494 BUREAU OF ANIMAL INDUSTRY. 



such as a severe bruise, a broken bone, an inflamed lung, or excessive 

 work, which has surcharged the ])lood with the waste products of the 

 combustion of the tissues, which were destroyed to produce force, or 

 the toxins of influenza in the blood, or the presence of irritating 

 material, either in the form of living organisms or of their products, 

 as in glanders or tuberculosis — the general train of s^-mptoms are 

 much the same, varying as the amount of the irritant differs in quantity, 

 or when some special quality in them "has a specific action on one or 

 another tissue. 



There is in fever at first a relaxation of the small blood vessels, which 

 may have been preceded by a contraction of the same if there was a 

 chill, and as a consequence there is an acceleration of the current of 

 the blood. There is, then, an deviation of the peripheral tempemture, 

 followed by a lowering of tension in the arteries and an acceleration 

 in the movement of the heart. These conditions may be produced by 

 a primary irritation of the nerve centers of the In-ain from the eflects 

 of heat, as is seen in thermic fever, or sunstroke, or by the entrance 

 into the blood stream of disease-producing organisms or their chemical 

 products, as in anthrax, rinderpest, influenza, etc. 



There are times when it is diflicult to distinguish between the exist- 

 ence of fever as a disease and a temporary feverish condition v hich is 

 the result of excessive work. Like the condition of congestion of the 

 lungs, which is normal up to a certain degree in the lungs of a race 

 horse after a severe race, and morbid when it produces more than tem- 

 porary phenomena or when it causes distinct lesions, the temperature 

 may rise from physiological causes as much as four degrees, so fever, 

 or, as it is better termed, a feverish condition, may follow any work 

 or other employment of energy in which excessive tissue change has 

 taken place; but if the consequences are ephemeral, and no recogniz- 

 able lesion is apparent, it is not considered morbid. This condition, 

 however, may predispose to severe organic disturbance and local inflam- 

 mations which will cause disease, as an animal in tliis conditioji is 

 liable to take cold and develop lung fever or a severe enteritis, if 

 chilled or otherwise exposed. 



Fever in all animals is characterized by the same general phenomena, 

 but we find the intensity of the symptoms modified by the species of 

 animals affected, by the races which subdivide the species, b}- the fami- 

 lies which form groups of the races, and by certain conditions in indi- 

 viduals themselves. For example, a pricked foot in a Thoroughbred 

 may cause intense fever, while the same injury in the foot of a Clydes- 

 dale may scarcely cause a visible general symptom. In the horse, fever 

 produces the following sj^mptoms: 



The normal body temperature, which varies from 99^ to 100- F., 

 is elevated from 1^ to 9°. A temperature of 102'^ or 103° F. is moderate 

 fever, 104° to 105° F. is high, and 100° F. and over is excessive. The 



