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 Condlv 

 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 

 Race, 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 Body, p. 824 , 

 Of Arterial 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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