IN THE TEMPERATURE OF THE HUMAN BODY. 13 
that the loss was made up for by the increase of heat from en muscu- 
lar movement. 
Simply heating the feet lowers the tension and temperature OR: 
as in Table IX and in Table X. The passage of a cloud before the 
sun seems to have acted by reducing the loss of heat, as the tempera- 
ture rose at the time. 
Further confirmation of the facts stated as to the modification of Page 426. 
arterial tension may be found in Marey’s work, De la Circulation du 
Sang, published in Paris in 1863. In that book the author ascribes 
the uniformity of the heat in the internal parts to the same cause as 
the author of the present paper ascribes the variations. 
The fact observed by Dr. W. Ogle in the St. George’s Hospital 
Reports for 1866, and by Drs. Ringer and Stewart in a paper read 
before the Royal Society this year, that the temperature falls at night, 
and is lowest at from 12 to 1 a.m., and begins to rise after that time, 
is simply explained on the theory given above ; for it depends on the 
custom of Englishmen going to bed at about that hour, and thus giving 
a large amount of heat to the cold bedclothes, which at first is expended 
in warming the sheets, &c., while later on in the night the bedclothes 
are warm, and therefore the body has only to make up for the heat 
diffused. 
Other natural phenomena can be similarly explained. Thus, on a 
cold day, the effect of sitting with one side of the body in the direct 
rays of a fire is to cause the other side to feel much colder than if there 
was no fire at all, because the fire lowers the tension over the whole 
body, and supplies heat to the full cutaneous vessels of one side, while 
the other side, being equally supplied with blood in the skin, does not 
% receive heat, but has to distribute it rapidly to the cold clothes, &c. 
P ee ae 8 ne 
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