ANTIPYRETICS are agents used to reduce the tempera ture in fever. They may be classified under two headings, namely, chemical and physical. Until about 1885 the chief chemical antipyretic was quinine, which was used most successfully in malaria. Soon after that numerous other drugs were introduced and it is mainly to them that the name of antipyretics is applied. Of them antipyrin, acetanilid and phenacetin have survived longest and even they are now looked upon with some suspicion because their use is so often accompanied by ill effects. Their action seems to be a specific effect on the heat regulating centre, situated some where in the brain. Through it they are thought to decrease the production of heat in the body and thereby lower temperature. Salicylates, such as aspirin, have a much more favourable and com paratively safe antipyretic action in fever. They cause dilatation of the peripheral blood vessels and sweating, and consequently a more rapid loss of heat from the body. The physical means of controlling unduly elevated temperature would seem the more satisfactory. They are cold baths, ice packs, alcohol sponges, and similar measures. The danger is slight and the results, although often only temporary, are sometimes quite striking.