Vol. XXX, No. 10 
908 
Journal of Agricultural Research 
MICROSCOPIC WORK 
The measurements of rabbit sper¬ 
matozoa from seven different slides are 
shown in Figures 1 to 7, together with 
the theoretical normal curves for 
populations of those sizes with those 
means and standard deviations. Slides 
Nos. 370, 371, and 372 were all made 
from the same sample of recovered 
semen. Slide 277 was made from semen 
of the same buck but recovered at a 
different time. 
Fig. 4. —Actual (solid line) and theoretical (broken 
line) frequency distributions of the head lengths 
of untreated rabbit spermatozoa. The proba¬ 
bility that the actual distribution is only a chance 
deviation from the theoretical is 0.12. (Slide 
No. 271) 
Fig. 1.—Actual (solid line) and theoretical (broken 
line) frequency distribution of the head lengths 
of untreated rabbit spermatozoa. The actual 
distribution is clearly bimodal and the probability 
that it is only a chance deviation from the theo¬ 
retical distribution is less than 0.001. (Slide 
No. 370) 
. I... — 1 ————————— 1 
Fig. 2.— Actual (solid line) and theoretical (broken 
line) frequency distribution of the head lengths 
of rabbit spermatozoa taken from the inside of 
the centrifuge tube after being centrifuged 5 
minutes at 1,600 r. p. m. The liquid had first 
been diluted with three times its volume of 
Ringer’s solution. Made from the same sample 
of semen as that in Figures 1 and 3. The proba¬ 
bility that the actual distribution is only a chance 
delation from the theoretical normal curve is 
0.207. (Slide No. 371) 
Fig. 3.—Actual (solid line) and tneoretical (nroken 
line) frequency distributions of the head lengths 
of rabbit spermatozoa taken from the outside of 
the centrifuge tube after being centrifuged five 
minutes at 1,600 r. p. m. The liquid had first 
been diluted with three times its volume of 
Ringer’s solution. Made from the same sample 
of semen as that used in Figures 1 and 2. The 
probability that the actual distribution is only a 
chance deviation from the theoretical normal 
curve is 0.84. (Slide No. 372) 
Fig. 5. —Actual (solid line) and theoretical (broken 
line) frequency distributions of the head lengths 
of untreated rabbit spermatozoa. The proba¬ 
bility that the actual distribution is only a chance 
deviation from the theoretical is less than 0.001. 
(Slide No. 277) 
Fig. 6.—actual (solid line) and theoretical (broken 
line) frequency distributions of the head lengths 
of untreated rabbit spermatozoa. The proba¬ 
bility that the actual distribution is only a chance 
deviation from the theoretical is 0.029. (Slide 
No. 249) 
z^/zzr//s z?/^ /z&?z& 
Fig. 7. —Actual (solid line) and tneoretical (Droken 
line) frequency distributions of the head lengths 
of centrifuged rabbit spermatozoa. From the 
outside portion of the centrifuge tube after being 
centrifuged eight minutes at 1,600 r. p. m. The 
probability that the actual distribution is only a 
chance deviation from the theoretical is 0.09. 
(Slide No. 263) 
