ANIMAL HEAT. 
By M. S. Pembrey. 
Contents :— Thermometry, p. 785 — Warm and Cold Blooded Animals, p. 787 — 
Temperature of Man and other Warm-Blooded Animals, p. 788 — Of Cold- 
Blooded Animals, p. . 792 — Hibernation, p. 794 — Influence of Various Condi- 
tions upon Temperature, p. 798 — Time of Day, p. 798 — Age, p. 803 — Muscular 
Work, p. 806— Mental Work, p. 807— Food, p. 809- Sleep, p. 810— Sex, p. 810 
— Bace, p. 811 — Menstruation and Pregnancy, p. 812 — Individual Peculiarities, 
p. 812 — Temperature of Surroundings, p. 812— Extreme Heat and Cold, p. 814 
—Baths, p. 818— Drugs, p. 820— Temperature of Different Parts of Bodv, p. 824 
—Of xYrterial and Venous Blood, p. 826— Of the Skin, p. 829— Regulation of 
Temperature, p 831 — Heat Production, p. 832 — Historical, p. 832 — Relation to 
Chemical Changes, p. 833 — Specific Heat of Body, p. 838 — Seats of Heat Produc- 
tion, p. 839 — Measurement of Heat Production, p. 844 — Calorimetry, p. 844 — 
Respiratory Exchange as a Measure of Heat Production, p. 847 — Heat Produc- 
tion in Cold- Blooded Animals, p. 849 — Regulation of Heat Loss, p. 850 — Influence 
of Size of Body, p. 852 — Influence of Nervous System, p. 854 — Development of 
Power of Regulation, p. 865 — Temperature of Body after Death, p. 866. 
The higher animals have within their bodies some source of heat and 
some mechanism to regulate the production and loss of heat, for in the 
height of summer and in the depth of winter their mean temperature is 
constant. Of this fact the ancients had but an imperfect knowledge ; 
they had no thermometers, and therefore could only judge from their 
sensations. Observations dependent upon the sensations of heat and 
cold are necessarily imperfect and often fallacious. The invention, 
therefore, of thermometers was imperative, if exact data upon the 
temperature of animals were to be obtained 
The Introduction of Thermometers.— Towards the close of the six- 
teenth century the first thermometers appear to have been made. 1 The credit 
of the invention has been attributed chiefly to Sanctorius of Padua, and 
Galileo ; the former based his thermometer upon the expansion of air enclosed 
in a bulb at the end of a tube which contained a coloured liquid ; while Galileo 
is said to have made, in 1612, the first alcohol thermometer. Boyle introduced 
the alcohol thermometer into England, where Hooke, in 1665, recommended 
that the zero of the scale should be the freezing point of water, which he and 
Boyle found to be constant. In 1680, Newton suggested the boiling point of 
water for a further graduation of the thermometer, and Halley a few years 
later proved that the point was a constant one, and recommended the use of 
mercury in the construction of thermometers. Fahrenheit first replaced spirit 
by mercury in 1720, and, after several attempts at graduation, introduced the 
scale which now bears his name. The introduction of the centigrade ther- 
1 Holloway, "The Evolution of the Thermometer," Sc. Prog., London, 1895-96, vol. iv. 
p. 413; Liebermeister, " Handbuch d. Path. u. Therap. des Fiebers," Leipzig, 1875, S. 3. 
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