to admit that albinism in man is a Mendelizing character, because it may assume various forms ranging from colorless to quite heavily pigmented conditions (blondes). We now find that albinism in guinea-pigs shows an even greater range of variation,[6] yet there can be no doubt of its fundamental unity as a Mendelian character, each grade of which is allelomorphic to every other grade and to normal pigmentation. [4] Castle and Phillips, 1914, Publ. No. 195, Carnegie Inst. of Wash. [5] Castle and Fish, Amer. Nat., Feb., 1915. [6] Wright, S. Amer. Nat., March, 1915. Goddard's findings as regards feeble-mindedness fit in perfectly with this scheme. That Goddard was unaware of it when his conclusions were reached is all the more evidence of their soundness because it shows that they were reached independently. Among albinos every higher grade of pigmentation dominates all the lower grades in inheritance, and so apparently it is with mental development; the higher grades dominate the lower. At every point there appears to be agreement in method of inheritance between albinism and feeble-mindedness. Each is a unit character but showing graded allelomorphic conditions which correspond probably with different stages of arrested development of pigmentation or mentality respectively. The fact noted by Goddard that the feeble-minded resemble savages, that is backward races of low mentality, has much interest to the student of evolution. It indicates that the evolution of intelligence has occurred by a gradual progressive advancement, stages in which reappear as the higher grades of feeble-mindedness. Of course it is not certain that the ontogenetic stages, at which mental development may be arrested, correspond accurately with earlier phylogenetic stages, but the idea receives considerable support from the observed resemblance between the mentality of morons and that of savage peoples, if the observation may be accepted as accurate. I do not understand however that Goddard makes any claim to first-hand familiarity with the mental life of savages, so that no great emphasis should be laid on the point. But the mere fact that RETROGRESSIVE variation in mentality is GRADED favors the view that its PROGRESSIVE evolution has been gradual, rather than the view that it has arisen by mutation or sudden loss of inhibitors. (Bateson, Davenport).