FACULTIES OF THE MIND. 2967 
In many species this active principle not only prompts 
the parent to prepare a suitable receptacle, and. deposit its 
egg therein; but, as in the case of many hymenopterous 
insects, to collect a quantity of food and deposite it in each 
cell, for the support of the larva when excluded. 
The last and most complicated effort of this instinct, 
consists in providing a regular supply of food for the young 
animals, while they are incapable of feeding themselves. 
In the mammiferous animals, the young are supplied. with 
milk at the first, and are accustomed by degrees to partake 
of that food on which they are afterwards to subsist. In 
birds, however, the food must be collected with much in- 
dustry, and, when brought to the nest, distributed in just 
proportions among the callow young. 
In the execution of these various tasks, we never witness 
any symptoms of reluctance or murmuring, the labour being 
performed with chearfulness. Neither can we discover any 
awkwardness, the mark of inexperience. The young and 
the old, guided by this mstinct, perform thei duty with 
equal alacrity and precision. 
c. In each species employing means to secure a suitable 
temperature.—In the case of oviparous animals, care must 
be bestowed to provide for the egg a suitable temperature 
to ensure its hatchmg. |The crocodile prepares a small 
hillock of sand at some distance from the water, with a hol- 
low in the middle, which she lines with leaves and. other 
vegetable matter; then deposites her eggs, and covers 
them over with leaves. The heat from the fermenting 
leaves, joined with that of the atmosphere, soon hatches 
them, Birds remain upon their eggs for weeks together, 
covering them carefully with their bodies, denying them- 
selves, during this period, all the enjoyments of liberty, and 
scarcely taking enough of food and exercise to keep them 
in a healthy state. Even in the interval of absence to obtain 
