Paresis strikes most frequently during life's most productive years. It is seen approximately three times as frequently in males as females, and over twice as frequently in whites as in Negroes. The usual incubation period is 10 to 24 years after infection. The simple dementing type of psychosis is more frequent than all other types combined. In the absence of previous treatment the spinal fluid complement fixation reaction is always positive and the spinal fluid cell count is almost always elevated. The blood serologic test may, rarely, be negative.

During the past several years, the Venereal Disease Program, in cooperation with a number of well-known clinics and hospitals throughout the country, has conducted a study to determine the effectiveness of penicillin in the treatment of asymptomatic neurosyphilis. A preceding report1has shown that factors such as age, race, sex, previous treatment, and re-treatment status have little or no relationship to clinical prognosis in penicillin-treated asymptomatic central nervous system (CNS) syphilis. The present report deals with the pretreatment and post-treatment status of the patient group in terms of results of blood and spinal fluid examinations. This study consists of 765 patients with asymptomatic neurosyphilis, whose histories were selected from the records of eight cooperating clinics in accordance with the following criteria: (1) reactive spinal fluid, i.e., abnormalities in the spinal fluid test for syphilis, colloidal test, total protein, or cell count, or