542 EVOLUTION OF HEAT, LIGHT, AND ELECTRICITY. 



standing the obstacle thus offered to the evaporation of the sweat, whereby, 

 it might be supposed, the temperature of the body would be considerably 

 elevated. In the first rabbit, which had a temperature of 100 before being 

 shaved and plastered, it had fallen to 89| by the time the material spread 

 over him was dry. An. hour afterwards, the thermometer placed in the 

 same parts (the muscles of the thigh and chest) had descended to 76. In 

 another rabbit, prepared with more care, by the time that the plaster was 

 dry, the temperature of the body was not more than 5^ above that of the 

 surrounding medium, which was at that time 692 ; and in an hour after 

 this, the animal died. The varnish appears to act by increasing radiation. 

 Dr. Sanderson 1 found that a rabbit, which in the normal state gave off only 

 3 heat-units in ten minutes, gave about 20 after varnishing, notwithstanding 

 that in the former case its temperature was constant at 39.5 C., while in the 

 other it sank from 36 to 25. In SocolofFs experiments, albumen rapidly 

 made its appearance in the urine, and tetanic convulsions occurred before 

 death. Neither wrapping the animal in wool, nor compelling it to breathe 

 oxygen, prevented the fatal result. After death a diffused parenchymatous 

 inflammation of the kidneys was observed, and ulcers were found in the 

 stomach consequent upon profound extravasation. These experiments and 

 observations place in a very striking point of view the importance of the 

 cutaneous surface as a respiratory organ, even in the higher animals; and 

 they enable us to understand how, when the aerating power of the Lungs is 

 nearly destroyed by disease, the heat of the body is kept up to its natural 

 standard by the action of the skin. A valuable therapeutic indication, also, 

 is derivable from the knowledge which we thus gain, of the importance of 

 the cutaneous respiration ; for it leads us to perceive the desirableness of keep- 

 ing the skin moist, in those febrile diseases in which there is great heat and 

 dryuess of the surface, since aeration cannot properly take place through a 

 dry membrane. Of the relief afforded by cold or tepid sponging in such 

 cases, experience has given ample evidence. 



435. It has been held that the Chemical theory of Calorification is insuf- 

 ficient to account for the total amount of Heat generated by a warm-blooded 

 animal in a given time; this assertion being founded upon the experimental 

 results obtained by M. Dulong. MM. Favre and Silberrnann 2 have shown, 

 however, that the original estimates require correction for the true calorific 

 equivalents of carbon and hydrogen ; and that this correction having been 

 made, the heat produced by the combustion of the Carbon which is contained 

 in the carbonic acid expired, and by the combustion of such a proportion of 

 the Hydrogen contained in the exhaled water as may be fairly considered to 

 have undergone oxygenation within the system ( 318), proves to be adequate 

 to compensate for that which would be dissipated by the evaporation of all 

 the water transpired from the skin and lungs, and also to maintain the tem- 

 perature of the body itself in an atmosphere of ordinary coolness. And to 

 the combustion-heat of carbon and hydrogen, we should also add that of 

 those relatively minute quantities of Phosphorus and Sulphur, which also 

 undergo oxidation within the system ( 414), whereby a small additional 

 amount of heat must be generated. Through whatever diversity of combi- 

 nations or successive stages of oxidation these elements respectively pass, in 

 their progress to complete or final oxidation, it may be regarded as an indis- 

 putable fact, that they give out precisely the same amount of heat in the whole, 

 an if they had undergone the most rapid combustion to the same dajrce of o.rida- 



1 Handbook for tho Physiol. Labor., 1873, p. 333. 



2 See their Memoirs, Des Chnleurs de Combustion, in Comptes Eendus, torn, xx, 



xxn. 



