Interstitial keratitis remains one of the most frequently encountered complications of late congenital syphilis. From one third to one half of patients with congenital syphilis have this disorder at some period of their lives.1 The fact that it is most resistant to antisyphilitic therapy as compared with other lesions2 has brought forth the suggestion that other factors besides spirochetal invasion of the cornea are responsible. Trauma,3 allergic states4 and endocrine disturbances,5 the last in view of the frequent onset of symptoms at puberty, have all been suggested as contributory causes. Sandler's6 and Arena's7 reports on rapid clearing of symptoms in cases of recent interstitial keratitis in from four days to three weeks after administration of sulfonamide compounds suggests that in some cases the probable cause of the acute flare-up is an organism or virus responsive to such therapy. No reports are as yet