THE MYSTERIOUS BALANCE. 
151 
spontaneous generation. It is five years since that 
was fitted and stocked, and committed to the manage¬ 
ment of Nature, with the sole exception of the external 
aid afforded by regular supplies of food for its inmates, 
which need not be taken account of, now that we are 
considering it as a world in which the balance of life and. 
death is sustained by the operation of principles ordained 
by the Creator. 
It is when we leave the principles, and attempt to 
classify the details of the scheme, that we become 
bewildered. The smooth revolution of the flywheel and 
the noiseless oscillation of the piston, convince the un¬ 
professional observer of a great engine, that mechanical 
motions are possessed of poetry; but if he would analyze 
the relations of the cog-wheels, the indications of the 
“ governor,” the “gauge/* and the pressure-valve, he 
must descend to hard facts, and forget for a while the 
sublime suggestions of a system of mechanism that throbs 
like a living creature. Admit a full glare of summer 
sun to the aquarium, and forthwith the water loses its 
pellucid fluidity, and becomes deeply tinged throughout 
of a dull green, as if some pigment had been dissolved in 
it. Instead of plants attached to stones and glass only, 
and animals that float unseen, the whole of the water is 
occupied by visible masses of animal and vegetable life; 
and if the fishes suffer, it will be from undue heat, not 
from the addition to the element in which they live of 
this new mass of being. Shut out the sunshine, let the 
fresh air play over the surface of the water, let moderate 
daylight stream through it as before, and speedily the 
green fog clears away, the water again becomes trans- 
