▁and ▁medieval ▁practice ▁was ▁to ▁draw ▁a ▁smaller ▁amount ▁of ▁blood ▁from ▁a ▁distant ▁location . ▁V es al ius ' ▁pam ph let ▁generally ▁supported ▁Gal en ' s ▁view , ▁but ▁with ▁qual ifications ▁that ▁rejected ▁the ▁in fil tr ation ▁of ▁Gal en . ▁ ▁In ▁ 1 5 4 1 ▁while ▁in ▁Bolog na , ▁V es al ius ▁discovered ▁that ▁all ▁of ▁Gal en ' s ▁research ▁had ▁to ▁be ▁restricted ▁to ▁animals ; ▁since ▁dis section ▁had ▁been ▁b anned ▁in ▁ancient ▁Rome . ▁Gal en ▁had ▁disse cted ▁Barb ary ▁mac a ques ▁instead , ▁which ▁he ▁considered ▁struct ur ally ▁closest ▁to ▁man . ▁Even ▁though ▁Gal en ▁produced ▁many ▁errors ▁due ▁to ▁the ▁an atom ical ▁material ▁available ▁to ▁him , ▁he ▁was ▁a ▁qualified ▁exam iner , ▁but ▁his ▁research ▁was ▁weak ened ▁by ▁stating ▁his ▁find ings ▁philosoph ically , ▁so ▁his ▁find ings ▁were ▁based ▁on ▁religious ▁pre cept s ▁rather ▁than ▁science . ▁V es al ius ▁contributed ▁to ▁the ▁new ▁Gi unta ▁edition ▁of ▁Gal en ' s ▁collected ▁works ▁and ▁began ▁to ▁write ▁his ▁own ▁an atom ical ▁text ▁based ▁on ▁his ▁own ▁research . ▁Until ▁V es al ius ▁pointed ▁out ▁Gal en ' s ▁substitution ▁of ▁animal ▁for ▁human ▁an atom y , ▁it ▁had ▁gone ▁un not iced ▁and ▁had ▁long ▁been ▁the ▁basis ▁of ▁studying ▁human ▁an atom y . ▁However , ▁some ▁people ▁still ▁chose ▁to ▁follow ▁Gal en ▁and ▁res ented ▁V