ON THE HABITS OF ANIMALS. 127 



without any sense, and yet they show some 

 degree of curiosity by their moving up to a 

 shining object to examine it; and when in 

 danger, they become suddenly suffused with a 

 decided blush of red, and then eject the con- 

 tents of their ink-bag, by which they become 

 concealed from observation. 



The oyster closes its shell when it comes in 

 contact with some objects, and opens it on 

 the flowing of the tide, so that its structure 

 is wonderfully adapted to the wants and cir- 

 cumstances of a creature so apparently un- 

 conscious of a want, or, if it had one, so in- 

 capable of supplying it. 



But let me turn to a higher order of animals ; 

 and I will begin with birds, and their instinct 

 of migration. You are aware that numbers of 

 birds arrive in this country in the spring from 

 far-distant regions, flying over immense tracts 

 of land and sea in one unerring line, and gene- 

 rally doing this in the night. This instinct 

 induces them to seek a warmer climate at one 

 season of the year, and a colder at another. 

 It cannot be supposed that the old birds lead 

 the young ones in these migrations, for it has 

 been ascertained that late broods have taken 



