ANIMAL HEAT. 411 



question of their use in enabling the system to resist exces- 

 sive cold. Davy states that " the effect of wine, unless used 

 in great moderation, is commonly lowering, that is, as to 

 temperature, while it accelerates the heart's action, followed 

 after a while by an increase of temperature." 1 We have 

 already discussed somewhat fully the physiological effects 

 of alcohol, and have shown that its use does not enable men 

 to endure a very low temperature for a great length of time. 

 This is the universal testimony of scientific Arctic explorers ; 

 and Dr. Hayes particularly states, that " in almost any shape, 

 it is not only completely useless, but positively injurious." 2 



The relations of animal heat to respiration and nutrition 

 constitute a most interesting and important division of the 

 subject, which will be more fully considered in discussing the 

 various theories of calorification. As a rule, when the respira- 

 tory activity is physiologically increased, as it is by exercise, 

 bodily or mental, ingestion of food, or diminished external" 

 temperature, the generation of heat in the body is correspond- 

 ingly augmented ; and, on the other hand, it is diminished 

 by conditions which physiologically decrease the absorption 

 of oxygen and the exhalation of carbonic acid. The only 

 positive experiments upon the influence of simple increase in 

 the number and extent of the respiratory acts are those of 

 Prof. Lombard. He found that when the respirations were 

 increased in depth and frequency for ten minutes, there was 

 a diminution of two degrees in the temperature over the 

 radial artery. There was also a very slight lowering of the 

 temperature, from '001 to *01 of a degree cent., in from a 

 minute to a minute and a half after suspension of respiration. 

 Prof. Lombard explains these phenomena by the mechani- 

 cal effects of the condition of the lungs upon the arterial 

 pressure. 3 



1 DAVY, Physiological Researches, London, 1863, p. 57. 



2 HAYES, Observations on the Relations existing between Food and the Capabilities 

 of Men to resist Low Temperatures. American Journal of the Medical Sciences, 

 Philadelphia, 1859, Xew Series, vol. xxxviii., p. 117. 



3 LOMBARD, Recherches experimentales sur quetguts influences non etudiees 



