Note 25 — DARWIN'S EXAMPLES.

This excessive thickening under disuse appears to be due partly to a positive lateral enlargement or increase of proportional weight of about 7½ per cent., and partly to a shortening of about 15 per cent. Carefully calculated, the reduction of the weight of the wing-bones in this breed is only 8·3 per cent. relatively to the whole skeleton, or only 5 per cent. relatively to the skeleton minus legs and wings. The latter method is the more correct, since the excessive weight of the leg-bones increases the weight of the skeleton more than the diminished weight of the wing-bones reduces it.