1. The absolute, quantitative agglutinin method has been used for the determination of the presence or absence of small amounts of specific polysaccharide in pneumococcus variants.
2. A technique is described for the removal of group specific antibody from antipneumococcus horse serum.
3. The type specific anticarbohydrate agglutinin and precipitin are not only present in identical amounts in Type I antipneumococcus horse serum, but a reduction in one is also accompanied by a quantitatively identical reduction in the other, providing evidence for their actual identity. In purified antibody solutions somewhat more agglutinin than precipitin is found, possibly owing to alteration of a portion of the antibody in the process of purification.