Those animals which conceal themselves[1] at certain periods of the year, as already mentioned, have no blood at those times, with the exception, indeed, of some very small drops about the heart. A marvellous dispensation of Nature! and very similar to that witnessed in man, where the blood is sensible of various modifications from the slightest causes; for not only, similarly to the bile, does it rush upwards to the face, but it serves also to indicate the various tendencies of the mind, by depicting shame, anger, and fear, in many ways, either by the paleness of the features or their unusual redness; as, in fact, the redness of anger and the blush of modesty are quite different things. It is a well-known fact, that when a man is in fear, the blood takes to flight and disappears, and that many persons have been pierced through the body without losing one drop of blood; a thing, however, which is only the case with man. But as to those animals which we have already mentioned as changing[2] colour, they derive that colour from the reflection[3] of other objects; while, on the other hand, man is the only one that has the elements which cause these changes centred in himself. All diseases, as well as death, tend to absorb the blood.