TOUCH. 193 



than with respect to the peculiar structure of their 

 feet ; at least, there can be little doubt that the pea- 

 cock, the bustard, and the ostrich, are more stupid 

 than the sparrow, the torn-tit, and the humming- 

 bird. 



It may certainly improve the tact of such birds as 

 possess the power of turning one of the toes either 

 backwards or forwards at pleasure. The osprey 

 (Pandion halieatus, SAVIGNY), for example, like the 

 eagles, has one back and three front toes, but it differs 

 both in having the outer toe larger than the inner ones, 

 and in this toe being moveable, so that the bird can 

 turn it back at pleasure, a disposition better adapted 

 for grasping the slippery fish on which it feeds, than 

 were it constructed like the feet of other birds. We 

 find a similar structure in the foot of the cuckoo, and 

 Dr. Drummond conjectures " that the cuckoo lays 

 her egg on the ground, and then conveys it in her foot 

 to the nest of its future foster parent *," though M. 

 Vaillant, as we have elsewhere seen, almost proves 

 that the egg is carried in the bill t. Dr. Drummond 

 is also disposed to consider the very large foot of the 

 nuthatch (Sitta Europcea) peculiarly adapted for 

 carrying nuts, and holding them firm till it opens 

 them with its bill. 



In man, the hand is without doubt the principal 

 organ of touch ; but we frequently also use the lips, 

 the tongue, and the teeth, for ascertaining the tactual 

 qualities of things. The teeth indeed, as we have 

 already remarked, have a very delicate perception of 

 some of the properties of substances, particularly 

 their cold, heat, and resistance, and are often em- 

 ployed to discover these properties. The lips, again, 

 form a very important organ of touch, as their mus- 

 cularity fits them so well for taking hold of whatever 



* Letters to a Young Naturalist, p. 207. 

 f Architecture of Birds, p. 376. 



