INTRODUCTIQ]^ xxxiij 



of South Americans change the colours of Parrots by 

 plucking out such feathers as they propose shall be 

 altered, and inoculating the spot from which the 

 feather was taken with the milky juice obtained from 

 certain glands of a small toad. The new feathers 

 now appear of a brilliant yellow colour, and on being 

 plucked out, it is said, grow again of the same colour 

 without any fresh inoculation. It taxes human in- 

 genuity to account for savages making such a dis- 

 covery. 



Beak and Feet. — Finally, let us consider the 

 covering of the beak and feet. The jaws of a bird, 

 as we have already remarked, no longer bear teeth, 

 but are ensheathed in horny cases. In many species, 

 as in the Petrels, for example, the beak-sheaths, in- 

 stead of being entire, one for the upper and one for 

 the lower jaw, are made up of a number of separate 

 pieces; while in the Puflfin, and one of the Pelicans, 

 ornamental plates are developed during the breeding- 

 season and shed immediately after. In the Pelican 

 this plate is square in shape, and borne on the ridge 

 of the beak near its middle; in the Puffin it is tri- 

 angular, and is attached to the base of the beak at 

 each side. 



The legs, to use the common term, as a rule are 

 covered, as in the reptile, by horny scales ; but in some 

 birds, as in Grouse, and Sand-grouse, and the Golden 

 Eagle, and many Owls, the shank of the legs, and 

 often the toes also, are covered by long feathers not 

 unlike long, silky hairs, and quite different in char- 

 acter from the quill-like feathers on the legs of the 



