NORTHEY 



Sample N R-Cold R- Normal U P 



13 



2 3 6 U .050 



3 3 12 11 2 .200 

 »+ 3 11 12 «♦ .500 



5 3 15 12 1 .100 



6 3 20 18 1 .100 



7 3 15 16 U .500 



Table III. Qiualitative evaluation of precipitates in gel diffusion of sera from "nor- 

 mal" and "cold exposed" rabbits. Antigen-egg albumin (Ea). 



of the egg albumin anti-egg albumin system. However, a significant 

 level was not attained at any other sample in this experiment. An 

 occasional significant value was also found in other experiments, 

 but these findings were not consistentwith most of the data. To date, 

 over 500 serum samples have been evaluated in this manner. The 

 same method has also been applied to measurements of the time 

 of precipitation. The results of one series of measurements at 

 closely spaced time intervals is given in Table IV. 



"Ring" Precipitin Titrations 



The "interfacial technique" has been used extensively as a 

 measure of the antibody "titer" of immune sera. In these studies, 

 serum samples from both study groups were titrated for antibody 

 content using different antigens and varyingbleeding schedules. The 

 result of one of these tests using egg albumin as antigen is shown 

 in Table V. 



The antibody titrations by the precipitin "ring" technique failed 

 to reveal any consistent trend toward higher antibody levels in either 

 of the study groups. However, when the less complex antigens, egg 

 albumin (Ea) (Table V) and bovine serum albumin (BSA) were used, 

 the antibody levels were somewhat higher in the "cold exposed" 

 group, whereas the animals maintained at room temperatures and 



116 



