308 



ANIMAL HEAT. 



rises, notwithstanding the consumption of oxy gen is less than in the 

 condition of glandular repose. 



A similar elevation of temperature is shown by the blood while tra- 

 versing the capillary circulation of the intestine and of the liver. The 

 following tables give the results of two series of observations by Ber-, 

 nard on the temperature of the blood entering and leaving these two 

 organs in the dog: 



TEMPERATURE OF THE BLOOD IN THE 

 Aorta. Portal Vein. 



36.8 38.8 



40.3 40.7 



39.40 39.5 



Portal Vein. Hepatic Vein. 

 40.2 40.6 



40.6 40.9 



40.7 40.9 



Thus the blood of the hepatic vein, after traversing two successive 

 capillary circulations, is warmer than that drawn from any other part 

 of the body. 



Even in the kidneys, when the secretion of urine is actively going on, 

 there is a rise of temperature in the blood of the renal veins. At the 

 same time, as in the submaxillary glands, the circulation is increased in 

 activitjr, the venous blood leaves the organ of a bright red color, and its 

 proportion of oxygen, according to Bernard, is only reduced to 88 per 

 cent, of that contained in the arteries, while in the condition of glandular 

 repose it is reduced to 33 per cent. 



The production of heat, therefore, is accomplished in the different 

 organs of the body with different degrees of intensity according to the 

 special nature of the act of nutrition in each one. In the muscles it is 

 accompanied by an increased consumption of oxygen and a deeper 

 coloration of the venous blood ; in the salivary glands and the kidneys 

 by a diminished consumption of oxygen and a less complete change in 

 the color of the blood. The blood coming from each organ has a higher 

 temperature in proportion to the activity of heat-production in the 

 organ itself; and thus the temperature of the venous blood varies in 

 different parts of the circulatory system, while that of the arterial blood 

 is everywhere sensibly the same. 



Cooling of the Blood in its Passage through the Lungs and Skin. 

 While in the other internal organs the blood is warmed during its pass- 

 age through the capillary vessels, in the lungs its temperature is slightly 

 diminished. This fact, which has been alternately asserted and denied, 

 owing to the difficulties of exact observation without introducing other 

 causes of a change of temperature, has been abundantly confirmed by the 

 more recent observations of Bering, Bernard, Heidenhain and Korner, 

 and Strieker and Albert. That of Hering was made upon a young calf, 

 otherwise in good condition, but presenting the malformation of ectopia 



