26 



MUTATIONS 



10" 



UJ 



u 



o 



Ul 



10 



< 



O 



a. 

 o 

 ae 



a. 



< 

 2 



10- 



to- 



10- 





STAGE 



Figure 6. Isotope dilution curves for a second 

 agammaglobulinemic, group A. Open points = 

 anti-A alone; solid points = anti-A (following 

 three stages with anti-B and B carrier). 



with the mixed coagglutination test. We felt that the most critical 

 kind of test would be to use cells and then look in control cultures 

 that had not been treated or in cultures that had been X-rayed for 

 cells that gave a type-B reaction when B red cells and anti-B 

 serum were added. We have never gotten any indication of a change 

 from to B. 



Lederberg: What about fluorescent antibody? 



Glass: We don't have any data on this. 



Atwood: Until recently I had thought that fluorescent antibody could 



