b ility ▁of ▁experimental ▁results ▁in ▁medical ▁research . ▁He ▁was ▁Director ▁of ▁the ▁Central ▁Institute ▁for ▁Ex perimental ▁Anim als ▁( CI E A ), ▁Japan ▁ ▁Development ▁of ▁Com pre h ensive ▁Animal ▁Ex periment ation ▁Systems ▁His ▁most ▁important ▁achiev ement ▁to ▁date ▁is ▁the ▁establishment ▁of ▁compreh ensive ▁animal ▁experiment ation ▁systems ▁using ▁strictly ▁defined ▁labor atory ▁animals ▁to ▁ass ure ▁reprodu ci b ility ▁of ▁experimental ▁results ▁in ▁medical ▁research . ▁Before ▁his ▁concepts ▁were ▁applied , ▁it ▁was ▁generally ▁considered ▁to ▁be ▁very ▁difficult ▁or ▁even ▁impossible ▁to ▁obtain ▁reprodu cible ▁results ▁in ▁medical ▁research ▁using ▁labor atory ▁animals , ▁mainly ▁due ▁the ▁traditional ▁cons ensus ▁that ▁the ▁animals ▁are ▁living ▁organ isms ▁with ▁individual ▁differences . ▁He ▁has ▁completely ▁changed ▁this ▁out - dated ▁parad ig m ▁in ▁medical ▁research ▁by ▁establish ing ▁compreh ensive ▁animal ▁experiment ation ▁systems . ▁ ▁One ▁of ▁the ▁factors ▁that ▁affect s ▁the ▁reprodu ci b ility ▁of ▁the ▁results ▁of ▁animal ▁experiments ▁is ▁the ▁proxim ate ▁environment ▁in ▁which ▁the ▁experiment ▁is ▁performed ▁including ▁the ▁temperature ▁and ▁hum id ity ▁of ▁the ▁animal ▁room , ▁the ▁size ▁of ▁c ages ▁and ▁care t akers . ▁The ▁concept ▁of ▁the ▁dram atype , ▁which ▁refers ▁to ▁the ▁effects ▁of ▁the ▁proxim ate ▁environment ▁on ▁the ▁phen ot ype , ▁was ▁introduced . ▁Russell ▁and ▁B urch ▁proposed ▁the ▁term ▁" d ram atype " ▁in ▁ 1 9 5 9 ▁from ▁the ▁stand point ▁of ▁animal ▁w elf are ▁(