MIYA, MARCUS AND PHELPS 



Temperature 



210 C 



20 C 



Treatment Mortality ratios at lU days 



(grouped) (single) 



Normal 

 Immune 

 Zymosan 

 Endotoxin 



Normal 

 Immune 

 Zymosan 

 Endotoxin 



8/10 

 1/10 

 6/10 

 9/10 



9/10 

 0/10 

 6/10 

 7/10 

 0/10 



10/10 

 2/10 

 8/10 

 7/10 

 0/10 



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

 intraperitoneally with 1 LDrn* of Staphylococcus aureus , strain Fritchie. Animals main- 

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

 •1 LDgQ of S. aureus = 75 x 10 organisms per mouBe. 



in groups or singly, were not afforded this protection. The results 

 obtained with endotoxin are equivocal. The mortality ratio of the 

 normal animals kept at 21° C was only 30 per cent (3/10), Results 

 to be presented later in this paper deal with mortality ratios ob- 

 tained when the challenge dose was increased to 10 LDca. 



Effect of chronic exposure following one LD c n dose. The animals 

 in this experiment were maintained at 2° C for 30 days in order to 

 allow acclimatization to the low ambient temperature. The animals 

 were specifically immunized or treated with zymosan or endotoxin 

 at this low ambient temperature. Following these procedures the 

 animals were challenged with one LD(-^ dose of S. aureus or K. pneu- 

 moniae . The results are shown in Tables VIII and IX. 



The animals receiving the S. aureus challenge (Table VIII) were 

 protected if they were specifically immunized. Such protection 

 occurred without regard to whether the mice were caged in groups 



176 



