The therapeutic value of uterotubal insufflation has been accepted by many writers because pregnancy has many times followed soon after the procedure. Admittedly, the possibility of a psychological influence cannot be dismissed, and true assessment of the method is difficult. Other procedures involving instrumentation of the cervical canal, such as dilatation of the cervix and hysterosalpingography, have been known for many years to be frequently followed by pregnancy. The modus operandi of "cure" by insufflation has been discussed at length by Rubin,1who considers it to be due to one or more of the following effects: establishing patency of the genital tract, removal of the cervical mucous plug, dilatation of the tubes, and possible psychic effect. Until five years ago, I performed tubal insufflation routinely, both as a diagnostic and as a therapeutic procedure in all cases of primary sterility at the sterility clinic and in the wards of