Many sick persons, on awaking, see everything in the colour of the morning sky, as if through a red veil: so, if in the evening they doze and wake again, the same appearance presents itself. It remains for some minutes, and always disappears if the eye is rubbed a little. Red stars and balls sometimes accompany the impression. This state may last for a considerable time.
129.
The aëronauts, particularly Zambeccari and his companions, relate that they saw the moon blood-red at the highest elevation. As they had ascended above the vapours of the earth, through which we see the moon and sun naturally of such a colour, it may be suspected that this appearance may be classed with the pathological colours. The senses, namely, may be so influenced by an unusual state, that the whole nervous system, and particularly the retina, may sink into a kind of inertness and inexcitability. Hence it is not impossible that the moon