66 LEO LOEB. 



tissue surrounds the structure, d points to a cavity filled with 

 small cuboidal cells. 



These findings will have to be interpreted in the following 

 way. At the time when the incisions were made into the uterus, 

 namely two days and sixteen hours after copulation, the ova had 

 probably already left the tube and had reached the upper part 

 of the uterine cavity. At this time one or more of the ova left 

 the uterine cavity through the incision into the uterine wall 



h V 



Fig. 6. Placental embryonal giant cells penetrate into the vessel wall, v, blood- 

 vessels; c, giant cells substitute vascular endothelial cells; c', a giant cell lying in 

 the host tissue; h, hemorrhages in the host connective tissue; d, cuboidal placental 

 cells of embryonal origin. 



and one of the ova passed around the outer side of the upper end 

 of the left uterine horn, and embedded itself in the connective 

 tissue between the tube and the upper end of the left uterine 

 horn. A part of the embryonal placenta in the course of de- 

 velopment penetrated farther into the musculature of the uterine 

 horn. The fertilization of this ovum had in accordance with the 



