Published online by Cambridge University Press: 15 May 2009
Examination of the records of a large number of quantitative Wassermann tests has suggested a new and simple criterion of a positive reaction. This is based upon a comparison of the amounts of complement giving complete lysis with any given serum, and with the negative control, respectively. Reasons are given for regarding this criterion as more satisfactory than that in common use. Details are given of the methods employed for the selection of a negative control serum, the estimation of degrees of lysis, and the provision of a suitable range of amounts of complement.