59 



I need scarcely say that the fish-culturist should examine the 

 waters in which young fishes are planted, in order to determine 

 the amount of their appropriate food available. It is not im- 

 possible that myriads of whitefish have been set free to perish 

 by starvation before the feeble fry could disperse widely enough 

 to secure a single meal. It seems to me also, that in every case 

 where it is proposed to introduce a new fish into waters already 

 populated, the first question to be asked should be, what fishes 

 do these waters already contain — and in what numbers — whose 

 food and whose relations to nature generally are substantially 

 the same as those it is intended to introduce ? 



And, finally, I would call attention to the necessity of keep- 

 ing continuous watch of the balance and abundance of plant and 

 animal life in its various leading forms in any body of water in 

 which it is thought desirable to maintain especial kinds of 

 fishes in the greatest number possible. The owner of a fish 

 pond especially, who makes himself acquainted with the entire 

 collection of animals and plants which his pond contains, and 

 keeps the run of these in their variations of number and habit, 

 from season to season and from year to year, will not only get 

 some practical hints thereby, which will aid him in the multipli- 

 cation and preservation of his fish, but will derive no small 

 amount of pleasure from his observations, and from the reason- 

 ings and reflections to which they will give rise. 



NOTE ON THE FIRST FOOD OF THE WHITEFISH. 



An elaborate account of this research was published in 1883, 

 in the first volume of the Bulletin of the Illinois State Labo- 

 ratory of Natural History ; but as this article was not widely 

 distributed among fish-culturists, the great practical importance 

 of the subject, will perhaps, justify the following extracts from 

 it : More light was thrown upon the earliest food habits of these 

 fishes by the discovery of raptatorial teeth upon the lower jaw, 

 than by the dissections of their alimentary canals. All the 

 families of fishes which I had previously studied whose young 

 were provided with teeth, were found strictly dependent at 

 first upon Entomostraca and the minuter insect larvae ; while 



