In a previous communication1 I proposed a precipitation reaction for syphilis in which strongly reacting serums showed precipitation within several minutes and weak ones at the end of three hours' incubation in the water bath. In this article I shall record further observations regarding: (1) the preparation of antigen; (2) the dilution of antigen for the tests; (3) the preparation of serum for the tests; (4) the optimum quantities of serum and antigen to be used in the tests; (5) the temperature and time of incubation, and (6) the reading of results.
THE PREPARATION OF ANTIGEN
The antigen is prepared essentially as outlined in the previous paper. A weighed amount of finely ground and dried heart muscle2 is extracted with several liberal quantities of ether until the supernatant ether is free from coloring matter. The ether is filtered off after each extraction and discarded. The heart muscle is
R. L. KAHN. A SIMPLE QUANTITATIVE PRECIPITATION REACTION FOR SYPHILISSECOND COMMUNICATION. Arch Derm Syphilol. 1922;5(6):734–743. doi:10.1001/archderm.1922.02350310043004