358 ANATOMY FOR NURSES [Chap. XVIII 



Abnormal variations. Fever. — The term fever is applied to 

 an abnormal condition, characterized by increased temperature, 

 increased heart-beat, increased respiration, increased tissue waste, 

 and faulty secretion. 



Cause. — The exact cause of fever is unknown. It is the result 

 of causes which disturb the balance between heat production and 

 heat elimination. One theory is that there is a heat centre in the 

 brain which controls the production and elimination of heat, and 

 toxic substances circulating in the blood or abnormal conditions 

 of the various organs of the body may interfere with the proper 

 functioning of this centre. The toxic substances circulating in 

 the blood may result from faulty metabolism, as in diabetes, 

 gout, etc. ; or from the action of bacteria, as in infectious dis- 

 eases ; or from injury to the tissues of a mechanical, thermal, or 

 chemical nature. 



Value of fever. — When fever is due to infection by bacteria, 

 the body seems better able to fight the infection if the tempera- 

 ture is elevated. For this reason fever is thought to be a protective 

 measure and antipyretics are not used unless the elevation is ex- 

 treme, or long continued. In this case measures must be taken 

 to reduce the temperature, or death may ensue from coagulation 

 of the proteins present in the nerve-cells of the brain and spinal 

 cord. 



Subnormal temperature. — In some maladies the temperature 

 falls distinctly below normal. This is no doubt chiefly due to 

 diminished metabolism. In cases of starvation the fall of tem- 

 perature is very marked, especially during the last days of life. 

 The diminished activity of the tissues first affects the central 

 nervous system ; the patient becomes languid and drowsy, and 

 finally unconscious ; the heart beats more and more feebly, the 

 breath comes more and more slowly, and the sleep of unconscious- 

 ness passes insensibly into the sleep of death. 



