ON THERAPEUTICS. 
67 
exertion; and even now we have a superstitious reverence 
for those legends, and rather incline to the opinion that mis¬ 
guided persons have occasionally changed all sorts of colours 
in consequence of a reckless disregard of the wise precepts 
that have descended in a straight line from the original 
“ oldest inhabitant.” 
In consequence of these wise precautions, an unfortunate 
horse in the road or in the field, hot, dusty, and dying of 
thirst, is not permitted to take the cool draught placed with¬ 
in his reach, from a prevalent belief that cold fluid under such 
circumstances must be injurious, when in truth the system is 
never so capable of resisting the action of extreme cold as 
when heated, no matter in what way. These popular delu¬ 
sions upon the subject of heat and cold are founded upon 
the fact that exertion usually precedes the excitement that 
accompanies perspiration. Exhaustion is a very reasonable 
result of exertion, and during exhaustion the body is in a 
particular manner sensitive to the effects of cold; therefore, 
instead of refusing cold draughts, or cold baths, or cold air, 
on the plea that the body is heated, we should only withhold 
them because the body is tired, and for no other reason. 
The exhaustion that follows excessive perspiration is not 
alone consequent upon exertion, as it is observed to a certain 
extent after the hot-air bath, where no bodily exercise is ne¬ 
cessary to produce excessive secretion. That (£ sweating” is 
a weakening process is admitted under ordinary circum¬ 
stances; why it is so we propose to explain. 
First. When produced by a heated atmosphere, or by 
clothing, or stimulant medicines, a certain nervous excitement 
is present, followed by depression, as a matter of course. 
Secondlv. Under all circumstances, the blood loses a large 
portion of its water, and the volume of the circulating mass 
is decreased as by the operation of bleeding. 
Thirdly. When perspiration results from exertion, mus¬ 
cular action is an additional and very active cause, and, asso¬ 
ciated with the other two, sufficient to account for the weak¬ 
ness which invariably follows repeated sweatings. 
If no exertion precede perspiration, the body may be ex¬ 
posed to the air with advantage, instead of danger. The ab¬ 
sorption of oxygen counteracts the depression ; and if in 
addition the animal be allowed a copious supply of cold 
water, the bulk of the circulating fluid is soon restored 
by the absorption which immediately takes place. 
Not only is the activity of the functions of the skin a ne¬ 
cessary condition of purity of body and fine health, but is 
even more important in disease, when a larger than ordinary 
