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32
of either in January or February, and one only of measles in
March.
Thus the diseases of this class come as it were in waves.
They seem to be brought in by some definite cause—usually the
importation of some person already ill with the disease ; then
they spread from one susceptible person to another; but it seems
a law of Providence that their power of affecting any individual
or the population of any given place is strictly limited in time.
This is more especially the case with cholera, whose ordinary
duration in any place varies from five to ten weeks. Moreover,
there is no doubt but that the matter or substance which constitutes
the infectious poison of these diseases lives and thrives in
all impurity—in the exhalations from unwashed skins and clothes,
in the vapours of the breath condensed in ill-ventilated rooms, in
impure water, filthy sinks, drains, closets and sewers, and in refuse
offal and garbage wherever they may be found.
Hence we are entitled to look on cholera, should the
Almighty think fit to send it, as a passing thunder storm; we
know that its duration is limited, and we know how to lessen its
power of propagation, at least, in this climate, and to a considerable
extent. The requisite measures are set forth in a well considered
"Memorandum for a plan of uniform action, in case of an
epidemic of cholera, by the Metropolitan Medical Officers of
Health," and in a Report which we have sent to the Sanitary
Committee.
We have the honour to be,
My Lords and Gentlemen,
Yours very obediently,
C. J. B. ALDIS, M.D.,
R. DRUITT.