The effects of syphilis are as complex and difficult to ascertain as the effects of gonorrhea are definite and directly attributable to this disease alone. For example, gonorrhea causes rheumatism by specific inflammation of the joint, while syphilis causes paresis by some vague means of which we are none too sure, and with the aid of certain other factors which we can not definitely ascertain, but which make one race far more vulnerable than another.
In the matter of heredity, gonorrhea destroys the race either by sterilizing a potential parent or by blinding a new-born infant; while syphilis leaves the parent neither sterile nor impotent; the child it may kill or brand with indelible disfigurement, or it may simply leave him liable to destruction by other agencies, notably by tuberculosis. Finally, the problem of race deterioration by syphilis is still further complicated by the alcoholism, the debauchery, and the moral
KEYES EL. SYPHILIS AS A CAUSE OF DEPOPULATION AND RACE DETERIORATION.. JAMA. 1907;XLIX(6):453–457. doi:10.1001/jama.1907.25320060003001a