902 
Journal of Agricultural Research v 0 i. xxx, xo. 10 
from 0° to 20° C. until all motility dis¬ 
appeared or until an odor of putrefac¬ 
tion was noticeable. In the case of the 
lower temperature some motility was 
observed as long as 60 hours after 
ejaculation in some samples, and al¬ 
most always as long as 48 hours. With 
temperature as high as 18° to 20° all 
motility disappeared sooner, sometimes 
in less than 24 hours. 
Temperature was not recorded ex¬ 
cept at the time of observation, and 
temperature control was not accurate, 
so that the only conclusion which can 
be drawn is the general one that sper¬ 
matozoa when kept in a liquid in vitro 
retain motility much longer at lower 
than at higher temperatures, and there¬ 
fore that the checking of their activity 
is due to bacterial growth in the me¬ 
dium or the accumulation of the by¬ 
products of their own activity or the 
exhaustion of their own supply of 
energy due to this greater activity, 
rather than to the mere lapse of time. 
Possibly they would remain active much 
longer inside the uterus where the 
toxic products of their own or of bac¬ 
terial activity would diffuse away to a 
considerable extent. Not all the 
spermatozoa in the same sample re¬ 
mained active for the same length of 
time, but usually a great many were 
inactive at the end of 24 hours, even 
though some remained active for more 
than 48 hours. Whether motility is a 
sufficient index of fertilizing ability is 
not revealed by these data. There is 
only the fact that two litters were 
produced after insemination with liquid 
which had been kept for 24 hours, in 
the one case at 10° to 18° C. and in the 
other at 13° to 17°. 
DISCUSSION OF RESULTS 
SEX OF ALL RABBITS PRODUCED 
Table I presents the sex of all the 
rabbits which have been produced in 
the flock of the genetics department of 
the University of Wisconsin in the last 
10 years. The classes marked “alco¬ 
holized” or “lead ” are from former 
experiments ( 6 , 7), the plan of which 
was to mate albino females to two 
males on the same day, one of the 
males being normal and the other in a 
chronic state of lead or alcohol poison¬ 
ing. One of the males was an albino 
and the other was homozygous for the 
pigment-producing factor and there¬ 
fore the paternity of the young pro¬ 
duced could be known. The individ¬ 
uals in the class marked, “dam had not 
copulated” are counted again in their 
appropriate insemination class, but are 
only counted once in the grand total. 
Also the individuals of the “fluid 
washed out” class are counted again in 
the “fluid withdrawn” class, but are 
only counted once in the grand total. 
The next to the last column in Table I 
gives the probable error to be expected 
on the basis of exact equality in the 
numbers of each sex. The last col¬ 
umn in Table I shows for each method 
of breeding just what proportion the 
deviation from exact equality bears to 
its probable error and therefore whether 
these deviations are likely to be the 
result of anything but chance. 
In this and the following tables the 
probable errors and the deviations are 
calculated upon the basis of an expecta¬ 
tion of exact equality in the sex ratios. 
As far as the chromosome theory of sex 
goes, equality is to be expected, but, as 
Table I.— Sex of rabbits produced in flock of the genetics department , University 
of Wisconsin , during 10 years 
Type of litter 
Sex 
Probable 
error 
1:1 
Devia¬ 
tion- 
probable 
error 
Males 
Females 
Unknown 
Sire alcoholized_ - 
6 
12 
7 
1.43 
2.10 
[Sired by poisoned buck... 
102 
93 
20 
4.71 
.96 
Lead_ - ---j 
[Sired by normal buck_ 
74 ! 
63 
a 32 
3.95 
1.39 
I 
[Dam had not copulated... 
12 ; 
10 
3 
1.6 
.63 
Fluid untreated_ 
ii 
17 
7 
1.8 
1.68 
Artificial insemination ..J 
Fluid cooled- 
18 
23 
6 
2. 16 
1.11 
Centrifuged, “inside”_ 
64 
64 
3 
3. 82 
[Centrifuged, “outside”... 
103 
97 
14 
4. 77 
I .63 
[Fluid withdrawn_ 
170 
! 205 
28 
6. 53 
2.68 
Natural service-- 
Fluid washed out_ 
18 
| 27 
i 1 
2. 26 
! 1.99 
i 
[No treatment.. 
421 
394 
174 
9. 63 
s 1.40 
Grand total_ _ .. 
969 
968 
291 
14. 84 
! .03 
Some of these may belong in the row above. 
