LARKS, WOODPECKERS, ETIC. 189 
of a surgeon who cuts away diseased flesh in order to 
save the life of his patient. 
The structure which enables these birds to carry 
on their mission is worthy of special notice. 
In the first place, the beak is long, strong, and 
sharply-pointed, and, urged by the powerful muscles of 
the neck, is admirably adapted to its task of chipping 
away the wood. ‘Then the tongue is not only un- 
usually long and slender, and so capable of insertion 
into the narrow tunnels cut by its insect victims, but 
is barbed in a rather singular manner at the tip, and 
lubricated with exceedingly glutinous saliva. Accord- 
ing to some authorities, the larger insects are trans- 
fixed by the bristle-like barbs, while the smaller 
adhere to the tongue on account of its glutinous 
properties ; others contend, however, that all insects 
alike are captured by the agency of the saliva alone. 
Again, as the bird must necessarily cling to the 
trunk itself while working away at a tree, the toes are 
long, and the claws sharp, curved, and extremely 
strong. The breast-bone, moreover, is much less 
prominently ridged than in the majority of birds, so 
that the body can be pressed closely against the tree, 
and the leverage upon the limbs minimised ; while, 
lastly, the feathers of the tail are so stiff and strong 
that the bird uses them as a kind of stool, pressing 
them upon the bark, and resting the greater part of 
its weight upon them. 
It will thus be seen that the entire frame of the bird 
is modified in accordance with its work, an admirable 
illustration of Nature’s law that structure shall always 
