Noguchi has presented in this text complete directions for making the important laboratory tests concerned with the diagnosis of syphilis. The first chapters contain detailed discussion of serum hemolysis, and the quantitative relations to be observed with such hemolysis. These facts are presented for the purpose of showing the importance of quantitative procedures in making serum diagnosis of syphilis. Instructions are given for preparing amboceptor and antigens, and for obtaining complement. Noguchi's system of serum diagnosis is described in detail, also Wassermann's technic. A discussion of the value of the serum diagnosis of syphilis is contained in one chapter. Another is concerned with the effect of treatment on this test. Mention is made of the luetin reaction, and its significance in tertiary, and congenital syphilis. A chapter considers examinations of the spinal fluid. In this are mentioned globulin tests and the procedure and significance of the Lange colloidal gold reaction.