74 LEO LOEB. 



merit of ova leading to these pathological structures begins only- 

 after birth. In a similar manner as we saw that embryonal 

 placenta as well as the embryo proper can develop from the 

 parthenogenetically segmenting ovum and that the embryonal 

 placenta can be formed without the simultaneous development of 

 the embryo proper, thus chorion epitheliomata may originate in 

 the ovary without any accompanying embryonal structures 

 proper. In other cases however there develop mainly the em- 

 bryonal structures proper or certain of their parts. 



This conception of these structures explains the fact that they 

 are mainly found in the germ glands. On the other hand, there 

 exists no reason, why we should expect that aberrant blastomeres 

 should mainly be found and develop at this place. Furthermore 

 I have never been able in the many hundreds of ovaries of guinea 

 pigs which I have examined microscopically to find a structure 

 resembling a misplaced blastomere. 



We still have to explain why these structures are occasionally 

 also found in the male germ glands and especially, why teratomata 

 occur also, although less frequently, at other parts of the body, 

 outside of the germ glands. As far as their occurrence in male 

 germ glands is concerned, it might be explained by the fact that 

 in a certain number of cases cells of both sexes may be found in 

 the same individual, that therefore true hermaphroditism occurs. 

 That this is not so rare an occurrence as has been assumed has 

 recently been shown by L. Pick.^ We have perhaps also to 

 consider the possibility that at a certaiipi stage of development 

 also the male germ glands are capable of developing in a similar 

 manner as the ova. However at the present time there exist no 

 facts supporting such an hypothesis. 



We know furthermore that in the course of embryonal de- 

 velopment the germ cells migrate. It is therefore conceivable 

 that occasionally one of their number may follow a wrong path 

 and thus give origin to the formation of the teratomata outside of 

 germ glands. While we are thus able to explain the origin of 

 these structures on the basis of a parthenogenetic development 

 of ova we do not intend to deny the possibility that under certain 

 conditions irregularities in the embryonal development may lead 



^ Cited from a review in the Miinch. med. Wochenschrift, 1913. 



