OF FISHES. 61 



very curious subject for new experiments, — that 

 of crossing the breeds of fishes, and offers a very- 

 interesting and untouched field of investigation, 

 which I hope will soon be taken up by some en- 

 lightened country gentleman, who in this way 

 might make not only curious, but useful discove- 

 ries." 



We have stated the fact that the ova are im- 

 pregnated out of the body of the mother, and it 

 may appear somewhat surprising that the mere 

 pouring of the seminal fluid from the milt of the 

 dead male, is equally successful. The vitality of 

 fishes is of an order so low, that the temperature 

 of the air or of the water, is generally equal to the 

 heat of their blood, — hence no vital property is 

 lost, even in the dead fish, if the experiment is per- 

 formed before the commencement of putrefaction. 



Jacobi, a German experimentalist, on the in- 

 crease of trout, and salmon, has satisfactorily set- 

 tled the question, that this operation can be done 

 very readily. That gentleman raised his own 

 trout, from the egg, which he accomplished in the 

 following manner. He had a box, with a wire gra- 

 ting at one end, for admitting the water, freely, 

 from a lively stream — and holes, at the other end 

 for the same water to pass out : thus there was a 

 running course over small pebbles, placed on the 

 bottom. In November and December, when the 



