t, Hans
Driesch, dedicates to the memory of Wigand two books in rapid
succession and reprehends the contemporaries of that master of science
for ignoring him. O. Hammann abandons Darwinism for an internal
principle of development. W. Haacke openly disavows Darwinism; and even
at the convention of naturalists in 1897, L. Wilser was allowed to
assert without contradiction that, "anyone who has committed himself to
Darwinism can no longer be ranked as a naturalist."

These are all signs which clearly indicate a radical revolution, and
they are all the more significant since it is the younger generation,
which will soon take the lead, that thinks and speaks in this manner.
But it is none the less noteworthy that the younger naturalists are not
alone in this movement. Many of the older men of science are swelling
the current. We shall recall here only the greatest of those whom we
might mention in this connection.

Julius von Sachs, the most gifted and brilliant botanist of the last
century, who unfortunately is no longer among us, was in the sixties an
outspoken Darwinian, as is evident especially from his History of
Botany and from the first edition of his Handbook of Botany. Soon,
however, Sachs began to incline toward the position assumed by Naegeli;
and as early as 1877, Wigand, in the third volume of his great work,
expressed the hope that Sachs would withdraw still further from
Darwinism. As years went by, Sachs drifted more and more from his
earlier position, and Wigand was of opinion that to himself should be
ascribed the credit of bringing about the change. During his last years
Sachs had become bitterly opposed to Darwinism, and in his masterly
"Physiological Notes" he took a firm stand on the "internal factors of
evolution."

During recent years I had the pleasure of occasional correspondence
with Sachs. On the 16th of September, 1896, he wrote me: For more than
twenty years I have recognized that if we are to build up a strictly
scientific theory of organic structural processes, we must separate the
doctrine of Descent from Darwinism. It was with this intention that he
worked during the last years of his life and it is to be hoped that his
school will continue his researches with this aim in view.

The tendency among naturalists to return to Wigand is well exemplified
in an article contributed to the "Preussischen Jahrbuecher" for
January, 1897, by Dr. Karl Camillo Schneider, assistant at the
zoological Ins