942 
gestive apparatus has been modified by his 
acquired habit of cooking or otherwise 
modifying his food, to which cause may 
even be attributed the unsoundness of the 
teeth of civilized man ; these, since they are 
no longer absolutely essential to survival, 
having undergone retrogression as regards 
their power of resisting bacteria, etc. His 
lingual muscles have been modified by his 
acquired habit of speech. His slowly-ac- 
quired habit of bipedal progression has 
resulted in immense and obvious physical 
alteration. Even the acquirement of sur- 
gical knowledge, at first rudimentary, but 
now highly advanced, has caused at least 
one important modification. Animals, as 
a rule, bear their young easily. When any 
disproportion exists between the foetal head 
and the maternal pelvis both mother and 
offspring perish and the peculiarity is not 
transmitted. Savage women are under 
much the same conditions, and give birth 
almost as easily aslower animals. But for 
ages civilized women in labor have received 
artificial aid ; they are, therefore, nearly all 
incapacitated for a time after the birth of 
each child; indeed, the recent advance of 
obstetric science has enabled so many of 
the otherwise unfit to survive among us for 
some generations past that now numerous 
women are quite unable of parturition with- 
out instrumental aid. 
The evolution of the power of acquiring 
characters, mental and physical, appears to 
me the most important, indeed the very 
central fact in the evolution of all the higher 
“The use of forceps was formerly very rare in mid- 
wifery practice, butis now very common. Doubtless 
this is mainly due to a change in fashion, the modern 
obstetrician, on the average, being more skilful and, 
therefore, more ready to use his instruments than his 
forebear ; but, doubtless, also, it is due in part to a 
growing disproportion between the maternal pelvis 
and the foetal head in highly civilized races. Itis not 
possible that the saving of so many narrow-hipped 
women and big-headed children can have left the 
race unaffected. 
SCIENCE. 
[N.S. Vou. VI. No. 156. 
animals. Beyond all other characters this 
has been steadily evolved by Natural Selec- 
tion, and therefore the higher placed an ani- 
mal is in the scale of life the more is it 
developed in him. Possibly some other 
mammals are as capable of acquiring phys- 
ical characters as man; it may be that as 
much of the physical development they 
undergo after birth is due to the effects of 
use and exercise ; but, beyond question, no 
other animal is mentally so receptive as 
man. His power of acquiring mental char- 
acters (7. e., his memory) is enormous, and 
so greatly does he depend on it for survival 
that, as we have seen, his inborn mental 
characters (7. e., his instincts), except in a 
few instances, have undergone complete 
retrogression. His mind, as I have said, is 
a blank at birth, and it follows, since so 
much is acquired, that the disposition or 
character of every man must be almost en- 
tirely acquired, and not inborn, as is usu- 
ally assumed. Part of the contents of his 
memory are recognizable (7. ¢., may be dis- 
tinctly remembered), but very much, es- 
pecially all thatis acquired during infancy, 
is not so. Wespeak of it as ‘ forgotten,’ 
but forgotten things, though they can no 
longer be represented in consciousness, yet 
leave their impress on the mind. To take 
an illustration: imagine twin infants in the 
same cot, one awake and the other asleep; 
suppose an event happens that alarms the 
waking child, but leaves the other unaf- 
fected ; suppose, again, that subsequently 
another event, observed by both children, 
occurs, which, owing to the apprehension 
and nervous irritability engendered by the 
previous event, again alarms the first child, 
and thus increases its irritability, but, be- 
cause of its previously undisturbed equa- 
nimity, again leaves the second unaffected 
by fear; imagine this process repeated ; 
then, though the original cause of fear 
were quite forgotten, the one child might 
well grow up of a much more timid and 
