n in cholera but all the data they require, and they will
afterwards prove every disease which can be mentioned to be contagious.
Hundreds of people, we will say, for instance, come daily from a sickly
district to a healthy one, and yet no disease for some time appears; but
at last an "inexplicable condition of the air," and "not appreciable by
any of our senses" (admitted by Dr. Macmichael and others as liable to
occur, but _only in aid_ of contagion), take place; cases begin to
appear about a particular day, and nothing is now more easy than to make
out details of arrivals, there being a wide field for selection; and
even how individuals had spoken to persons subsequently attacked--had
stopped at their doors--had passed their houses, &c.[8] Causation is at
once connected with antecedence, at least for a time, by the people at
large, who see their government putting on cordons and quarantines,
and the most vague public rumour becomes an assumed fact. We even
find, as may be seen in the quotation given from Dr. Walker's report,
that contagionists are driven to the "somehow or other" mode of the
introduction of cholera by individuals; so that it may be deplored, with
respect to this disease, in the words of Bacon, that "men of learning
are too frequently led, from ignorance or credulity, to avail themselves
of mere rumours or whispers of experience as confirmation, and sometimes
as the very ground-work, of their philosophy, ascribing to them the same
authority as if they rested upon legitimate testimony. Like to a
government which should regulate its measures, not by official
information of its accredited ambassadors, but by the gossipings of
newsmongers in the streets. Such, in truth, is the manner in which the
interests of philosophy, as far as experience is concerned, have
hitherto been administered. Nothing is to be found which has been duly
investigated,--nothing which has been verified by a careful examination
of proof."

[Footnote 8: Since the above was written it has been very clearly shewn
how easily proofs of _this kind_ may be furnished to all disposed to
receive them. We perceive that a disease officially announced as _the
true_ cholera, has existed for nearly a month past at Sunderland, and
that among the thousands of people who left it within that time, nothing
could be more easy, had the disease appeared epidemically in other parts
of England, than to point out the _particular individual_ who had
"brought