MICROBIC VIRULENCE AND HOST SUSCEPTIBILITY IN PARATYPHOID-ENTERITIDIS INFECTION OF WHITE MICE : VII. SEASONAL VARIATION IN THE SUSCEPTIBILITY OF DIFFERENT STRAINS OF MICE TO PER Os INFECTION WITH THE TYPE II BACILLUS OF MOUSE TYPHOID (BACILLUS PESTIS CAVIÆ).

Seasonal variations are described in the response of five strains of mice to inoculation with the Type II bacillus of mouse typhoid (Bacillus pestis caviæ). There occurred in the case of all strains a high peak of mortality during the spring, a lower death rate during the summer, and a subsequent autumn rise in the number of deaths.