A plan, now under way, to evaluate independently in the United States serologic procedures for the diagnosis of syphilis has much to commend it. Briefly, it is proposed to collect and transport comparable specimens of blood from approximately 1,000 donors to all serologists of this country who have described an original modification of a complement fixation or a flocculation test. Specimens sent to serologists most distant from the point of collection will be forwarded by air mail, and delivery to nearby serologists will be purposely delayed so that the delivery time to all participants will coincide. Great care will also be exercised in the selection of the donors. The first group will consist of syphilitic patients who have received varying amounts of anti-syphilitic treatment, and the third, or control group, of individuals who, on the basis of previous serologic and clinical examinations, are believed to be almost certainly not syphilitic.