ON THE NATURE OF THE CHILL-PRODUCING PRINCIPLE IN ANTIPNEUMOCOCCUS SERUM.

1. By means of a test method, which is described, the presence or absence of the chill-producing principle in antipneumococcus serum may be determined. 2. This principle may be present in normal blood or serum, homologous as well as heterologous, and the measures employed to obtain an antibody solution are not essential factors in its formation. 3. The chill reaction may be mitigated by the administration of nitrites and by opium and antipyretics. It is doubtful whether this fact offers any practical therapeutic application. 4. The reaction has no relationship to anaphylaxis or to certain toxic effects of drawn blood which have been studied by Freund, Starling and others. 5. The chill-principle appears to be formed only in blood which has been allowed to stand. Our experiments do not show that the reaction is dependent on formed elements, fibrinogen, or lipoids. 6. Anticoagulants, filtration, dialysis and moderate heating are without effect in removing the principle from the solution containing it. 7. By changes in the sodium chloride and hydrogen ion concentration in antibody solutions an acid globulin and an alkaline globulin fraction may be obtained. The acid globulin fraction, whether or not phospholipin is present, contains the greater part of the chill-principle and a small part of the antibody substance; the alkaline globulin fraction contains the greater part of the antibody substance and a smaller part of the chill-principle. The acid globulin fraction is not itself the chill-principle but serves as a carrier of this, probably through an adsorptive process.