NATURAL 
climates, and indeed in all. climates, 
in certain cases, seems to depend 
upon the same principle. It is 
also probable, that the heat of the 
preceding day, enables the dews 
of the night to prepare the system 
for the- stimulating effeéts of the 
heat of the succeeding day; so that, 
ef two persons who should expose 
themselves without precaution to 
the cold of night and the heat of 
the following day, he who should 
have been most exhausted the day 
before by the heat, would, if other 
circumstances could be rendered 
alike equal, be most injured by the 
hext alternation. 
Several circumstances, such as 
the redness and swelling of the 
parts exposed to cold, together 
with the frequent occurrence of in- 
flammatory disorders not long after 
jexposure to cold, were calculated 
to mislead observers into a belief 
that these disorders were thé diz 
rect effect of cold. Yet the great 
difference in the state of a part 
during inflammation, and under 
the influence of cold, might have 
induced them to suspect that so 
slightan analogy might be illusive : 
and, after taking into the account 
Other well-ascertained faéts, they 
ought to have concluded that the 
theory was false. Linnzus, in a 
paper in the Ameenitates Acade- 
micz, expresses his astonishment at 
the impunity with which the heated 
Laplander rubs himself with snow, 
or even rolls in the snow, and 
drinks the cold snow-watcr. We 
every day see horses in a state of 
the most profuse perspiration free. 
ly washed with cold“ water, and 
always without injury. 1 have 
several times within these two years 
caused horses accustomed to be sta- 
bled, to be turned out for a single 
Vor. XXXVIII. 
HISTORY: 
night in winter: and no cough, ca- 
tarrh; or other disorder; has ever 
been the consequence. It appears, 
therefore to me, that within certain 
limits, and those not very narrow, 
the transition from a higher to a 
lower temperature is attended with 
no danger to animals in a state of 
tolerable health; and a person, I 
conceive, might suddenly pass from 
a higher to a lower temperature 
without inconvenience, even where 
the difference is so great as to be 
capable of producing considerable 
inflammation, if the change should 
be made with equal celerity in a 
contrary dire€tion. On this; though 
an interesting subject for observa. 
tions on man, and experiments on 
animals, we want precise facts; 
and I state the principle in order to 
induce observers to compare it with 
the facts that fall in their way. 
Besides the succession of heat 
and wice versa, there is a third case 
well worthy of consideration ; and 
this where part of the body is ex- 
posed to one of these powers, and 
the remaining part to the other; 
as, for instance where a stream of 
comparatively cold air flows upon 
part of the body of a person sitting 
in a warm room, and perhaps also 
drinking stimulating liquors. In 
making chemical experiments it of- 
ten happens that a eold (catarrh) is 
taken, if the hands be much im- 
mersed in cold water, when the 
laboratory is much heated; by 
adding warm water, to raise the 
temperature of that in the trough, 
this danger is easily avoided. In 
these cases the effect seems to be 
the same as that of the succession 
of heat to cold. In persons whose 
bowels are extremely liable to be 
affected, it sometimes happens, as 
I have myself known it to happen, 
Dd 
[401 
