NATURALIZATION OF FISHES. 183 



t 

 larger waters. A supply of fish food which is now pre- 

 carious and only obtained by a long trip to rivers and 

 lakes, might be thus made certain and brought to one's 

 own premises or immediate neighborhood. 



Concerning the hybridizing of fish, I would here re- 

 mark that many erroneous notions prevail, and some very 

 impracticable suggestions have been made by those who 

 should know better, about crossing different genera or 

 species. When fish culture was in its incipiency, some of 

 the learned men of France, amongst whom (if I remember 

 correctly), certain renowned biologists were included, sug-. 

 gested crossing the pike with the salmon. I have no 

 knowledge of any results from experiments of this kind 

 which are reported to have been made at Huningue, but I 

 doubt whether the ova of one genus (to say nothing of that 

 of a different family), can be impregnated with the milt 

 of another. If species of the same genus were even 

 crossed, it is reasonable to suppose that the progeny would 

 not be endowed with reproductive powers. They would, 

 doubtless, be mules. There is a limit to the violation or 

 interference with certain laws of nature, and hybrids when 

 produced, are inferior animals. "We see it in the produce 

 of the horse and ass, where the reproductive power is lost ; 

 and in the mulatto, where the physical condition of the 

 Caucasian or the negro, in most cases, deteriorates. Ex- 

 periments in hybridizing, therefore, may develope certain 

 truths that might be interesting to biologists ; but that 

 new species or mules of larger growth or greater excellence 

 can be thus produced, it is unreasonable to hope for. 



