Abstract
A study of the nature of the beta naphtol reaction of plasma, the “fibrinogen B-test, has been undertaken, giving the following results: 1) The formation of a gel, by addition of beta naphtol to some pathological plasmas, is due to precipitation of fibrinogen and not to formation of fibrin. 2) The beta naphtol reaction of plasma depends upon the fibrinogen concentration as well as upon other plasma components. 3) The existence of a special fibrinogen variety, of importance for the beta naphtol reaction, cannot be stated at present.