ANTIGENS AS BIOCATALYSTS 37 



sanilic acid which had a calculated molecular weight of 114,000 and 

 contained 78 diazo-arsanilic acid groups combined with one casein 

 molecule. A calculation of the serological results showed that the ratio 

 by weight of antigen to antibody was 1 : 18, or adopting a liberal figure, 

 was at least 1 : 10. 



Analyzing their quantitative data, they stated that if the most 

 probable calculation is made, on the basis of the Biichnerian hypothe- 

 sis, 15 ml. of immune serum should contain IS.By of arsenic. In actual 

 experiments this volume of serum showed no trace of arsenic, though 

 trial runs showed that the method would detect 1 .Oy of arsenic. 



In a study previously cited, Heidelberger, Kendall, and Soo Hoo 

 (1933) immunized rabbits against a red azo dye, R-salt-azo-benzidine- 

 azo-crystalline egg albumin. If the red colored whole antigen or its 

 red prosthetic group had been incorporated into the antibody ac- 

 cording to the Biichnerian hypothesis, the immune sera, or the isolated 

 antibody should be colored. The immune sera from the rabbits showed 

 no trace of color. 



Wollman and Bardach (1935) showed the falseness of the Biich- 

 nerian hypothesis by a highly sensitive anaphylactic test. The fact 

 that by means of an anaphylactic test the presence of a protein in a 

 mixture of several proteins can be detected was used to determine 

 whether or not a protein antigen, assumed by the theory to have been 

 incorporated in the homologous antibody molecule would cause ana- 

 phylactic shock in guinea pigs sensitized against the same antigen. 

 The guinea pigs sensitized against egg albumin and horse serum and 

 injected with homologous protein suffered shock and death, but the 

 sera of rabbits immunized against these antigens produced no symp- 

 toms of anaphylaxis in another group of guinea pigs sensitized respec- 

 tively against egg albumin and horse serum. 



Haurowitz, et al. (1942) found that homologous antibodies pro- 

 duced in rabbits to iodo-proteins, bromo-protein, caseinogen (phospho- 

 protein) and arsanil-azoprotein did not contain any of the determinant 

 group of the antigen or a serologically related group. 



In the absence of any other plausible explanation which could be 

 offered at present, the most logical possibility therefore is that anti- 

 body production is directed by antigen acting as a catalyst at the site 

 of the antibody formation. This point of view appears to meet the 

 criteria of the well known catalytic processes employed in all branches 



