CH. III.] DESTRUCTION CAUSED BY LARGE JACK. 43 



contained a good supply of white fish, they rather 

 lost than gained weight, probably, as Mr Maltby 

 imagines, in consequence of there being a smaller 

 body of water running through it, and that colder, 

 from being nearer the source. 



At the commencement of the year 1857, he had 

 purchased and turned into the Lake at Boilsfut 

 nine hundred Carp of a particularly good breed, 

 weighing, one with another, a pound each; but of 

 these, when the water was let out in the month 

 of October, not a single one was to be found, the 

 Jack not having suffered a solitary individual to 

 escape them. Since that time Mr Maltby has 

 allowed no Jack to be put into his water, as stock, 

 above a pound in weight, which (as younger fish 

 do not gain weight so fast,) will not increase in 

 a year to more than about three or four pounds. 

 It is only after attaining that weight that their 

 growth becomes so astonishingly rapid. 



In the Lake at Boilsfut, Jack, Perch, and 

 white fish breed fast, but the fish born in that 

 Lake do not increase so fast by two-thirds as 

 those born in La Hulpe; so that, although their 

 transport from the one to the other is expensive, 

 yet it is made up for by the increase of weight in 

 the fish transported. 



