Experience of artificial fertilisation, such as is effected with
ornamental plants in order to obtain new variations in colour, has
led to the experiments which will here be discussed. The striking
regularity with which the same hybrid forms always reappeared whenever
fertilisation took place between the same species induced further
experiments to be undertaken, the object of which was to follow up the
developments of the hybrids in their progeny.
To this object numerous careful observers, such as Kölreuter, Gärtner,
Herbert, Lecoq, Wichura and others, have devoted a part of their lives
with inexhaustible perseverance. Gärtner especially, in his work “Die
Bastarderzeugung im Pflanzenreiche” (The Production of Hybrids in the
Vegetable Kingdom), has recorded very valuable observations; and quite
recently Wichura published the results of some profound investigations
into the hybrids of the Willow. That, so far, no generally applicable
law governing the formation and development of hybrids has been
successfully formulated can hardly be wondered at by anyone who
is acquainted with the extent of the task, and can appreciate the
difficulties with which experiments of this class have to contend. A
final decision can only be arrived at when we shall have before us the
results of detailed experiments made on plants belonging to the most
diverse orders.
Those who survey the work done in this department will arrive at the
conviction that among all the numerous experiments made, not one has
been carried out to such an extent and in such a way as to make it
possible to determine the number of different forms under which the
offspring of hybrids appear, or to arrange these forms with certainty
according to their separate generations, or to definitely ascertain
their statistical relations[24].
[24] [It is to the clear conception of these three primary
necessities that the whole success of Mendel’s work is due. So far as
I know this conception was absolutely new in his day.]
It requires indeed some courage to undertake a labour of such
far-reaching extent; it appears, however, to be the only right way by
which we can finally reach the solution of a question the importance of
which cannot be over-estimated in connection with the history of the
evolution of organic forms.
The paper now presented records the results of such a detailed
experiment. This experiment was practically confined to a small plant
group, and is now, after eight years’ pursuit, concluded in all
essentials. Whether the plan upon which the separate experiments were
conducted and carried out was the best suited to attain the desired end
is left to the friendly decision of the reader.