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are observed by many investigators in all kinds of animals during 
the development of the ovary. They generally break up into pri- 
mary follicles before birth (Coert, von Winitwartrer). Then the un- 
differentiated cells of the cords form the follicular epithelium for 
the eggeells in the cords. If the medullary cords do not break up 
into primary follicles before, they certainly do so shortly after birth. 
Bünrer could not find them in the rabbit a few days after birth, 
though Coerr and Winiwartrr described them in the embryos of 
this animal. As von Winiwartrer found them even 6 weeks after 
birth in the rabbit, it is evident, that we must take into conside- 
ration large individual differences. They seem to appear very regu- 
larly in the mature ovaries of carnivores and insectivores. SCHMALTZ 
mentions them as a regular phenomenon in the dog’s ovary and 
less regular in the cat’s. 
Harz, Bonnier, PALADINO, VAN WINIWARTER, COERT and WIcHSER 
found them in human embryos. RieLANDER (1904) found them in a 
girl of only a few weeks old. They consist of clear, protoplasmatic 
cells by a thin, structureless membrane. This agrees remarkably 
well with what I saw, but is different from what SCHMALTZ saw in 
the dog’s ovary. The latter describes the cords as groups of granular 
cells with round nuclei, which sometimes surround a small lumen. 
In newly-born infants egg-cells occur besides (BUHLER). Kerper and 
Marr, (Handbuch der Entwickelungsgeschichte d. Menschen 1911) 
mention that the medullary cords are rather often found in the first 
years of life, but only seldom in the ovary of adult women. Bünrer 
saw them in a girl of 2 years old, but not in older ovaries. The 
preparation described here is interesting, because it contains very 
clearly embryonic rests (ingrowths of germinal epithelium and 
medullary cords). The appearance of these rests is not so rare that 
it would justify this communication. I think, however, I can point 
out a connection between the presence of the medullary cords and 
the appearance of the numerous atypical vesicles. 
While studying the sections of a medullary cord in the series 
(fig. 4) one perceives that egg-cells still occur in the medullary cords 
(cf. section 4 in fig. 4 and fig. 16), but one can see at the same 
time that the medullary cord is able to swell at a certain spot and 
is transformed there into a vesicle, in which often more than one 
egg-cell occur. 
It is obvious in the series that the medullary cord, after swelling 
and developing into a vesicle, afterwards regains its former appear- 
ance. This is an indication that the medullary cord of fig. 4 is 
not one that is accidentally connected with a vesicle, but that the 
