CANCER RESEARCH 27 



the basis of embryonic malformations. It is very probable that many 

 embryomata especially those of the ovaries and testicles owe their origin 

 to the parthenogenetic development (development without previous fer- 

 tilization) of a germ cell, a suggestion made more probable through the 

 discovery of Jacques Loeb that in various classes oi invertebrates ova 

 can be induced by artificial means to develop without previous fertiliza- 

 tion. And yet the majority of pathologists believe with Bonnet and 

 Marchand that such embryomata just as other mixed tumors of child- 

 hood are due to embryonic aberrations, to a separation of early cells 

 which are formed in the course of the early division of the previously 

 fertilized ovum or to the abnormal fertilization of a little cell separated 

 normally from the egg previous to the entrance of the spermatozoon. 



However, this hypothesis can not be easily reconciled with the fact 

 that the majority of embryomata appear in the germinal.glands (ovaries 

 and testicles), an observation which can be readily explained, if we 

 assume that these embryomata are due to the parthenogenetic develop- 

 ment of ova in the ovarian follicles. This is the more probable as I 

 found that in about 10 per cent, of the ovaries of young guinea-pigs 

 formations occur which can not very well otherwise be explained than 

 as embryonal structures, placental 1 as well as embryonic in the stricter 

 sense, developing abnormally from ova in the ovarian follicles and grad- 

 ually being destroyed by the surrounding tissues. A previous fertiliza- 

 tion could be excluded in these cases. 



Moreover in the ovaries of various mammals one can not rarely 

 observe ova in athretic (degenerating) follicles which show the first, 

 somewhat irregular segmentations, and in the armadillo as many as 

 eight cells may, according to H. H. Newman, be seen. 2 



While these observations explain satisfactorily the relatively frequent 

 occurrence of embryomata in the germinal glands, they may also explain 

 the embryomata found at other places, inasmuch as it is known that the 

 germ cells migrate in various directions in the developing embryo, before 

 they reach the germinal gland. In some cases however blastomeres 

 (cells formed in the course of the early segmentation of the egg) may 

 form the matrix of the tumors, inasmuch as it has been shown in certain 



1 The placenta is an organ of partly embryonic, partly maternal origin 

 which is attached to the uterine wall and which transmits nourishment to the 

 embryo. 



2 The first cleavages of ova in athretic follicles of mammalian ovaries pre- 

 viously described by various investigators and also by myself can not all be ex- 

 plained as maturation divisions which precede the segmentation; we may see 

 occasionally ova which have divided into a number of segments, several or the 

 majority of which may contain nuclei and at the same time observe in two seg- 

 ments mitotic figures or their remnants, the position and character of these seg- 

 ments making it extremely improbable that they represent polar bodies (Leo 

 Loeb, Archiv f. milcroscop. Anatomie, Bd. 65, 1905). 



