why I
recommend such a study to be undertaken when the subject of it is alone
and given up to his own thoughts, and before he is spoken to: and this
partly for the reason that it is only in such a condition that
inspection of the physiognomy pure and simple is possible, because
conversation at once lets in a pathognomical element, in which a man can
apply the arts of dissimulation which he has learned: partly again
because personal contact, even of the very slightest kind, gives a
certain bias and so corrupts the judgment of the observer.

And in regard to the study of physiognomy in general, it is further to
be observed that intellectual capacity is much easier of discernment
than moral character. The former naturally takes a much more outward
direction, and expresses itself not only in the face and the play of
feature, but also in the gait, down even to the very slightest movement.
One could perhaps discriminate from behind between a blockhead, a fool
and a man of genius. The blockhead would be discerned by the torpidity
and sluggishness of all his movements: folly sets its mark upon every
gesture, and so does intellect and a studious nature. Hence that remark
of La Bruyere that there is nothing so slight, so simple or
imperceptible but that our way of doing it enters in and betrays us: a
fool neither comes nor goes, nor sits down, nor gets up, nor holds his
tongue, nor moves about in the same way as an intelligent man. (And this
is, be it observed by way of parenthesis, the explanation of that sure
and certain instinct which, according to Helvetius, ordinary folk
possess of discerning people of genius, and of getting out of their
way.)

The chief reason for this is that, the larger and more developed the
brain, and the thinner, in relation to it, the spine and nerves, the
greater is the intellect; and not the intellect alone, but at the same
time the mobility and pliancy of all the limbs; because the brain
controls them more immediately and resolutely; so that everything hangs
more upon a single thread, every movement of which gives a precise
expression to its purpose.

This is analogous to, nay, is immediately connected with the fact that
the higher an animal stands in the scale of development, the easier it
becomes to kill it by wounding a single spot. Take, for example,
batrachia: they are slow, cumbrous and sluggish in their movements; they
are unintelligent, and, at the same time, extremely tenacious of life