MIYA, MARCUS AND PHELPS 



Table XII. Effect of chronic cold stress (2° C) on mortality of mice challenged 

 intraperitoneally with 10 LU^q* of Staphylococcus aureus, strain Fritchie. Animals 

 maintained for 30 days, immunized or treated and challenged at noted temperatures. 

 *10 LDcQ of S. aureus = 50 x 10® organisms per mouse. 



represent definitive results concerning whether nonspecific immun- 

 ization procedures were as efficacious as specific immunization pro- 

 cedures. And once more, specific immunization offered the greatest 

 resistance to experimental disease. This increased resistance was 

 not affected by acute exposure to 2° C. The extent of protection af- 

 forded the animals by treatment with zymosan or endotoxin did not 

 approach that afforded by specific immunization. By comparing the 

 mortality ratio of the control animals with that of the zymosan 

 treated animals, a probability valueof significance is obtained. This 

 significant degree of protection was independent of acute cold ex- 

 posure. No significant differences in mortality ratios were noted be- 

 tween control animals and endotoxin treated animals. 



Effect of chronic exposure foUowir^ larger doses . Animals in this 

 experiment were maintained at 2° C for 30 days to allow acclimati- 

 zation. The animals were specifically or nonspecifically immunized 

 at this low ambienttemperature, and were caged in groups of 10. The 

 challenge dose was increased to several LDj-^ 's in order to obtain 



180 



