612 Note on Russo’s attempt to show differentiation, etc. 
generate and the other suspiciously similar to examples in my 
possession of an early stage of that condition. 
Thus it is with great regret I am obliged to conclude he has 
not proved what, at first sight, seemed to be such a clear exposi- 
tion of the correctness of my own belief. 
At the same time it is to be noted that the ova he figures 
which have absorbed lecithin, are represented as having done so 
in very various degrees. If this be so it is of interest inasmuch 
as it bears upon the constitutional variability of ova and of the 
power to affect them, to stimulate or to retard the growth and 
maturation of certain of them, by means of different foods supplied 
to the mother. I have elsewhere shown there is an overwhelming 
mass of evidence in favour of the view that F. larvae require more 
nourishment than do M. larvae for their successful development, 
and that the same relative requirements are probably evinced 
by ovarian ova of different sexes ; it is not impossible then that 
the variable amount of lecithin in different healthy ova, shown by 
Russo, may have important bearing on this point. 
