104 IMMUNO-CATALYSIS 



resistance does not involve a continued production of an antibody-like 

 substance capable of combining with a drug to neutralize its toxic 

 effect. On the other hand the only resistance a host develops to an 

 antigenic toxin is believed to be by means of the production of 

 specifically combining and neutralizing antibodies during a limited 

 period. 



Consideration of the above discussed questions seems to show that 

 the phenomenon of immunity is conditioned by the presence of anti- 

 genic units but that this conditioning disappears when the antigenic 

 units are eliminated from the host system. 



6. On Jordan's Autocatalytic Theory of Antibody 

 Formation 



Jordan (1944) has proposed an autocatalytic theory of antibody 

 production. According to this theory, the multiplication of a gene or a 

 virus only in the presence of itself, is a basic autocatalytic phenomenon 

 in all living processes including the formation of antibody. The mole- 

 cules, or fractions of molecules which possess the ability for parallel 

 orientation and are capable of multiplication are identical and exhibit 

 affinities for each other. A molecule M, which is capable of multipli- 

 cation, may be composed of /^l, /a2, iS fractions each of which pos- 

 sesses the property of attracting others to itself. These molecular frac- 

 tions per se, in solution, by themselves possess very little tendency to 

 combine with each other; they do so, however, when M is present form- 

 ing another molecule identical with M. The attraction among the 

 fractions jul, /x2, ju.3 is attributed to resonance of the fractions. That is, 

 two substances are said to attract each other through resonance when 

 they possess groupings identical or nearly so. Jordan had earlier ex- 

 pressed similar views concerning this question which had been denied 

 by Pauling and Delbriick (1940) on grounds that the resonance 

 energy would be so small as to be ineffective. Reasoning in similar 

 fashion, Jordan (1940) had postulated that antibodies and specific 

 antigens are identical, a postulate which is related to the concept of 

 Biichner (1893). This likewise has been refuted by the chemical- 

 immunological evidence supplied by Haurowitz, et al. (1942). The 

 latter investigators using iodo-proteins, bromo-protein and arsonil- 

 azoprotein as antigens showed that none of the antibodies contained the 



