290 STUDIES ON PATHOLOGIC OVA. 



that the incipient structural changes are microscopic and can be detected long 

 before changes in external form and color occur. 



Since the chorionic vesicle almost invariably is surrounded by more or less 

 blood and decidua in cases of abortion, it is naturally difficult to detect early gross 

 post-mortem changes in it by inspection alone. However, the earliest noticeable 

 external change in the villi is a decrease in translucency and a dulling of their 

 surface. The villi of very young specimens also seem to become somewhat larger 

 in caliber and look stiffer and slightly bulbous in places. They also frequently 

 are somewhat matted, as was the case in No. 1878, a very young specimen, a 

 portion of which is shown in figure 188, the chorionic vesicle of which measured 

 but 10 by 12 mm. However, in No. 1843, which is a still younger specimen, 

 measuring 5 by 6.5 mm. (figure 7, plate 1, Chap. IV) and shows more marked 

 maceration changes upon microscopic examination, these changes, nevertheless, 

 were not evident to the unaided eye, for the vesicle was unusually translucent. 

 The chorionic and villous epithelium has sloughed over most of this vesicle and 

 the remaining tissues stain but weakly. The cell-boundaries also are rather in- 

 distinct and the yolk-sac shows marked changes. 



The first noticeable change in histologic structure seen in routine prepara- 

 tions seems to be a blurring of the structural detail in the tissues and a haziness in 

 appearance of the cytoplasm. This early state is followed, if not preceded, by auto- 

 lytic changes. As has so frequently been emphasized, evidences of disintegration, 

 noticeable particularly in the central nervous system, supervene very early and 

 the brain and cord become swollen and the folds become effaced, as shown in 

 figure 185. These changes are accompanied and may be followed by complete 

 dissociation of the constituent elements, with some shifting if not migration of 

 cells. All the constitutent cells become rounded, the cytoplasm may disappear 

 entirely, and the nuclei become more pycnotic. When this stage is reached the 

 structure of the brain and cord is quite uniform and cells of various origins may 

 all be quite properly designated as round cells, for all look alike, the changed 

 nuclei only remaining. The entire central nervous system, for example, may be 

 composed of these densely packed round cells and be characterized quite properly 

 upon superficial appearances alone as lymphoid, as suggested by Giacomini. 

 Finally, however, the nuclei also disintegrate and form a fine, granular material, 

 spoken of by Mall as nuclear dust. Morever, not only the nervous system, but all 

 the organs of small fetuses, may be so transformed, as illustrated in figure 186. 



These things, however, do not necessarily or materially change the form of the 

 cyema, and the effects produced by retention in utero after death will depend not 

 so much upon the exact duration of the retention as upon the age of the cyema. 

 A few weeks may suffice not only to change greatly the external form or the inter- 

 nal structure of young cyemata, but to effect complete absorption. In case of an 

 approximately mature fetus, on the other hand, such a short period of retention 

 after death might modify the form inappreciably and result merely in maceration 

 of the epidermis. 



