1869.] Fluctuations in the Temperature of the Human Body. 425 



sion, 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., II., III., 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 temperatures, 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 recognized by the subject of 

 experiment, from the sensations they produce ; a feeling of warmth fol- 

 lowed 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 di- 

 rectly, 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 ten- 

 sion of the whole body soon falls, from the accumulation of heat in the 

 covered parts causing a lowering in the tension generally, and a con- 

 sequent 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, as in Table IV., be- 

 tween 1 1.45 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 that the 

 loss was made up for by the increase of lieat from the muscular move- 

 ment. 



Simply heating the feet lowers the tension and temperature together, 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 temperature rose 

 at the time. 



