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Berthollet, Claude Louis, Comte

(Encyclopedia)Berthollet, Claude Louis, Comte klōd lwē, kôNt bĕrtōlāˈ [key], 1748–1822, French chemist. His contributions to chemistry include the analysis of ammonia and prussic acid and the discovery of ...

fatigue, in physiology

(Encyclopedia)fatigue, in physiology, inability to perform reasonable and necessary physical or mental activity. Muscle fatigue, for example, results when the contractile properties of muscle are reduced, and conti...

acne

(Encyclopedia)acne, common inflammatory disease of the hair follicles and sebaceous glands characterized by blackheads, whiteheads, pustules, nodules and, in the more severe forms, by cysts and scarring. The lesion...

vinegar

(Encyclopedia)vinegar, sour liquid consisting mainly of acetic acid and water, produced by the action of bacteria on dilute solutions of ethyl alcohol derived from previous yeast fermentation. The coloring and flav...

cassava

(Encyclopedia)cassava mănˈēŏk [key], name for many species of the genus Manihot of the family Euphorbiaceae (spurge family). The roots, which resemble sweet potatoes and are eaten in much the same way, yield ca...

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 ...

sting

(Encyclopedia)sting, in zoology, organ found in bees, many wasps, some ants, and in scorpions and sting rays, used defensively as well as to kill or paralyze prey. In the bee and the wasp the venom is produced by g...

bismuth

(Encyclopedia)bismuth bĭzˈməth [key] [Ger. Weisse Masse=white mass], metallic chemical element; symbol Bi; at. no. 83; at. wt. 208.98040; m.p. 271.3℃; b.p. about 1,560℃; sp. gr. 9.75 at 20℃; valence +3 or ...

bleaching

(Encyclopedia)bleaching, process of whitening by chemicals or by exposure to sun and air, commonly applied to textiles, paper pulp, wheat flour, petroleum products, oils and fats, straw, hair, feathers, and wood. C...

acetate

(Encyclopedia)acetate ăsˈĭtātˌ [key], one of the most important forms of artificial cellulose-based fibers; the ester of acetic acid. The first patents for the production of fibers from cellulose acetate appea...