At the market I chose those animals that blushed most easily and frequently, just as the slave-dealer picks out for the harem those women who charm by blushing more vividly than the others. If one studies attentively the loss of colour in the ears of a rabbit when perfectly quiet, one can nearly always discover the cause in some external circumstance. Often while the animal has red ears and is breathing quietly, one notices a sudden change in the rhythm of respiration; the rabbit lifts its head, looks around, or sniffs; a contraction of the blood-vessels follows, and the ears become pale. After a few minutes, if nothing happens, the ear becomes red again. Any noise causes renewed pallor. A whistle, a cry, a sound of any kind, the bark of a dog, a sunbeam suddenly penetrating into the cage, the shadow of a swiftly passing cloud, the flight of a distant bird, each suffices to produce a rapid loss of colour in the ears, shortly followed by a more vivid flush. We may therefore maintain that the circulation of blood in the ears reflects the psychic condition of the animal, and that nothing takes place either in itself or in its surroundings without immediately acting upon these blood-vessels. Thus the fact observed by Schiff receives confirmation, but the explanation which I give of it differs from his. The dilatation and contraction of the arteries in the rabbit’s ear can no longer be compared to the movements of an accessory heart, and, in my opinion, correspond to the colour or pallor of the human face. In this manner the phenomenon is deprived of the exceptional character with which it was introduced into science, and takes its place amongst those observable in man and nearly all animals. We may see the same phenomenon noticeable in the rabbit’s ear, in the cock’s comb and wittles; during emotion the fleshy protuberances and the skin on the neck of the turkey distinctly blush and grow pale, and in men and dogs not only the face but also the feet are subject to these changes of colour.