OCEAN GAEDENS ; 



Valisneria spiralis being planted at the same time 

 in some earth, beneath a layer of sand in the same 

 vessel. All went on well by this arrangement, with- 

 out any necessity for changing the water ; the 

 oxygen given off by the plant proving itself suffi- 

 cient for the supply of its animal co-tenants, and the 

 water therefore remaining clean and pure, until some 

 decaying leaves of the Valisneria caused turbidity, 

 and confervoid growth began to accumulate on the 

 sides of the vessel. To remedy this evil, Mr. War- 

 rington brought to bear the results of previous obser- 

 vations on water in natural ponds under analogous 

 circumstances; and, guided by these observations and 

 their results, he placed a few common pond- snails in 

 the vessel containing his gold-fish and plant of Valis- 

 neria. 



The new inmates, immediately upon their intro- 

 duction, began to feed greedily upon the decaying 

 vegetable matter, and all was quickly restored 

 to a healthy state. They proved, indeed, of still 

 further advantage, for the masses of eggs which they 

 deposited evidently presented a kind of food natural 

 to the fishes, which was eagerly devoured by them, 

 so that the snails became not only the scavengers, 

 but also the feeders of the little colony. And so this 

 first of true Aquaria prospered; the animals and 



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