MIYA, MARCUS AND PHELPS 



confuse the analysis of data. The results of the experiment are shown 

 in Table XVII. The majority of deaths occurred between 4 and 6 days 

 post- challenge; no deaths of animals occurred after 10 days following 

 challenge. Again, acclimatization at 2° C for 40 days resulted in 

 mortality ratios similar to those observed in the animals kept at 

 21° C, Unacclimatized mice had increased mortality ratios in all 

 treated groups compared to the 21° C control mice except in the im- 

 munized groups. Zymosan appeared to give greater protection than 

 endotoxin; in fact, the 20 out of 20 deaths in the endotoxin group 

 occurred by the fourth post-challenge day. If the mice were acclima- 

 tized and treated with endotoxin, only 7 in 20 deaths occurred. Thus, 

 it would appear that acclimatization enhances host resistance to 

 challenge in addition to decreasing the increased mortality ratios in 

 the groups treated with endotoxin. The value of specific immunization 

 is apparent in the unacclimatized mice. 



Low Ambient Temperature and Ehrlich Ascites Tumor 



The effect of temperature on neoplastic diseases has been studied 

 by various investigators (Fay and Henny, 1938; Smith and Fay, 1939; 

 Bischoff and Long, 1939; Wallace et al., 1944; Fuller et al., 1941; 

 Goldfeder, 1941; Wallace et al., 1942; Tannenbaum and Silverstone, 

 1949; Griffiths et al., 1961). Effects on the tumor take, incidence of 

 spontaneous tumor formation, growth, or regression were noted as a 

 result of high or low ambient temperatures, but no consistent effects 

 have been noted. In this respect, the effect of temperature on neo- 

 plastic disease becomes as complicated as that observed with regard 

 to bacterial or viral disease. 



Since the Ehrlich ascite tumor produces certain effects in mice 

 similar to infectious disease, for example, rapidly progressive 

 disease, it was chosen as a model to study the effect of cold stress 

 on the disease process. Mice were exposed in the cold room in large 

 animal cages containing 50 mice and acclimatized to this tempera- 

 ture for 45 days. Two days prior to challenge the mice were caged 

 in groups of six. The mice were given unlimited amounts of Purina 

 mouse chow and tap water. Mice kept at room temperature were 

 randomly separated into groups of 12, 



186 



