SPECIFIC AND NONSPECIFIC RESISTANCE 



Number of 



Organisms 



Ambient Temperatures 

 21® C 2® C 20 C 



(grouped) (grouped) (single) 



immu- immu- immu- 



normal nized normal nized normal nized 



Table II. Effect of acute cold stress (2° C) on mortality of mice challenged with 

 Klebsiella pneumoniae . Unacclimatized animals injected at room temperature, then 

 placed at noted temperatures. ♦? day mortality (dead/total). ♦♦Titer before challenge. 



When temperatures are measured on mice grouped five per cage 

 and maintained at 21^ C,the results shown in Figure II are obtained. 

 The rectal and upper respiratory cavity temperatures are about the 

 same in magnitude, while the skintemperatures range about 2^ C to 

 2.5^ C less. The temperature curves again parallel each other, but 

 they do not exhibit any marked fluctuations as seen with mice main- 

 tained singly or grouped at 2*-* C, Essentially, the temperatures of 

 the mice remained quite constant throughout the experiment. The 

 data charted in Figure 12 demonstrate that mice singly caged and 

 kept at 21° C exhibited temperature curves that were almost identi- 

 cal with those obtained with grouped mice maintained at the same 

 ambient temperature. 



Effect of Acute and Chronic Exposure to Low Temperatures on 

 Survival of Mice Challenged with Klebsiella Pneumoniae 



Acute exposure experiments . Mice were immunized at room 

 temperature and then were challenged with varying numbers of 

 K. pneumoniae. Immediately following this procedure, the mice 

 were transferred to an ambient temperature of 2° C, The con- 



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