SPECIMENS COMPOSED OF VILLI ONLY. 53 



attached, and sooner or later seem to lead to fetal death. It is interesting that 

 fetal death in these cases is not the result of invasion of the conceptus, or even of 

 its villi, by the inflammatory process itself. It is possible that the production 

 of toxins may be a factor, but the morphologic evidence seems to point to inter- 

 ference with the nutritive supply through decidual and chorionic changes. It is 

 not difficult to see that the accumulation of pus in the region of attachment of the 

 villi, or even the accumulation of large masses of leucocytes, must seriously inter- 

 fere with the free intervillous circulation. Obstruction to the blood-current, if 

 sufficiently severe, would also lead to the death of the cyema, and finally to that 

 of the chorionic vesicle itself in consequence of interference with the indispensable 

 gaseous interchanges. 



No matter how severe the infection of the uterus was found to be, or how large 

 the accumulations of pus at the region of implantation, well-preserved villi never 

 were found infiltrated with cells of maternal origin. When infiltration was present 

 within the stroma the latter, and especially the epithelium of the villi, could be 

 shown to be degenerate. If, on the other hand, the infectious process was intro- 

 duced directly into the chorionic vesicle, the latter soon disintegrated and the 

 infection extended into the stroma of the villi also. An insuperable difficulty 

 encountered in connection with the question of infection in many cases is the 

 inability to determine positively whether the infection existed within the uterus 

 before implantation occurred, or whether it was incidental to mechanical inter- 

 ference. An examination of the material seems to show that the final effect upon 

 the villi, and of course also upon the membranes of the embryo, rarely may be the 

 same in both cases. This probably is due to the fact that a young conceptus 

 may be loosened partially only, at the time of interference or of infection, thus 

 establishing conditions which lead to its death. As a rule, however, in these cases 

 maceration changes are likely to be much more rapid than under conditions of a 

 chronic endometritis pre-existent to the conception. Nevertheless, mild general 

 or a severe local preimplantation endometritis no, doubt could produce results 

 wholly comparable to those resulting from a mild general uterine infection incident 

 to mechanical interference, -especially in the case of young conceptuses. It is 

 conceivable that in the case of a low-grade endometritis, the fertilized ovum may 

 undergo a perfectly normal development for a restricted period, and then suffer 

 from more or less sudden interference with its development through exacerbation 

 or extension of the infectious process, just as might be the case under other condi- 

 tions. Ordinarily, however, it would seem that the changes within the conceptus 

 should be more gradual, and also much more general under conditions of a chronic 

 endometritis than under those of accidental or incidental infection. Nevertheless, 

 the changes in the villi sometimes appear wholly comparable in both cases. The 

 stroma in many of them finally undergoes what Mall has called mucoid degenera- 

 tion, with complete disappearance of the mesenchyme and final disintegration 

 of the epithelium. The blood-vessels generally become effaced at a very early 

 day before the stroma has undergone any important changes. Rarely, as the en- 



