[30] Summing up the main points of these introductory remarks, I propose
to deal with the subjects mentioned above at some length, devoting to
each of them, if possible at least an entire lecture. The decisive facts
and discussions upon which the conclusions are based will be given in
every case. Likewise I hope to point out the weak places and the lacunae
in our present knowledge, and to show the way in which each of you may
try to contribute his part towards the advancement of science in this
subject. Lastly I shall try to prove that sudden mutation is the normal
way in which nature produces new species and new varieties. These
mutations are more readily accessible to observation and experiment than
the slow and gradual changes surmised by Wallace and his followers,
which are entirely beyond our present and future experience.

The theory of mutations is a starting-point for direct investigation,
while the general belief in slow changes has held back science from such
investigations during half a century.

Coming now to the subdivisions and headings under which my material is
to be presented, I propose describing first the real nature of the
elementary species and retrograde varieties, both in normal form and in
hybridizations. A discussion of other types of varieties, including [31]
monstrosities will complete the general plan. The second subdivision
will deal with the origin of species and varieties as taught by
experiment and observation, treating separately the sudden variations
which to my mind do produce new forms, and subsequently the fluctuations
which I hold to be not adequate to this purpose.


[32]
B. ELEMENTARY SPECIES