from aqua fortis
to aqua fontis, the influence is always more or less stimulating, and it
is capable of depressing the vital powers in proportion to its power of
exciting them. Thus the hydropathists have in their hands the power of
producing all the stages of the most vehement fever, from the rigor of
the severest cold fit to the fiercest excitement which the heart and
brain will bear, succeeded by a perspiration proportionately violent;
and hence sometimes inadvertently they lose a patient by the production
of a sudden sinking like the collapse of cholera. Some tact and skill,
therefore, are requisite for the safe employment of such an agency as
cold water.

Paracelsus treated that form of St. Vitus' Dance which prevailed in his
day, and which he called _chorea lasciva_, by cooling his patients in
tubs of cold water; and Priesnitz brings his patients also to the right
point by baths that allow no idleness to whatever function of nature may
remain capable of action within them, and thus he often removes partial
complaints by a general diversion. Aubrey, in his account of the great
Harvey, informs us of a bold piece of practice with cold water. He says,
that when Harvey had a fit of the gout that interfered with his studies,
"He would sitt with his legges bare, though it were frosty, on the leads
of Cockayne-house, put them into a payle of water till he was almost
dead with cold, and betake himself to his stove, and so 'twas gone."
Harvey doubtless knew how to balance matters in his own mind between the
risk and the remedy, and he might feel justified in treating himself
with less gentleness than his patients; but, perhaps, physicians should
try such extreme remedies only on themselves. Since Harvey's day, the
virtues of cold water in fever and inflammation have been abundantly
tested, and we find it is capable of producing contrary effects,
according to the condition of the body at the time. Thus, if it be long
applied, or applied when the vital action is low, it dangerously
depresses the vascular system, to be followed by a more or less
dangerous and obstinate reaction; but if the system be tolerably strong,
without being very excitable, the use of cold in a moderate degree
always safely increases vigor. It is therefore always safe so far to
employ cold, as will help to maintain the ordinary temperature of the
body. Thus, in fever, when the skin is hot, sponging it with cold water
is both most refreshing and curative;