Prior to the work of Woehler, who synthesized urea more than a century ago, vital processes and products were considered inseparable from the living body, and the doctrine of vitalism proclaimed them forever beyond the poor power of mankind to understand or reproduce. The tiny crack produced by Woehler in the structure was enlarged by many others, and vitalism is long since defunct. Among the ruins, however, there remains hidden certain knowledge which still awaits excavation. It is with such a fragment, namely the enigma of immunity, that this report is concerned.
It has long been recognized that antibodies are carried in close association with the globulin fraction of the blood plasma. While certain workers, notably Huntoon1 and Olitzki and Frankel,2 attempted to separate them from all protein substances, others considered that this is impossible and accepted the belief that they are themselves globulins of a specialized