ASPHYXIA. —Partial or complete unconsciousness due to an insuffi cient supply of oxygen in the blood. The condition may result suddenly, as in drawing food into the windpipe (in choking) ; by being immersed in water (in drowning) ; by pressure on the lungs (in pleurisy) ; or by insufficient lung space to oxidise the blood (in simple or tuberculous pneumonia). It may result from the taking of large doses of certain drugs, notably those that in breaking clown in the body liberate paramidoplienol ; particularly acetanilid (found in most headache-powders) and phenacetin. It may occur also in acute alcoholism, or acute opium poisoning. It may develop as a chronic condition in many heart-diseases, and in poisoning by gas or other poisons, notably the anilines. The chief symptoms and treatment are described under DROWNING, and POISONING.
ASPIDIUM (MALE-FERN).—The dried rhizome of Aspidium Filix mas or of Aspidium marginalis, two ferns more or less widely distributed throughout the world. The former is found fairly extensively throughout
the world ; the latter is common to Canada and the United States. The active principle is not thoroughly known, filicic acid and several closely allied compounds being thought to he the most important constituents. The action of aspidium is unique. It has the property of killing tapeworms, which it does fairly rapidly and very effectively. The drug is rarely absorbed, as it has some irritating properties causing mild catharsis, but if absorbed, and in comparatively large quantities, symptoms of poisoning may develop. The most important of these are convulsions, accompanied by intestinal irritation, pain, vomiting, purging, relaxation, etc. An un common accompaniment of the poisoning is a more or less permanent partial or complete blindness. The drug is used as a rule in the form of an oleo resin in doses of one-half to one teaspoonful.
ASSIMILATION.—See under ORGANS OF DIGESTION in INTRODUCTORY