“…Meyer (1919) has made a truly monumental contribution to the literature of 48 cases of hydatidiform degeneration in tubal pregnancies, but Novak (1947) discussing this, suggests that the diagnosis in most cases was based on uncertain stromal and vascular changes which have not obtained general acceptance, and Pettit (1941) also appears to have ignored Meyer's claims in her study of the cases previously reported. There is considerable disagreement also as to the frequency of hydatidiform mole in ectopic pregnancy, and although Phaneuf (1937) states that hydatidiform degeneration occurs in 3 per cent of all cases of ectopic pregnancy he does not quote a single case, and in a series of g cases of hydatidiform mole which he describes all werc uterine in situation. Sherman's (1935) agrees with Schumann that in theory the condition should occur fairly frequently, and indeed the tendency to hydatidiform change, particularly in an early transitional form, which has been noted in many abortions as well as in tubal pregnancy, as for example by Hertig and Edmonds (rg40), suggests that the condition should be fairly common, but the fact remains that very few unexceptionable cases have been reported.…”