In Pursuit of the Gene

12 ¨ VIVA PANGENESIS
produced brilliant nerve cells and the other for dull ones, and the two
forms existed in equal numbers in both parents, then one would see a bellshaped
distribution of intelligence among the offspring. The classes F and G
would correspond to those lucky few who had chanced to inherit a collection
consisting of a vast excess of gemmules for superior neurons; the majority
of the population in the middle ranges, in the classes e, d, c, b, a, A,
B, C, D and E, inherited a nearer to equal mixture of superior and dull
gemmules, and the unfortunate classes f and g, the so-called “idiots” and
“imbeciles,” were the recipients of a nearly uniform collection of inferior
gemmules. 41
With the particulate theory of inheritance provided by pangenesis, not
only did Galton have a mechanism to explain the normal distribution of intelligence,
but he could also use the distribution of intelligence in one generation
to predict the distribution in the next one. Four pages from the end
of Hereditary Genius, he spelled out how a breeding program would work:
“Not only might the average qualities of the descendants of groups A and B,
A and C, A and D, and every other combination be predicted, but also the
numbers of them who deviate in various proportions from those averages.”
42 In the eleventh hour, it appeared, Galton had hit upon something
big—a unifying principle that lent an air of scientific credibility to his theory
of hereditary genius and his hopes for improving the human race.
While Darwin’s pangenesis seemed to give a tremendous boost to Galton’s
theory of hereditary genius, there was one big problem with it from his
point of view. As Darwin conceived of them, the particles were extremely
malleable. If the environment modified the hereditary material, then identifying
the talented and encouraging them to breed with each other could
hardly be more effective than spreading the advantages of good nutrition,
housing, sanitation, and education. However, if he could throw out the inheritance
of acquired traits and keep the particles, Galton could have his
cake and eat it too.
¨ SHORTLY AFTER PUBLISHING Hereditary Genius, Galton wrote Darwin
to propose that they conduct a joint experiment to test the theory of pangenesis.
Galton did not mention his doubts about the Lamarckian implica-