The cutaneous lesions of lupus erythematosus are so deforming that they occupy the attention of both the physician and the patient to the exclusion of the manifestations of the disease on the mucous membranes. Furthermore, the lesions on the mucous membranes, although generally erosions, and therefore raw surfaces, do not usually give the same discomfort as do, for instance, herpes or mucous patches, and the patient rarely draws the physician's attention to them. They are important, however, as giving one an insight into the nature of the disease as being something more than a mere local cutaneous affection, and they are also important because it is occasionally necessary to differentiate them from other affections of the mucous membranes, especially those occasioned by syphilis. The following eleven cases show lupus erythematosus in seventeen locations on the mucous membranes: Case 1. —A woman, aged 38, consulted me, July 23, 1909, on account