92 THE STRUCTURE AND LIFE OF BIRDS chap. 



thigh-joint moved rather more than half an inch, the 

 movement of the sternum being almost too slight to 

 measure. I do not wish to represent this experiment 

 as one of much value. However, the conditions of 

 flight were so far reproduced that the weight of the 

 body was hanging upon the wings and so hindering 

 the movement of the breast while leaving the back 

 free ; it is true, there was none of the pressure — which 

 during flight must be very great — of the wings upon 

 the coracoids and clavicles. But would not the only 

 effect of this pressure be to render the breastbone and 

 the bones united with it still less ready to move ? 

 When a bird flies with his body sloping upward, as 

 he always does when he wishes to rise, I believe the 

 process of breathing will be the same, with the 

 difference that the Latissimus Dorsi will not contract 

 sufficiently to raise the back nearly to the horizontal. 

 There is yet another posture which birds commonly 

 adopt, and in which the problem of breathing does not 

 seem altogether a simple one. A chicken sleeps with its 

 breast resting on its perch. And gulls, geese, ducks, 

 and other birds will often lie with their breasts on the 

 ground. In this case the movement of the breast is 

 out of the question, and sometimes ocular evidence 

 may be obtained that it is the back that moves. I 

 have spent a considerable time in watching a Chinese 

 goose at the Zoological Gardens, while it lay on its 

 breast and uttered loud and uncouth noises. The 

 hinder part of the back rose visibly. And this was 

 not surprising, for there was no weight upon the legs, 

 and it is this of course which makes back-breathing 

 impossible when the bird is in a standing posture. 



