Columbia Encyclopedia

Search results

403 results found

vampire bat

(Encyclopedia)vampire bat, name for the blood-drinking bats of the family Desmodontidae, found in the New World tropics. Vampire bats feed exclusively on the blood of living animals and are thus the only true paras...

sulfa drug

(Encyclopedia)sulfa drug, any of a class of synthetic chemical substances derived from sulfanilamide, or para-aminobenzenesulfonamide. Sulfa drugs are used to treat bacterial infections, although they have largely ...

biochemistry

(Encyclopedia)biochemistry, science concerned chiefly with the chemistry of biological processes; it attempts to utilize the tools and concepts of chemistry, particularly organic and physical chemistry, for elucida...

leprosy

(Encyclopedia)leprosy or Hansen's disease hănˈsənz [key], chronic, mildly infectious malady capable of producing, when untreated, various deformities and disfigurements. It is caused by the rod-shaped bacterium ...

drugs

(Encyclopedia)drugs, substances used in medicine either externally or internally for curing, alleviating, or preventing a disease or deficiency. At the turn of the century only a few medically effective substances ...

grafting

(Encyclopedia)CE5 Two methods of grafting grafting, horticultural practice of uniting parts of two plants so that they grow as one. The scion, or cion, the part grafted onto the stock or rooted part, may be a s...

dementia

(Encyclopedia)dementia dĭmĕnˈshə [key] [Lat.,=being out of the mind], progressive deterioration of intellectual faculties resulting in apathy, confusion, and stupor. In the 17th cent. the term was synonymous wi...

allergy

(Encyclopedia)allergy, hypersensitive reaction of the body tissues of certain individuals to certain substances that, in similar amounts and circumstances, are innocuous to other persons. Allergens, or allergy-caus...

citrus fruits

(Encyclopedia)citrus fruits, widely used edible fruits of plants belonging to Citrus and related genera of the family Rutaceae (orange family). Included are the tangerine, citrange, tangelo, orange, pomelo, grapefr...

Rockefeller Foundation

(Encyclopedia)Rockefeller Foundation, philanthropic institution established (1913) by John D. Rockefeller, Sr., to promote “the well-being of mankind throughout the world.” During its first 14 years the foundat...