28 Report of the American 



The mode of fecundation adopted is an imitation of the Russian method, 

 differing from it in this point, that the milt is applied directly to the eggs 

 and through contact secured before any water is used ; while the Russian 

 experimenter used to put water with the milt before applying it to the 

 eggs. I don't know that there is any advantage in our method, but I 

 think it rather safer. It requires no great haste ; the pan of eggs and 

 milt may even be made to await for man}" minutes the convenience of 

 the operator without detriment. The ratio of fecundation obtained at 

 Bucksport by this method is about ninet^'-eight per cent. , and the aver- 

 age rate of fecundation in all eggs taken in 1872, including numerous 

 experiments, was 96.7 per cent. The average at Oriand in 1871 Avas 96 

 per cent. These results are so satisfactory that I have made no attempt 

 to apply any other method except in an experimental way. 



The rate of fecundation is obtained by very careful observation. At a 

 certain stage of the development of a fecund egg, the germ begins to ex- 

 pand laterally, sfending out a thin fold, which at last completely encloses 

 the yolk. At any time during the growth of this fold, the position of its 

 advancing maigin can be traced by a line of colored oil globules, arrang- 

 ed in a circle on the surface of the yolk. This circle is at first quite 

 small, and surrounds the colored disk so plainly Aisible on the upper side 

 of the yolk. It enlarges day by day until it divides the surface of the 

 yolk into two equal parts. As it progresses beyond this point, it becomes 

 smaller, and finally it closes entirel3\ This process begins, in water of 

 the temperature of fortj'-three degrees F. at about the thirteenth, day and 

 is completed in seven or eight days. As it never takes place in an un- 

 fecund egg, its occurrence is positive proof of fecundation. To observe 

 it, a strong light should be thrown up through the egg, and the most con- 

 venient way of effecting this is to place the egg over a hole in a piece of 

 sheet metal, and hold it up to a window. To obtain the ratio of fecunda- 

 tion, a definite number of eggs is examined from each lot, and the result 

 made the basis of a strict calculation. 



The manipulation of the fish is performed at a distance of some twenty 

 rods from the hatching house, to which the eggs are carried in pails after 

 they have completed the absorption of water. The hatching house is a 

 wooden building seventy feet long and twenty-eight wide. A feed trough 

 runs down one side of it, and discharges water into forty hatching troughs 

 that run across the room. The feed pipes are of inch-and-a-half lead 

 pipe, and are all set into the feed trough at exactly the same height, so 

 that if a partial stoppage of water accidentally occurs, what still con- 

 tinues to run will be divided amongst all the troughs instead of being 

 drawn awa}^ from part of them by others at a lower level, as might be the 

 case under a diflferent arrangement. The volume of water used is about ten 



