There is one point, it may be noted in passing, at which dreams do not usually correspond with some of the phenomena with which we may most naturally compare them. I refer to their presentation of colour. In the dreams of most people colour is rare. We seem usually, from this point of view, to remember a dream as we would remember a photograph, or, if any colour at all is present, a tinted drawing. Judging from my own experience, I should say that it is difficult to decide whether the absence of colour is due to its actual absence from the dream imagery, or merely to its failure to make any impression on memory. Some careful observers have, however, stated that the colour of their dream imagery is definitely grey. Thus Beaunis states that his dream imagery is usually _en grisaille_, like an image recalled in the waking state, though occasionally the colour is vivid, and Dr. Savage says that in his dreams colour is rarely or never present. 'I see landscapes of black and white, and flowers assume their true form, but not their colours.'[29] This greyness of dream imagery corresponds to the disappearance of colour under chloroform anaesthesia. 'So long as the eyes could be held open voluntarily,' says Elmer Jones, 'vision seemed quite normal, save that the colours of the spectrum faded out into a grey band.' Even in the early stage of some insanities also, as Stoddart has found, some degree of colour-blindness is present.[30] Grace Andrews states, indeed, that in nearly half of her own visual dreams colour sensations were included. This seems to me exceptional. In my own experience, the emergence of a single colour, which usually strikes me as beautiful, is not rare. I see, for instance, a friend drinking wine copiously from a large goblet, and I judge by the colour of the wine that it is hock, or I am impressed by the shimmering grey tone of the poplin dresses worn by a group of ladies, which seems to indicate that the tone of the whole picture was not grey. I am inclined to think that when colour in a dream becomes more pronounced than this, the dream is not normal, but is associated with some degree of cerebral disturbance, and especially the presence of headache. This would agree with the fact that persons subject to migraine are liable to visual colour phenomena. As an example of a vivid colour dream associated with headache, I may bring forward the following: I dreamed that an artist of note, with whom I am acquainted, was painting my portrait. (The pose of the portrait was standing, but I was lying down; this, however, caused me no surprise.) I saw the colours of the picture with great vividness, and I noted the extreme rapidity with which the artist painted; thus the red and black pattern of the necktie he had given me was suddenly changed to a totally different blue pattern, and the whole picture then appeared as a harmony of blues, the rapidity with which the artist effected these changes impressing me as very remarkable.