Schoepfung des Menschen und seiner Ideale."(48) In the first of these works
Haacke combats, energetically and with much detail, Weismann's
"preformation theory," and defends "epigenesis," for which he endeavours
to construct graphic diagrams, his aim being to make a foundation for the
inheritance of acquired characters, definitely directed evolution,
saltatory, symmetrical, and correlated variation.

The principles of the new school are very widespread to-day, but we cannot
here follow their development in the works of individual investigators,
such as Reinke, R. Hertwig, O. Hertwig, Wiesner, Hamann, Dreyer, Wolff,
Goette, Kassowitz, v. Wettstein, Korschinsky, and others.(49)

The Spontaneous Activity of the Organism.

What is particularly luminous in all the theories that express the most
recent anti-Darwinian tendency is that they tend to bring into prominence
the mysterious powers of living organisms, by means of which, instead of
passively waiting for natural selection and the continual accumulation of
unceasing variations, they are able spontaneously and of themselves to
bring forth what is necessary for self-maintenance, often what is new and
different, of course not unlimitedly, but with considerable freedom and
often with a surprising range of possibilities. It is, perhaps, partly the
fault of the one-sidedness of strict Darwinism that this consideration has
been so slowly brought into prominence and subjected to investigation and
experiment. It is bound up with the capacity that all forms of life have
of reacting spontaneously to "stimuli" and, to a certain extent, of
helping themselves if the conditions of existence be unfavourable. They
are able, for instance, to produce protective adaptations against cold or
heat, to "regenerate" lost parts, often to replace entire organs that have
been lost, and, under certain circumstances, to produce new organs
altogether. If all this be true, it seems almost like caprice to follow
only the roundabout theory of the struggle for existence, and not to take
account of these spontaneous capacities of the living organism directly
and before all other factors in the attempt to explain evolution. There is
no end to the illustrations that are being adduced, that must force
investigation to pass from merely superficial considerations of the
struggle for existence type to the deeper and more real problems
themselves.

An effectively modified and adapted type of Alpine f