▁system ▁of ▁classification ▁had ▁been ▁popular ▁for ▁a ▁time ▁after ▁its ▁first ▁publication ▁in ▁ 1 8 1 9 – 1 8 2 0 . ▁In ▁a ▁myst ical ▁scheme ▁this ▁grouped ▁separately ▁created ▁gener a ▁in ▁" os cul ating " ▁( k iss ing ) ▁circles . ▁ ▁Both ▁Ernst ▁May r ▁and ▁Cy ril ▁Dar ling ton ▁interpret ▁B ly th ' s ▁view ▁of ▁natural ▁selection ▁as ▁maintain ing ▁the ▁type : ▁" B ly th ' s ▁theory ▁was ▁clearly ▁one ▁of ▁elim ination ▁rather ▁than ▁selection . ▁His ▁principal ▁concern ▁is ▁the ▁maintenance ▁of ▁the ▁per fection ▁of ▁the ▁type . ▁B ly th ' s ▁thinking ▁is ▁decided ly ▁that ▁of ▁a ▁natural ▁the olog ian ..." ▁" What ▁was ▁the ▁work ▁of ▁B ly th ? ... ▁B ly th ▁attempts ▁to ▁show ▁how ▁[ selection ▁and ▁the ▁struggle ▁for ▁existence ] ▁can ▁be ▁used ▁to ▁explain , ▁not ▁the ▁change ▁of ▁species ▁( which ▁he ▁was ▁anxious ▁to ▁dis cred it ) ▁but ▁the ▁stability ▁of ▁species ▁in ▁which ▁he ▁ar d ently ▁believed ." ▁ ▁In ▁this ▁negative ▁form ulation , ▁natural ▁selection ▁only ▁pres erves ▁a ▁constant ▁and ▁un change able ▁type ▁or ▁ess ence ▁of ▁created ▁form , ▁by ▁elimin ating ▁extreme ▁variations ▁or ▁un fit ▁individuals ▁that ▁devi ate ▁too ▁far ▁from ▁this ▁ess ence . ▁The ▁form ulation ▁goes ▁back ▁to ▁the ▁ancient ▁Greek ▁phil os opher ▁Emp ed oc les , ▁and ▁the ▁the olog ian ▁William ▁Pale