1. Tested quantitatively, antibody recovered by dissociation of specific precipitates from antipneumococcus sera reacts with homologous polysaccharide almost as does the antibody in the original sera.
2. The dissociation methods employed appear to yield a portion of all of the anticarbohydrates of differing reactivities in the sera, rather than a fraction of low or high reactivity.
3. The reversible inactivation of purified pneumococcus anticarbohydrate by formaldehyde is confirmed, and the failure of data on the formaldehyde-antibody reaction to permit a choice between alternative theories of specific precipitation is shown.