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 G. bankiva.
The actual weight of the main bones of the leg and wing in twelve breeds is given in the two first columns in Table 7.I. The calculated weight of the wing-bones relatively to the leg-bones, in comparison 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. (7/73. 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;--in Dorkings as 557 : 248, or as 100 : 44; and so on for the other breeds. We thus get the series of 62, 52, 44 for the relative weights of the wing-bones in G. bankiva, Cochins, Dorkings, etc. And now taking 100, instead of 62, for the weight of the wing-bones in G. bankiva, we get, by another rule of three, 83 as the weight of the wing-bones in Cochins; 70 in the Dorkings; and so on for the remainder of the third column in the table.)
TABLE 7.I. (Weights in grains.)
COLUMN 1. Actual Weight of Femur and Tibia.
COLUMN 2. Actual Weight of Humerus and Ulna.
COLUMN 3. Weight of Wing-bones relatively to the Leg-bones in comparison with these same bones in Gallus bankiva.
1. 2. 3.
Gallus bankiva -- wild male 86 54 100
1. Cochin -- male 311 162 83 2. Dorking -- male 557 248 70 3. Spanish (Minorca) -- male 386 183 75 4. Gold-Spangled Polish -- male 306 145 75 5. Game, black-breasted -- male 293 143 77 6. Malay -- female 231 116 80 7. Sultan -- male 189 94 79 8. Indian Frizzled -- male 206 88 67 9. Burmese Jumper -- female 53 36 108 10. Hamburgh (pencilled) -- male 157 104 106 11. Hamburgh (pencilled) -- female 114 77 108 12. Silk (black-boned) -- female 88 57 103
In the eight first birds, belonging to distinct breeds, in this table, we see a decided reduction in the weight of the bones of the wing.
In the Indian Frizzled fowl, which cannot fly, the reduction is carried to the greatest extent, namely, to thirty-three per cent of their proper proportional weight. In the next four birds, including the Silk hen, which is incapable of flight, we see that the wings, relatively to the legs, are slightly increased in weight; but it should be observed that, if in these birds the legs had become from any cause reduced in weight, this would give the false appearance of the wings having increased in relative weight. Now a reduction of this nature has certainly occurred with the Burmese Jumper, in which the legs are abnormally short, and in the two Hamburghs and Silk fowl, the legs, though not short, are formed of remarkably thin and light bones. I make these statements, not judging by mere eyesight, but after having calculated the weights of the leg-bones relatively to those of G. bankiva, according to the only two standards of comparison which I could use, namely, the relative lengths of the head and sternum; for I do not know the weight of the body in G. bankiva, which would have been a better standard. According to these standards, the leg-bones in these four fowls are in a marked manner far lighter than in any other breed. It may therefore be concluded that in all cases in which the legs have not been through some unknown cause much reduced in weight, the wing-bones have become reduced in weight relatively to the leg-bones, in comparison with those of G. bankiva. And this reduction of weight may, I apprehend, safely be attributed to disuse.
To make Table 7.I. quite satisfactory, it ought to have been shown that in the eight first birds the leg-bones have not actually increased in weight out of due proportion with the rest of the body; this I cannot show, from not knowing, as already remarked, the weight of the wild Bankiva.