THE SURFACE OF VIRUSES 



141 



kinetics, except at very low temperatures. Some indication of a 

 second type of antigen was found below 80° C. 



100 



;e50 



o 



E 



£ ZO- 



IC 



— OX _ 



oV 



o. 



10 15 20 



Time of inoctivation 



25 



30minutes 



Fig. 5.6. Thermal action on the serological affinity of T-1 phage as measured 

 by the neutralization of plaque formation. 



These results can be analyzed as in the table. The values found 

 for infectivity are given for reference. 



The results found by Dimond and the author for SBMV in- 

 dicate that there are curved lines on this logarithmic scale. These 

 can be analyzed into the sum of two lines and interpreted as the 

 separate inactivation curves for two antigens. Approximately 

 60% of the antigenic activity has a rapidly changing reaction 



