A QUANTITATIVE STUDY OF THE PRECIPITIN REACTION BETWEEN TYPE III PNEUMOCOCCUS POLYSACCHARIDE AND PURIFIED HOMOLOGOUS ANTIBODY.

1. A quantitative study of the reaction between the soluble specific substance of Type III pneumococcus and its homologous antibody has been made. 2. The entire reaction, from excess of antibody, to excess of specific substance with its accompanying inhibition zone effect, may be expressed by three mass-law equations. 3. The significance of these findings is discussed.