Examination of radiographs from thirty‐six women after extra‐amniotic injection of 20% NaCl containing contrast medium revealed as follows: (a) In most cases, the solution spread around the entire amniotic sac. (b) In no case was filling of the fallopian tubes observed. (c) In most cases, the solution disappeared from the uterus within four hours. (d) In some cases, the solution disappeared immediately from the uterus and appeared in the uterine veins and urinary bladder, indicating intravascular injection. Effective myometrial contractions was obtained when the solution was retained in the uterus for one to two hours. Further retention did not shorten the interval between injection and delivery.