98 



cept for the purpose of inspection. The fish in these 

 three boxes have suffered but little natural loss, have 

 grown quite rapidly and are now from one to one and 

 a half inches in length. They were hatched April 20tl] 

 and placed in the boxps the same day. 



Three lots of fry of different hatchings were placed in 

 small aquaria a,t the batching station and have been fed 

 exclusively o,n, plankton from the river, daily towings 

 being made for the purpose. These have grown faster 

 than those in the river. Pive or six specimens are fully 

 two inches in length, and twenty or more have already 

 developed the adipose (^orsal. 



Under a microscope the stomach contents of the 

 aquarium fry sjiow some microscopic forms, but for the 

 most part comprise only such forms as are clearly visi- 

 ble to t,he unaided eye. In the aquaria, these forms 

 dart about with great activity, a fiea-hke movement 

 that often enables them to elude their pursuers, thougl^ 

 singled out ancl followefl and struck at repeatedly by the 

 same fish. Their vigilance and ability to suddenly 

 vamose, and the difiiculty with which their capture is 

 effected by strong and vigorous fry, suggests the 

 thought that if the regimen of the millions of half- 

 starved and emaciated fry that have been turned out_, 

 was restricted to this particular class, of, forms, their 

 failure to report later on is readily accounted for. 



The results of these experiments, meagre though 

 they may be, have a special value in that they strongly 

 indicate that a reasonably exact knowledge of all the 

 essential conditions to be considered in planting, are 

 within our reach. We are enabled to catch a glimpse 

 of what it seems possible to accomplish through a sys- 

 tematic and scientific investigation of the waters, with 

 special reference to the white fish problem, and along 

 the line of inquiry siiggested by these experiments. 

 Several years ago an investigation of this nature was 



