72 LEO LOEB. 



desirable that a confirmation of our interpretation of these ovarian 

 structures should be obtained. The findings which we have just 

 communicated offer the desired confirmation. In our new ob- 

 servations we have also to deal with embryonal structures found 

 in the peritoneal connective tissue and developing in an abnormal 

 situation without being aided by the host tissue through the 

 formation of a decidua. We have of course to consider the fact 

 that in the ovary the limitation of space is still more marked than 

 in the connective tissue on the outer side of the fallopian tube and 

 of the uterus. In both cases the placental structures preponderate 

 over the embryonal ones proper; in both a retardation in the de- 

 velopment is found and a preponderance of certain placental struc- 

 tures. Such favored structures are the layers of cuboidal cells, 

 lining cavities, forming papillary excrescences into these cavities 

 and surrounded at the periphery by giant cells which latter pene- 

 trate in both cases into the surrounding tissue, especially around 

 the blood vessels, the wallsof which they may perforate, thus giving 

 rise to hemorrhages. The identity of both formations, namely of 

 the experimentally produced extrauterine pregnancy which we 

 have just described and of the embryonal structures developing 

 parthenogenetically in the ovary becomes quite evident, when 

 one compares the microscopic sections of both of these formations. 

 The microphotographs and the drawings also show the similarity. 



The similarity of the embryonal structures proper becomes 

 clear through a comparison of Figs. 2, 3, and 6 in the former 

 communication {Zeitschrift fiir Krebsforschung) ,^ and of Figs. 

 2 and 3 in the present communication. The similarity of 

 the placental structures is made evident through a comparison 

 of drawings i, 2 and 4 in the Archiv f. mikrosk. Anatomie,^ of the 

 Figs. 10, 12, 14 and 15 in the Zeitschrift fur Krehsforschung with 

 Figs. 4 and 5 of the present article. On several of these former 

 figures there were also represented the relations of the wandering 

 giant cells to the blood vessels and the hemorrhages resulting 

 therefrom. 



Our new observations render it therefore certain that a fargoing 

 par theno genetic development of ova takes place in the ovaries of a 



^ Loc. cii. 

 2 Loc. at. 



