284 STUDIES ON PATHOLOGIC OVA. 



Besides, upon a priori grounds alone it would seem that the adverse conditions which 

 cause the death of the embryo, and eventually also that of the entire conceptus, 

 alone would make conditions of post-mortem growth rather unfavorable even for 

 the most resistant of the dependent tissues. Other factors also would tend to make 

 these conditions unfavorable for the occurrence of post-mortem proliferation, even 

 for such growth as we have in recent years come to know as growth in vitro. I have 

 rarely found appearances identical with those seen in certain artificial cultures, as 

 figure 175 so well illustrates; but these appearances involved connective tissue 

 only and always occurred in the interior of the chorionic membrane, or between the 

 latter and the amnion when the two were separated somewhat. Nevertheless, the 

 rareness of these appearances in itself throws much doubt on the occurrence of 

 genuine growth after death, and in view of the fact that I have been unable to 

 find any thickening of the chorionic and amniotic membranes at these places, I 

 am more inclined to regard such appearances as these as due to a migration rather 

 than to an actual proliferation of cells. Nor have I seen much evidence in favor of 

 a post-mortem migration other than that of cells intravascular in origin. What has 

 been termed lymphoid infiltration or transformation seems to be due rather to a 

 degeneration of cells in loco, the degenerate forms simulating round cells and thus 

 giving rise to misinterpretations. Indeed, the idea that a complete transformation 

 of the entire body of the embryo into round cells can occur without the phagocy- 

 tosis of the cells composing the various organs seems to imply that this so-called 

 lymphoid infiltration really is a transformation in loco. That an apparent tem- 

 porary increase in volume of the central nervous system has been noted is not 

 surprising. But this does not postulate an actual increase in the number of cells 

 any more than the old observation of maintenance in weight and volume of the 

 central nervous system under conditions of inanition implied that the nerve-cells 

 remained unchanged. That the latter is not the case was shown by Meyer (1917 h ). 



It may be recalled that Merttens (1894) also reported finding obliteration of 

 the blood-vessels due to proliferation of the intima. However, since Merttens 

 found these obliterative vascular changes only in the chorion lave, his conclusion 

 that these changes undoubtedly were post-mortem is open to very serious doubt. 

 This doubt is greatly increased by the facts that Merttens suspected the existence 

 of lues in a case in which these obliterative changes were present and that almost 

 complete obliteration of the vessels was present in a specimen which was regarded 

 as having been retained only 1 1 days. Since calcium deposits were present in this 

 specimen, the latter estimate is open to grave doubt, however. 



Berlin (1907), although aware of the fact that an ante-mortem obliterative 

 endarteritis had been shown to occur in conceptuses, nevertheless concluded that 

 the degree of obliteration found in the placental vessels roughly parallels the dura- 

 tion of the retention. She added that the processes found by her recall those 

 observed in portions of a blood-vessel isolated by ligature and represented appear- 

 ances within the placental vessels almost identical with those represented in figure 

 175. In spite of the similarity of these figures, it would seem unwarranted, how- 

 ever, to assume that phenomena identical with those observed in the chorionic 



