pollinated artificially. Still others do not lend themselves to such
operations, but have to be left free to the visits of bees and of
humble-bees, this being the only means of securing seed from every
plant. At the time of the harvest the seeds should be gathered
separately from each plant, and this precaution should also be observed
in studies of the hereditary percentage at large, and in all scientific
pedigree-cultures. Every lot of seeds is to be sown in a separate pan,
and care must be taken to sow such quantities the three to four hundred
seedlings will arise from each. As soon as they display their
cotyledons, they are counted, and the number is the criterion of the
parent-plant. Only parent-plants with the highest percentages are
selected, and out of [418] their seedlings some fifty or a hundred of
the best ones are chosen to furnish the seeds for the next generation.

This description of the method shows that the selection is a double one.
The first feature is the hereditary percentage. But then not all the
seedlings of the selected parents can be planted out, and a choice has
to be made. This second selection may favor the finest tricotyls, or the
strongest individuals, or rely on some other character, but is
unavoidable.

We now come to the description of the cultures. Starting points are the
stray tricotyls which are occasionally found in ordinary sowings. In
order to increase the chance of finding them, thousands of seeds of the
same species must be inspected, and the range of species must be widened
as much as possible.

Material for beginning such experiments is easily obtained, and almost
any large sample of seeds will be found suitable. Some tricotyls will be
found among every thousand seedlings in many species, while in others