AQUARIUM. 9 



cated the results of an experiment whicli he had been 

 prosecuting for nearly a year, " On the adjustment 

 of the relations between the animal and vegetable 

 kingdoms, by which the vital functions of both are 

 permanently maintained." Two small gold fish were 

 placed in a glass receiver of about twelve gallons' 

 capacity, covered with thin muslin to exclude dust and 

 soot. The vessel was half filled with spring water, 

 with a bottom of sand and mud, and some loose frag- 

 ments of limestone and sandstone, so arranged as to 

 afford shelter and shade. A small specimen of Valis- 

 neria sjnralis was at the same time planted in the 

 mud, and kept in place by a stone. The whole was 

 then left midistm'bed. 



Everything went on well for a time, till it was 

 found that the natural decay of the older leaves of 

 the plant began to produce turbidity in the water, and 

 a confervoid growth accumulated on the sides of the 

 vessel, and on the surface of the water. To meet this 

 emergency, Mr. Warington introduced a few common 

 Pond- snails [Limnea), which greedily fed on the de- 

 caying vegetable matter and slimy mucous growth, 

 so as quickly to restore the whole to a healthy state. 



The result was now quite satisfactory. The plant 

 throve and increased greatly by offshoots and suckers; 

 the fishes continued to preserve their health and 

 beauty, while the snails deposited enoraious masses 

 of eggs ; thus supplying food for the fishes, as well as 

 performing the office of scavengers. 



Thus the success of the experiment was esta- 

 blished, and an Aquarium was formed in fresh water ; 

 which has continued to prosper to the present time : 



