846 ANIMAL HEAT. 



For experiments on man, Currie, 1 and afterwards Liebermeister 2 and others, 

 used a bath as a water calorimeter ; this method is liable to many sources of 

 error. Scharling, 3 Vogel, 4 and Him 5 used a method which was simple, but at 

 the same time untrustworthy ; the subject of the experiment was enclosed 

 within a small chamber standing in a room with a constant temperature ; the 

 production of heat was determined from the difference between the tempera- 

 ture of the chamber and that of the room. Leyden employed a partial 

 calorimeter for experiments in man ; a limb was enclosed in a suitable water 

 calorimeter. 



It is probable that the simplest and most useful method for clinical 

 purposes is that introduced by Waller 6 ; the deep and surface temperatures 

 of different parts of the body are determined, the evaporation of water from 

 the skin is estimated by a hygrometer, argl the temperature of the surrounding 

 air is noted. If the calorimetric value of the thermometer scale be pre- 

 viously determined on a surface giving off heat at a known rate, it is possible 

 from the data obtained to calculate the emission of heat. The apparatus, in 

 fact, constitutes a heat manometer measuring the temperature difference 

 between the skin and atmosphere. 



The results of calorimetric experiments. Lavoisier 7 and Craw- 

 ford 8 concluded from their results that the heat produced by an animal 

 could be almost entirely accounted for by the combustion represented 

 by the discharge of carbon dioxide and water. Dulong 9 and Despretz's 10 

 data, when corrected by Liebig, 11 Helmholtz, 12 Gavarret, 18 Ludwig, 14 Milne 

 Edwards, 15 and Liebermeister, 16 lead to a similar conclusion, but since the 

 more exact experiments of Eubner and others, they have had only a 

 historical interest. 17 



The table on p. 847 gives some of the more important results 

 obtained by various observers. 



It has been already shown that the heat, measured directly with a 

 calorimeter, is equal to that calculated from the heats of combustion of 

 the constituents of the food (Eubner 18 ), and it will be seen later that the 

 production of heat in different warm-blooded animals is proportionate to 

 the surface of their bodies (Rubner). 19 During digestion and muscular 

 work the production of heat is greatly increased. 



According to Langlois, 20 the production of heat in children is pro- 

 portionate to the surface of their skin, and shows a daily variation. 



1 " Medical Reports on the Effect of Water, Cold and Warm, as a Remedy in Fever and 

 other Diseases," Liverpool, 1798. 



2 Arch.f. Anat., Physiol. u. wissensch. Med., 1860, S. 520, 589 ; 1861, S. 28 ; " Hand- 

 buch der Path. u. Therap. des Fiebers," 1875, S. 142. 



z Journ. f. prakt. Chem., Leipzig, 1849, Bd. xlviii. S. 435. 



4 Arch. d. Ver. f. wissensch. Heilk., Leipzig, 1864, S. 442. 



5 " Recherches sur 1'equivalent mecanique de la clialeur," Paris, 1858. 



6 " Proc. Physiol. Soc.," Journ. Physiol., Cambridge and London, 1894, vol. xv. 



7 Hist. Acad. roy. d. sc., Paris, 1780, p. 355. 



8 " Experiments and Observations on Animal Heat," 1788, 2nd edition. 



9 Ann. d. chim. etphys., Paris, 1843, Se"r. 3, tome i. p. 440. 



10 Ibid., 1824, SeV. 2, tome xxvi. p. 337. 



11 "Thierchemie."S. 28. 



12 "Encyclop. Worterb. d. med. Wissensch.," 1846, Bd. xxxv. S. 523. 



13 " De la chaleur produite paries etres vivants," 1855, p. 219. 



14 "Lehrbuch d. Physiol.," 1861, Aufl. 2, Bd. ii. S. 739. 



15 " Le9ons sur la physiologic," 1863, tome viii. p. 23. 



16 "Handbuch der Path. u. Therap. des Fiebers," 1875, S. 134. 



17 For a discussion of these results see Rosenthal, Hermann's "Handbuch," Bd. iv. Th. 2, 

 S: 358. 



Ztschr.f. BioL, Munchen, 1894, Bd. xxx. S. 135. This article, pp. 833-37. 



19 Ztschr.'f. BioL, Munchen, 1883, Bd. xix. S. 535. This article, p. 853. 



20 Centratbl.f. Physiol., Leipzig u. Wien, 1887, S. 237. 



