Male Fern is the dried root of Dryoptcris filix-mas, or Dryopteris marginalis, perennial herbs of the north temperate zone, and mountainous regions of the tropics.

Pharmacodynamics.

Central Nervous System. - Male Fern depresses the upper centers, and stimulates the reflex excitability of the cord.

Muscular System. - No direct action.

Respiration depressed by centric action.

Heart is depressed by centric action.

Blood-pressure. - Falls with decreased heart-action.

Alimentary Canal. - Irritant.

Secretory Glands. - No effect.

Metabolism. - Male fern destroys red blood-corpuscles.

Temperature. - No effect.

Absorption is very slow, so that the accompanying purge usually sweeps the drug out before constitutional symptoms develop. Some subjects are susceptible to its action, and may be acutely poisoned. Its absorption is facilitated by the presence of oils.

Excretion. - Nothing seems definitely known about the elimination of Aspidium.

Local Action. - None.

Eye. - Filix-mas sometimes induces a neuritis of the optic nerve.

Symptoms.

Therapeutic Doses.

Usually no symptoms, but may produce results very alarming.

Too Large Doses.

Vomiting and purging.

Acute colic.

Muscular weakness.

Mental confusion.

Drowsiness.

Collapse, coma, and death.

Therapeutics.

Male Fern is used for the expulsion of the tapeworm. It is given after a fast, and should be followed in eight hours by a saline purge. Castor oil, or any other kind of oil, should not be used for a purge following Aspidium.

Dosage.

Oleoresina Aspidii, 2 Gm. Not to be repeated within seven days.

Thymol is used to expel hookworm. It is given, after ten hours fasting, in doses of 0.75 Gm., repeated twice at 15-minute intervals. Four hours later a brisk saline purge is given. Oil of any kind must not be allowed the patient, as it renders the thymol freely absorbable, resulting in alarming poisoning with weakness, apathy, and collapse.