In 1913, with the installation of the syphilis clinic at the University of Michigan, a study of the spinal fluid in all cases of syphilis was begun. Previous to this time important contributions suggesting the frequency of involvement of the nervous system in early syphilis had already appeared in the literature in France by Ravaut,1 in Germany by Altman and Dreyfus,2 and in this country by Engman3 and his co-workers. In 1914 and 1915 studies from this clinic appeared on the involvement of the nervous system, particularly in reference to the secondary period of the disease, by Wile and Stokes.4 The results of these studies showed that the invasion of the nervous system occurred extremely early, that it was frequently seriously involved without symptoms, and that serious involvement might escape detection unless the routine lumbar puncture was practiced on all cases. The high percentage of involvement