268 THE NATURE-STUDY REVIEW [ 4 :q-uBc.,. q o8 



covered. Later a graph was made which showed these relations 

 in a very striking way. 



One of the first things done was to sketch a young bird in 

 dorsal view, indicating the location of down and of the dark 

 streaks where feathers soon began to appear — the feather tracts. 

 Sketches were also made of the head showing the eyes, the ears 

 and the character of the bill as compared with that of the adult 

 bird. Even the fact that birds have ears was new to some mem- 

 bers of the class. 



The leg and foot were examined and the parts compared with 

 the parts of the human leg and foot. Every one interpreted the 

 ankle joint as the knee. To correct this misconception a study 

 of the frame work of the leg was made from chicken bones (col- 

 lected from the remains of clubhouse Sunday dinners) carefully 

 cleaned and mounted in position upon cardboard. These leg- 

 skeletons were compared with drawings of corresponding parts 

 in the human skeleton and we discovered that a bird stands upon 

 its toes and that "its heel is well up the leg." 



We also noticed the little bare wing, the end of which much 

 resembled a tiny mitten with hand and thumb. The framework 

 of the wing was studied in the same manner as the leg and its 

 parts compared with those of the human arm. We found that 

 the little mitten really covered a hand with two fingers and a 

 thumb. Drawings of both leg and wing skeleton were made and 

 fully labeled. 



By this time, when the birds were six days old, the feathers 

 (still in their sheaths), had become conspicuous and gave the 

 explanation of the dark streaks down the head and back and on 

 the wings. The natal down, the only covering at first, was 

 plainly seen to be growing out from the skin attached to the end 

 of the new feather. In a few hours, at the end of the sheath and 

 still bearing its little shred of down, appeared the vane of the 

 feather, very much resembling a tiny camel's hair brush, the 

 sheath forming the handle. 



Now was the opportune time for studying the structure and 

 development of the feather. Sketches were made and labeled as 

 laboratory work; the minute structures were studied under the 

 microscope, explained and sketched on the blackboard until the 

 relation of barb, barbule and barbicel was clear and the nice 

 adaptation of this wonderful structure- -a feather — was seen in 



