The stimulating effect of T.A.B. vaccine in tetanus tosoid is established in the present experiment in comparison with alum-toxoid which has hitherto been recommended as the best preparation for active immunization but is unsuitable for human beings on account of its irritating action. The associated T.A.B. vaccine in tetanus toxoid is found to have the advantage of serving the dual function of a preventive against enteric fever and also a stimulus to the antigenic property of tetanus toxoid. In actual application to human cases, especially soldiers during war time, active prophylaxis against tetanus is preferable as it gives far better protection than immunization with specific antiserum. The combination of tetanus toxoid and T.A.B. vaccine for the double prophylaxis against tetanus and enteric fever by a series of 3 injections is, therefore, to be recommended to military hygienists for further trial.