n may eventually pass away.

There is, however, a very _real paralysis_ which occurs sometimes in
infants and young children. It comes on for the most part quite
suddenly, often unaccompanied by any sign of brain disorder, but tending
nevertheless to issue in great permanent impairment of the power over
the affected limb or limbs, and eventually to interfere with their
growth and thus to produce serious deformity.

It is in general impossible to assign any distinct exciting cause for
the affection, though the fact that in two-thirds of the cases it occurs
between the ages of six months and three years, proves it to be in some
way intimately associated with teething. The oldest child in whom I have
ever seen it was aged between seven and eight years, and the youngest a
little under six months. It is of excessive rarity for the arm alone to
be affected, but it is by no means unusual for the legs alone to be
paralysed; though in the majority of instances power is lost on one side
only, the leg and arm being both involved.

A child goes to bed quite well, or at the worst having seemed slightly
ailing and feverish for a day or two, and on waking in the morning it is
suddenly discovered that power is lost over one leg or both, or over
both arm and leg of one side. The loss of power is at first seldom
complete, though neither arm nor leg can be used to any good purpose,
and during the ensuing twenty-four hours the palsy often grows worse,
and sometimes affects one or both limbs of the opposite side. After that
time recovery in general begins. It is now and then speedy, so that in
three or four days all trace of the paralysis may have disappeared.
This, however, is a fortunate exception to the general rule, which is
that amendment is very tardy, showing itself first in the arm,
afterwards in the leg, and, if both sides have been affected, more on
one side than on the other. Unless the improvement is very rapid, it is
almost always only partial, and the palsied limb, though it does not
lose sensation, regains but little power; it grows much more slowly than
the other, is always colder and wastes considerably, while, some muscles
still retaining more power than others, it becomes twisted out of shape,
and requires all the skill of the orthopaedic surgeon to remedy or at
least to lessen the consequent deformity.

It has been ascertained that this form of palsy depends on a state of
congestion, or overfilling of the minute blood