ous , ▁fake ▁b arks ▁from ▁other ▁trees , ▁such ▁as ▁hol ly . ▁By ▁the ▁middle ▁of ▁the ▁ 1 7 th ▁century , ▁b ark ▁as ▁a ▁treatment ▁was ▁becoming ▁widely ▁discussed . ▁Pre jud ices ▁raised ▁against ▁the ▁use ▁of ▁it , ▁especially ▁those ▁claim ing ▁that ▁the ▁Jes uit ' s ▁b ark ▁had ▁no ▁p urg ative ▁properties ▁and ▁could ▁not ▁treat ▁disease . ▁To ▁counter ▁this , ▁Francesco ▁T ort i , ▁who ▁first ▁system atically ▁studied ▁the ▁effect ▁of ▁cin ch ona ▁in ▁the ▁treatment ▁of ▁mal aria , ▁wrote ▁a ▁book ▁which ▁he ▁titled ▁Th era pe ut ice ▁Special is ▁ad ▁Feb res ▁Period icas ▁P ern icios as . ▁ ▁Tree ▁of ▁fe vers ▁▁ ▁One ▁highlight ▁of ▁the ▁Th era pe ut ice ▁Special is ▁is ▁the ▁drawing ▁" tree ▁of ▁fe vers ", ▁where ▁different ▁fe vers , ▁such ▁as ▁branches ▁of ▁the ▁tree , ▁are ▁divided ▁into ▁categories : ▁on ▁the ▁left , ▁those ▁that ▁respond ▁to ▁cin ch ona , ▁are ▁shown ▁as ▁branches ▁covered ▁with ▁b ark , ▁while ▁on ▁the ▁right ▁are ▁those ▁for ▁which ▁cin ch ona ▁is ▁in effect ive , ▁and ▁are ▁dep icted ▁as ▁den ud ed ▁le a fl ess ▁branches . ▁T ort i ▁clearly ▁identified ▁cin ch ona ▁as ▁a ▁specific ▁ther apy ▁for ▁inter mitt ent ▁fe vers , ▁as ▁opposed ▁to ▁continued ▁fe vers , ▁which ▁he ▁held ▁were ▁rarely ▁treat able ▁with ▁cin ch ona . ▁In