Since vaccines of the typhoid group are administered intravenously in arthritis, iritis, thrombo-angiitis obliterans and other conditions and since there does not seem to have been any adequate study of the reaction caused by these vaccines, an inquiry into the more detailed nature of the normal response to the injection should serve a useful purpose. During a series of experiments designed to determine the effect of various hypothalamic lesions on the course of fever induced in cats by the intravenous injection of typhoid-paratyphoid vaccine, sixteen normal cats were studied. Pinkston1 recorded the inguinal temperature of twelve normal cats to which typhoid-paratyphoid vaccine had been administered intravenously. He made readings every 10 to 30 minutes "until the body temperature had started toward normal." Cannon and Pereira2 described the temperature curves obtained for ten normal cats after intravenous or intramuscular injection of a suspension of dead typhoid bacilli. They did