Page:Proceedings of the Royal Society of London Vol 69.djvu/163

Rh with the physical was occupying our attention in another field, the indefatigable Dr. Lee undertook the tabulation and calculation of the coefficients of heredity in the case of seven mental and three physical characters for pairs of brothers. The number of pairs dealt with in each case were 800 to 1000. The method adopted was that of the memoir on " The Inheritance of Characters not capable of Exact Quantitative Measurement."* Thus, under the heading Conscientiousness were two divisions, Keen and Dull, and the teacher might place a cross on either of these or on the dividing line. Similar divisions occurred in the other categories, except that Intelligence was given six and Temper three subdivisions, &c. The collecting schedules will be fully described when the whole bulk of material is finally reduced and published. My sole object in the present preliminary notice is to draw attention to the following results :

Coefficients of Collateral Heredity. Correlation of Pairs of Brothers.

Physical Characters. Mental Characters.

(Family Measurements.) (School Observations.)

Stature '5107 Intelligence -4559

Forearm 0'4912 Vivacity -4702

Span, 0'5494 Conscientiousness '5929

Eye-colour 0'5169 Popularity 0'5044

Temper '5068

(School Observations.) Self-consciousness 0'5915

Cephalic index 0"4S6i Shyness '5281

Hair-colour "5452

Health. . '5203

Mean -5171 Mean 0'5214

The physical characters were measured or observed on two entirely different groups of individuals in the one case, adults, in the other, children, were examined. Both groups, however, give very like mean results, i.e., 0'5170 and 0'5172. Dealing with the means for physical and mental characters we are forced to the perfectly definite conclu- sion : That the mental characters in man are inherited in precisely the same manner as the physical. Our mental and moral nature is, quite as much as our physical nature, the outcome of hereditary factors.

The probable error of the coefficients given is about 0*02 at most ; the differences between the individual values and their significance will be fully considered in the final memoir.


 * ' Phil. Trans.,' A, vol. 195, pp. 79-150.