Catsarewonderfulformanyreasons,includingtheirpurr.Whenthey’recontent(orsometimeswhenthey’reanxious,orinpain,orinneedofattention,ortoself-soothe)theypurr.It’softenclaimedthatcatspurrtospeeduphealingofphysicalinjuries.It’sprobablynottrue.Inamyriadofcatarticles,healingeffectsareusuallyconnectedtothevibrationalfrequencyofthepurring,whichisanimmediateredflagformethatsignalspseudoscience.Thebasicideaof“healingthroughvibrations”hasfloatedaroundformorethan100years;aninventorin1920createdavibrating“Rifemachine”thatcrackpotsclaimcureseverythingfromcancertoLymedisease.

