far-reaching displacement of the organic equilibrium.
What Darwin calls the correlation of parts, and in no way denies, is here
maintained in strong opposition to his doctrine of the isolated variation
of individual parts; every member or character of the organism depends
upon others, and variation of one affects many, and in some way all of the
rest.

This theory is for the most part intended by its champions to be purely
naturalistic. But every one of its points yields support to teleological
considerations, most obviously so the concrete instances of correlation.
If any one were to attempt to make a theory of evolution from a decidedly
teleological standpoint, he would probably construct one very similar to
the one we are now considering.

It is noteworthy that it has generally been the botanists who have
especially supported these views of saltatory evolution in a definite
direction and according to internal law, who have therefore tended to
react most strongly from Darwinism. We find examples in Naegeli's large and
comprehensive work, "Mechanisch-physikalische Theorie der
Abstammungslehre"; and, before him, in Wigand's "Darwinismus und die
Naturforschung Newton's und Cuvier's"; in von Koelliker's "Heterogenesis";
in von Baer's "Endeavour after an End"; in the chapter added by the
translator, Bronn, to the first German edition of the "Origin of Species,"
where he urges weighty objections against the theory of selection, and
refers to the "innate impulse to development, persistently varying in a
definite direction"; in Askenasy's oft-quoted "Beitraege zur Kritik der
Darwinschen Lehre," also referring to "variation in a definite direction,"
for instance, in flowers; in Delpino's views, and in the works of many
other older writers. But we must leave all these out of account here,
since we are concerned only with the present state of the question.

De Vries's Mutation-theory.

The work that has probably excited most interest in this connection is De
Vries' "Die Mutationstheorie: Versuche und Beobachtungen ueber die
Entstehung von Arten im Pflanzenleben."(46) In a short preliminary paper
he had previously given some account of his leading experiments on a
species of evening primrose (_OEnothera lamarckiana_), and the outlines of
his theory. In the work itself he extends this, adding much concrete
material, and comparing his views in detail with other theories. Darwin,
he says, had already distinguished between