NUMBER OF OVA: ALBINO RAT 4il 
OBSERVATIONS 
Under this head we shall merely present and describe our re- 
sults, leaving the interpretation of them for the section en- 
titled ‘Discussion.’ © 
1. The comparison between the weight of ovaries and number of ova 
on the right and left sides 
There is, so far as I am aware, no statement concerning either 
the weight relations of the right and left ovaries, or concerning 
the number of ova in these. 
To determine the weight relation between the ovaries when 
the left ovary is taken as the standard, we divide the entire series 
into two groups according to the presence or absence of the cor- 
_ pora lutea. 
A. This group contains all cases in which the weight of one 
ovary is less than 10 mgm. and no corpora lutea are present. 
There are twenty such cases (up to 110 days), eleven of these have 
the ratio smaller than one, and seven the ratio larger than one, 
while in two cases the ratio equals one. The average ratio of 
all twenty cases is 0.93 for the right ovary. This ratio seems 
to indicate that in the absence of the corpora lutea the right... 
ovary tends to be lighter than the left, though the difference is 
not great. 
B. To this group belong all cases in which the weight of one 
ovary is greater than 10 mgm. and which show corpora lutea. 
We have altogether sixteen cases, among these thirteen cases 
show the ratio smaller than one, while three show the ratio more 
than one. The average of the ratios of the entire sixteen cases 
is 0.85 for the right ovary, thus giving a greater difference be- 
tween the right and left ovaries in this group than in the former. 
The ratios for all thirty-six cases become 0.90, thus revealing 
clearly a tendency at all ages for the right ovary to weigh less 
than the left. 
On the relative weights of the right and left ovaries of other 
mammals there are no observations. Wiedersheim (’97) states 
that in birds the right ovary undergoes an early and more or 
