POST-MORTEM INTRAUTERINE CHANGES. 287 



illustrates proliferative obliteration of the vascular lumen which undoubtedly was 

 ante-mortem. However, it must be recalled that not all of a chorionic vesicle 

 necessarily dies at the same time, and that implanted villi, or those in very young 

 conceptuses which are not yet dependent upon the fetal circulation, may well con- 

 tinue to live and perhaps even continue to grow for some time. But such villi 

 hardly can justly be designated as dead, and since death of the cyema does not 

 necessarily result in simultaneous death of the entire conceptus, this distinction 

 is not an unimportant one. 



There seems to be no agreement among writers, however, as to which of the 

 tissues of the cyema are most resistant to post-mortem changes. Litthauer (1887) 

 found the muscles of certain fetuses well preserved, although the cartilages had 

 lost all their normal structure. Virchow, Wyder, and Baumgarten, according to 

 Litthauer, also found that the muscles are among the most resistant of structures. 

 Giacomini (1888) thought the central nervous system very resistant, but Engel 

 came to a contrary conclusion. Phisalix (1890) thought the epithelium the most 

 easily affected by pathological processes, and while there is great difference of 

 opinion, all investigators seem to be agreed that the cyema is affected before the 

 vesicles. 



Von Winckel (1904) spoke of three grades of maceration in the cyema, the 

 first being that of bleb formation, the second that in which the epidermis is broken 

 and shed in fragments, thus exposing the chorion, and the third stage that in which 

 the joint capsules and ligaments are loosened, the joints consequently relaxed, 

 and the extremities contorted. Von Winckel also set an approximate time-limit 

 for the occurrence of these stages, the last stage being reached in three weeks. 

 Nevertheless, von Winckel concluded that the degree of maceration could not be 

 used as a criterion for the determination of the duration of intrauterine retention. 

 Muller also was impressed by the post-mortem changes, and rightly stated that 

 many embryos are deformed beyond recognition by maceration, bleb formation, 

 and mummification. 



Although it is incorrect to regard the changes which many conceptuses undergo 

 after death and before abortion as maceration in the customary sense, no other 

 word seems to be available. These changes undoubtedly are accompanied by 

 softening, collapse, deformation, and no doubt also by autolysis. Whether im- 

 bibition and swelling are invariably present I do not know, but if they occur they 

 usually are slight and their effects minor in character. Most of the changes 

 enumerated here may occur under sterile conditions, and since maceration, even in 

 this restricted sense, must effect changes, not only in the chemical composition, but 

 also in the microscopic structure of cells, long before changes in external form of 

 embryo or chorionic vesicle become apparent, a discussion of maceration changes 

 really should begin with these. But the earliest modifications in microscopic 

 structure remain very largely, and those in chemical composition almost wholly, 

 unknown to us at present. 



Although it undoubtedly is true, as stated by Miiller (1847), that very young 

 embryos may retain their form surprisingly long after death if retained in sterile 



