268 PHILOSOPHY OF ZOOLOGY. 
food, some birds, as the common duck, cover the eggs care- 
fully with down and straw to preserve their warmth, and 
probably likewise to conceal them from foes. When the eggs 
are hatched, the old birds for some time continue to sit at in- 
tervals on the young brood, to preserve their temperature. 
Among the mammiferous animals, the same instinctive 
carefulness, when requisite to keep their young offspring 
warm, is equally apparent. Some make a common bed, as 
the sow, and permit the young ones to lie in her bosom. 
The rabbit, on the other hand, covers her young ones at the 
first with hair, and closes up the entrance to her nest, to 
prevent the circulation of cold air. 
d. In each species keeping its own offspring im a suit- 
able state of cleanliness.—The circumstances attending the 
birth of many animals, call for the immediate exertion of 
the parent to remove those things which at the time or af- 
terwards would injure or incommode. ‘Thus, in the nests 
of birds the fragments of the eggshells, if permitted to 
remain, would bruise and otherwise injure the young. 
These, however, the parent birds take up in their bill, 
and remove them to a distance. In the case of young 
quadrupeds, the rapidity of evaporation from their moist 
surface, immediately after bth, would prove injurious to 
them. But the mother, as may be seen in the case of the 
sheep, cow, or mare, forgetting the pains of parturition, be- 
gins to lick the hair and make it dry. 
But these are not all the evils which the instinctive 
power we are now considering prompts the parents of ani- 
mals to remove. Before the young birds are capable of 
voiding their excrement over the margin of the nest, the 
old ones convey away the mutings, which are at first cover- 
ed with a pellicle, in their bills, and drop them at a distance 
from their nest. With rabbits and other quadrupeds, 
whose young dwell in holes, and are born blind, without 
