LYSIS AND RESORPTION OF CONCEPTUSES. 275 



was donated to Stanford University by Dr. Eugene V. Falk, of Modesto, Cali- 

 fornia, had the villi rather sparsely and irregularly distributed, as shown in figure 

 7 (plate 1, Chap. IV). However, the entire specimen was so splendidly preserved 

 that investigators of unique opportunity and experience were uncertain as to its 

 normality. Even after careful inspection under low magnification, the writer, 

 too, felt uncertain, but on receipt of the specimen he informed Dr. Falk that it 

 probably was pathologic. This opinion was based almost wholly on the irregular 

 distribution of villi, their complete absence on part of the surface, the large size 

 of the yolk-sac, the unusual translucence of the entire specimen, and upon the 

 apparent absence of the embryonic disk. About one-third of the entire surface 

 of the chorionic vesicle was devoid of villi, and where they were present they seemed 

 to be in widely different stages of development. They differ markedly not only 

 in length and in diameter, but also in the complexity of their branching. Some 

 which were represented by fine threads were found to be represented by stroma 

 only, the epithelium having been stripped, probably during the removal of the 

 blood from which the specimen was freed before it was received at the laboratory. 

 Other villi are torn, those which are preserved are clubbed but slightly, and some 

 are so short that they look like little droplets on the surface of the chorionic mem- 

 brane. Those near the bare areas are almost transparent, but nearer the other 

 pole they become more opaque. The caliber varies from 0.16 to 1 mm. and the 

 greatest length is 2.25 mm. The chorionic vesicle measured 6 by 4 by 5 mm. 

 and the partially invaginated yolk-sac 2 by 2.6 by 1.8 mm. A smaller, less trans- 

 parent vesicle, which was thought to represent the amnion, was seen between the 

 yolk-sac and the chorionic membrane, but no embryonic disk could be recognized. 

 An examination of the microscopic sections of this vesicle showed that it was 

 macerated. The epithelium is missing in many places and the histologic details 

 are wanting. Hence this chorionic vesicle very evidently ceased to live some 

 time before it was aborted, and this conclusion is corroborated also by the clinical 

 history. The menstrual age of the specimen is 39 days, but the chorionic vesicle, 

 which was approximately spherical, measured only 6.5 mm. instead of 35 to 40 

 mm. as implied 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. It is interest- 

 ing, and probably 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 undisturbed to the time 

 of abortion whenever the pregnancy is terminated spontaneously, or perhaps 

 better, without the intervention of external or internal mechanical forces or fac- 

 tors. It may be largely because of this fact that conceptuses from abortions 

 resulting from intrauterine causes are always macerated. 



