FACULTIES OF THE MIND. 267 



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 hyrnenopterous 

 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 instinct, perform their 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 hatching. 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 alienee to obtain 



