In repeating Schiff’s observations I used certain precautions which others would perhaps have thought superfluous. Instead of watching the rabbit while holding it in my hands, I thought to spare it all emotion, by enabling myself to observe the ears without its becoming aware of the fact. For this purpose I had a cage made in such a manner that it fitted exactly into the inside frame of a window, and whereas it was impossible for the rabbits to look into the room, I could watch quite easily, without being seen, through a few holes in the cage. By means of this simple arrangement I could observe the rabbits at my leisure, and study their habits while they were quiet, without a suspicion that they were being noticed. The first time that I so watched them, I saw, to my surprise, that the ears were no longer so red as when the animals were startled by feeling themselves seized and held fast in my hands on the table. The rapid movements of dilatation and contraction in the blood-vessels of the ear, the sudden blushing and loss of colour so characteristic of the timidity of these animals, were no longer observable. The artery of the ear remained dilated and of a vivid red for a long time, often for hours. I noticed this especially in summer, when the animals were uniformly tranquil. A state of absolute repose, however, is not always accompanied by an expansion of the blood-vessels. All rabbits have not ears equally red or pale at the same time and under the same conditions. A similar circumstance may be noticed at any time in the faces of men. Young rabbits blush more easily than old ones. Often while watching the buck and doe with the young ones, one could see the ruddy ears of the latter turn pale every now and then, while the former, like old people with us, remained calm and had pale ears. But even amongst the young ones of the same litter, one finds considerable differences in the facility for blushing.