112 Practical Zoology. 



2. Take one of the body feathers, and compare it with the 

 quill. In what lies the chief difference? 



3. Find a feather that is wholly composed of "down," if there 

 be such ; examine the " down " with a microscope. 



4. Pick a small part of the breast, and study one of the fine, 

 hairlike pinfeathers. How does it differ from the feathers already 

 examined ? 



5. Take a primary feather that is in good condition and set it 

 erect in the hole in the end of a trunk key. The hole should 

 be deep enough to hold most of the length of the free end of the 

 quill, but must not be so deep as to catch the vane and interfere 

 with the free rotation of the feather. Instead of a key you may 

 use a spool, piece of glass or metal tubing, or anything with a 

 smooth hole of suitable depth and width. Now hold the feather, 

 thus supported, vertically before your face and gently blow against 

 it. How does the feather turn? In what position does it remain? 

 Try this with the feather in different positions at the beginning of 

 the experiment. Compare the results of this experiment with the 

 observations made in blowing against the inside and outside of the 

 wing, and explain the advantages of the shape, structure, arrange- 

 ment, and mode of overlapping of the feathers. Try the breath 

 on the secondary feathers as above directed. If you were using 

 a quill for a pen, would it make any difference what kind of a 

 feather you took? Would it make any difference whether it came 

 from the right wing or the left wing? 



6. Study the arrangement of the feathers ; do feathers grow on 

 all parts of the body? A fledgeling shows this point well. Push 

 aside the feathers along the line of the ridge of the pigeon's 

 breastbone and examine the skin ; do feathers grow here ? Look 

 for other unfeathered areas. Note how the feathers overlap. 



7. Pick the feathers from one side of the pigeon, just to the 

 middle line ; lay the bird on the feathered side, and make a draw- 

 ing, showing (i) the outline of the feathers, and (2) the outline 

 of the body within. 



8. Pick off all the feathers of a pigeon or hen and weigh them. 



