138 MECHANISM OF THE MUSCLES. 



Fig. 27. 



a, the muscle going over the joint at b, and passing behind the leg, 

 and around the joint at c, and then coining down behind the 

 foot at d, it proceeds to the claws ; and the weight of the bird 

 bending the joints b and c, the muscle is bent at the same 

 time, and the claws are drawn closely and firmly around the 

 perch. 



B. It has often appeared to me wonderful that 

 birds should be able to rest so quietly upon a rocking 

 branch, without losing their hold and falling off in 

 their sleep. I see there is nothing overlooked by 

 the wisdom of the Creator, and that not even a spar- 

 row alights without him. 



A. " In some animals which are sometimes obli- 

 ged to stand for a great length of time, we find curi- 

 ous contrivances for assisting the action of the mus- 

 cles. Thus, the sea birds, as the heron, which wade 

 upon the shores of the sea and in the marches for 



