THE INHERITANCE OF MENTAL ABILITY 113 
problem. So eminent an authority on insanity as Dr. Henry 
Maudsley has stated, ‘‘It is no exaggeration to say that there 
is hardly ever a man of genius who has not insanity or nervous 
disorder of some form in his family.” Moreau de Tours who did 
much to bring the relation between genius and insanity into 
prominence regarded genius as a “‘neurosis, or abnormal exalta- 
tion of the intellectual faculties.” Lombroso, who has written 
most copiously on this topic, finds that men of genius commonly 
exhibit neuropathic traits indicative of a degenerate taint, and 
have many peculiarities in common with the actually insane. 
The foibles, eccentricities and weaknesses of men of genius have 
afforded a theme for almost endless comment. And it is not to be 
wondered at that those who contend that genius represents a sort 
of pathological variation have no difficulty in collecting a number 
of instances which fit their case. But a doctrine based on evi- 
dence especially selected to prove the thesis rests upon a very 
inadequate basis. What most of the writers who have accepted 
this doctrine have done is simply to collect all the cases that they 
could find in which men of eminence became insane or exhibited 
occasional eccentricities. However extensive and imposing such 
a collection of facts may be, it really proves nothing if one ex- 
cludes, as is usually done, the very numerous cases which do not 
bear out the theory. 
The obviously scientific method of attacking the problem 
would be to ascertain the percentage of insanity in a rather large 
random sample of people of superior ability, and to compare it 
with the percentage of insanity in the general population of 
corresponding limits of age. The only writer with whom I am 
acquainted who has ever attacked the subject by an impartial 
statistical method is Havelock Ellis in his Studies of British 
Genius. Selecting, according to certain rules, 1,030 names from 
the Dictionary of National Biography, he found that, even when 
slight or dubious cases were included, the percentage of men and 
women who became insane was not more than 4.2 per cent. A 
study of the parents of these British men of genius showed, 
contrary to Maudsley’s statement, that insanity could not be 
