NATURAL HISTORY OF THE QUINN AT SALMON. 
73 
EXPERIMENTS ON THE VITALITY OF SPERMATOZOA. 
Vitality in water. Experiment No. 1 . — Milt was mixed with water until the 
mixture became of a milky appearance, which was the condition desired for fertiliz- 
ing the ova at the spawning platform. Small quantities of the mixture were taken 
from time to time and examined under a compound microscope. After several 
repetitions of the experiment it was found that the spermatozoa remained active in 
the water from 3 to 5 minutes, the length of time varying slightly in each experi- 
ment. Each time the spermatozoa were placed on the slide they were very active for 
about 30 seconds, after which time nearly all became attached by the tail to the 
slide or cover. The head continued to move for a few seconds longer, but all 
motion ceased after 65 seconds from the time the milt was placed on the slide. 
Experiment No. 2 . — Water was mixed with milt as in the above experiment and 
a small quantity used to fertilize eggs every half minute for S.} minutes, with the 
following results, the eggs being freshly spawned in each case: 
Time milt had been in the water. 
Percent- 
age of 
fertiliza- 
tion. 
Time milt liad been in the water. 
Percent- 
age of 
fertiliza- 
tion. 
93 
4.5 minutes 
r 
88 
0 
38 
5.5 minutes 
0 
4 
(> minutes . . . 
0 
2 minutes 
8 
6.5 minutes _ 
0 
2.5 minutes 
3 
7 minutes ..... 
2 
3 minutes . 
8 
7.5 minutes 
0 
3.5 minutes 
1 
8 minutes . 
0 
4 minutes 
0 
8.5 minutes 
0 
The experiment was tried three times, but the results were practically the same. 
At one time a number of eggs were immersed in water taken from the top of the 
can in which the spawn was taken from the spawning platform to the hatchery. 
This water was white from the superfluous milt which had been spawned from 
3 to 10 minutes. None of the eggs so treated were fertilized. 
From these experiments it will be seen that the milt and eggs should be thor- 
oughly mixed while in the spawning pan and within 30 seconds from the time 
the milt is mixed with water. 
Activity in normal salt solution /' — Milt was mixed with normal salt solution 
until the liquid was distinctly whitish, and a portion of it was at intervals poured 
over freshly spawned eggs. After a short time the eggs were washed with fresh 
water. The per cent fertilized in each case is given in the following table: 
Time solution had been spermatized. 
Percentage of fer- 
tilization. 
First 
attempt. 
Second 
attempt. 
1 minute 
74 
98 
2 minutes . 
83 
4 minutes _ ... 
55 
5 minutes ... 
79 
6 minutes 
70 
8 minutes 
34 
15 
“Normal salt solution, 0.75 per cent common salt in water. 
