er opposition from the English school--the
biometricians--who amongst the post-Darwinian school are assumed to be the
lineal descendants of Darwin.

And in this connection we should not forget that just this sort of process
was supposed to take place in the inheritance of use and disuse. What is
gained in one generation forms the basis for further gains in the next
generation. Now, Darwin not only believed that acquired characters are
inherited but turned more and more to this explanation in his later
writings. Let us, however, not make too much of the matter; for it is much
less important to find out whether Darwin's ideas were vague, than it is to
make sure that our own ideas are clear.

If I have made several statements here that appear dogmatic let me now
attempt to justify them, or at least give the evidence which seems to me to
make them probable.

The work of the Danish botanist, Johannsen, has given us the most carefully
analyzed case of selection that has ever been obtained. There are,
moreover, special reasons why the material that he used is better suited to
give definite information than any other so far studied. Johannsen worked
with the common bean, weighing the seeds or else measuring them. These
beans if taken from many plants at random give the typical curve of
probability (fig. 74). The plant multiplies by self-fertilization. Taking
advantage of this fact Johannsen kept the seeds of each plant separate from
the others, and raised from them a new generation. When curves were made
from these new groups it was found that some of them had different modes
from that of the original general population (fig. 81 A-E, bottom group).
They are shown in the upper groups (A, B, C, D, E). But do not understand
me to say that the offspring of each bean gave a different mode.

[Illustration: FIG. 81. Pure lines of beans. The lower figure gives the
general population, the other figures give the pure lines within the
population. (After Johannsen.)]

On the contrary, some of the lines would be the same.

The result means that the general population is made up of definite kinds
of individuals that may have been sorted out.

That his conclusion is correct is shown by rearing a new generation from
any plant or indeed from several plants of any one of these lines. Each
line repeats the same modal class. There is no further breaking up into
groups. Within the line it does not matter at all whether one chooses a big
bean