338 HYDATIFORM DEGENERATION IN TUBAL AND UTERINE PREGNANCY. 



of this period may very incorrectly express that at any other time. This could fail 

 to be true only if the incidence of death of the conceptuses and their susceptibility 

 to hydatiform degeneration were exactly uniform throughout every period of 

 intrauterine life. But we know that neither is true, for it is common knowledge that 

 by far the great majority of the cases of uterine hydatiform degeneration, recorded 

 in the literature, are mature specimens of total or partial degeneration obtained 

 in the later months of pregnancy. Although such specimens may contain villi in 

 various stages of degeneration, they nevertheless represent end or near-end results. 

 Like the fetuses which rarely accompany them, they are full-term or near-term 

 products when regarded as hydatiform degenerations, and unless we are to assume 

 that conceptuses once affected by hydatiform degeneration always survive up to 

 this period, statistical deductions based upon the cases that do survive can give us 

 little idea of the actual frequency of the condition throughout the entire period 

 of antenatal life. 



That the specimens upon which past and also present opinion is based usually 

 were large, is confirmed by the belief in the prevailing clinical criterion of the 

 existence of a disproportionately large uterus in cases of hydatiform mole. The 

 emphasis laid on this by clinicians is well illustrated by Seitz, who says that cases 

 in which the uterus is too small are the exception. Indeed, it seems that the validity 

 of this clinical dictum has been questioned only very recently by Briggs (1912). 

 Since most early conceptuses showing hydatiform degeneration have been inhibited 

 in growth before being aborted, it probably is only the specimens which persist 

 that produce a uterine enlargement greater than could normally be expected. 

 However, since as emphasized by Gierse (1847), Storch, Hiess, and others most 

 hydatiform moles are expelled early and spontaneously, it is evident that these can 

 not have been adherent that is, have penetrated very deeply or they would 

 not have been expelled early and spontaneously. Furthermore, maceration changes 

 so commonly present in aborted hydatiform moles indicate very clearly that a large 

 percentage of them, together with the decidua, had been more or less completely 

 detached from the uterine wall some time before abortion occurred. 



As far as one can gather from the literature, uic present opinion regarding the 

 incidence of hydatiform degeneration would be parallelled quite correctly if, in the 

 case of measles, we assumed that it was as common in octogenarians as in children. 

 Measles, indeed, is an extremely rare disease in advanced age, but it nevertheless 

 is very common in infancy. This is exactly the mistake we have made regarding 

 hydatiform degeneration. It may be and undoubtedly is a rare disease at or near 

 term, as Gierse also stated, but it probably is the commonest of all diseases during 

 the earliest months of gestation. The typical large hydatiform mole is an end 

 result which it has taken long months to develop. No one seems to have followed 

 its evolution, although hydatiform degeneration, whether total or partial, is, of 

 course, gradual in its advent. 



The records of the Mall Collection contained 8 cases of hydatiform mole in 

 the first 2,400 accessions, showing a frequency 8 times as great as that given by 

 Williamson, or an excess of 700 per cent. Since the first 2,400 accessions contain 



