THE BALANCE OF LIFE IN THE AQUARIUM. 43 5 



with which the next are painted, and we live man and brute on the 

 debris of the past. 



I see all this and more in the aquarium ; it teaches me lessons in 

 physics, and, I trust, also teaches me that the moral and spiritual truths 

 of the universe may be illustrated, sometimes explained, by a patient 

 study of the commonest things. The aquarium is a world in little ; it 

 sustains itself. For the moment, I put aside the law of gravity as a 

 universal law, and the presence of the atmosphere as a universal thing, 

 and I call it a world, needing no aid, for its continuance and the per- 

 fect adjustment of its balance of power, from external things. I take 

 a vessel of glass, a few pebbles, a few pieces of sandstone-rock, and a 

 sufficiency of water, and to that I commit my fishes and insects, and 

 say, " There is your world ; the order of Nature is such that you may 

 henceforth live and die without human interference." I say nothing 

 here of the details of management ; I am looking for instruction in the 

 laws of life and death. 



The two requisites of animal life, food and air, must be generated 

 in this world, or it ceases to instruct me ; yet the water contains but 

 little of each, and whence is its supply to come ? God has ordained 

 such a wealth of organic forms that, wherever the conditions of life are 

 found, life takes possession of the spot, whether it be the bottom of the 

 ocean, the dripping roof of a cave, the expanse of the viewless air, or 

 the mimic lake I call an aquarium. Forthwith the dead stones become 

 alive with greenness, the glass walls assume the semblance of a 

 meadow, the milky hue of the water disappears as the earthy particles 

 it held in solution subside, and the light that streams through it takes 

 a tint of greenness. There is an order of vegetation appointed to oc- 

 cupy such sites, and almost every non-metallic, and some metallic sub- 

 stances too, become speedily coated with conferva?, when their surfaces 

 are kept moist a sufficient length of time. Were it not so, the inhabi- 

 tants of my world must perish ; and to prove the fact I try an experi- 

 ment. I place some fishes in a clean vessel of water, without pebbles 

 and without rock ; the moment the first dim bronzy speck appears, I 

 rub it off the glass, and so thwart the course of Nature. The fishes 

 soon exhaust the water of its oxygen, and though the water attempts 

 to renew its supplies by absorption from the atmosphere, the compen- 

 sation is too slow, the fishes come gasping to the surface, and in a 

 short while perish. 



Even then I learn something from their death if I leave the vessel 

 in the hands of Nature. Death has no sooner spread his black banner 

 over my household gods than life of another kind arises to confound 

 him, and the microscope reveals to me myriads of animals and plants, 

 and organisms that seemingly occupy an intermediate place between 

 the two great kingdoms, rioting upon the wreck that death has made. 

 My half-dozen dead fishes have given birth to existences numerous aa 

 the stars in heaven, or as the sand upon the sea-shore, innumerable. 



