STRUCTURE OF THE WING . 
7 
away, leaving its beantifnl long tail in the hands of its would-be captor. At last the bird was 
replaced safely in its cage, but presented a very forlorn aspect in consequence of the loss of its 
tail. A very few days, however, showed the tips of some new feathers, that had already 
grown long enough to pass beyond the tail coverts, and in a month or so the long tail was even 
more beautiful than ever. There seems, indeed, to be a very marked analogy between the 
feathers of birds and the tusks or horns of many mammals. Both depend greatly on the sex 
and age of the animal to which they belong, and their shape and dimensions are unfailing 
indications of the vigor or feebleness of their owners. 
The expanse of the outstretched wings of every flying bird is so very great in comparison 
with the size of the body, that there is need of very great muscular development in order to 
give the powerful strokes by which the body of a bird is urged through the atmosphere. It is 
for this purpose that the breast-bone is furnished with the deep keel which has already been 
mentioned, for its projecting edge and sides aflord attachment to muscles of enormous size, 
which are devoted to the purpose of drawing the wing forcibly downwards. Although in the 
gallinaceous birds, of which the common barn-door fowl is a familiar example, the pectoral 
muscle, as it is called, is not so largely developed as in many of the swift- winged birds, it 
attains to considerable dimensions, as may be seen by every one in carving a common fowl, 
whether it be boiled or roasted. This muscle forms the solid and delicately-flavored meat 
which is attached to the wing when removed, and also constitutes the greater part of the 
“ breast.” 
Strength, however, is not the only requisite in a bird’ s wing. It is evident that if the 
stroke were only made upwards and downwards, the bird would never rise in the air, much 
less make any progress forwards. On gently moving the wing of a dead bird, we shall see 
how beautifully its opening and closing is managed, so that on the stroke the feathers beat 
the air with their flat sides, but present their sharp edges as they return for another stroke. 
This movement is copied by the oarsman as he throws back the blade of his oar for another 
stroke, and is called “feathering,” on account of the source from which it is derived. The 
means by which this object is attained is through a most perfect and beautiful arrangement of 
the wing muscles, which are so fashioned as to give the wing a slight and involuntary turn just 
as it is thrown backwards after making its stroke. 
The reader who desires to understand this curious structure, cannot do better than to 
denude the wing of some bird of its feathers, to remove the skin, and lay bare the muscles. 
If he then moves the wings as if in flight, he will see, by the play of the different muscles, the 
part which they take in the general movement, and the wonderful harmony in which every 
individual muscle works with its fellows. Next let him pass a smooth but blunt edge, such 
as a small paper-knife, or the flat handle of a scalpel, between the different muscles and sepa- 
rate them throughout their entire length. By pulling each muscle in turn with a pair of 
forceps, he will see its object, and will be able to form a very good idea of the manner in 
which all the muscles act while working simultaneously in moving the wing. 
In the generality of birds, the senses of touch and taste seem to be but little developed, 
while those of sight, hearing, and smell are decidedly acute. 
The sense of touch can be but very slight in a creature that is covered with feathers 
over the whole of its body ; whose limbs are either plume-clad or tipped with horn, and whose 
mouth is defended by a hard, horny beak. There are exceptions in the case of the ducks, 
and many similar birds, whose beaks are soft and evidently possessed of delicate tactile 
powers, but in the generality of birds this sense is decidedly dull. Taste, again, can have but 
little development, as the tongues of most birds are devoid of the soft and sensitive sur- 
face which is found in the tongue of man and the mammals in general. At the base of the 
tongue the nerve-bearing papillae are found in some genera of birds, but even in them these 
organs of taste occupy but a small portion of the tongue, and can give but little indication 
of savor. In many birds, indeed, such as the woodpecker and the humming-bird, the tongue 
is employed in a manner analogous to the same organ in the ant-eaters, being used to pro- 
cure food and to draw it into the mouth. This structure will be described more at length 
when we come to treat of the birds where it is especially developed. 
