MIYA, MARCUS AND PHELPS 



and the mortality of the animals was followed for 90 days after 

 challenge. The results in Table XVIII show that again low ambient 

 temperatures did not influence the final mortality ratios regardless 

 of challenge dose. However, when mortality is plotted as a function 

 of time, a significant delay in mortality again is seen (Fig, 14), This 

 delay in mortality is most pronounced in the animals receiving the 

 highest challenge dose. At lower challenge doses, the mice died 

 more rapidly when kept at 2° C than when kept at 21° C. 



DISCUSSION 



At the onset of this investigation, it was felt that knowledge of the 

 metabolic behavior of the bacterial challenge agents was important 

 in order to assess properly any subsequent data obtained when 

 these agents were employed. The experimental results indicated 

 that temperatures lower than 37° C affected the oxygen uptake 

 but not the generation time of the organisms. The only apparent 

 effect of lowered temperatures employed was to increase the 

 lag phase. 



Along with the above information, the necessity to determine 

 the effect of low ambient temperatures on the body temperature of 

 the mice used in our experimental set-up became apparent. As a 

 first approximation, we assumed that if the body temperature 

 changed as a result of cold exposure, then the change could directly 

 influence the course of the experimental disease by enhancing or 

 depressing the ability of the organisms to grow and develop. Our 

 results showed that the rectal temperature of mice exposed to 

 2° C fluctuated within the first 24 hour period of cold exposure, 

 but stabilized thereafter at a temperature 1° C to 2 C higher than 

 mice kept at room temperature. The fluctuation was more pro- 

 nounced in mice caged singly as compared to those caged in groups 

 of five. In contrast, Walker and Boring (1958) showed that rectal 

 temperatures of mice exposed to 4° C decreased approximately 

 1 C, The differences between results of the two groups reporting 

 might be ascribed to a significant technical detail; that is, we in- 



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