THE BONES. 



39 



parts arising from the prevailing opinion that the part c D 

 in the bird's limb is the part which corresponds with what 

 we usually term the leg, namely, B to c, that is, from our 

 knee to our ankle ; whereas, the bone B c in the limb of the 

 bird is, in fact, its real leg-bone. For its thigh we must 

 look still higher, hidden as it usually is amongst the 

 feathers, and, probably, by many, scarcely known to exist. 

 The great difference between the limbs of birds and human 

 beings consists in this, that what we are apt to term the leg 

 of a bird is, in fact, the part which answers to our ankle. 

 This will be easily seen by a little closer examination. Let 

 us look, then, at the joint B in the two figures: in the 

 human figure it is at once seen to be the knee, and on 

 referring to the same letter in the leg of the bird, we shall 

 find that it is the true knee also ; for supposing it to kneel, 

 that is, to bend its leg, so that the fore part of the joint 

 should touch the ground, it can only do so at the joint B, 

 it being as obviously impossible from the structure of the 

 joint c, that it could bend the part c D forwards, so as to 



