400 NUTRITION: 



than in the portal veins. These figures are the result of 

 numerous experiments made on dogs. The maximum of 

 thirty-three observations upon the temperature in the aorta 

 was 105*8, and the minimum, 98*78 ; the maximum of 

 thirty-two observations upon the portal vein was 106*34r, 

 and the minimum, 100*04 ; the maximum of thirty-five ob- 

 servations upon the hepatic veins was 107, and the mini- 

 mum, 99*86V Compared with the aorta, the temperature 

 of the portal vein was generally found to be higher (maxi- 

 mum of differencej 0*9) ; but in a few instances, five out of 

 fifteen, it was a very little lower, which is explained by Ber- 

 nard by the supposition that the intestinal canal is not en- 

 tirely removed from external modifying influences. These 

 results show that the blood coming from the liver is warmer 

 than in any other part of the body. 



The general fact that the superficial parts are cooler than 

 those less exposed to loss of heat by evaporation, observed 

 by Hunter, 3 Davy, 8 and others, does not demand extended 

 discussion ; but in a series of experiments by Breschet and 

 Becquerel, 4 who were among the first to employ thermo- 

 electric apparatus in the study of animal heat, it was found 

 that the cellular tissue was from 2*5 to 3*3 cooler than the 

 muscles. This difference will be readily understood when 

 we consider the production of heat in the general system, 

 and more especially in the highly-organized parts. 



A most interesting question, in this connection, relates 



1 BERNARD, op. cit., p. 84. We have calculated these results from an elabo- 

 rate table given by Bernard, but have disregarded two observations (Nos. 17 

 and 18, table in.), made on animals after death, the circulation being kept up 

 by artificial respiration. 



2 HUNTER, Experiments and Observations on Animals, with respect to the Power 

 of producing Heat. Observations on certain Parts of the Animal (Economy ', Lon- 

 don, 1792, pp. 108, 115. 



3 DATY, Researches, Physiological and Anatomical, London, 1839, vol. i., p. 

 150, et seq. The paper here referred to first appeared in the Philosophical 

 Transactions, in 1814. 



4 BRESCHET ET BECQUEREL, Premier memoire sur la chaleur animate. Annales 

 de chimie et de physique, Paris, 1835, tome lix., p. 129. 



