Abstract
1. The antitryptic titer of the serum can be increased by subcutaneous injections of serum lipoids (antitrypsin) and of the lipoids from egg yolk. 2. Animals so injected show a relative immunity to acute anaphylactic shock (two minimum lethal doses). 3. Extraction of lipoids contained in antigens increases the toxicity of the antigen when injected into a sensitized animal. 4. Sublethal doses of soap solutions injected simultaneously with the antigen (purified horse serum albumen) prevent anaphylactic shock. 5. The refractory state following anaphylactic shock is related in part to an increase in the antitryptic titer of the serum.