ADAPTATION OF STRUCTURE TO HABITS. 
227 
not the kind of nourishment which determines the 
structure. 
The equipment of an animal is always adapted to the 
special work it has to perform. Its tools, so to speak, 
are simple, and yet are always of the most perfect 
mechanism; they may be excessively diverse, and yet 
their intimate connection with the home and vocation is 
easily recognizable. This will appear quite clear to us if 
we hold strictly to the assumption that every animal is 
the product of its home, and chooses, almost of its own 
free will, the mode of living which best accords with the 
gifts Nature has bestowed upon it. A judicious selection 
of certain members of the feathered tribe will show us 
the marvellous adaptability of their equipment, namely, 
their construction, plumage, weapons of offence and 
defence, means of motion, colouring, &c. 
Let us first examine a Falcon, the very impersonation 
of a powerful, dexterous and active robber. Its body is 
strongly and compactly built; the breast arched, and the 
skeleton well knit together; it is covered with smooth, 
close-lying feathers; attached to the body we find long, 
pointed wings, the pinion-feathers of which are ex¬ 
ceedingly hard and elastic; the short arm-bones admit 
of great rapidity of movement, and the manner in which 
they are bent affords an ample surface, to which the 
muscles are attached; the tail, which plays the part of 
rudder, is long and rounded, and the feathers of the 
same are broadly webbed, thus offering a large surface 
capable of expansion. The splendid eye renders the 
perception of the smallest and most distant object a 
matter of facility; it is large and concave, and thus 
adapted for seeing at long distances ; added to which 
it is placed forward in the head, and is highly mobile, 
2 H 
