64 ABNORMALITIES OF MAMMALIAN EMBRYO BEFORE IMPLANTATION. 



ectoblast. It is also shown in section in figure 2, plate 1. The other vesicle (B) is 

 collapsed and wrinkled, its texture granular and almost opaque (the opacity is 

 slightly exaggerated in fig. 7v), the nuclei hardly visible. Microscopic section 

 confirms the external appearance of degeneration, showing the cells to be granular 

 and their relations distorted (fig. 3). It is interesting to note that the preservation 

 of the cells is better at one pole of the vesicle than at the other. In the ovaries of this 

 sow there were 7 corpora lutea; in the uterus 6 vesicles, of which 2 were entirely 

 normal, 2 normal in texture but collapsed and cup-shaped, and 2 abnormal, as 

 illustrated. In addition there was 1 unsegmented ovum, thus accounting for all the 

 ruptured follicles. 



Figure 4 shows another case of the same sort with cupping of the vesicle and a 

 partial break-down of the cells. This was obtained from another healthy uterus 

 containing 1 normal vesicle and 4 of the collapsed type. 



Inner cell mass. 



Fio. 1. A normal (A) and a path- 

 ological (B) ovum obtained from 

 the same uterus. The more de- 

 tailed structure of these speci- 

 mens is shown in figure 7, plate 

 2. The pathological ovum is 

 wrinkled and compressed. Here 

 it is shown from a side view; in 

 figure 7 its broader surface is 



Nuclei. Bhown ' 



A B 



A third sow contained a still more interesting series of 4 vesicles. These were 

 5 mm. in diameter, a size attained by normal pig embryos at about the twelfth day, 

 according to the studies of Assheton. In 3 the abnormality consisted of total 

 absence of an embryonic area; in order to make sure of this point the vesicles were 

 fixed in the fully dilated condition by injection of Bouin's fluid. I am indebted to 

 my colleague, Dr. C. H. Heuser, for friendly aid in the preparation of these speci- 

 mens. When dilated the 3 vesicles were of even thickness at all points of their 

 walls. Microscopic section of one of them showed it to be composed of the usual 

 two layers of cells. 



The fourth specimen from this uterus showed, on the contrary, a distinct mass, 

 slightly larger than the embryonic area found in a normal vesicle of the same 

 dimensions, but opaque, white, and projecting from the surface of the vesicle by a 

 pedicle, so that altogether it was not unlike a little mushroom in appearance. 

 Figure 6 shows a section of this curious specimen, in comparison with a normal 

 embryo from a vesicle of the same size (fig. 5). The little tumor is composed of 

 cells of diverse staining reaction, disposed in an irregular way, but including three 

 or four minute vesicular cavities, one of which appears in the section. The whole 

 arrangement rather suggests a malignant papilloma; whether the tumor is at the 

 site of the embryonic area itself or at some other part of the vesicle (the embryonic 

 area being absent, as in the other blastodermic vesicles in the same uterus) can not 



