relatively to the plants self-fertilised for five generations. They were
then as 100 to 91, and now as 100 to 66 in height. The intercrossed
plants (i.e., those which had been intercrossed for the last five
generations) likewise exceed in height the self-fertilised plants, as
occurred in all the previous generations with the exception of the
abnormal plants of the third generation. On the other hand, the
Westerham-crossed plants are exceeded in height by the intercrossed; and
this is a surprising fact, judging from most of the other strictly
analogous cases. But as the Westerham-crossed plants were still growing
vigorously, while the intercrossed had almost ceased to grow, there can
hardly be a doubt that if left to grow for another month they would have
beaten the intercrossed in height. That they were gaining on them is
clear, as when measured before they were as 100 to 119, and now as only
100 to 108 in height. The Westerham-crossed plants had also leaves of a
darker green, and looked altogether more vigorous than the intercrossed;
and what is much more important, they produced, as we shall presently
see, much heavier seed-capsules. So that in fact the offspring from the
self-fertilised plants of the fourth generation crossed by a fresh stock
were superior to the intercrossed, as well as to the self-fertilised
plants of the fifth generation--of which latter fact there could not be
the least doubt.

These three lots of plants were cut down close to the ground and
weighed. The twenty-one Westerham-crossed plants weighed 32 ounces; the
twenty-two intercrossed plants, 34 ounces, and the twenty-one
self-fertilised plants 7 1/4 ounces. The following ratios are calculated
for an equal number of plants of each kind. But as the self-fertilised
plants were just beginning to wither, their relative weight is here
slightly too small; and as the Westerham-crossed were still growing
vigorously, their relative weight with time allowed would no doubt have