166 



LIVING CREATURES. 



closely, placing a barb of the vein under a microscope, 

 if possible. 



Procure the bones of a bird that ought to be easily 

 done and see how the frame of the creature is built, 

 and how the different parts suit the habits and pur- 

 poses of the bird's life. The foot is an interesting 

 piece of mechanism. Have you never found, at the 

 joint where the foot and the "drumstick" meet, a 

 tendon or cord which, by being pulled, will draw the 

 claws in ? 



Mallard Duck. 



You can find it in the chicken's foot ; see if it is also 

 in the duck's foot. And now give a reason, if you 

 can, why, when a chicken holds to its roost all night, 

 its foot does not grow tired. If the same arrangement 

 should be found in the duck's foot, of what use would 

 it be, since the duck does not perch? You would find 

 your hand very tired were you compelled to grasp a 

 pole for eight hours without rest. 



