ANIMAL HEAT 387 



or sufficient heat to raise 4,550 gallons of water 1-8° F., or to raise 

 44 gallons from freezing to boiling point. Wolff, quoted by 

 Tereg, gives a table showing the heat lost per diem by cattle, 

 horses, sheep, and pigs, for every 500 kilos (1,100 pounds) of 

 body weight : 



Horse at moderate work - - - 24,500 large calories. 



hard work - 37,200 ,, „ 



Ox resting, and on moderate diet - 18,600 ,, ,, 



Sheep, with fine wool - - 27,700 ,, „ 



Pigs, fattening ... - 35,000 ,, „ 



Post-mortem Rises of Temperature are frequently observed, 

 and some of the observed temperatures have been remarkably 

 high. The writer recorded in the horse 109 F. between the liver 

 and diaphragm. The explanation afforded is that metabolism 

 is still occurring in the tissues, but since there is no circulation 

 to carry the heat away the temperature of the part rises. 



Pathological. 



The actual processes occurring in fever are not known. It cannot 

 be definitely stated whether the increase in temperature is due to 

 an increased production of heat or to a disturbance of the mechanism 

 by which the loss of heat is regulated — probably both causes are 

 in operation. It has been supposed by some that fever may be 

 due to the action of bacterial poisons on the heat -centres, and it 

 has been stated that cultures which produce fever in the intact 

 animal no longer do so on division of the pons, which cuts off the 

 basal ganglia heat -centre from the rest of the body. Others have 

 considered that, though the nervous mechanism is at fault in some 

 cases, in others the activity of the heat-forming tissues themselves 

 is at fault. This view receives some support from the action of 

 agents employed in the treatment of fever ; whereas some, like 

 quinine, act on the tissues, others, like antipyrin, appear to 

 produce their effects through the nervous system, particularly on 

 the vessels of the skin. Fever leads to a marked increase in the 

 metabolism of protein. This is shown by an increase in the output 

 of nitrogen ; uric acid appears in the herbivora. Ammonium salts of 

 organic acids and kreatinine are increased, and kreatine, which 

 normally does not appear in the urine, may now be found. The 

 absolute amount of urea is greater than normal, but its proportion 

 to the other urinary nitrogenous substances may be relatively 

 less. Fever is probably a protective mechanism in infective pro- 

 cesses ; nevertheless, high temperatures effect great damage to the 

 body -tissues, especially the heart - muscle, and methods which 

 control temperature appear clinically to give the best results in 

 treatment. 



