J. BRONFENBRENNER 1065 



The explanation of this tendency became apparent when the mechanism under- 

 lying the Abderhalden reaction was studied by the methods analogous to those used 

 in the study of immunity reactions. This approach was suggested by the observation 

 that a serum giving a characteristic Abderhalden reaction may be rendered inactive 

 upon heating for half an hour at 56°-6o° C, and that upon the addition of a suitable 

 amount of fresh normal serum (complement ?) it regains its activity while retaining 

 its original specificity.' The experiments of the writer have demonstrated that the 

 elements of the serum which are responsible for its specificity may be removed by ad- 

 sorption with a corresponding substratum in the manner analogous to that of adsorp- 

 tion of antibodies by the corresponding antigen.^ Moreover, it became evident that 

 when the serum is thus exhausted of its specific elements by adsorption with the sub- 

 stratum, the ferments present in the serum become active and digest the protein of 

 the serum itself.^ The latter phase of the phenomenon has been questioned by Abder- 

 halden, who suggests that the products of digestion thus appearing in the serum, 

 after its separation from the substratum, originate not in the serum itself, but in the 

 traces of substratum which fail to be completely removed from the serum in cen- 

 trifugating,'' However, the writer has shown that the products of digestion obtained 

 under these circumstances exhibit toxicity for experimental animals entirely independ- 

 ent of the nature of the substratum used, and depending only on the nature of the 

 serums — thus indicating that the latter undoubtedly is the source of the toxic diges- 

 tion products. Similar conclusions have been reached by Jobling, Petersen, and 

 Eggstein^ who found that the substratum, after contact with the serum, becomes more 

 resistant to the tryptic digestion as a result of having adsorbed the anti-ferment of 

 the serum. 



1 Stephan, R.: Miinchen. med. Wchnsckr., 61, 801. 1914; Hauptmann, A.: ibid., p. 1167. 1914; 

 Bettencourt, N., and Menezes, S.: Compt. rend. Soc. de biol., 77, 162. 1914; Bronfenbrenner, J.: 

 Proc. Soc. Exper. Biol. 6* Med., 12, 3. 1914; Abderhalden, E., and Grigorescu, L.: Med. Klin., 10, 

 728. 1914; Abderhalden, E.: Ahwehrfermente (4th ed.), p. 154. Berlin, 1914. 



2 Bronfenbrenner, J.: Proc. Soc. Exper. Biol, b' Med., 12, 3. 1914. 



3de Waele, H.: loc. cit.; Bronfenbrenner, J.: Proc. Soc. Exper. Biol, b" Med., 12, 7. 1914; /. 

 Exper. Med., 21, 221. 1915. 



"t Abderhalden, E.: Fermentforschung, 5, 130. 1921. 



5 Bronfenbrenner, J.: Penn. Slate M. J., 18, 2. Oct., 19T4; Bronfenbrenner, J., Mitchell, W. J., 

 and Titus, P.: loc. cit.; Bronfenbrenner, J.: J. Exper. Med., 21, 221. 1915. 



'* Jobling, J., Petersen, W., and Eggstein, A.: /. Exper. Med., 22, 401. 1915. 



