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LEO LOEB. 



their proliferation leads to the formation of papillary excrescences 

 into the cavities. These excrescences fill sometimes a great part 

 of these cavities. Mitoses often appear in these cuboidal cells. 

 Fig. 4 shows such a placental structure at a higher magnification. 



Fig. 4. A placental cavity lined with cuboidal cells, c, giant cells; d, cuboidal 

 cells lining a cavity and forming papillary excrescences; c' , a giant cell penetrating 

 into the surrounding connective tissue; !>, blood vessels; A, hemorrhages in the con- 

 nective tissue; u, experimentally misplaced uterine epithelium. 



d points to a cavity lined with cuboidal cells. The cuboidal cells 

 form papillary proliferations into the lumen. The cavity bulges 

 into the surrounding tissue at <^i. The cavity is surrounded on 

 several sides by giant cells c and these giant cells protrude into 

 the cavity and divide it into two parts. These giant cells have 

 the power to penetrate farther into the surrounding tissue inde- 

 pendently. C\ represents such a giant cell, which penetrates 

 into the surrounding' fibrous tissue. Surrounding this placental 

 structure we find connective tissue in which there are many hemor- 

 rhages Ifi. U represents a cavity lined with uterine epithelium. 

 V represents a blood vessel. Fig. 5 represents a drawing of a 

 similar placental structure. D represents the cavities lined with 

 cuboidal cells, and partly filled with the proliferated cuboidal 



