A celebrated case to which Darwin attached importance was that of Lord Morton's mare, reported to the Royal Society in 1820. This mare, after bearing a hybrid by a quagga (a striped equine related to the zebra) produced, to a black Arabian horse, three foals showing a number of stripes, and in one of them more stripes were present than in the quagga hybrid. This seems at first sight strong evidence in favour of "infection" of the mare by the early quagga mate. But it appears that stripes are frequently seen in high-caste Arab horses, and colts cross-bred from such and other breeds of horse sometimes present far more distinct bars across the legs and other zebra-like markings than were seen in the late offspring of Lord Morton's Arabian mare. The fact appears to be that all the living species of the horse family (horses, asses, quaggas, and zebras) are descended from an ancestry of "striped" equines, and are liable occasionally to "throw back" to their striped ancestry, more or less. Professor Cossar Ewart determined some years ago to submit the matter to direct experiment, and has related his results in a book ("The Penicuik Experiments," 1899). The South African equine called the quagga, which was that used by Lord Morton, having become extinct, Professor Ewart made use of a richly striped Burchell's zebra. Thirty mares put to this animal produced seventeen hybrids, and subsequently these mares, put to horse-stallions, produced twenty pure-bred foals. All the zebra hybrids were richly and very distinctly striped. Of the twenty later pure-bred horse-foals from the same mares three only presented stripe-like markings at birth, and these were few and indistinct. They disappeared when the foal's coat was shed. Their mothers were Highland mares. But the value of the faint striping in these three instances as evidence in support of telegony is at once destroyed by the fact that Professor Ewart obtained at the same time pure-bred foals from similar Highland mares which had never seen a zebra. Two of these pure-bred Highland foals showed stripes at birth, and one acquired stripes later; and further, whilst the stripes on the foals born after hybrids had been produced by their mothers disappeared with the foal's coat, the stripes on the three pure-bred colts whose mothers had never been near a zebra persisted for a longer period. Similar experiments confirmed these results, showing that traces of striping are no more likely to occur on the offspring of a mare which has previously produced a mule with a zebra or an ass, than on one whose dam has neither seen nor been near to a zebra or an ass. Lord Morton's case thus falls to the ground.