HEAT IN RELATION TO THE HUMAN BODY 29 



assembly halls with their moisture-laden air, may be due in 

 part to the evaporation of perspiration from the clothing. 



SUMMARY 



The human body as an instrument for doing work may very properly 

 be considered a machine. Its care in order to secure the largest service 

 from it requires a degree of intelligence surpassing that needed generally 

 in the management of machinery. Conditions must be maintained 

 favorable to its repair through growth. Undue destruction of its parts 

 by excessive or improper use must be avoided. Proper balance must 

 be maintained between its waste and repair. 



Any impairment of the powers of the body is a serious handicap 

 throughout life. The harm due to ignorance is just as serious as though 

 done by deliberate choice. Much of the ill-health of later life, and 

 many of the limitations of the body in its usefulness as a machine, are 

 often directly traceable to an unwise manner of living during childhood 

 and youth. 



All motion occurring in the body in the performance of work involves 

 an expenditure of energy. All the activities of digestion, respiration, 

 and circulation, together with those of the brain and nervous system 

 as a whole, require a supply of energy without which the bodily proc- 

 esses would cease. 



The temperature of the body is maintained by chemical changes 

 within the body known as oxidation. Any considerable departure 

 from a normal temperature of 98 F. makes impossible, too, a continu- 

 ance of the bodily processes, and death results. 



One of the chief functions of the skin is the regulation of body 

 temperature by disposing of any excess of bodily heat in the vaporiza- 

 tion of perspiration. When by reason of old age, wasting disease, 

 impaired digestion or assimilation, the temperature of the body runs 

 much below normal, extra clothing must be worn and warmth from 

 without the body must be provided. 



Colds may result from a bodily state of depression due to fatigue. 

 At such times germs lodged in the lungs and nasal passages are given 

 opportunity for rapid development because of the lessened powers of 

 resistance of the body. Colds may be the result of a congested and 

 inflamed condition of the nasal passages, stomach, intestines, or kid- 

 neys, due to an excessive blood supply sent to them at a time when the 

 surface of the body is thoroughly chilled. Whatever promotes an 



