272 STUDIES ON PATHOLOGIC OVA. 



progressed uninterruptedly until birth. The histologic picture alone is conclusive 

 proof to the contrary. In the absence of any larger portion of the conceptus it is 

 impossible to say about how far development had proceeded, but it is unlikely 

 that it proceeded much beyond the first month. In any case, disintegration, 

 solution, and resorption of almost the entire conceptus surely must have consumed 

 several weeks at least. Indeed, it is possible that the ovum never became firmly 

 attached, though embedded in the decidua. 



In other cases it also seems likely that the fertilized ovum became embedded 

 quite normally, but that it was strangulated by severe hemorrhage which loosened 

 the attaching villi, thus interrupting the intervillous circulation. Since the 

 resulting stagnation of the blood must make impossible the indispensable chemical 

 interchanges upon which the life of the embryo depends, the latter probably dies 

 first. It is decidedly interesting that considerable hemorrhage, sufficient, in fact, 

 to result in the death of both the embryo and the chorionic vesicle, can. occur 

 while the whole conceptus still is surrounded by the decidua capsularis, without 

 rupture of the latter. The failure of absolute or complete absorption of the last 

 few small remnants of this conceptus probably may be attributed to the fact that 

 the small remnants of degenerate trophoblast and syncytium which remain, or the 

 influence of the corpus luteum, no longer were able to inhibit menstruation. Hence 

 the decidua, together with these few small remnants of the conceptus, were expelled 

 in toto, and it may be extremely significant that this occurred exactly two menstrual 

 months after the beginning of the last period. Since 3 other specimens of a series 

 of 17 composed of villi only were aborted at the time of recurrence of the regular 

 period, the idea that abortion occurs oftener at this than at any other time would 

 seem to receive some confirmation. Moreover, it would seem quite natural that a 

 detached decidua which has subserved its functions would be more likely to be 

 shed at this time and that an unabsorbed conceptus, which had been converted 

 essentially into a foreign body, should then also be expelled. Since detachment 

 of the decidua also permits regeneration of the mucosa and isolates the conceptus, 

 it removes the inhibitory effects of the conceptus upon the maternal organism and 

 clears the way for a return to the normal non-pregnant status. 



It is impossible to decide how far the development of this conceptus had pro- 

 gressed before its death, but the marked extent of the absorption shows beyond 

 doubt that the latter would have been completed long before the advent of the 

 next or third menstrual period had the second period also been inhibited. Under 

 these circumstances the empty decidual cast would then have been expelled alone 

 and might well have directed attention to the possibility of the existence of a tubal 

 rather than a uterine pregnancy. 



A second case is No. 970, donated by Dr. R. W. Hammack, of Manila. This 

 specimen is interesting not only because it is a case of marked intrauterine absorp- 

 tion, but also because it was obtained with the entire uterus at necropsy. The 

 chorionic vesicle, which measured only 3 by 5 mm., together with the entire thick- 

 ness of the decidua and the musculature, is shown in section in figure 170 (plate 

 16, Chap. XI). The uterine cavity contains some blood and the entire decidua 



