36 IMMUNO-CATALYSIS 



colloidal platinum catalyzes the combination of oxygen and hydrogen 

 with the formation of water, copper sulphate catalyzes the rate of 

 oxidation of an aqueous solution of sodium sulphite, and urease the 

 transformation of urea into ammonium carbonate, etc. no traces of 

 catalysts are found in the molecules of the reaction products. 



Doerr and Friedli (1925) were perhaps the first to undertake the 

 task of showing the absence of antigenic substances in the antibody 

 molecule by chemical analysis of the latter. By immunizing rabbits 

 with atoxyl-containing azo-proteins, highly active anti-atoxyl specific 

 immune sera were obtained. Analysis of these specific sera with a 

 highly sensitive chemical method failed to show the presence of ar- 

 senic. On the basis of their findings they concluded that antibody 

 cannot be a metabolite originating from the substance of antigen. 



Following the above mentioned work Berger and Erlenmeyer 

 (1931) diazotized the sodium salt of p-aminophenylarsenic acid 

 (atoxyl) and coupled it with normal horse serum. The purified antigen, 

 which contained 0.000,449 g. arsenic per ml. of solution, was used for 

 the immunization of rabbits, administering four intravenous injections 

 of 2.0, 4.0, or 6.0 ml. of antigen solution. The animals were bled 13 

 days after the last injection. The immune sera thus obtained re- 

 acted with the antigen solution of 1 : 3200-6400 dilution. Using 30 ml. 

 of immune serum for the chemical detection of arsenic they did not 

 find any trace of arsenic in two rabbit sera. The serum of a third 

 rabbit showed a faint trace which was definitely weaker than a positive 

 control containing 10~^ g. (O.Oly) arsenic. A rabbit weighing two 

 kilos was calculated to contain 90 ml. of serum so that the arsenic 

 content of the total serum in none of the three rabbits could have been 

 0.000,03 mg. (0.03y). 



For the detection of the arsenic in serum they used a micro method 

 based on the Marsh test whereby an amount of arsenic as little as 

 O.Oly (10~^ g.) could be demonstrated. In order to show whether ar- 

 senic was present in the serum they analyzed the sera of rabbits im- 

 mediately— 314 to 20 minutes— after injecting them with atoxyl. Their 

 positive findings thus showed that arsenic, if present, in serum can 

 be determined under the experimental conditions. The evidence, there- 

 fore, appears to show conclusively that arsenic in antigen is not 

 incorporated in the resulting antibody. 



Hooker and Boyd (1932) immunized rabbits with casein-diazo-ar- 



