NATURAL HISTORY MISCELLANY. 659 
where the eggs are hatched, and, on the young leaving these sacs, 
they fall off. The young, according to Carpenter, undergo five 
changes in their development. 
Besides these little creatures we have mentioned there are many 
more about which much might be said. 
We have monads, vibrios in great numbers, always present in 
the water of our aquarium: not only there we may state, but in 
the Montreal water this spring we detected shee 
in two instances, living vibrios in the wi Sow 
water immediately taken from the pipe. 
In concluding this sketch of the inhabi- 
tants of our aquarium the following re- 
marks may not be out of place. 
How little is known, by the great mass 
of mankind, of the various creations pos- 
sessed with the wonderful and unknown 
principle, ‘life,’ respecting which much 
more might, perhaps, be known by means 
of patient microscopic research. By its 
aid we may learn how admirably each little 
organ plays its part, and how the various 
members contribute to each of these crea- 
tures’ happiness in their struggle for life, 
for, for some wise purpose, every animated 
being, from the monad to the whale is bat- 
tling for existence. 
There is not, perhaps, a single species of 
animated being whose existence depends 
not, more or less, upon the death or de- 
struction of others. 
In the plan of nature death and dissolution seem to be apei 
sable for the support and continuance of animal life. 
Man may be said, with a few exceptions, to have universal ‘i em- 
pire over the other animals. Carnivorous animals and birds are 
also engaged in this general work of destruction. 
In fishes, also, as their habits demonstrate, from the least to the 
greatest, their appetite is almost insatiable, and their object in 
life seems to be either to devour other fishes or to avoid their own 
destruction. 
Insects, also, are no or to the rule. 
AMER. NATURALIST, VOL 42 
We find the same 
