It may be noted that red and perhaps yellow have been stated to be the only colors visible in dreams; this is possibly due to the blood-vessels. Such an explanation is probable with regard to the various subjective visual sensations which constitute an aura in epilepsy, among which, as Gowers notes, red and reddish yellow are most frequently found. Féré has further noted that in various emotional states somewhat resembling epilepsy, and even in mystic exaltation, red may be subjectively seen. Simroth has gone so far as to argue that not only is red fundamental in human color psychology, but that in living organisms generally, even as a pigment, red is the most primitive of colors, that since the algæ at the greatest sea-depths are red it is possible that protoplasm at first only responded to rays of long wave-length, and that with increased metabolism colors became differentiated, following the order in the spectrum. If it is really the case that in the evolution of the race familiarity with the red end of the spectrum has been earlier and more perfectly acquired than with the violet end, and that red and yellow made a more profound impression on primitive man than green and blue, we should expect to find this evolution reflected in the development of the individual, and that the child would earlier acquire a sensitiveness for red and orange and yellow than for green and blue and violet. This seems actually to be the case. The study of the color sense in children is, indeed, even more difficult than in savages; and many investigators have probably succumbed to the fallacies involved in this study. Doubtless we may thus account for some discrepancies in the attempts to ascertain the facts of color perception and color preference in children, while doubtless also there are individual differences which discount the value of experiments made on only a single child. A few careful and elaborate investigations, however, especially that of Garbini on 600 North Italian children of various ages, have thrown much light on the matter. There is fairly general agreement that red is the first color that attracts young children and which they recognize. That is the result recorded by Uffelmann in Germany, while Preyer found yellow and red at the head; Binet in France concluded that red comes first; Wolfe in America reached the same result, and Luckey noted that his own children seemed to enjoy red, orange and yellow very much earlier than they could perceive blue, which seemed to come last. Baldwin, indeed, found in the case of his own child that blue seemed more attractive than red; his methods have, however, been criticised, and his experiments failed to include yellow. Mrs. Moore found that her baby, between the sixteenth and forty-fifth weeks, nearly always preferred a yellow ball to a red ball; this was doubtless not a matter of color, but of brightness, for there is no reason to suppose chromatic perception at so early an age.