ON THE FATE OF THE HUMAN EMBRYO IN TUBAL PREGNANCY. 23 



Between the villi were islands of necrotic trophoblast about 1 mm. in diameter and 

 of a yellowish color. This seems to be the normal process in the development of 

 the chorion, because as it advances there must be an extensive destruction of many 

 of the primary branches of the villi. The condition may be compared to that 

 observed in a dense forest of large trees, in which one can observe all stages of 

 destruction of the branches that can not get sunlight. First, the branches near the 

 main trunk of the tree die and then the larger branches succumb in case their tips 

 do not reach the sunlight. Between the villi in this specimen there were found 

 occasional hemorrhages and some amount of scattered blood. Whenever this 

 blood comes in contact with the trophoblast, it in turn becomes active, for it has 

 something to feed on, but in general the spaces between the villi are empty or partly 

 filled with its degenerating branches, so there seems to be here no question regarding 

 the absence of a normal intervillous circulation; without question, however, an 

 extensive hemorrhage is often present in very early stages and specimens inter- 

 mediate to those and the one just described are necessary in order to explain the 

 transition from such specimens to those of Bryce and Teacher, Peters and Herzog, 

 and No. 782, just described. 



This stage we have in No. 836. The specimen came to the laboratory imme- 

 diately after the operation, was carefully opened, and fixed alive in corrosive acetic. 

 The specimen came from a young woman who had been married for 4 years, this 

 being her first pregnancy. The uterus was removed for a myomatous condition. 

 There was no history indicating any other disease. It was sent to the laboratory 

 immediately and we succeeded in opening the uterus without injuring the implan- 

 tation of the mass. The ovum was covered with decidua reflexa, below which 

 tortuous vessels were apparent. On one side the sac (the implanted chorion) was 

 adherent to the uterine mucosa (decidua vera). With a sharp scalpel the entire 

 mass was dissected away from the uterus and brought under a binocular microscope 

 in warm salt solution. The middle portion of the free surface was opened carefully, 

 beautiful young villi being found, and the delicate wall of the chorion was next 

 opened. Within were seen a transparent young embryo, 4 mm. long, and its 

 umbilical vesicle. Through this opening in the chorion warm 40 per cent saturated 

 aqueous solution of HgCl 2 containing 5 per cent glacial acetic acid was gently intro- 

 duced and the entire mass placed in 500 c. c. of this fixation fluid. The main body 

 of the uterus was dissected free from the myomatous nodule and fixed in 10 per cent 

 formalin, the site of the implanted ovum being marked with a short wooden rod. 



Later on the implanted chorion was cut into slabs and numerous photographs 

 and drawings were made. This gave an opportunity to study carefully the villi 

 and the spaces between them. The block which formed the middle zone of the 

 ovum was about 4 mm. thick. The chorion was composed mostly of sharp white 

 villi, with a small amount of blood at one point near the chorionic membrane; other- 

 wise the intervillous spaces were filled with necrotic tips of villi or with a clear fluid. 

 At the bases of the villi that is, on the uterine side the chorion was partly encir- 

 cled with a hemorrhage which apparently involved the tips of the villi for about 

 one-half of the base. Otherwise the tips had come into contact with the uterus 



