英语翻译
Saltisasnecessarytolifeaswater.InmanyareasofAfricapeopleoncedranktheurine(尿)ofanimalsbecausetheyhadnoothersourceofsalt.Withoutsalt,humanbeingsdie.
Thehumanbodydemandsthattheamountofsaltinthebloodalwaysstaythesame.Whenthebodydoesnotgetenoughsalt,itprotectsitselfbylettinglesssaltleavethebodyinurineandsweat.Butitcannotreducethisoutputtozero.Somesaltisalwaysescaping.Onacompletelysaltlessdiet,likethatofsomepeopleinAfrica,thebodysteadilylosessmallamountsofsaltthroughthekidneys(肾)andsweatglands(腺).Itthentriestoadjusttothislossbyspeedingupitssecretion(分泌)ofwater.Inthisway,thebodyattemptstokeeptheamountofsaltinthebloodatthenecessarylevel.Theresultisaslowdryingupofbodyand,finally,death.Thepersondiesofthirst.
Incaseswherethereislittleornowatertodrink,thebodytriestodotheoppositething.Again,itmustkeepthesaltlevelinthebloodconstant.Becauseithaslittlewater,itattemptstostopwaterfromleavingthebodyandtoincreaseitssecretionofsalt.But,aswiththeescapingsalt,itcannotbecompletelysuccessful.Somewaterstillleavesandthepersoneventuallydiesofthirst.Inshort,thebody’snormalneedsforsaltandforwaterarebothpartsofthesameimportantneedtokeepthesaltlevelinthebloodconstant.