ANTIGENS, HAPTENS, ANTIBODIES. ETC. 



and 7:>-amino -phenol- ^-galactoside, 



-til 



CH„OH 



HO 



H OH 



XH,, 



diazotised them and coupled them with albumm and 

 globulin in the usual way to make antigens. It will be 

 seen that the only difference between the glucose and 

 galactose derivatives is in the arrangement of the hydrogen 

 atom and hydroxyl group on carbon atom 4 of the 

 sugar molecule. Yet this small difference is sufficient 

 to make the new antigens specific and to obliterate the 

 specificity of the proteins to which they are coupled ; thus 

 the glucoside -globulin antigen gives no reaction with the 

 galactosicle -globulin antiserum but does react with the 

 glucoside-albumin antiserum. The inhibition reactions 

 by the homologous haptens were equally specific, the 

 glucose-derivative hapten having no effect on the reactions 

 between galactose-derivative antigens and antisera, and 

 vice versa. When ;;-amino-phenol-« -glucoside, 



HO 



