FISH-PRESERVES. 115 



prey. In Germany, it is called the Doctor-fisli, 

 and hence its introduction. The Pike is chiefly 

 useful in checking undue increase, so that food may 

 be abundant for those which remain. Each of the 

 ponds should be fished once in three years. The 

 salesmen in London, he states, aU agree, that if a 

 regular supply of fresh-water fish were kept up, good 

 prices and large consumption would be the result : 

 at all events, the system of stocked fish-ponds must 

 be productive of profit, tending to increase the 

 quantity of cheap food, and producing a gain for 

 that which now constitutes a loss. 



The luxurious extent to which Salt-water Vivaria 

 were maintained by the Romans, at the height of 

 their power, is well known. LucuUus cut through 

 a mountain near Naples to introduce sea water into 

 one of his preserves, and many had valuable stores 

 near the shore. Some were of such magnitude, that 

 Hirrius lent Cassar 2000 Mur^enae at one time. 

 Mullets, Doradoes, Scisense, Turbots, Soles, and a 

 variety of shell-fish, were all provided with separate 

 compartments. (Grif. Cuv., x. 670). — Three sea- 

 water preserves are mentioned by Dr. M'CuUoch as 

 existing in Scotland ; one in Wigtonshire, another 

 in Fifeshire, and a third in Orkney ; and the num- 

 ber might be multiplied indefinitely. They are 

 constructed upon the plan of hollowing out a basin 

 or lake of considerable depth, which is to be kept 

 subject to the influence of the tide, although at its 

 lowest ebb a hirge body of inland water is still to 

 be retained. Its only connexion with the sea is 



