86 DISEASES OF CATTLE. 



The location selected for feeling the pulse in cattle is where the sub- 

 maxillary artery winds around the lower jaw bones, just at the lower 

 edge of the flat muscle on the side of the cheek. Or if the cow is lying 

 down, the metacarpal artery on the back part of the fore fetlock is very 

 convenient for the purpose. Any superficial artery, it may be said, will 

 give the pulsations, but in order to ascertain the peculiarities it is nec- 

 essary to select an artery which may be pressed against a bone. 



TEMPERATURE ANIMAL HEAT. 



The heat of the body is due to chemical and vital changes which 

 occur within the Tmimal, and is maintained at an average temperature, 

 with but slight variations, in all seasons, without regard to the tem- 

 perature of the surrounding atmosphere. The principal source of ani- 

 mal heat is oxidation, which takes place in the tissues throughout the 

 body. The oxygen in the red corpuscles unites with the carbon (and 

 forms carbonic acid gas) and with hydrogen (and forms water), and the 

 chemical union is always accompanied by heat. Heat is lost from the 

 body by evaporation, radiation, conduction, and with the escape of 

 urine and feces, which prevents increase above the normal temperature. 

 The vasoinotor nerves, by regulating the size of the arteries, regulate 

 the supply of blood to the parts, and thus assist in maintaining an 

 average temperature. The average normal temperature of cattle in 

 confinement is about 101 F.; in oxen at work, or cattle at liberty, it is 

 about 102 F. In calves it ranges a fraction of a degree higher. In 

 very old animals it is lower than the average normal temperature. The 

 method of ascertaining the temperature is by inserting the bulb of a 

 clinical thermometer into the rectum, leaving sufficient remaining out- 

 side by which to withdraw it. It should remain in the gut between 

 three and four minutes. (Plate in, Fig. 1.) 



Some veterinarians are very expert in judging the temperature by 

 inserting their fingers in the mouth, but this method requires much 

 practice, both on the healthy and diseased animal. The hand or finger 

 in the mouth will detect an elevation of temperature, but the thermom- 

 eter is better, especially in the beginning or incubative stage of disease. 

 The hand on the surface of the body can not give an idea of internal 

 temperature, because the surface may feel cold while the interior is 

 elevated above the normal. Increase above the normal temperature 

 does not point to a particular disease, but in conjunction with other 

 symptoms it is a valuable aid; and during the progress of a disease it 

 is a guide. 



The changes which take place in tissues are increased by disease, and 

 as a consequence the temperature is elevated, which, if continued, con- 

 stitutes fever. Congestion, being an excessive quantity of blood in a 

 part, is accompanied by an elevation of the temperature. Inflammation 

 involves changes in the blood-vessels and circulation ; there is escape 

 of fluid blood and corpuscles from vessels, and changes in the inflamed 



