Chap. VII. 



THE EFFECTS OF DISUSE. 



271 



length of the femur and tibia with the humerus and ulna, and likewise 

 these same bones with those of G. bankiva ; the result was that the wing- 

 bones in all the breeds (except the Burmese Jumper, which has unna- 

 turally short legs) are slightly shortened relatively to the leg-bones; 

 but the decrease is so slight that it may be due to the standard specimen 

 of 0. bankiva having accidentally had wings of slightly greater length than 

 usual ; so that the measurements are not worth giving. But it deserves 

 notice that the Silk and Frizzled fowls, which are quite incapable of 

 flight, had their wings less reduced relatively to their legs than in almost 

 any other breed ! We have seen with domesticated pigeons that the bones 

 of the wings are somewhat reduced in length, whilst the primary feathers 

 are rather increased in length, and it is just possible, though not pro- 

 bable, that in the Silk and Frizzled fowls any tendency to decrease in the 

 length of the wing-bones from disuse may have been checked through the 

 law of compensation, by the decreased growth of the wing-feathers, and 

 consequent increased supply of nutriment. The wing-bones, however, in 

 both these breeds, are found to be slightly reduced in length when judged 

 by the standard of the length of the sternum or head, relatively to these 

 same parts in 0. bankiva. 



The actual weight of the main bones of the leg and wing in twelve 

 breeds is given in the two first columns in the following table. The 

 calculated weight of the wing-bones relatively to the leg-bones, in com- 

 parison with the leg and wing-bones of G. bankiva, are given in the third 

 column,— the weight of the wing-bones in G. bankiva being called a 

 hundred. 73 



Table I. 





Names of Breeds. 



Actual 



Weight of 



Femur and 



Tibia. 



Actual 



Weight of 



Humerus and 



Ulna. 



Weight of Wing- 

 bones relatively to 

 the Leg-bones, in 

 comparison with 

 these same bones 

 in G . bankiva. 



1 



2 

 3 

 4 



5 



6 



7 



8 



9 



10 



11 



12 



Gallus bankiva . . . . wild male 

 Cochin male 



Spanish (Minorca) . . male 

 Gold Spangled Polish male 

 Game, black-breasted male 



Sultan male 



Indian Frizzled . . . . male 

 Burmese Jumper . . female 

 Hamburgh (pencilled) male 

 Hamburgh (pencilled) female 

 Silk (black-boned) . . female 



Grains. 



86 

 311 

 557 

 386 

 306 

 293 

 231 

 189 

 206 



53 

 157 

 114 



88 



■ Grains. 



54 



162 



248 



183 



145 



143 



116 



94 



88 



36 



104 



77 



57 



100 



83 



70 



75 



75 



77 



80 



79 



67 



108 



106 



108 



103 



It may be well to explain how the 

 calculation has been made for the third 

 column. In G-. bankiva the leg-bones 



are to the wing-bones as 86 ; 54, or as 

 (neglecting decimals) 100 : 62 ;— in 

 Cochins as 311 : 162, or as 100 : 52 ;— 





