340 



VETERINARY PATHOLOGY. 



in the excretions (air, perspiration, urine and feces), as well as 

 by direct radiation. The relative amount of heat dissipation by 

 the excrements and bv radiation varies in diiTerent animals. 



Normal temperature is the balance of equilibrium maintained 

 between thermogenesis (generation of heat) and thermolysis 

 (dissipation of heat). The normal temperature of an animal 

 used during the day is about 1° F. higher in the evening than in 

 the morning. 



Fever is a condition in which the equilibrium between ther- 

 mogenesis and thermolysis has been overthrown, i. e., there is 

 a disturbance of metabolism accompanied by increased tempera- 

 ture. It is nut a disease but a symptom complex, common to 

 several different pathologic conditions. Fever should be dif- 

 ferentiated from heat stroke and sunstroke. In heat stroke there 

 is no disturbance of thermogenesis or thermolysis, but the ther- 

 mnlvtic centers are unable to cope with the existing external 

 conditinns, and there is accumulation of heat in the l:)ody, whereas 

 fever is a result of disturl)ed equilibrium between thermogene- 

 sis and thermiJvsis. Sunstroke is a condition produced by the 

 action of actinic or chemic rays 'd the sun upon the nerve cen- 

 ters, temperature variations lacing only a predisposing factor. 



Etiology. — Ve\er is usually caused In- bacterial products 

 as toxins, endotoxins and bacterial proteids. Tissue products 

 as leucomains, peptones and various albumins are also capable 

 of producing fever. Certain therapeutic agents are causative fac- 

 tors of fever. 



Course. — The course of a fever may be divided into four per- 

 il ids or stages, as follows: 



Onset (stadium increment! ) is the period of increase between 

 the time of normal temperature and the time that the tempera- 



Fi-. isn. — ChartH Hhowing two fever curves. On the left is given the Irinperalurr and 



on tlK' toj) each number si^nilirs one day or 24 liours. From 1 to 13 is the 



unset; from 13 to 17 and '20 respectively the Acme; frnm IT to 32 is 



a gradual ih.elin'L- (l\-sis); and on 20 is shown a rapid 



declined (crisis). 



