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or expense which may have been incurred, and we shall at once own the truth of the Poet's saying, that—
"Each drop of water is a world containing
Creatures more numerous than the men of Earth."
Before proceeding to treat of the Freshwater Aquarium, we may briefly mention a few matters—which, though apparently trifling, are yet essential to the success of the Marine tank, as also the well being of the inhabitants of it.
It has already been stated that it is quite unnecessary to change the water, but it may be well occasionally to aerate it by dipping up a small quantity and pouring it rapidly back into the tank, but even this is opposed to the true principles of "compensation," and need only be resorted to where the animals become sluggish, and the fishes find their way to the surface to obtain there what they should find in their own element. A small syphon of gutta percha or tin will be handy, should it be necessary to draw off or replace the water. The short end must be placed below the surface of the water in the tank, and the mouth applied to it until the water flows, which it will continue to do without further trouble so long as the short end remains under water.
It may so happen, (it is but human nature) that certain species do not dwell amicably with their mates, and others from some cause or the other (not at once apparent) may sicken,—in such a case, remove them without delay to small glass vases where they may be treated as circumstances require. The readiest mode of removing them to and fro is, by means of a small
