MILNER ON THE ARTIFICIAL CULTURE OF THE SHAD. 433 



stage of their condition is known to fish-breeders as the " spawn-rising," 

 referring to the greater bulk in the pan from the increase in size of each 

 egg. The increase in size and hardness continues for several minutes, 

 during which the water is poured oft' and fresh water poured into the 

 j)an two or three times, and the eggs gently stirred with the fingers. In 

 pouring in the water the edge of the dipper is placed against the sides 

 of the pan and the stream directed between the eggs and the sides of the 

 pan, as it is likely to damage the eggs if poured directly down upon them. 



In the white-fish eggs it was observed that before impregnation an 

 egg placed upon a hard substance was easily crushed by a slight pres- 

 sure of the finger, but after impregnation the shell membrane became 

 so tough and turgid that a very strong pressure with the finger failed 

 to break it. 



The assertion is made by nearly all experienced in shad-breeding, that 

 there is a considerable fall in the temperature of the water in the pan 

 containing eggsduring impregnation ; some of them judge from the sense 

 of touch, and others have made the test with a thermometer, the amount 

 of reduction claimed being from six to ten degrees. Having made this 

 test with a thermometer on several occasions, I have to say that it never 

 resulted for me, though on one occasion a very large number of eggs were 

 in the pan. The temperature in the pan was 69° when the milt was applied, 

 and the thermometer was put into the pan and the bulb immersed and 

 allowed to remain, showing not the least change, though every phenom- 

 enon of impregnation occurred. When the changes of water were made 

 the thermometer was each time inserted, but showed the same tempera- 

 ture as the river, the test being continued nearly one hour. 



10. — THE SUSQUEHANNA, DELAWARE, AND HUDSON RIVERS. 



On the Delaware Eiver, hatching operations were begun by Dr. J. H. 

 Slack, with Mr. Holton and Chester Green, at Lambertsville, N. J., on 

 June 12, and continued until June 27, resulting in the placing of 433,000 

 young shad in the Delaware and 15,000 in the Monongahela, at Greens- 

 burgh, Pa. 



The hatching-station at Washington was broken up on the lltli ot 

 June, and the same evening, accompanied by Mr. Welsher, on his way 

 to Marietta, Pa., to work in connection with the Pennsylvania commis- 

 sioners, and Mr. Mason, we went north to find a later migration of the 

 shad. 



At Newport, the Pennsylvania commissioners, operating with one of 

 Mr. Green's men, had obtained up to date forty-three spawners, out of a 

 little more than one thousand shad taken, and producing, according to 

 Mr. Boehm's notes, 1,500,000 eggs. A greater success would have re- 

 sulted if there had been a regnar fishery establislied at this point. 



We soon ascertained that there was not much prospect of procuring 

 shad for transfer westward, and took the next train for Albany, N. Y. 

 S. Mis. 74 28 



