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Looking to the cases which I have collected of cross-bred animals closely resembling one parent, the resemblances seem chiefly confined to characters almost monstrous in their nature, and which have suddenly appeared such as albinism, melanism, deficiency of tail or horns, or additional fingers and toes; and do not relate to characters which have been slowly acquired by selection.
Looking to the cases which I have collected of cross-bred animals closely resembling one parent, the resemblances seem chiefly confined to characters almost monstrous in their nature, and which have suddenly appeared such as albinism, melanism, deficiency of tail or horns, or additional fingers and toes; and do not relate to characters which have been slowly acquired by selection.
The other cases of this interesting exhibit show a large variety of birds and animals under conditions of somewhat abnormal variation, in the one case of albinism and the other of melanism. These cases are, for the casual visitor, perhaps the most striking of all, although, of course, they teach no such comprehensive lessons as the other exhibits just referred to.
Many authors have claimed that they have little intelligence, but this opinion is not true. Ordinarily the reproductive functions are normal, and if we exclude the results of the union of two albinos we may say that these individuals are fecund. Partial albinism is seen.
The fact that the volume containing Hutton's paper contained also his epoch-making paper on geology finds curiously a duplication in the fact that Wells's volume contained also his essay on Albinism, in which the doctrine of natural selection was for the first time formulated, as Charles Darwin freely admitted after his own efforts had made the doctrine famous. The very next year after Dr.
Albinism is not uncommon in the blackbird; I have seen two partial instances lately; one was constantly visible in my garden and meadows, with head nearly all white, and the other I saw in the public garden at Bournemouth, with the peculiarity still more developed. A white martin, or swallow, came into the house of a friend near Aldington, and was regarded as an unfavourable omen.
D'Aube, by his observations on white rabbits, believes that the influence of consanguinity is a marked factor in the production of albinism; there are, however, many instances of heredity in this anomaly on record, and this idea is possibly in harmony with the majority of observers.
Among albinos every higher grade of pigmentation dominates all the lower grades in inheritance, and so apparently it is with mental development; the higher grades dominate the lower. At every point there appears to be agreement in method of inheritance between albinism and feeble-mindedness.
The youth leaned on a staff, and at his feet crouched two long-haired dogs. Bob turned his horse in that direction. When he had approached, he saw the boy to be about seventeen years old. His hair was very light, as were his eyebrows and eyelashes. Only a decided tinge of blue in his irises saved him from albinism. His lips were thick and loose, his nose flat, his expression vacant.
Nature is doing her best to even matters by letting albinism run riot among the sparrows, and best of all by teaching sparrow hawks to nest under our eaves and thus be on equal terms with their sparrow prey. The starlings are turning out to be worse than the sparrows. Already they are invading the haunts of our grackles and redwings.
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