RESORPTION OF CONCEPTUSES. 299 



by the menstrual history. That growth ceased long before the 

 occurrence of the abortion is implied also by the fact that Dr. 

 Falk stated that the patient had a slight uterine hemorrhage about 

 10 or 12 days before the abortion. It is interesting, and prob- 

 ably also significant that the date of this hemorrhage also coin- 

 cides with the time when the first lapsed period was due. This 

 is possible because this conceptus apparently had been dead 

 sufficiently long to fail to inhibit the return of menstrual bleeding. 

 Since the size of the chorionic vesicle suggests an age of 10 to 12 

 days, this assumption seems warranted, especially since it may 

 be assumed that development probably never proceeds undis- 

 turbed to the time of abortion, whenever the pregnancy is ter- 

 minated spontaneously or perhaps better, without the inter- 

 vention of external or of internal mechanical forces or factors 

 It may be largely because of this fact that conceptuses from 

 abortions resulting from intrauterine causes always are macerated. 



Careful examination of the serial sections generously made in 

 the Carnegie Laboratory of Embryology, fails to reveal any 

 remnant of the body of the embryo except perhaps a small nodule 

 shown above (2) in Fig. 8. Yet according to the menstrual age 

 the embryo should be 10-12 mm. long. The appearance of this 

 nodule suggests that it may be a remnant of the primitive streak 

 in spite of its deep location, although it may also be a rudiment 

 of the allantois. The yolk sac is large and invaginated and its 

 size out of all proportion to that of the embryonic Anlage. 

 Between the latter and the chorion there is a rather large mass 

 of cells containing a space which I take it, represents the am- 

 niotic cavity. An examination of this cavity and of the sur- 

 rounding cells suggests that it resulted from splitting as is the 

 case in bats and as is assumed for man. The cavity, to be sure, 

 may have resulted from dissolution of the cells in situ and if in 

 fact it represents the early amniotic cavity, then it is certain 

 that whatever its genesis, it was not formed in consequence of 

 folding. It would seem then that we have here a conceptus in 

 which the process of development of the embryo itself was in- 

 hibited very early and that the yolk sac and the chorion con- 

 tinued to grow for some time. 



Aside from showing a probable and hitherto unobserved stage 



