APPENDIX VII. 327 



54. Feed two similar lots of young fry, one wholly on 

 curd, the other wholly on liver, and compare results. 



55. Feed young trout fry plentifully on the young of other 

 fish, as suckers, perch, and shiners, and note the result. 



56. Take young trout fry that are attacked by animal 

 parasites, and give them a salt bath, as described on page 

 258, and note the result. 



57. Observe the effect of the parasites on young fry not 

 subjected to the salt bath. 



Experiments with Large Trout. 



58. Count the number of respirations of large trout at a 

 temperature of 36°, 45 , 70 , and 8o°, and compare the 

 results. 



59. Freeze large trout carefully, but stop the freezing 

 before the body becomes stiff. Thaw out gradually, and 

 note the result. 



60. Let a large trout become motionless from suffoca- 

 tion in still water, then try the effect of vigorous aeration 

 of the water in restoring him. 



61. Ring a bell and make loud noises near trout where 

 you can see them and they cannot see you, and note 

 whether they appear to hear the sounds. 



62. Feed one lot of trout wholly on minnows for three 

 months, and a similar lot on worms, a third lot on meat, 

 a fourth lot on all three, and compare results. 



63. Subject a fish attacked by fungus to the salt bath 

 described on page 258, and note the result. 



64. Cross the various species of the Salmo family with 

 each other, and note and publish the results. 



65. Whoever has the opportunity, and sufficient pa- 

 tience, will render a great service to the fish-cultivating 

 world by fully testing the experiment of breeding in and 

 in with peculiar varieties of trout, as the Chinese do with 

 gold fish, and publishing the results. 



