OF THE MOTIONS OF THE FINGERS.

The movements of the fingers principally consist in extending and
bending them. This extension and bending vary in manner; that is,
sometimes they bend altogether at the first joint; sometimes they
bend, or extend, half way, at the 2nd joint; and sometimes they bend
in their whole length and in all the three joints at once. If the 2
first joints are hindered from bending, then the 3rd joint can be
bent with greater ease than before; it can never bend of itself, if
the other joints are free, unless all three joints are bent. Besides
all these movements there are 4 other principal motions of which 2
are up and down, the two others from side to side; and each of these
is effected by a single tendon. From these there follow an infinite
number of other movements always effected by two tendons; one tendon
ceasing to act, the other takes up the movement. The tendons are
made thick inside the fingers and thin outside; and the tendons
inside are attached to every joint but outside they are not.

[Footnote 26: This head line has, in the original, no text to
follow.] Of the strength [and effect] of the 3 tendons inside the
fingers at the 3 joints.

The movement of the torso (355-361).