From the foregoing study there are indications:
1. Of toxicity in all fresh human serum for the guinea pig; this toxicity tends to disappear after 48 hours after bleeding, and its manifestations are strikingly similar to those of the heterophilic antibody in immune rabbit serum.
2. Of an increased toxicity in the serum of antisera-treated human cases; this is usually coexistant with the production of other antibodies; it tends likewise to disappear in time after treatment; differential absorption experiments indicate that its character is heterophilic, and its manifestations differ from those of anaphylaxis in that certain circulatory effects—hemorrhage and increased edema in the lungs and distension of the right heart—are added to the usual findings in true anaphylactic deaths.