proportions proceeds differentially in the first or in the second and third dimensions. 1 Castle, W. E., Proc. Nat. Acad. Sci., 10, 19-22 and 181-182 (1924). 2 Sumner, F. B., Ibid., 10, 178-180 (1924). Castle, W. E., Carnegie Inst. Pubi., No. 320 (1922). 'Cohen, J. I., Nature, 144 944 (1939). Cohen, J. I., J. Mental Science, 86, No. 362 (1940). 6 Pearl, R., Constitution and Health, London, Kega...