92 HORSE, SWINE AND POULTRY, DISEASES 



FEVERS. 



Fever is a general condition of the animal body in which there 

 is an elevation of the animal body temperature, which may be only 

 a degree or two or may be 10 F. The elevation of the body tempera- 

 ture, which represents tissue change or combustion, is accompanied 

 by an acceleration of the heart's action, a quickening of the respira- 

 tion, and an aberration in the functional activity of the various 

 organs of the body. These organs may be stimulated to the per- 

 formance of excessive work, or they may be incapacitated from car- 

 rying out their allotted tasks, or, in the course of a fever, the two 

 conditions may both exist, the one succeeding the other. Fever as a 

 disease is usually preceded by chills as an essential symptom. 



Fevers are divided into essential fevers and symptomatic fe- 

 vers. In symptomatic fever some local disease, usually of an inflam- 

 matory character, develops first, and the constitutional febrile phe- 

 nomena are the result of the primary point of combustion irritating 

 the whole body, either through the nervous system or directly by 

 means of the waste material which is carried into the circulation 

 and through the blood vessels, and is distributed to distal parts. 

 Essential fevers are those in which there is from the outset a gen- 

 eral disturbance of the whole economy. This may consist of an ele- 

 mentary alteration in the blood or a general change in the consti- 

 tution of the tissues. Fevers of the latter class are usually due to 

 some infecting agent and belong, therefore, to the class of infectious 

 diseases. 



Essential fevers are subdivided into ephemeral fevers, which 

 last but a short time and terminate by critical phenomena; inter- 

 mittent fevers, in which there are alterations of exacerbations of the 

 febrile symptoms and remissions, in which the body returns to its 

 normal condition or sometimes to a depressed condition, in which 

 the functions of life are but badly performed ; and continued fevers, 

 which include contagious diseases, such as glanders, influenza, etc., 

 the septic diseases, such as pyemia, septicemia, etc., and the eruptive 

 fevers, such as variola, etc. 



Whether the cause of the fever has been an injury to the tis- 

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

 excessive work, which has surcharged the blood with the waste prod- 

 ucts of the combustion of the tissues, which were destroyed to pro- 

 duce 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 

 symptoms are much the same, varying as the amount of the irritant 

 differs in quantity, or when some special quality in them has a spe- 

 cific 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 cur- 

 rent of the blood. There is, then, an elevation of the peripheral 

 temperature, followed by a lowering of tension in the arteries and 

 an acceleration in the movement of the heart. These conditions 



