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vested in the Medical Officer of Health and Inspectors,
to obtain clear evidence of the over-crowding of a particular
room. But it is quite possible, by providing
the means for due ventilation, so to mitigate one great
mischief of overcrowding, the befoulment of the air, as
to obviate greatly the rise and spread of sickness. Few
families of the very poor class can afford to occupy
more than one room. A vast number of the rooms
inhabited by this class do not exceed 600 cubic feet in
capacity. The average number of occupants of such
a room is five, giving 120 cubic feet to each person;
whereas the whole 600 would be barely enough. Such
a defect can only be compensated for by a free current
of fresh air.
But the supply is frequently limited to what can
enter by one window looking into a narrow confined
court; up a stair-case, which serves as a shaft to carry
up the foul air from a back yard, and a lower room,
also crowded with inhabitants; and the accidental downdraft
from a chimney. Such dwellings seem to have
been constructed on the theory that poor people require
less air than others. At any rate, not a few owners
of such dwellings adhere very pertinaciously to the
assumption that increased ventilation is not necessary.
It may be useful to state, that it is a law in medicine
that poisons do not act unless in a certain degree of
concentration. Aerial poisons, such as animal miasmata
which result from the decomposition of sewage-matters,
and the exhalations from respiration and transpiration