374 A MANUAL OF VETERINARY PHYSIOLOGY 



in temperature between the rectum and the thin skin of the 

 breast in the horse, while at the same external temperature 

 the limbs of this animal, which are naturally cold, in consequence 

 of the underlying tissues having very little vascularity, may 

 indicate 25-4° C. (44 F.) difference between the pasterns and 

 the rectum. 



The Normal Temperature of Animals. — The wide differences 

 which exist in the normal temperature of animals of the same 

 class is remarkable. The following observations were made 

 principally by Siedamgrotzky. 



Horse : The temperature varies between 38-0° to 38-2° C. 

 (100-4° to 100-8° F.). Age has a slight influence, being some- 

 what higher in extreme youth and lower in old age. 



Cattle : The normal temperature is from 38-7° to 38-8° C. 

 (ioi-8° to 102° F.). Wooldridge* places the mean at 38-5° C. 

 (101-4° R), and gives the variations at 38° to 39-3° C. (100-4° to 

 102-8° F.). 



Sheep : In these animals the greatest variation in temperature 

 occurs, viz., from 38-4° to 41-0° C. (101-3° to 105-8° F.). Prob- 

 ably the majority of temperatures lie between 39-7° to 40-2° C. 

 (103-6° to 104-4° F.). The cause of the variation is unknown. 



Swine : The average temperature is 39-0° C. (103-3° F-)» varying 

 from 38-2° to 407° C. (100-9° to 105-4° F.). 



Dog : The dog is liable to important variations, depending on 

 the external temperature. According to Dieckerhoff, it varies 

 from 37-4° to 39-4° C. (99*5° to 103° F.). Other observers place 

 it at 38-2° to 38-4° or 387° C. (100*9° to 101-3° or 101-7° F.). 



Variations in Body Temperature. — A rise or fall in body 

 temperature does not necessarily imply an increase or dimi- 

 nution in the production of heat. To demonstrate increased 

 heat production it is necessary to show that the metabolism is 

 increased, that more oxygen is absorbed, and more carbonic 

 acid produced. In all animals there is a daily variation in 

 temperature, the lowest records being obtained in the early 

 morning, 2 to 4 a.m., the highest in the evening, 6 to 8 p.m., 

 after which the temperature falls during the night. These varia- 

 tions are due to metabolism ; during rest the metabolism sinks, 

 the tide is low, while during activity it rises. The temperature 

 of the young animal is higher than that of the adult, while the 

 temperature of animals in temperate climates living in the open 

 is lower than those under cover ; in the case of the horse as 

 much as 1° F. difference in temperature has been registered 

 under this condition. In the tropics the temperature of 

 animals exposed in the open ; during the day, is higher than that 



* ' The Temperature of Healthy Dairy Cattle.' See Proceedings of the 

 Royal Dublin Society, vol. x., part hi., 1905. 



