Varicella presents little difficulty in diagnosis under ordinary circumstances. Our experience, however, has led us to believe that confusion of the disease with variola occurs often enough to warrant the presentation of certain data which we have derived from a statistical study of 775 cases of varicella admitted to the contagious diseases department of the Cincinnati General Hospital from 1913 to 1926. AGE A point not sufficiently appreciated, although occasionally mentioned in the literature, is the number of adults who contract the disease. Of the 775 cases of our series, 1.4 per cent occurred in patients under 6 months of age; 11.7 per cent in those from 6 months to 2 years; 36.4 per cent in those from 2 to 6 years; 24.2 per cent in those from 6 to 12 years; 6.8 per cent in those from 12 to 20 years, and 19.4 per cent in those above 20