572 EEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



thought that by doing this very rapidly I might insure success. Thespawu- 

 ing-season of the " uase" for 1856, however, was over, and I had to defer 

 my experiments till April, 1857. lu that month the " nase" spawned 

 iu exceptionably large numbers and several times ; I consequently had 

 an opportunity of watching them closely during the spawning-process, 

 and the observations I then made led me into the right path. 



Very frequently two lish would leap close together from the water, 

 which led me to suppose that daring this violent motion the spawn 

 which sits very loosely in the body of the fish, and the milt which flows 

 off very easily, might be dropped in the air, and that the eggs might 

 possibly be impregnated by the milt before they touched the water. 



Although I, of course, could not observe the very act of impregna- 

 tion — which, as I supposed, took place — during the very short time occu- 

 pied by the leap of the fish, it became almost a certainty to my mind 

 when I took into consideration the exceedingly violent motion of the 

 fish and the extreme ease with which both the milt and the roe are 

 emitted. 



I was led to make farther observations, proving the fact that fresh 

 spawn when brought into contact with water swells very rapidly and 

 sticks to any objects that present themselves, by seeing several tame 

 ducks devour very eagerly the spawn found on the stony bottom. Wheu 

 taking up some of the stones, I chiefly found their lower surface thickly 

 covered with spawn. 



I must here remark that the strong current in these spawning-places 

 indirectly contributes to the better protection of the spawn by driving 

 it below the stones. If the spawning took place in gently -flowing water, 

 the eggs would stick to the upper surface of the stones, and be exposed . 

 to many enemies. 



I now made experiments with four different methods of impregnation, 

 using only entirely healthy and mature fish, of which I could easily pro- 

 cure a large number. These fish were caught while spawning, and on 

 the spot experimented upon. 



1. I again used the "wet" method of last year, with this difference, 

 however, that immediately after having squeezed the roe out of the fish, 

 the milt was stirred in. This was done as rapidly as possible ; at any 

 rate, much quicker than the year before. 



2. Assisted by a man, I poured into a flat vessel, filled with Bober 

 water, milt and roe at the same time, stirring the water immediately. 



3. Into a flat vessel containing but little water, I poured ^rs^ the milt, 

 so that after stirring the water immediateh', it had a whitish color; 

 then without delay I poured the roe into this mixture. 



4. A fish containing roe was dried carefully and rapidly with a cloth, 

 (occasionally, also, with the hands,) and the " dry^^ roe placed in a flat ves- 

 sel containing no water. Over this was placed the milt of a fish, (that 

 had likewise been dried beforehand with a cloth.) so as to cover the 

 largest possible number of eggs. As soon as this was done, water was 



