260 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



Doubtless it makes a great difference whetber tlie Diilt is mixed 

 thoroughly with the water, or is permitted to settle in a body to the 

 bottom, as it will when dropped gently into water. In the latter case 

 the water may not gain access to the 'main mass of the milt for some 

 time. 



9. — DURATION OF CONTACT NECESSARY TO INSURE FECUNDATION. 



In the ordinary course of procedure the milt was in contact with the 

 eggs not far from a minute before the application of water, and from 

 twenty minutes to an hour, or even longer, thereafter. In two instances, 

 immediately after the application of the milt and the stirring of the 

 eggs enough to diffuse it among them, it was washed off by rinsing the 

 eggs several times with clean water, the whole being done with the 

 utmost possible dispatch. 



Experiment 14. — Lot 125, containing 3,300 eggs ; the eggs were rinsed 

 with clean water immediately after milting; fecundation, 100 per cent* 



Experiment 15. — Lot 127, containing 2,700 eggs; rinsed immediately 

 after milting; fecundation, 100 per cent. 



From this it appears that fecundation is effected so quickly that, for 

 practical purposes, it may be considered instantaneous. 



10. — TEMPERATURE OF WATER AND DEVELOPMENT OF EGGS. 



The temperature of the water in the hatching-house when the first 

 eggs wera deposited, was 44^ F., and they developed rapidly. On the 

 3d day of November it had fallen to 42°, and from that time till the 16th 

 it vibrated between 42^° and 39°. On the 20th it sunk to 37°, and on 

 the 21st to 35°. -About this point it remained until the last week in 

 December, when it sunk to 33°, the temperature of the air outside being 

 — 19°. During the rest of the winter it generally stood at 33i° or 34°, 

 occasionally rising to 3(>°. In the spring it sunk instead of rising, the 

 water being colder during the first half of April than at any other time 

 during the season. This I attribute to the abundance of snow and ice- 

 water running into the brook at that time. No difficulty was experi- 

 enced in keeping the building warm enough to avoid any iujurious freez- 

 ing, although on several occasions, when the night was extremely cold 

 and the fires dull, ice formed in some of the troughs. 



In this extremely cold water, of course the development of the eggs 

 was very slow. In the first lot the heart of the embryo was beating 

 De.cember 10, but the eyes were not black until January 9, seventy- 

 three days from fecundation. In spring-water the same stage would be 

 reached in about thirty days. On the 7th day of February the circula- 

 tion was barely established in the embryos taken November 21. In 

 those taken November 14 it was distinct and the embryos active ; in 

 those of November 9 the circulation was stronger and the embryos 

 larger, but there was still no sign of color in the eyes, although ninety 

 days had passed since fecundation. The only disadvantage in this slow 



