388 PATHOGENIC BACTERIA. Wright and Semple assert that dead cultures of the typhoid bacillus may be used for the test, as bacilli killed by a temperature of 60° C. agglutinate perfectly. They have the advantage of being easily kept. Rumpf,1 and Kraus and Buswell2 report a number of cases of typhoid which were favorably influenced by the introduction hypodermically of small quantities of steril- ized cultures of Bacillus pyocyaneus. These experiments are still too new to deserve extended mention. Following the lines of experimentation suggested by Haffkine's researches upon preventive vaccination against cholera Asiatica, Pfeiffer and Kolle, and Wright and Sem- ple have used the subcutaneous injection of sterilized cul- tures as a prophylactic measure. One c.cm. of a bouillon culture sterilized, by heat is thought to be sufficient Wright and Semple report 18 cases in which it was used, and by experiment showed the blood to be changed simi- larly to that of typhoid patients and convalescents. This change consisted in the destruction of motility and agglu- tination of the bacilli, as seen in Widal's reaction. It is hoped that we can gauge the duration of the immunity thus acquired by the frequent use of Widal's test. One of the most important and practical points for the physician to grasp in relation to the subject of typhoid fever is the highly virulent character of the discharges from the bowels. In every case the greatest care should be taken for a proper disinfection of the feces, a rigid attention to all the details of cleanliness in the sick- room, and the careful sterilization of all articles which are soiled by the patient. If country practitioners were as careful in this particular as they should be, the disease would be much less frequent in regions remote from the filth and squalor of large cities with their unmanageable slums, and the distribution of the bacilli to villages and towns, by watercourses polluted in their infancy, might be checked. 1 Deutsche med. Wochenschrift, 1893, No. 41. 2 Wien. klin. Wochensckrift, July 12, 1894.