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It is indeed an absurdity to the "pure line" Mendelian, but not to one who appreciates the fact that Mendelian units are subject to quantitative variation sometimes continuous, sometimes discontinuous. An example of the former is found in the hooded pattern of rats, of the latter in albinism and other Mendelizing characters which assume multiple allelomorphic conditions.
These are mere varieties, produced by albinism, and may belong to any of the castes already described. It has been further ascertained that the elephants of different Indian countries vary a good deal in point of size. Those from the southern districts, and some of the larger islands, are larger and stronger than the elephants of Nepaul and other mountain countries in the north.
Every one must have heard of cases of albinism, prickly skin, hairy bodies, etc., appearing in several members of the same family. If strange and rare deviations of structure are truly inherited, less strange and commoner deviations may be freely admitted to be inheritable.
There was no one to tell him that he was living in a country and an age that were afterwards to appear among the most ignorant and cruel on record. He himself had not yet discovered the "gentility-nonsense," nor did he ever discover that gentility was of the same family, if it was not an albinism of the same species, as pious and oily respectability.
Partial albinism, necessarily congenital, presenting a piebald appearance, must not be confounded with leukoderma, which is rarely seen in the young and which will be described later. Albinism is found in the lower animals, and is exemplified ordinarily by rats, mice, crows, robins, etc. In the Zoologic Garden at Baltimore two years ago was a pair of pure albino opossums.
Melanism, the opposite of albinism, is rarer, and the only instance I have seen was that of a black bullfinch at Aldington; it had evidently been mobbed as a stranger by other birds of its kind, as it was injured and nearly dead when captured. I had the specimen stuffed as a curiosity, though I am not fond of stuffed birds.
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 through selection.
Leukoderma is a pathologic process, the result of which is a deficiency in the normal pigmentation of the skin, and possibly its appendages. Its synonyms are leukopathia, vitiligo, achroma, leukasmus, and chloasma album. In India the disease is called sufaid-korh, meaning white leprosy. It differs from albinism in being an acquired deficiency of pigment, not universal and not affecting the eye.
The white elephant is celebrated in the religious history of Oriental nations, and is an object of veneration and worship in Siam. White monkeys and white roosters are also worshiped. In the Natural History Museum in London there are stuffed examples of albinism and melanism in the lower animals. Melanism is an anomaly, the exact contrary of the preceding.
I do not mean such varieties as are termed `accidental, arising from albinism or like circumstances, but every species or variety known to naturalists and acknowledged as `permanent. The bears from which these skins are to be taken must be killed in their native haunts, and by your own hands with no other assistance than that of an attendant whom I shall appoint to accompany you.
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