d can reach no advanced age, is self-evident. Let us review
the circumstances once more with especial reference to the health of the
workers. The centralisation of population in great cities exercises of
itself an unfavourable influence; the atmosphere of London can never be
so pure, so rich in oxygen, as the air of the country; two and a half
million pairs of lungs, two hundred and fifty thousand fires, crowded
upon an area three to four miles square, consume an enormous amount of
oxygen, which is replaced with difficulty, because the method of building
cities in itself impedes ventilation. The carbonic acid gas, engendered
by respiration and fire, remains in the streets by reason of its specific
gravity, and the chief air current passes over the roofs of the city. The
lungs of the inhabitants fail to receive the due supply of oxygen, and
the consequence is mental and physical lassitude and low vitality. For
this reason, the dwellers in cities are far less exposed to acute, and
especially to inflammatory, affections than rural populations, who live
in a free, normal atmosphere; but they suffer the more from chronic
affections. And if life in large cities is, in itself, injurious to
health, how great must be the harmful influence of an abnormal atmosphere
in the working-people's quarters, where, as we have seen, everything
combines to poison the air. In the country, it may, perhaps, be
comparatively innoxious to keep a dung-heap adjoining one's dwelling,
because the air has free ingress from all sides; but in the midst of a
large town, among closely built lanes and courts that shut out all
movement of the atmosphere, the case is different. All putrefying
vegetable and animal substances give off gases decidedly injurious to
health, and if these gases have no free way of escape, they inevitably
poison the atmosphere. The filth and stagnant pools of the
working-people's quarters in the great cities have, therefore, the worst
effect upon the public health, because they produce precisely those gases
which engender disease; so, too, the exhalations from contaminated
streams. But this is by no means all. The manner in which the great
multitude of the poor is treated by society to-day is revolting. They
are drawn into the large cities where they breathe a poorer atmosphere
than in the country; they are relegated to districts which, by reason of
the method of construction, are worse ventilated than any others; they
are