TACTILE SENSIBILITY. 
53 
we find a tongue which, by its softness and nervous organization, 
renders taste possible. In all other species the organ is so hard and 
rudimentary that it cannot produce the phenomenon of taste, inasmuch 
as no dissolution of the food takes place. As some prefer a certain 
kind of food, it is thought that this food pleases their palate more than 
any other. But one grave objection may be urged to this conclusion, 
— namely, that the birds swallow without masticating. 
Touch, or tactile sensibility, is, as Nicholson remarks, very poorly 
developed in birds. Their body is entirely, or almost entirely, covered 
with feathers ; the anterior limbs, being converted into wings, are 
useless as tactile organs; and the posterior limbs are clothed in feathers 
or homy scales. No doubt the tongue is an organ of touch, as well as 
of prehension ; but being generall}' encased in a stiff, horny sheath, it 
cannot possess an acute sensibility. " In some birds, however, such as 
the common duck, the texture of the bill is moderately soft, and it is 
richly supplied with filaments of the fifth nerve ; so that in these cases 
tlie bill doubtless constitutes a tolerably efficient tactile organ." And 
for the same purpose is probably used the " cere," or fle.shy scale, found 
at the base of the bill in some species. 
So far as general sensibility is concerned, the bird cannot be pro- 
nounced defective ; and to external influences he is particularly sen- 
sitive. The ancients remarked what the moderns have confirmed ; 
the accuracy with which atmospheric changes are felt and foretold by 
the bird. Thus Virgil says, as rendered by Dryden : — 
" Wet weather seldom hurts the most unwise, 
So plain the signs, such prophets are the skies : 
The wary crane foresees it first, and sails 
Above the storm, and leaves the lowly vales 
The swallow skims the river's watery face 
The crow, with clamorous cries, the shower demands, 
And single stalks along the desert sands." 
The reader cannot fail to have noticed the evident depression 
of birds during inclement weather, and the striking revival of their 
gaiety and liveliness when the sunshine returns : — 
" Then thrice the ravens rend the liquid air, 
And croalving notes proclaim the settled fair. 
