installments or costly laboratory equipment. It demands chiefly
assiduity and exactitude. Any one who has these two qualities, and who
has a small garden at his disposal is requested to take part in this
line of investigation.

In order to observe directly the birth of new forms it is necessary, in
the first place, to be fully clear concerning the question as to what
forms are to be expected to arise from others, and before proceeding to
a demonstration of the origin of species, it is pertinent to raise the
question as to what constitutes a species.

Species is a word, which always has had a [11] double meaning. One is
the systematic species, which is the unit of our system. But these units
are by no means indivisible. Long ago Linnaeus knew them to be compound
in a great number of instances, and increasing knowledge has shown that
the same rule prevails in other instances. Today the vast majority of
the old systematic species are known to consist of minor units. These
minor entities are called varieties in systematic works. However, there
are many objections to this usage. First, the term variety is applied in
horticulture and agriculture to things so widely divergent as to convey
no clear idea at all. Secondly, the subdivisions of species are by no
means all of the same nature, and the systematic varieties include units
the real value of which is widely different in different cases. Some of
these varieties are in reality as good as species, and have been
"elevated," as it is called by some writers, to this rank. This
conception of the elementary species would be quite justifiable, and
would at once get rid of all difficulties, were it not for one practical
obstacle. The number of the species in all genera would be doubled and
tripled, and as these numbers are already cumbersome in many cases, the
distinction of the native species of any given country would lose most