An attempt has been made to include in this review the more important additions to the knowledge of syphilis, particularly hereditary syphilis, since the last comprehensive review of the subject in this journal.1 Publications dealing with certain phases, such as the technic of the Wassermann reaction, have been purposely omitted. The bibliography of those phases which are discussed is by no means complete, only representative publications having been selected.
INCIDENCE OF SYPHILIS
A definite determination of the incidence of hereditary syphilis is impossible from any data now available. Most of the studies concerning its incidence are open to the criticism of having dealt with selected groups. As have others before them, Belding and Hunter2 have observed the incidence of syphilis to increase as the social and economic scale is descended. Nearly 14 per cent of adult patients cared for in the hospital free of charge were syphilitic, while