840 THE FEMALE GENITAL TEACT. 



In the growing placenta we always meet in the decidua-layer with multi- 

 nuclear masses, sharply marked from the surrounding myxomatous basis- 

 substance. These clusters are numerous in earlier stages of the developing 

 placenta, where t'-ie decidua itself is only of a relatively small diameter ; 

 while the fully tloveloped placenta, in its solid part, is of a noticeable width, 

 but altogether devoid of the clusters above mentioned. On the contrary, 

 single elements, surrounded by the net- work of the myxomatous connective 

 tissue, are present only in a comparatively small number in the growing 

 decidua, while they constitute the whole solid part of the fully developed 

 placenta. This fact led the authors to the conclusion that the isolated 

 decidua-elements originate from multinuclear clusters. 



The only way to examine a placenta, in my opinion, is to cut the tissue 

 with a razor after it has been sufficiently hardened by a repeatedly changed 

 one-half per cent, chromic acid solution. I cannot advocate the picking 

 method of the villous portion, and still less, of course, that of the decidua. 

 By cutting we oftentimes succeed in obtaining thin sections of the villosities 

 in different directions, perfectly fit for examination even by the highest 

 powers of the microscope. Such sections are easily made through the solid 

 part of the placenta ; while picking will always bring to view debris of the 

 tissue only, as a rule mangled to such an extent that a close examination 

 under the microscope is a matter of impossibility. 



Specimens obtained from the solid part of a placenta of the six months' 

 development, with a power of about 500 diameters, show a great number of 

 bioplasson formations, partly built up by large nucleated elements, partly by 

 a uniform granular mass, in which there are imbedded nuclei in a more or less 

 varying number. Besides, we meet with clusters, in which nuclei cannot be 

 recognized, but a differentiation into smaller granular spindle-shaped ele- 

 ments can be traced out. These masses, as a rule, are distinctly bounded 

 toward the surrounding myxomatous basis-substance, which, owing to its 

 apparently homogeneous, highly refracting structure, is a well-defined forma- 

 tion. The net-work of the myxomatous connective tissue is partly loose and 

 delicate, including in almost every mesh a granular plastid, this being either 

 provided with or devoid of a nucleus, while in other places the myxomatous 

 net-work is very heavy, its meshes being narrow and filled with a light, 

 apparently homogeneous, structureless-looking substance. A still higher 

 development of the connective tissue can be found only around the arteries, 

 the adventitia of which is a combination of myxomatous with fibrous connec- 

 tive tissue, inasmuch as bundles of delicate fibers form an elongated net-work, 

 and in the meshes of these again granular, partly nucleated plastids are 

 visible. The veins, on the contrary, being sinuous and irregular in their out- 

 lines in a hardened specimen, are directly surrounded by loose myxomatous 

 connective tissue. 



Sections made through the solid part of a placenta of nine months, if seen 

 with a power of 500 diameters, show the complete absence of clusters, the 

 " giant-cells " of the authors, and the whole tissue is decidedly myxomatous 

 in structure. The meshes of this tissue are partly filled with single, chiefly 

 nucleated plastids, many of which, owing to the prevalent amount of basis- 

 substance, are very narrow, and contain a light, apparently structureless 

 substance. Besides, a considerable amount of fibrous tissue is to be seen 

 principally in the neighborhood of arteries, the adventitia of which is alto- 

 gether fibrous in structure. Where several arteries run through the stroma 



