XOVKMBEB 13, 1903.] 



SCIENCE. 



635 



himself that problem, which really resolved 

 itself into three separate investigations^ 

 namely, a sufficiently wide inquiry into the 

 actual values of inheritance of the physical 

 characters in man, and this was carried out 

 by the measurement of upwards of 1,000 

 families; a comparison of the inheritance of 

 the physical characters in man with that of 

 the physical characters in other forms of life; 

 and an inquiry into the inheritance of the 

 mental and moral characters in man. In re- 

 spect of this last set of investigations children 

 were taken in schools of different sorts all over 

 the country, and the opinions of teachers were 

 asked upon the characters of their pupils in 

 respect of the physical, mental and moral re- 

 semblances between brother and brother, sister 

 and sister, and brother and sister. Six thou- 

 sand circulars were thus sent out to about 

 200 schools. In respect of physical characters 

 the data included the cephalic index — /. e., 

 ratio of the length to the breadth of the head, 

 the span, color of eye and hair, curliness of 

 hair, athletic power and health. In respect of 

 all these the measure of the fraternal resem- 

 blance, indicated by the well-known regression 

 line, was as two to one — that is to say, that 

 if one of the pair exceeded the mean by a 

 certain amount, the other of the pair tended 

 to exceed the mean by half that amount ; and 

 similarly in respect of defect from the mean. 

 This was always true for all the physical char- 

 acters yet worked out in man. Now, seeing 

 there was this surprising uniformity in the 

 inheritance of the measurable physical char- 

 acters, could these results be extended to 

 psychical characters? Could we — that was 

 the whole problem — get a corresponding re- 

 gression line of two to one in steepness or 

 slope in respect of mental and moral char- 

 acters. A very large number of observations 

 made on 1,918 pairs of brothers as to vivacity, 

 assertiveness, introspection, popularity, con- 

 scientiousness, temper, probity, handwriting 

 and general ability showed that while the line 

 of regression was one to two or 50 to 100 in 

 respect of physical characters, the smaller 

 number was represented in respect of mental 

 and moral characters by 51 ; while in respect 

 of a large number of pairs of sisters it was 



52, and these two numbers tended to approxi- 

 mate to 50 with an allowance for probable 

 error. Hence there could be small doubt that 

 intelligence or ability followed precisely the 

 same laws of inheritance as general health, 

 and both followed the same laws as cephalic 

 index or any other physical character. There 

 was a true line of regression in each case 

 (.5 or 1 to 2), and it could safely be said that 

 general health in the community was inherited 

 in precisely the same manner as head-measure- 

 ments or body-lengths. What results followed 

 therefrom ? By assuming our normal distri- 

 bution for the psychical characters, there was 

 found, in addition to self-consistent results, 

 the same degree of resemblance between phys- 

 ical and psychical characters; and that sarne- 

 ness involved something additional — namely, 

 a like inheritance from parents. We in- 

 herited our parents' tempers, conscientious- 

 ness, shyness and ability, even as we inherited 

 their stature, forearm and span. Again, 

 within broad lines, physical characters were 

 inherited at the same rate in man and the 

 lower forms of life. The irresistible conclu- 

 sion was that if man's physical characters 

 were inherited even as those of the horse, the 

 greyhound or the water-flea, what reason was 

 there for demanding a special evolution for 

 man's mental and moral side^ If the rela- 

 tion of the psychical characters to the physical 

 characters was established, what was its les- 

 son? Simply that geniality and probity and 

 ability might be fostered by home environ- 

 ment and by provision of good schools and 

 well-equipped institutions for research, but 

 that their origin, like health and muscle, was 

 deeper down than those things. They were 

 bred and not created. It was the stock itself 

 that made its home envirormient, and the 

 education was of small service unless it were 

 applied to an intelligent race of men. Our 

 traders had declared that we were no matcli 

 for Germans and Americans. There did seem 

 to be a want of intelligence to-day in the 

 British merchant, workman or professional 

 man. The remedy was not in adopting for- 

 eign methods of instruction or in the spread 

 of technical education. The reason of the 

 result was that the mentally better stock in the 



