Now let me return to the recent division of biological opinion into
two main streams--Lamarckism and Weismannism. Both Lamarckians and
Weismannists, not to mention mankind in general, admit that the
better adapted to its surroundings a living form may be, the more
likely it is to outbreed its compeers. The world at large, again,
needs not to be told that the normal course is not unfrequently
deflected through the fortunes of war; nevertheless, according to
Lamarckians and Erasmus-Darwinians, habitual effort, guided by ever-
growing intelligence--that is to say, by continued increase of power
in the matter of knowing our likes and dislikes--has been so much
the main factor throughout the course of organic development, that
the rest, though not lost sight of, may be allowed to go without
saying. According, on the other hand, to extreme Charles-Darwinians
and Weismannists, habit, effort and intelligence acquired during the
experience of any one life goes for nothing. Not even a little
fraction of it endures to the benefit of offspring. It dies with
him in whom it is acquired, and the heirs of a man's body take no
interest therein. To state this doctrine is to arouse instinctive
loathing; it is my fortunate task to maintain that such a nightmare
of waste and death is as baseless as it is repulsive.
The split in biological opinion occasioned by the deadlock to which
Charles-Darwinism has been reduced, though comparatively recent,
widens rapidly. Ten years ago Lamarck's name was mentioned only as
a byword for extravagance; now, we cannot take up a number of Nature
without seeing how hot the contention is between his followers and
those of Weismann. This must be referred, as I implied earlier, to
growing perception that Mr. Darwin should either have gone farther
towards Lamarckism or not so far. In admitting use and disuse as
freely as he did, he gave Lamarckians leverage for the overthrow of
a system based ostensibly on the accumulation of fortunate
accidents. In assigning the lion's share of development to the
accumulation of fortunate accidents, he tempted fortuitists to try
to cut the ground from under Lamarck's feet by denying that the
effects of use and disuse can be inherited at all. When the public
had once got to understand what Lamarck had intended, and wherein
Mr. Charles Darwin had differed from him, it became impossible for
Charles-Darwinians to remain where they were, nor is it easy to see
what course was open to them except to cast about for a theory by
which they could get rid of use and disuse altogether. Weismannism,
therefore, is the inevitable outcome of the straits to which
Charles-Darwinians were reduced through the way in which their
leader had halted between two opinions.
This is why Charles-Darwinians, from Professor Huxley downwards,
have kept the difference between Lamarck's opinions and those of Mr.
Darwin so much in the background. Unwillingness to make this
understood is nowhere manifested more clearly than in Dr. Francis
Darwin's life of his father. In this work Lamarck is sneered at
once or twice and told to go away, but there is no attempt to state
the two cases side by side; from which, as from not a little else, I
conclude that Dr. Francis Darwin has descended from his father with
singularly little modification.
Proceeding to the evidence for the transmissions of acquired habits,
I will quote two recently adduced examples from among the many that
have been credibly attested. The first was contributed to Nature
(March 14, 1889) by Professor Marcus M. Hartog, who wrote:--
"A. B. is moderately myopic and very astigmatic in the left eye;
extremely myopic in the right. As the left eye gave such bad images
for near objects, he was compelled in childhood to mask it, and
acquired the habit of leaning his head on his left arm for writing,
so as to blind that eye, or of resting the left temple and eye on
the hand, with the elbow on the table. At the age of fifteen the
eyes were equalized by the use of suitable spectacles, and he soon
lost the habit completely and permanently. He is now the father of
two children, a boy and a girl, whose vision (tested repeatedly and
fully) is emmetropic in both eyes, so that they have not inherited
the congenital optical defect of their father. All the same, they
have both of them inherited his early acquired habit, and need
constant watchfulness to prevent their hiding the left eye when
writing, by resting the head on the left forearm or hand. Imitation
is here quite out of the question.
"Considering that every habit involves changes in the proportional
development of the muscular and osseous systems, and hence probably
of the nervous system also, the importance of inherited habits,
natural or acquired, cannot be overlooked in the general theory of
inheritance. I am fully aware that I shall be accused of flat
Lamarckism, but a nickname is not an argument."