Page 425. 
12 ON SOME OF THE MINOR FLUCTUATIONS 
the amount of heat diffused by the body to surrounding substances ; 
and so we should expect that by increasing the arterial tension, thus 
lessening the cutaneous circulation, the blood would become hotter 
from there being less facility for the diffusion of its heat, and that by 
lowering the tension, thus increasing the cutaneous circulation, the 
blood would become colder throughout the body, from increased 
facility for conduction and radiation. 
That such is the case is proved by Tables I, II, III, IV, V, and VI, 
where, by stripping the warm body of clothing, in a cold air, when the 
tension was low (as in Tables IV, V, shown by the sphygmograph- 
trace), the temperature and tension rose, at the same time that the 
surface became colder. 
In Tables I, If, IIIf, IV, V, and VI, by covering the nude body 
with badly conducting clothing, when the tension was high, the surface- 
heat soon accumulated sufficiently to cause a sudden reduction of 
arterial tension, commonly called a glow, and a rapid fall in the tem- 
peratures, from the larger amount of blood exposed at the surface of 
the body to the influence of colder media. 
Changes in the arterial tension are easily recognised by the subject 
of experiment, from the sensations they produce; a feeling of warmth 
followed by a shiver, or a shiver itself, generally shows that the tension 
is lowered, while the opposite effect follows a rise in the tension; and 
this can be generally confirmed by the sphygmograph-trace. A bounding 
weak pulse shows a low, and a small thready one a high tension. - 
We know, from the observations of Davy and others, that by 
reducing the tension in one part of the body the tension of other parts 
is lowered; thus by placing one hand in hot water, a thermometer in 
the other rises. In Tables VII and VIII, it is shown that by putting 
the feet in hot water (at 110° to 115°) the lowering of the tension was 
so great that the amount of heat lost into the air considerably exceeded 
that gained'to the body from the water, so that the temperature of the 
body began to fall directly, and decreased considerably ; and it was 
noticed that on adding more hot water chills were produced, which 
was the same as the effect of first putting the feet in the water. 
By covering a small part of the body with a bad conductor, the 
tension of the whole body soon falls, from the accumulation of heat 
in the covered parts causing a lowering in the tension generally, and 
a consequent greater carrying away of heat. In this way the fall after- 
sitting down on a bad conductor when nude can be explained 
(Table VII). 
A glow is felt in the skin directly upon short muscular movement, 
as stooping, and the temperature falls at the same time, asin Table IV, 
between 11.45 and 12.20, and in Table XI, between 5.0 and 5.15. In 
the latter case the muscular movement was carried to such an extent 
