STERNA OF WINGLESS BIRDS. 315 



must be the one which has the sternal apparatus most 

 exclusively formed for the support of the anterior 

 part of the body only. Thus in it we should have a 

 real analysis of this most characteristic part of the 

 structure of birds, not by mere dissection, where we 

 are left to guess at the use of the organ from its form 

 and its connexion with other organs, but actually in 

 the living bird. By this means we should be able to 

 separate the two functions of the sternal apparatus — 

 the simple and more general, which supports the 

 body of the animal, and the more complicated and 

 variable, which relates to the operation of flying. 



STERNA or WINGLESS BIRDS. 



Wingless, though the epithet commonly given to 

 those birds that are incapable of flight, is not accurate. 

 There is no bird absolutely wingless, even though 

 it should have the bones of the wing wholly within 

 the integuments. When we reflect a little on the 

 matter, we find that such might be expected. A 

 wing is an organ of flight, and the performing of 

 that operation is the chief apparent use of the 

 wing. But the wing is also, independently of its 

 action in flying, an integrant part of the structure of 

 a bird — a part which the bird has, whether it be in 

 motion or at rest. Now, it should always be borne 

 in mind, that an animal is a perfect structure, and 

 that all its parts are in concert, whether it be in a 

 state of action or in a state of repose. One part does 

 not, therefore, merely bear up, or move the other, 

 as in the case of our structures and machines. In our 

 moving structures we have to apply some external 

 'power to put the structure in motion, after all its parts 

 are completed ; but the motive force of the animal 

 is internal, and we cannot locate it to one part of the 



