1. Sera from which the protective lipoids (unsaturated fatty acids) have been removed are toxic for the homologous animal.
2. The toxicity is due to three factors: (a) an alteration in the mechanism of coagulation, with resulting intravascular coagulation; (b) the exposure of the native serum proteins; (c) the formation of toxic split products (primary proteoses) by autolysis.
3. A definite maximum of toxicity can be determined, with a final stage of atoxicity due to continued autolysis.
4. Hirudin and sodium citrate do not protect animals.
5. Heating to 70° C. destroys, or greatly lessens, the toxicity of the serotoxin, although the isolated proteoses are toxic after boiling.
6. The return of the extracted lipoids (saponified) neutralizes the toxicity.
7. Unsaturated soaps also neutralize the toxicity.
8. Sublethal doses produce extreme prostration, marked fall in body temperature, no eosinophilia, and an increase of antitrypsin.
9. Sublethal doses of rapidly prepared chloroform sera cause a decrease in coagulation time; sublethal doses of autolyzed sera cause an increase in coagulation time.
10. Previously injected animals are more resistant (increased antiferments).
11. Iodized animals are less resistant (decreased antiferments).