulcers, fistula, etc.

A blister over the region of the heart will often afford marked relief in pericarditis.

A cantharidal plaster applied over the course of the affected nerve frequently affords great relief from pain in neuralgia and some forms of sciatica.

In subacute or chronic inflammatory diseases of the brain and spinal cord, such as meningitis, blisters applied to the nape of the neck or along the course of the cord, a little to one side of the vertebras, will often favorably influence the course of the disease.

Blisters are frequently of service in synovitis and periostitis of the larger bones. A blister applied to the epigastrium will sometimes allay gastric pain and obstinate vomiting.

Blistering over the region of the ovary is an efficient means of relieving the symptoms of chronic ovaritis, and a blister applied to the mastoid region will frequently be of benefit in otitis media.

Small patches of tinea tonsurans and of tinea circinaia may be removed by blistering.

Liniments and lotions containing tincture of cantharides are among the best means of curing alopecia.

Internally. - Certain diseases of the genito-urinary organs, as debility of the bladder with accompanying incontinence of urine, chronic pyelitis, chronic catarrh of the bladder, etc., are benefited by small doses of tincture of cantharides.

Gleet, prostatorrhea, and spermatorrhea are benefited by this drug. Menorrhagia and amenorrhea occurring in debilitated women will often be benefited by cantharides.

Tincture of cantharides, with tincture of iron, tincture of nux vomica, and phosphoric acid, is a useful combination in impotence, the result of old age, sexual excesses, or masturbation.

In scaly skin diseases cantharides often proves very serviceable after arsenic and the external application of tarry preparations have failed.

Administration. - A cantharidal blister should not be allowed to remain on the skin for more than twelve or twenty-four hours, six to eight hours usually being sufficient. Care should be taken of the blisters, as they are apt to be infected very readily.

The obstinate ulcers which sometimes follow the use of cantharides blisters may be treated effectively by Goulard's cerate.

For internal use the tincture of cantharides is the only preparation to employ.