938 
acquired factor play in all that is men- 
tal in man, that I have been unable to dis- 
cover any action in him which is purely in- 
stinective. Purely reflex actions he has in 
plenty, as, for instance, the movements of 
the various hollow viscera; but of the few 
instincts which survive in him (e. g., pa- 
rental and sexual love) none apparently 
are gratified without the aid of rational 
action. Consider, for instance, how greatly 
the instinctive appreciation of female 
beauty is modified by the acquired factor ; 
there are savage tribes who mutilate, to 
render beautiful as they think, the faces of 
their women to a frightful degree.* Con- 
sider, again, how much there is rational 
(e. g., the coordination of her muscles) in 
the mother’s care of her offspring. 
As in the case of physical characters, no 
systematic attempt has been hitherto made 
to differentiate between the mentally ac- 
quired and the inborn. As a result, much 
confusion and inaccurate thinking is mani- 
fest in writings, scientificand otherwise. I 
propose to deal with these to some extent 
presently ; but first it would be interesting 
to trace, in however slight a manner, the 
evolution of the power of acquiring mental 
traits in animals. But, even before doing 
this, one other digression I may permit 
myself, since it has an important bearing 
on much that follows. It has been main- 
tained that acquired characters, mental and 
physical, are transmissible. I will not here 
pause to consider whether such characters 
as I have ventured to denominate ‘ en- 
forced,’ nor whether such characters as 
result from the complete or partial repro- 
duction of lost parts, are transmissible. 
The battle has been fought in countless 
publications, and I do not know that 
I have now anything very new or original 
to add; but I should like to say a little 
concerning the alleged transmissibility 
*Our women have worn crinolines and chignons 
and still wear earrings and corsets. 
SCIENCE. 
[N.S. Vou. VI. No. 156. 
of such characters as result from use 
or experience, for instance, the acquired 
enlargement of the blacksmith’s muscle 
through use, or the mental change involved 
in the acquirement of a knowledge of mathe- 
matics through experience. Characters like 
these are held by a section of biologists to 
be transmissible, in part at least... But 
when a parent acquires such charac- 
ters they reappear in the child only in 
response to stimulation similar to that 
which caused them to arise in the 
parent. For instance, without such stimu- 
lation the child gets neither the enlarged 
muscles nor the knowledge of mathe- 
matics; in fact, the child must in all 
cases, acquire such characters afresh ; from 
which it is plain that that which is ac- 
quired by the parent does not become in- 
born in the child. 
It may, however, be maintained by Neo- 
Lamarckians that stimulation causes not 
only the acquirement of a character, but 
increases also the power of acquiring 
it, and that it is this increase in the 
parent which is transmitted to the child, 
and which renders more easy the ac- 
quirement of the character by the latter. 
But there is no tittle of evidence showing 
that the stimulation which results in the 
acquirement of a character (mental or 
physical) causes also an increase in the 
power of acquiring it. The converse is 
in fact true ; the infant’s power of acquir- 
ing characters, mental and physical, is im- 
mense, and to it is mainly owing the de- 
velopment he undergoes in his passage 
from infancy to old age; but this 
power steadily declines in his long stimu- 
lated parts (mental and physical), till 
in the old man it is reduced to a mini- 
mum and tends to vanish. Clearly, then, 
as regards such characters as result from 
use and experience there can be no trans- 
mission to the child; therefore, as regards 
them, evolution must have proceeded 
