182 
ANIMAL PHYSIOLOGY. 
depend almost solely upon this useful animal 
for their existence. No extremes of tempe- 
rature in our atmosphere seem inconsistent 
with animal life. In the little pools formed 
by the temporary influence of the sun upon 
the surface of the arctic snows, animalcules 
have been found in a state of activity ; and the 
tracts of red snow, which frequently cover the 
surface of arctic and alpine regions for miles 
in extent, are formed, not merely by the little 
cryptogamic plant elsewhere described (Veget. 
Phys. § 48), but by incalculable multitudes of 
certain species of animalcules, and by the eggs 
of other kinds. And the ocean of those in- 
hospitable regions is tenanted, not only by the 
whales and other monsters which we think of 
as their chief inhabitants, whose massive forms 
are only to be encountered ' few and far be- 
tween,' but by the shoals of smaller fishes, and 
inferior animals of various kinds, upon which 
they feed, and through the vast fleets of which 
the mariuer sails for many miles together. 
" On the other hand, even the hottest and 
most arid portions of the sandy deserts of 
Africa and Asia are inhabited by animals of 
various kinds, provided that vegetables have 
existed there. The humble and toilsome ants 
make these their food, and become in turn the 
prey of the cunning ant-lion and of the agile 
lizard ; and these tyrants are in their turn kept 
under by the voracity of the birds which are 
adapted to prey upon them. The waters of 
the tropical ocean never acquire any high tem- 
perature, owing to the constant interchange 
which is taking place between them and those 
of colder regions ; but in the hot springs of 
various parts of the world, we have examples 
of the compatibility of even the heat of boiling 
water with the preservation of animal life. 
Thus, in a hot spring at Manilla, which raises 
the thermometer to 187 degrees, and in another 
in Barbary, whose usual temperature is 172 
degrees, fishes have been seen to flourish. 
Fishes have been thrown up in very hot water 
from the crater of a volcano, which, from their 
lively condition, was apparently their natural 
residence. Small caterpillars have been found 
in hot springs of the temperature of 205 de- 
grees; and small black beetles, which died 
when placed in cold water, in the hot sulphur 
baths of Albano. Intestinal worms within the 
body of a carp have been seen alive after the 
boiling of the fish for eating ; and the inhabit- 
ants of some little snail-shells, which seemed 
to have been dried up within them, have been 
caused to revive by placing the shells in hot 
water for the purpose of cleaning them. 
" The lofty heights of the atmosphere, and 
the dark and rayless depths of the ocean, are 
tenanted by animals of beautiful organization 
and wonderful powers. Vast flights of butter- 
flies, the emblems of summer and sunshine, 
may sometimes be seen above the highest peaks 
of the Alps, almost touching with their fragile 
wings the hard surface of the never-melting 
snow. The gigantic condor or vulture of the 
Andes has been seen to soar on its widely- 
expanded wings far above the highest peak of 
Chimborazo, where the barometer would have 
sunk below ten inches. The existence of 
marine fishes has been ascertained at a depth 
of from 500 to 600 fathoms ; and in the Arte- 
sian well lately sunk in Paris to a depth of 
about 1800 feet, the water has recently brought 
up a number of small black fishes, which, 
being without eyes, seem to have been pro- 
duced in the depths from which it springs." — 
Pp. 10—12. 
The author, in his first chapter, expatiates 
on the vital operations of animals, and the in- 
struments by which they are performed. We 
are then introduced to a general view of the 
animal kingdom, which is described as in five 
divisions, and beautifully illustrated with en- 
gravings, showing the internal and external 
structure of some of the most important in 
each class. The next chapter treats of the 
nature and sources of animal food ; and here 
the author explains fully the various modes of 
procuring it, the effect of the food upon the 
different species, the animals that live on each 
other, and takes a general review of all the 
important tribes, down to the lowest order of 
animal creation. From this he proceeds to 
discuss the process of digestion and absorp- 
tion ; and there are engravings of the diges- 
tive organs of various animals, from man down 
to the beetle. We come now to a description 
of the blood and its circulation, in which the 
arterial systems in man and inferior animals 
are well illustrated ; and the next chapter ex- 
plains the act of respiration, and its effects on 
the system, or rather, the part which it per- 
forms in animal life. Then follows, succes- 
sively, remarks on secretion, and the general 
purposes of the secreting process, the nutritive 
operations, animal luminousness, heat, and 
electricity. The functions of the nervous syS'- 
tem, with illustrations, occupy a large portion ; 
and not much less is taken up with an inte- 
resting review of the various senses, the power 
of motion, nature of the voice, and instinct, 
and intelligence; and deeply interesting is the 
general review of the habits and architecture 
among the various tribes, many of the most 
remarkable being brought forward with appro- 
priate illustrations, showing not only the nu- 
merous modes of building their habitations, 
but their contrivances to procure and preserve 
food, and various other manifestations of intel- 
ligence. The comparison between man and 
other animals is curious, and the conclusion 
of the chapter is worth quoting. r . He says — 
