774 REPORT OF COMMISSIONER OF PISH AND FISHERIES. [12] 



would have been five days old to-day bad they survived. These were 

 found to have attained their climax of development on the 25th, after 

 which they began to die rapidly. To-day all traces of our promising- 

 brood of the 22d have vanished from their attachments. 



This ill-fortune we have supposed to be due to the high temperature 

 of the water prevailing since the 23d. To correct this supposed unfa- 

 vorable condition, Colonel McDonald has arranged for a current of well 

 water to flow around the jars in the closed circuit to lower the tempera- 

 ture in the latter and maintain it at an approximately uniform*point. 



J^dy 28. — I again overhauled the slips of mica forming my miniature 

 collecting apparatus in the incubating apparatus, as well as the shells, 

 with the result that no adherent oyster fry was discovered. The abun- 

 dance of compound stalked infusorians as well as test-building species 

 on the surface of the mica collectors was remarkable. The temperature 

 of the water to-day ranged from 82° to 88° F. ; that of the air was 96° F. 



July 29. — I reexamined the collectors put into the incubating appa- 

 ratus of the 22d ; like the search of yesterday it resulted in discovering 

 nothing, although the second lot of ova put in the apparatus No. 1 on 

 the 26th ought to be now pretty well developed. The contrivance for 

 reducing the temperature and rendering it constant in the incubator 

 works very well ; the thermometer in apparatus No. 1 indicates a practi- 

 cally uniform temperature ranging from 79° to 80° F. To test this last 

 modification of the incubating apparatus, I introduced a lot of fertilized 

 ova at 2.30 p. m. to-day. 



July 30. — I find all of the eggs of yesterday dead. Examined the 

 mica, shells, sides of the jars, and sediment, and failed to find any live 

 embryos remaining. The temperature in the jars of the closed circuit 

 with cooling attachment has been maintained uniformly at 78° F. all 

 day. 



July 31. — Search for embryos of the 29th repeated, with no indica- 

 tions of any live ones. I fertilized another lot to-day at 3 p. m. Wind 

 very high, water in the bay very boisterous and muddy ; placed a part of 

 the eggs above mentioned in an aquarium without any provision for 

 changing or aerating the water. I find in fact, by increasing the vol- 

 ume of fresh, pure water in the aquarium to about 200 times the bulk 

 of the water used to fertilize the eggs, that I have no further trouble 

 with i^utrescent action, as was shown by the subsequent behavior of 

 this aquarium. This last lot of ova was not put into the aquarium 

 until a decided advance in their development had been noted. 



August 1. — Embryos fertilized at 3 p. m. July 31 still alive to-day at 

 11 a. m. in the aquarium, into which I had put a few thousands yester- 

 day at 4 p. m. At 4.30 p. m. to-day I put in another lot of ova, which 

 had been fertilized at 3.15 p. m. The impregnation, conducted accord- 

 ing to my new method, was very successful. Some of this new lot were 

 put into the closed circuit and a part into an aquarium with plants. I 

 put none into my plain aquarium, in which I did not change the water 

 or supply with ijlauts. 



