492 



Journal of Applied Microscopy. 



profession ; but a few years will suffice to place the physician, who does not 

 understand its manipulations and advantages in the rear ranks in the onward 

 march of progress and success. 



The time is not far distant when the microscope will be an indispensable 

 adjunct to the advancement of every art and science, to the professional and to 

 the layman, recognized as one of the most potent of civilizing factors. 



M. A. Goldstein, B. S., M. D. 

 St. Louis, Mo. 



Notes on the Histology of the Amnion. 



I recently utilized for microscopical purposes a human afterbirth, delivered 

 at full term in a normal labor, which possessed two distinct fetal sacs, the 

 amnion being completely separate from the chorion and never having become 

 united to the latter, as is ordinarily the case. The anomaly was reported in the 

 Medical Aews, New York, July 1, 1899, page 12. The thin and distinct amnion 

 in this case, with its free and definite outer surface, presented such distinct 

 pictures of the outlines of the mature amnionic cells, as brought out by the 

 silver-nitrate method, in conjunction with nuclear stains, that a note of the 

 appearances presented seems worthy of record. 



Figure 1. F.pithelial cells lining inner surface of the amnion, (x 1000.) 



1. The epiblastic cells lining the free inner surface of the amnion (that 

 directed toward the fetus) were simple squamous epithelium cells (Fig. 1). 

 They were flat and thin, uniting in a single layer edge to edge, with slightly 

 wavy margins, and were polygonal (often pentagonal and hexagonal), elongated, 

 or irregular in shape. Their nuclei were circular or oval ; most of the cells were 

 uninucleated, but cells containing two, three, or eveji four nuclei were common. 

 In size the dimensions of the cells (diameters or diagonals) ranged usually from 

 about .015 to .022 millimeter, the extremes measured being .Oil and .088 mm.; 

 the nuclei were about .004 to .00.55 mm. in diameter. Similar appearances and 

 results as to these epithelium cells were obtained in silver-nitrate preparations of 

 the membranes froin a normal afterbirth. 



2. The subepithelial or outer portion of the amnion, making up the chief 

 thickness of the membrane, is a mesoblastic connective-tissue layer, consisting 



