CHAPTER XIII. 

 POST-MORTEM INTRAUTERINE CHANGES. 



In discussing post-mortem changes, it is necessary to distinguish between the 

 death of and changes in the cyema and the vesicles, that is, between inti acyemic 

 and extracyemic changes. Such a distinction would be unnecessary if the death 

 of the one were impossible without that of the other. It has been assumed in the 

 past not only that the latter is not the case, but that the fetal vesicles may sur- 

 vive the cyema for some time. Under such circumstances, then, considerable 

 post-mortem changes might take place within the cyema and perhaps within the 

 amnion also, while the chorion might remain largely, even if not wholly, unaffected. 

 Since such an assumption involves the implication that the fetal circulation is 

 not indispensable for the life of the chorionic vesicle even after the usual time of 

 the advent of the former, an assumption of independent survival of the entire 

 vesicle would seem somewhat venturesome, although it is highly probable that 

 certain constituents of the chorion nevertheless might survive death of the cyema. 



That the amnion, which usually is non-vascular, and which fuses with the 

 chorion quite early in development, may survive death of the embryo is entirely 

 possible, not only because it is nutritionally more independent, especially in its 

 early stages, but also because survival of the chorion would condition survival of 

 the amnion after the latter fuses with the former. The belief, not only in the 

 survival, but also in the growth of the fetal vesicles after death of the cyema, is 

 relatively old and rests largely upon the disproportion in size between the embryo 

 and the chorionic vesicles so frequently seen, and upon the existence of a similar 

 disproportion between the placenta and the fetus in cases of retained abortions. 

 According to Panum, von Baer, describing a rather firm, brownish-red, bean- 

 shaped lump, unlike an embryo of either bird or mammal, which was surrounded 

 by an envelope and in relation to a vascular area, was said to have regarded it as 

 a liver which had continued to grow after the death of the embryo. It seems that 

 von Baer came to this conclusion, largely because of the color of the gross specimen 

 and because he thought it possible that in poorly regulated incubators the "vege- 

 tative" portions of the body of the embryo very often continue to live, although 

 the "animal" parts die. It must be added, however, that Panum (1860), from 

 whose monograph this statement is taken, added that he thought von Baer only 

 regarded these questions as propositions for investigation and proof, and not as 

 established facts. However, Giacomini (1893) adduced experimental evidence in 

 favor of such a belief, for he stated that the membranes also continued to grow in 

 rabbits in which the cyema had been killed experimentally. He further stated 

 that, although the embryo may be inhibited in growth or even be destroyed com- 

 pletely, the chorion and amnion not only may show no degenerative change, 

 but actually may continue to grow. His (1891) spoke of evidence of an interrupted 

 growth, and Giacomini (1894) also believed in the occurrence of an inhibition of 

 growth before the death of the embryo occurred. According to Waldstein (1913), 



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