RIVER GARDENS; 
the aquatic plants of his tank haying so perished, 
he found the water become suddenly impure, and 
his fish die. In this state of affairs he had direct 
recourse to the hook of Nature for further informa¬ 
tion. He examined natural ponds, in which a certain 
amount of decaying vegetation must necessarily he 
found, yet without causing putrefaction of the water. 
His next step was, doubtless, to procure por¬ 
tions of such decaying matter, and examine its 
peculiar condition. It was then, we may imagine, 
that he found the remains in question covered with 
Water-snails, which, acting as natural scavengers, 
were consuming the putrescent substances as fast as 
they occurred, and so preventing the results which 
had proved so fatal to his tank. This was his great 
and original discovery. He added Water-snails to 
his tank, and the crowning element of success was 
achieved. Thenceforth his miniature lake went on 
as self-supporting as its great prototypes among the 
mountains, all the main conditions insisted on by 
the laws of Nature having been complied with. 
The reading of the paper containing these interest¬ 
ing facts, and the publication of subsequent essays 
on the same subject, in the “ Annals of Natural 
History,” must give Mr. Warrington the honour of 
being the more immediate founder of the Aquarium, 
12 
