THE OCCURRENCE OF SUPERFETATION

Abstract

From time to time reports of alleged instances of human superfetation appear in current medical literature. Reports of similar instances in other mammals occur also, although more rarely, in the nonmedical literature. As recent instances of the former may be cited the cases reported by Logan¹and Gustetter.²Of instances of the latter may be mentioned the cases of King,³Summer⁴and Harman.⁵The latter group of cases were found in the rat, the mouse, the cat and the cow, respectively. Without accepting the alleged cases in mammals with bicornate uteri as unequivocal, it is easy to see that aside from ectopic implantations, the conditions under which superfetation necessarily would have to occur in the human uterus may be totally different from those that may obtain in bicornate uteri. Since the usual intermenstrual period in women is twenty-eight days, it would also seem, as often