W. H. MANWARING 1085 



LIMITATIONS OF THE ENZYME THEORY 



Unlike the Ehrlich theory, however, the enzyme theory would not attempt to ex- 

 plain and co-ordinate all known immunological facts. For example, the enzyme theory 

 would not attempt to explain the variations in natural resistance in different tissues and 

 in different animal species. It would make no assumption as to the physiological role 

 of so-called "specific antibodies." Nor would it assume that the formation of these 

 substances is the only specific immunological adaptation in the body. With these 

 limitations, however, the enzyme theory would offer as plausible an explanation of 

 known immunological facts as that offered by the specific receptor hypotheses. I be- 

 lieve the enzyme theory of antibody formation is the most promising substitute for 

 the Ehrlich theory, at the present day. 



