INCREASED RESISTANCE TO SYPHILIS IN THE RABBIT FOLLOWING PROLONGED ADMINISTRATION OF URINARY ESTROGENS I. FEMINIZING EFFECTS OF ESTROGENS ON ADULT MALE RABBITS

THIS PAPER is concerned with a study bearing on the relationship between sex and immunity to syphilis. The origin of the problem lies primarily in a body of clinical observations which show that syphilis in many respects is a much milder disease in women than in men, and that pregnancy apparently plays an important role in activating, or in enhancing, the defensive reaction against this disease. Our immediate interest in the problem arose through contact with a case of severe secondary syphilis in a multiparous Chinese woman who had passed through the menopause before contracting the disease. The failure of sex and of many pregnancies to afford protection against an infection incurred at this late period of life attracted our attention. There was to be considered the probable importance of the waning sexual functions as a factor influencing the state of susceptibility.