▁quantities ▁to ▁be ▁of ▁use . ▁He at ley , ▁although ▁the ▁junior ▁member ▁of ▁the ▁team , ▁possessed ▁a ▁natural ▁gift ▁for ▁ing enu ity ▁and ▁in vention . ▁It ▁was ▁he ▁who ▁suggested ▁transfer ring ▁the ▁active ▁ing red ient ▁of ▁pen ic ill in ▁back ▁into ▁water ▁by ▁changing ▁its ▁acid ity , ▁thus ▁pur ifying ▁the ▁pen ic ill in . ▁ ▁He at ley ▁recorded ▁these ▁tri als , ▁carried ▁out ▁on ▁eight ▁m ice ▁in ▁May ▁ 1 9 4 0 , ▁in ▁his ▁di ary : ▁" After ▁supp er ▁with ▁some ▁friends , ▁I ▁returned ▁to ▁the ▁lab ▁and ▁met ▁the ▁professor ▁to ▁give ▁a ▁final ▁do se ▁of ▁pen ic ill in ▁to ▁two ▁of ▁the ▁m ice . ▁The ▁' controls ' ▁were ▁looking ▁very ▁sick , ▁but ▁the ▁two ▁treated ▁m ice ▁seemed ▁very ▁well . ▁I ▁stayed ▁at ▁the ▁lab ▁until ▁ 3 : 4 5 ▁a . m ., ▁by ▁which ▁time ▁all ▁four ▁control ▁animals ▁were ▁dead ." ▁ ▁On ▁returning ▁home , ▁he ▁real ised ▁that ▁in ▁has te ▁and ▁darkness , ▁he ▁had ▁put ▁his ▁under p ants ▁on ▁back ▁to ▁front , ▁and ▁noted ▁this ▁in ▁his ▁di ary ▁too , ▁adding ▁" It ▁really ▁looks ▁as ▁if ▁pen ic ill in ▁may ▁be ▁of ▁practical ▁importance ." ▁In ▁order ▁to ▁conduct ▁tests ▁on ▁human ▁patients , ▁even ▁more ▁of ▁the ▁drug ▁had ▁to ▁be ▁produced , ▁and ▁again ▁it ▁was ▁He at ley ▁who ▁real