UYDATIFORM DEGENERATION IN TUBAL AND UTERINE PREGNANCY. 343 



ments of the central nervous system, of the heart, liver, and cartilages. The entire body is 

 chaotic in its structure, and small fragments of the nervous system are scattered throughout 

 its entire extent. This would seem to indicate that the disruption of the tissues was 

 mechanical. The material in which these remnants are contained is composed of coagulum, 

 some mesenchyme, cellular detritus, blood and polymorphonuclear leucocytes, degenerated 

 cells, which appear to have been phagocytic, but which are more likely fusion products or 

 "symplasma" (as Bonnet called them). A few remnants of vessels are found only in the 

 fragments of cartilage. 



This short review of the gross appearance of the cases of hydatiform degenera- 

 tion recognized by the unaided eye with the customary criteria, originally classed 

 as such in the Mall Collection, shows that they vary decidedly in their gross, naked- 

 eye characteristics, both as to size and appearance. No. 1640 scarcely is distin- 

 guishable as a case of hydatiform degeneration from gross appearances alone, 

 unless one's attention is directed especially to the matter, but all the rest of the 

 specimens, both small and large, not only are easily recognizable, but are so char- 

 acteristic that they could not possibly be overlooked. As was indicated above, the 

 incidence of these specimens of hydatiform degeneration among the first 2,400 

 accessions in the Mall Collection was 1 in every 261 abortuses, or more than 8 

 times the incidence given by Williamson, and 1.3 times that given by Essen-Moller. 

 Although this incidence is so much higher, it does not necessarily contradict the 

 statements of Williamson, for it represents the incidence of hydatiform degenera- 

 tion in abortuses belonging very largely below 7 months. Nor does it tell the whole 

 story for these months, for since the incidence of hydatiform degeneration given 

 in the records of the Mall Collection is based upon determinations made essentially 

 in the usual way that is, by unaided inspection of the gross specimen alone we 

 must regard it also merely as an apparent, not as the actual incidence. For, as will 

 appear later, the actual incidence can be revealed only by a careful gross and 

 microscopic study of all specimens, both normal and pathologic. Such a study has 

 not as yet been completed, but 348 uterine specimens classed as pathologic, and 

 105 pathologic tubal specimens, contained in the first 1,187 accessions, were care- 

 fully examined. 



The actual number of cases of hydatiform degeneration found among the 348 

 uterine abortuses classed as pathologic was 112, or 32.4 per cent of the whole. The 

 incidence of hydatiform degeneration in the pathologic tubal pregnancies was 

 somewhat higher even 44 specimens of undoubted hydatiform degeneration in 

 105, or 41.9 per cent. Since nearly all the tubal specimens are young, while the 

 uterine series contains many more relatively older ones, the effect of this fact upon 

 the determined relative incidence of hydatiform degeneration among the patho- 

 logic tubal and uterine specimens must be borne in mind. For a reliable conclusion 

 regarding the relative incidence in the uterine and tubal pregnancies it would be 

 necessary to select a series from each, composed of specimens of approximately 

 corresponding ages. What the incidence of hydatiform degeneration is among the 

 uterine and tubal specimens classed as normal I do not know, but it undoubtedly 

 is far below that in those classed as pathologic. It is well to remember, however, 



