APPENDIX VII. 305 



19. Pack eggs in moss at the first appearance of the eye- 

 spots, examine and note as before. 



20. Place eggs, as soon as taken, on ice, keep on ice, 

 and see how long they will be hatching. 



21. Freeze eggs solid, in water, at different stages of 

 development, and note the result. 



22. Freeze as before in the air. 



23. Place a few eggs on a copper-wire screen, and 

 note the discoloration and absorption of copper. 



24. Allow a few eggs, after the eye-spots appear, to re- 

 main considerably covered with sediment, and note the 

 deformity of the embryo when hatched. 



25. Subject eggs of different ages to high temperatures 

 of water, and note what degree of heat they will live 

 through. 



Experunents with Alevins cuid Yoiing Fry. 



26. See how long five alevins will live in a gill of water 

 at 36°, at 42°, at 50°, at 60°, at 70°. 



27. Freeze alevins solid, thaw out, and return to the 

 water in hatching box, and watch for a month. Mem. : 

 Take care, during the freezing, not to disturb the fish, as it 

 will tear itself against the forming ice, and die from the ef- 

 fect of the laceration. The best way to freeze eggs or 

 young fish is to take a dry glass tumbler which has been 

 exposed to a great degree of cold, and pour into it the 

 specimens to be experimented with, together with about a 

 spoonful of water. The water, with the specimens, will 

 'mmediately freeze solid. 



28. Expose alevins to a rising temperature, and note 

 what degree of heat they will survive. 



Experhnetits with Young Fiy. 



29-31. Repeat with trout fry the experiments with 

 alevins marked 26, 27, and 28. 



