792 REPORT OF COMMISSIONER OF FISH AISD FISHERIES. [< ] 



placed in the ice chest, could be seen as a dark band around one side of 

 the yelk. These eggs continued their development, or at least a goodly 

 proportion of them did, up to the middle of the fourth day, when they were 

 ■well developed, showing eyes, protovertebrae, ear-cavity, and the heartas 

 a single-chambered pulsatile organ. They appeared to be healthy and in 

 good condition ; but gradually the water became filled with sloughs and 

 decomposing animal matter, and early in the fifth day, or by the morn- 

 ing of the 17th of June, the fish were all dead. The eggs were accord- 

 ingly thrown away and the apparatus again cleaned and placed in readi- 

 ness for a third trial. 



It had become pretty evident that the trouble was in the water, and 

 we determined to try the next time the effect of more thorough aeration 

 upon it. Accordingly at 30 p. m. of June 17 a third lot of about 50,000 

 eggs was placed in the cone, with the water in the supply-reservoir at 

 72°. By 7 a. m. of the 18th the temperature had been brought down 

 to 64°, and by 12 a. m. to 53°. It was kept thereafter during the trial 

 at an average of 51°. At intervals of two to three hours after the 

 water had commenced running, the water in the supply reservoir and 

 that in a second cone, Fig. 3, /t, which had been arranged to receive 

 the outflow^ of the first before the water passed into the second leservoir^ 

 was thoroughly agitated for five to ten minutes. This was accom])lished 

 by the use of a dipper, running the dipper down deep in the vessels and 

 getting the water from near the bottom, then lifting the dipper high 

 above the vessels before pouring it back, so as to give the water as 

 much of a fall as possible. In addition to this method of purifying the 

 water a certain quantity was taken two or three times each day from 

 the surface of the hatching-cone. In this manner it was intended to 

 take of that water which had just passed over the eggs about the same 

 quantity that would be added to the supply-tank as fresh water by the 

 melting of the ice, and in taking it from the hatching-cone any sloughs 

 or dirt which had accumulated around the top of the cone could be in- 

 cluded. Under this treatment the eggs progressed in their develop- 

 ment and appeared in fine condition uj) to the middle of the fifth day, 

 or one day longer than those of the second lot. At this time they were 

 at the same stage of development as the second lot upon the fourth day ; 

 but it is to be borne in mind that the second lot was started in warmer 

 and fresh water before being placed in the cone, while these passed 

 through their entire development in the stale water. On the afternoon 

 of the fifth day the water, despite the constant aeration, began to 

 have a rank, fishy odor and to foam slightly in the supply-reservoir. 

 Notwithstanding this the eggs appeared in a good and healthy con.lition. 

 On the morning of the sixth day, however, or the 23d of June, the foam 

 on the water was very considerable in amount and the eggs were quite 

 noticeably affected. As much of the water as couhl i)ossibly be spared 

 was then taken off through the hatching cone, together with as much 

 of the slough and dead material ;is could be scpaiated from the good 

 eggs, and a filter of charcoal i)laced under the supi>ly tube of the supply- 



