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Mr Heape, Note on Russo's attempt to show 
At Prof. Bateson’s suggestion I have examined Russo’s histo- 
logical evidence and compared his figures with my own prepara- 
tions of rabbits’ ovaries, with the following result : 
Russo’s histological methods are, so far as I understand them, 
specially adopted to enable him to demonstrate the existence of 
fatty matter in the ovum and surrounding tissue. He describes 
and figures two kinds of ova ; the one in which fat is more or less 
abundantly evidenced both in the ovum, in the zona radiata and, 
in some cases, in the surrounding follicular tissue ; the other in 
which no such deposit of fat is seen ; and he maintains, as I 
understand him, that while the former are F. ova, those in which 
no fatty matter is present are M. ova. 
In view of the belief which is very generally held and which I 
admit I am myself strongly disposed to credit, that females require 
more nutriment than males for their successful development, this 
demonstration by Russo deserves special attention. 
He figures many ova of different ages, from very young to 
fully mature ova, in which fatty material is present in varying 
degree, and it may be that the lecithin he supplied is responsible 
for some of that fat. But it is I believe known that lecithin is 
normally present in the yolk of eggs, and we are at once arrested 
by the query why, if that be so, do certain ova figured by him 
show no sign of its presence. 
He figures two such ova and especially refers to them as 
M. ova. 
The first of these is an ovum lying in the centre of a large 
follicle surrounded by its discus proligerus. It is drawn on too 
small a scale to admit of detailed criticism, but there are indica- 
tions that foreign elements are present among the cells of the 
discus. I find examples among my own preparations of a similar 
appearance, and when examined under a higher power it is seen 
to be due to the presence of leucocytes. I have no doubt what- 
ever that the presence of leucocytes in a follicle is a sure sign of 
degenerative change, and though I cannot assert Russo’s figure is 
that of a degenerating follicle, it is not free from the suspicion that 
such is the case, and it is to be regretted he did not give a more 
detailed drawing of it. 
© 
Of the second “ male ” ovum figured by Russo there can be no 
such doubt. He calls it a ripe ovum ready to be discharged from 
the ovary, and it is represented possessed of a nuclear spindle, 
lying free in a sharply-bounded cavity the cells surrounding which 
are more or less cubical or flattened. The cavity is either a hole 
in the discus or the follicular cavity itself, probably the former. 
The specimen is highly magnified and only a few of these sur- 
rounding discus (follicular ?) cells are included in the drawing. 
Now no such condition is ever seen in the healthy, ripe follicle 
