Occasionally the piebald patches tend to be symmetrically arranged, and sometimes the eyeballs are pigmentless (pink) and sometimes pigmented (black).
The wild mouse, rat and rabbit are self-coloured, but the domesticated forms include various piebald patterns, such as spotted forms among mice, and the familiar black and white hooded and dorsal-striped pattern of some tame rats.
The experiments of the latter author show that, if a gametically pure black rat be crossed with an albino derived from a piebald black and white ancestry, all the offspring in successive litters will be black; but if the same black parent be crossed with albinoes extracted from parents of which one or both are grey, then both grey and black members will appear in the successive litters.
He then proceeded to clear Pomerania of the piebald imperial host composed of every nationality under heaven, and officered by Italians, Irishmen, Czechs, Croats, Danes, Spaniards and Walloons.
And this brings us to the question as to whether in a piebald animal the pigmented hairs are in any way different from the pigmentless or white hairs.
No adequate investigation of this subject has yet been made, but some observations made by the author of this article, on the piebald black and white rat, show that differences connected with the microscopic structure exist.
And it is possible that this albino, had it developed colour, would have been of the piebald pattern.
But the author of this article has quite recently reared some albinoes in which the familiar shoulder hood and dorsal stripe of the piebald rat is perfectly obvious, in spite of the absence of the slightest pigmentation.
More remarkable is the case of certain cattle, whose skin is piebald, marked by a general ground colour over which are scattered patches of unpigmented coat.
Fat-rumped sheep, Ovis steatopyga, are common to Africa and Asia, and are piebald with rudimentary horns, and a short hairy coat, being bred entirely for their milk and flesh.
Gunn, of Edinburgh University, who has recently been investigating the subject of albinism in man, there is reason to believe that a condition of piebald albinism occurs also in Europeans (Scotsmen).
Thus these albinoes exhibit a pattern of pink skin similar in form with the black pattern of the piebald rat.