Abstract 1. 1. By rapidly increasing doses of antigen it is possible to reach a relatively high state of hyposensitization. This method, however, is not void of danger, and a cautious gauging of the doses and of the time intervals between injections is indicated. It should be used only when urgency is necessary. 2. 2. Late reactions occur more commonly than with usual methods of injection of antigen. 3. 3. The treatment can be carried out with greater advantage if several frequent minute initial doses are given before an increase is made. A more rapid increase is then, relatively free of danger. 4. 4. The evidence presented here indicates that it is dangerous to follow the routine for increase in dosage prescribed by Besredka for the prevention of anaphylactic shock.