Problems in Immunology 151 



sense of an immunity arrested at too early a stage; or is it 

 an imperfect immunity in the sense of a deviation of the 

 immune process so that abnormal antibodies are formed 

 capable of attachment to certain cells or tissues and there 

 causing damage when antigen appears? The beginnings of 

 an answer may perhaps lie in Mary Loveless's finding of the 

 two separate antibodies involved in the allergic state: the 

 sensitizing antibodies, occi^rring mainly in the P-globulin 

 fraction of serum, and the neutralizing antibodies, which 

 are found mainly in the y-globulin portion. And although 

 any protein is potentially an allergen, what is the reason 

 for the extreme potency of some of the large polypeptides 

 such as those found in cottonseed and the castor bean? 

 This would seem an excellent problem for the chemists 

 who occupy themselves with the sequences of amino acids. 

 Moreover, the most active pollen fractions contain carbo- 

 hydrates, and it is not known whether these are themselves 

 active or are merely adventitious impurities of the actual 

 allergen. 



What of the Future? 



This brief recital by no means exhausts the list of un- 

 solved problems. I have mentioned enough of these con- 

 tinuing riddles of immunology to indicate that some of 

 them, at least, are almost daily becoming less and less 

 obscure, and that modern quantitative immunochemical 

 methods are supplying, and will continue to furnish, 

 powerful tools for their ultimate solution. 



