THE Wassermann test for syphilis was discovered by the logical pursuit of a coherent series of observations. From the first it has proved of the highest value for the diagnosis of an infection which is “often obscure. But it soon turned out that it was simply an empirical trick and not an application of the general principle which it was originally supposed to illustrate. If the typhoid bacillus, typhoid antibody, and fresh blood serum are mixed together, the three will combine in such a way that the substance in (or property of) fresh serum known as “complement “will disappear. If typhoid antibody is not present, the complement remains and its presence or absence can be determined by a test mixture of red blood corpuscles and red blood corpuscle antibody, in which the red cells will be dissolved if complement is also present. Supposedly the same would apply to a mixture of the spirocheete of syphilis, syphilitic antibody, and complement; and just as typhoid antibody, and therefore typhoid infection, can be detected by this Bordet-Gengou reaction, so was it thought that syphilitic antibody could be found in a patient's serum and syphilitic infection thereby inferred. In practice the idea seemed to work excellently, until it was found that an alcoholic extract of, e.g., normal heart muscle would do as well as spiro-chaetes. The reaction is therefore not specific, and as a matter of fact it is given by the blood in a proportion of cases of many protozoal infections. But it is specially constant in syphilis, and, as other protozoal infections are rare in Great Britain, it comes to be a splendid empirical method of diagnosing that disease.
Journ. Path. Bact. vol. xxv. pp. 291, 522; Proc. Roy. Soc., A, vol. cii. p. 710.
The Serum Diagnosis of Syphilis: the Wassermann and Sigma Reactions Compared. Medical Research Council: Special Report Series, No. 78. (London: H.M. Stationery Office, 1923.) 5s. 6d.