English greyhounds taken to the high plateau of Mexico could not at first run well, on account of rarefied air. Their whelps entirely got over the difficulty.
Mr. Lewes somewhere[567] tells of a terrier pup whose parents had been taught to 'beg,' and who constantly threw himself spontaneously into the begging attitude. Darwin tells of a French orphan-child, brought up out of France, yet shrugging like his ancestors.[568]
Musical ability often increases from generation to generation in the families of musicians.
The hereditarily epileptic guinea-pigs of Brown-Séquard, whose parents had become epileptic through surgical operations on the spinal cord or sciatic nerve. The adults often lose some of their hind toes, and the young, in addition to being epileptic, are frequently born with the corresponding toes lacking. The offspring of guinea-pigs whose cervical sympathetic nerve has been cut on one side will have the ear larger, the eyeball smaller, etc., just like their parents after the operation. Puncture of the 'restiform body' of the medulla will, in the same animal, congest and enlarge one eye, and cause gangrene of one ear. In the young of such parents the same symptoms occur.
Physical refinement, delicate hands and feet, etc., appear in families well-bred and rich for several generations.
The 'nervous' temperament also develops in the descendants of sedentary brain-working people.
Inebriates produce offspring in various ways degenerate.
Nearsightedness is produced by indoor occupation for generations. It has been found in Europe much more frequent among schoolchildren in towns than among children of the same age in the country.
These latter cases are of the inheritance of structural rather than of functional peculiarities. But as structure gives rise to function it may be said that the principle is the same. Amongst other inheritances of adaptive[569] structural change may be mentioned:
The 'Yankee' type.