e last two years--that we have
learnt what that unseen power was. The Angel of Death which moved
through the Old Bailey Sessions House in bygone days was, indeed, a
living thing. It passed silently and unseen from the prisoner to the
warder, from him to the usher, thence to the bar--the jury and the
exalted judge. It had no wings, yet it moved slowly and surely
carrying black death with it. This terrible and mysterious assassin
has at last been unveiled. The shroud of concealment has been torn
away and there the dire monster stands--naked, remorseless and
hideous. It is of small size, though it makes us all shrink with
horror and disgust. It has six claw-like legs and no wings. It is, in
fact, neither more nor less than the clothes louse, the _Pediculus
vestimenti_. The filthy, crowded condition in which the prisoners were
kept, and (let us well remember and reflect thereon) the personal want
of cleanliness of judge, jury, barristers and ushers, rendered the
existence of the little parasite and its effective transference from
man to man possible. Those pompous emblems of authority, the horsehair
wigs--those musty robes of unctuous dignity--were full of dirt, and
harboured the wandering bearer of typhus infection. Gaol-fever was due
to dirt; its infecting germs were distributed by loathsome insects.

It is an interesting and really instructive thing to pass in review
the gradual process by which the cleanliness of the population of
Western Europe has advanced, and to observe that, consciously or
unconsciously, the end pursued has been, step by step, the removal
from man's body outside (and inside), from his clothing, from the
water he drinks, from the food he eats, from the air he breathes, and
from the surfaces with which he necessarily comes into contact,
of injurious parasites and hurtful living things which lurk
in dirt and rubbish. At first the larger and more obvious hurtful
creatures--snakes, rats, mice, scorpions, blow-flies--were eliminated
by some elementary attempts at removal of rubbish and kitchen
middens. Then ticks (which African savages still do not trouble to
remove from their bodies) and later fleas and bugs became unpopular;
lice were long regarded as inevitable, and even beneficial, and by
some populations and by part of the most civilised at the present day,
are still, not merely tolerated, but favoured. In a country school in
France a child who was found to be afflicted in this way was the
daughter