368 G. HAROLD DREW 



Another possible explanation of the development of the ciliated 

 epithelium would be to consider that it was derived from the cil- 

 iated cells of the oviduct which ramifies through the ovary, though 

 it would be difficult to understand how these cells could migrate 

 to the walls of the cyst, and there form a continuous lining, while 

 all the other parts of the ovarian tissue degenerate. To test this 

 view two series of experiments were made. In one series only 

 portions of the ovary taken from the extreme apex on the convex 

 side were implanted: in this part of the ovary there is no oviduct, 

 only the alveoli with the contained ova being present; the area 

 thus free from the ciliated oviduct is small, but there is sufficient 

 to make at least three implantations from each ovary with cer- 

 tainty that no ciliated cells are being introduced. In the parallel 

 series of experiments portions of the ovary containing as much of 

 the oviduct as possible were implanted. In both cases similar 

 cysts lined with ciliated epithelium were produced. Other ex- 

 periments were made in which pieces of the oviduct, which in its 

 main branches is easily seen from the surface, were dissected out 

 as carefully as possible, shaken in sterile sea water to remove any 

 adhering ova, and then implanted: in these cases complete ab- 

 sorption and replacement by fibrous tissue often occurred, but 

 in cases where cyst formation took place there was no formation 

 of ciliated epithelium. Thus it is proved that the formation of 

 this layer is independent of the presence of the ciliated cells of the 

 oviduct. 



Another point investigated was the relation of the ripeness 

 of the ovary to the formation of the ciliated epithelium. It was 

 found that this reaction did not take place as a result of the im- 

 plantation of the spent or immature ovary, but only occurred 

 when an ovary which was obviously full of ova, and of a bright 

 orange or vermilion color, was used for the experiment. After 

 the animals had been kept in the experimental tanks of the Labor- 

 atory for some time, the ovary often lost its bright color, and 

 though full of ova became somewhat pale and unhealthy looking : 

 experiments in which portions of the ovaries of sach animals were 

 implanted gave very uncertain results; sometimes the cysts were 

 lined with ciliated epithelium, but more often this was absent, 



