[1] Cattell"s investigations of American men of science

disproves this statement for Americans
[1] Cattell"s investigations of American men of science
disproves this statement for Americans. He finds that only a
few men enter the ranks of that class of men after the age of
fifty, and that none of that age reach the highest place. The
fecund age is from 35 to 45; ('American Men of Science,' p.
575.)