In the main, then, the doctor learns that if he gets ahead of the
superstitions of his patients he is a ruined man; and the result is that
he instinctively takes care not to get ahead of them. That is why all
the changes come from the laity. It was not until an agitation had been
conducted for many years by laymen, including quacks and faddists of all
kinds, that the public was sufficiently impressed to make it possible
for the doctors to open their minds and their mouths on the subject of
fresh air, cold water, temperance, and the rest of the new fashions in
hygiene. At present the tables have been turned on many old prejudices.
Plenty of our most popular elderly doctors believe that cold tubs in the
morning are unnatural, exhausting, and rheumatic; that fresh air is a
fad and that everybody is the better for a glass or two of port wine
every day; but they no longer dare say as much until they know exactly
where they are; for many very desirable patients in country houses have
lately been persuaded that their first duty is to get up at six in the
morning and begin the day by taking a walk barefoot through the dewy
grass. He who shows the least scepticism as to this practice is at once
suspected of being "an old-fashioned doctor," and dismissed to make room
for a younger man.
In short, private medical practice is governed not by science but by
supply and demand; and however scientific a treatment may be, it cannot
hold its place in the market if there is no demand for it; nor can the
grossest quackery be kept off the market if there is a demand for it.