▁suit ▁and ▁set ▁himself ▁shr inking ▁as ▁well , ▁although ▁they ▁would ▁never ▁meet ▁again ▁due ▁to ▁the ▁inf init es imal ▁chance ▁of ▁trac ing ▁the ▁same ▁path ▁through ▁the ▁sub atomic ▁world s . ▁ ▁The ▁assistant , ▁sent ▁as ▁an ▁invol unt ary ▁sc out , ▁shr inks ▁further ▁and ▁further , ▁through ▁the ▁per il ▁of ▁being ▁attacked ▁by ▁a ▁micro organ ism , ▁down ▁to ▁various ▁world s , ▁inhab ited ▁by ▁various ▁be ings ▁who ▁at ▁their ▁times ▁scales ▁have ▁seen ▁him ▁approach ▁for ▁years ▁or ▁centuries , ▁including ▁intellig ent ▁g ase ous ▁be ings , ▁cave ▁people , ▁space - f aring ▁bird like ▁be ings ▁who ▁fle e ▁to ▁their ▁moon ▁to ▁escape ▁self - rep lic ating ▁machines ▁who ▁have ▁over run ▁their ▁planet ▁and ▁will ▁likely ▁go ▁on ▁spread ing ▁through ▁the ▁universe ▁at ▁that ▁scale , ▁and ▁others ▁the ▁narr ator ▁mentions ▁only ▁in ▁passing , ▁of ▁widely ▁varying ▁forms . ▁One ▁race ▁of ▁int ang ible ▁be ings ▁teach es ▁the ▁narr ator ▁skills ▁for ▁cont rolling ▁matter ▁with ▁thought . ▁Though ▁it ▁lies ▁within ▁the ▁power ▁of ▁some ▁advanced ▁races ▁to ▁halt ▁his ▁shr inking ▁or ▁grant ▁him ▁release ▁from ▁life ▁( for ▁he ▁finds ▁he ▁has ▁become ▁imm ort al ) ▁none ▁will ▁inter f ere . ▁ ▁The ▁narr ator ▁eventually ▁finds ▁his ▁way ▁down ▁to ▁a ▁blue ▁planet ▁where ▁exam ined ▁by ▁scient ists ▁who ▁under est imate ▁his ▁intelligence ▁due ▁to ▁communication ▁difficulties ▁( he