. Carnegie Institution of Washington publication. 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
. Carnegie Institution of Washington publication. 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. Mi
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