1. The serum ferments are practically unaltered by a primary injection of foreign protein. 2. During the course of sensitization the injection of the antigen is followed by the mobilization of a non-specific protease which increases in rapidity and intensity as the maximum period of sensitization is reached. 3. Acute shock is accompanied by: (a) The instantaneous mobilization of a large amount of non-specific protease; (b) a decrease in antiferment; (c) an increase in non-coagulable nitrogen of the serum; (d) an increase in amino-acids; (e) a primary decrease in serum proteoses. 4. Later there is a progressive increase in the non-coagulable nitrogen, in proteoses, and in serum lipase. 5. The acute intoxication is brought about by the cleavage of serum proteins (and proteoses) through the peptone stage by a non-specific protease. 6. The specific elements lie in the rapid, mobilization of this ferment and the colloidal serum changes which bring about the change in antiferment titer.