326 



HUMAN UTERUS AND FCETAL APPENDAGES. 



disappearance of the reflexa, membranes from the second and third months 

 should be examined. 



Section of Decidua Reflexa of Two Months. At this time the reflexa starts 

 from the edge of the placental area as a membrane of considerable thickness, but 

 it rapidly thins out, the very thinnest point being opposite the placenta. Ex- 

 amination of sections shows that the entire reflexa is undergoing degeneration 



which is found to be more advanced the 

 more remote the part examined is from 

 the placenta. The chorion laeve lies 

 very near the reflexa, being separated 

 only by the villi, which are already very 

 much altered by degeneration. In the 

 region half-way between the base and 

 the apex of the reflexa the tissue (Fig. 

 1 88) shows only vague traces of its 

 original structure. Only here and there 

 can a distinct cell with its nucleus be 

 made out. Most of the cells have 

 broken down and fused into irregular 

 hyaline masses without organization. 

 Ramifying through the fused detritus 

 appear strands and lines, which are 

 more darkly stained by both carmine 

 and hematoxylin. On account of their 

 fibrous appearance, these strands are 

 often spoken of as fibrin, although they 

 are presumably not the same as the 

 true fibrin from the blood. The fibrin 

 is much more developed upQn the inner 

 or chorionic side than upon the outer 

 side of the reflexa. On the inner side it 

 forms a dense network, which fuses with 

 the degenerated ectoderm of the cho- 

 rionic villi wherever the villi are in con- 

 tact with the decidua. It also ramifies nearly half-way through the decidua, 

 the ramifications being followed easily, owing to the dark staining of the sub- 

 stance. Over the outside of the decidua the fibrin forms a much thinner layer 

 or may be only indistinctly formed. 



In a decidua reflexa of three months the conditions are essentially the same, 



FIG. 188. SECTION OF HUMAN DECIDUA REFLEXA 

 AT Two MONTHS. 



