Weight of Negro Brains. Prof. Baymond Pearl points out in Science (Nov. 9, 1934, vol. 90, No. 2080) that the data upon which is based the generally accepted view that the skull capacity and the brain weight of the Negro, whether pure or mixed, tends on the average to be smaller than in whites, are meagre; but the older records contain much of value, only needing biometric analysis forpresent day purpose. Morton (1849) gives a combined mean cranial capacity for Negroes of 1,360-1 c.c. as against whites, 1,489-6 c.c. (91-3 per cent); Peacock (1865), Negro, 1,295 c.c., as against whites, 1,465 c.c.; Duckworth (1904), Group ii, (African), 1,388 c.c. Group iv, (Eurasian), about 1,500 c.c. (92-5 per cent). Calculations of weight are, Peacock (1865) 1,256-3 gm. (calculated from Peacock's data); Waldeyer (1894) 1,148 gm. and 1,234 gm. (from Topinard). Bean (1927) reported from 117 autopsies that the Negro males had a smaller brain weight than whites, the difference being larger relatively than in respect of either liver, kidneys, spleen, heart, appendix or pancreas. The most recent figures are F. W. Vint (1934), the average adult Kenya male being 1,276 gm., the extremes 1,006 gm. and 1,644 gm.; that is, being 10-6 per cent lighter than a not too sound general European mean brain weight; the average skull capacity was 1,230 c.c. Next to Vint's series, the longest series of Negro brain weights is derived from 400 autopsies made during the American Civil War by Surgeon Ira Russell. These data were dissected by 8. B. Hunt and published in the J. Anihrop. Soc. London, 7, 1869. The biometric constants have now been calculated. The mean is, white, 1,470-6 gni. ± 16-2; black, 1,354-8 gm. ±6-8. Coefficient of variations, white, 8-02 gm. ±0-79; black,8-87 gm. ±0-36. The mean is about 207 gm. greater than Waldeyer's figure and only 78-8gm. greater thanVint's. The value of the coefficient of variation is not far from the 8 per cent which has been shown to be characteristic for brain weight variability in accurately weighed samples. The mean brain weight for the black series is 92-1 per cent of the white, agreeing approximately with Morton, Duckworth, Peacock and Vint. The smoothness in the decline of the means with a putative increase in Negro blood is noticeable. The relative variability of the Negro brain weight appears to be slightly greater than that of the whites.