The practice of making routine serological tests for syphilis on all admissions is carried on in many mental hospitals, but no assessment of the advantage of this procedure at the present time seems to have been reported. Rosahn (1958), viewing the matter from the laboratories of a general hospital, concluded that syphilis was still a sufficiently important disease to justify routine screening tests. Bell (1959) studied the admissions in a 12-month period to a large Canadian general hospital He pointed out that some previous figures (Editorial, J. Amer. med. Ass., 1957), based on total numbers of positive reactors, did not give a realistic measure of the value of the testing procedure, and he attempted to determine the proportion of admission screening tests which were of practical significance, in that the clinicians concerned were led to initiate treatment as a result of them. He found a “useful discovery rate” (discounting two patients who he thought might well have had elective serology performed in any case) of 0·03 per cent.