The intravenous injections of infected distilled water have been shown to develop three types of fever curves on rabbits. (1) With doses of more than 10 cc/kg the curve falls suddenly after. injection by shock. (2) With 1.25-10 cc/kg a diphasic curve appears in which the second peak is higher than the first. (3) With doses of less than 0.5 cc/kg a diphasic curve in which the first peak is. higher than the second is obtainable. If the doses injected are reduced to 0.125 cc/kg or less, one of the two peaks is extinguished and a monophasic curve established. The author has further analysed a large series of fever curves and suggested that the second peak has some meaning in the tolerance against pyrogenic reactions of the test animals.
