42 THE AMERICAN MONTHLY [Feb. 



capabilities of the winners of these prizes, I will here 

 state that I am writing this series from a personal ex- 

 perience with the matter, having myself practically kept 

 fresh water (and I may add, also marine) aquaria for a 

 good many years. The system and details of working 

 laid down are, therefore, the result of practical knowl- 

 edge. 



I do not think it is necessary, in the pages of this 

 journal, to enter very deeply into the science involved in 

 the maintaining of an aquarium. Most of its readers are, 

 doubtless, aware of the compensating action of the vari- 

 ous animal and vegetable organisms, whereby the bal- 

 ance of life is kept up, and the fishes, etc., supply car- 

 bonic-acid gas which the plants, if in good health, util- 

 ize in the formation of their tissues, transforming it into 

 pure oxygen, which being dissolved by the water, is 

 taken up by the fishes and other animal organisms to be 

 utilized in the aeration of their blood. From a consid- 

 eration of these facts, it naturally follows that in our 

 aquarium we must have a supply of healthy plants to 

 manufacture the oxygen required, if the fishes are to be 

 kept for a long time in a satisfactory state of prosperity. 

 Given the suitable conditions, and it is perfectly possible 

 to keep the aquarium for many years without changing 

 the water, or moving animals or weeds. In practice I 

 have done this myself, though if the aquarium keeper 

 has a sufficiency of time on his hands, I think an occa- 

 sional turning out and cleaning is more likely to produce 

 a pleasing effect on the eye than leaving the tank to it- 

 self for the longest possible time. A great deal, how- 

 ever, depends upon the amount of water employed. 



In setting up the aquarium, the first thing must neces- 

 sarily be the manufacture of the tank itself. And here 

 we are confronted by the question of the most suitable 

 dimensions. I do not think, in the case of a fresh water- 

 tank, the depth is a matter of very great importance, 



