NORTHEY 



using the human serum antigen attained a slightly higher level of 

 antibody. Of interest too is that in the group in which daily blood 

 samples were taken, the additional "stress" created by cold ex- 

 posure did not significantly alter a steady rise in the antibody 

 level (Table VI and Table VII). 



Number of Days 



Following Mean Antibody Titer Mean Antibody Titer* 



Initial Injection Cold exposed Non-Cold exposed 



3 1-2500 1-3000 



6 1-5000 1-8000 



9 1-5000 1-10,000 



12 1-5000 1-10,000 



18 1-2U00 1-10,000 



2U 1-6500 1-10,000 



H8 1-7000 1-10,000 



Table VI. Mean precipitin tilers of "normal" antl "cold exposed" rabbits immunized 

 with human serum, 'Mean titer calculated on the basis of antibody titers obtained from 

 precipitin titrations of 6 samples of rabbit antiserum. 



Starch Gel Electrophoresis 



The technique of electrophoresis in starch gel offers a method 

 of increased sensitivity over that of paper electrophoresis, and 

 under proper conditions, it is possibletoresolveas many as fifteen 

 components in human serum (Moretti et al., 1959). This method was 

 utilized for a comparison of the sera from "normal" and "cold ex- 

 posed" animals in order to detect the possible presence of any 

 "abnormal proteins" which might be formed as a result of cold 

 exposure. Conversely, the failure of the "cold exposed" animal to 

 form any of the "normal" serum sub- fractions could also be recog- 

 nized. Simultaneous analysis of sera from both "cold exposed" and 

 "normal" rabbits immunized with antigens of varying complexity 

 provides a convenient method for these evaluations. 



Samples were analyzed by starch gel electrophoresis in an appa- 



118 



