9 ▁– ▁ 2 1 ▁December ▁ 1 9 0 7 ) ▁was ▁a ▁German ▁der mat ologist ▁who ▁was ▁a ▁native ▁of ▁Hamburg . ▁▁ ▁After ▁ear ning ▁his ▁medical ▁doctor ate ▁in ▁ 1 8 7 2 , ▁he ▁worked ▁briefly ▁as ▁a ▁hospital ▁assistant ▁at ▁the ▁Berlin ▁Char ité . ▁He ▁later ▁started ▁a ▁private ▁hospital ▁for ▁der mat ology ▁and ▁sy ph ilis ▁in ▁Berlin . ▁His ▁clin ic ▁was ▁known ▁for ▁being ▁techn olog ically ▁advanced , ▁and ▁it ▁was ▁the ▁first ▁to ▁have ▁a ▁F insen ▁ult rav io let ▁light ▁ther apy ▁device ▁and ▁X - ray ▁machine . ▁In ▁ 1 9 0 2 ▁he ▁became ▁a ▁professor ▁at ▁the ▁University ▁of ▁Berlin . ▁ ▁L ass ar ▁is ▁remembered ▁for ▁the ▁creation ▁of ▁public ▁bath ▁houses ▁for ▁low - in come ▁individuals ▁in ▁Germany ▁and ▁Austria . ▁These ▁bath ▁houses ▁were ▁constructed ▁in ▁the ▁interest ▁of ▁public ▁h yg iene , ▁at ▁a ▁time ▁when ▁poor er ▁people ▁didn ' t ▁have ▁private ▁bath s ▁or ▁show ers . ▁In ▁Germany , ▁the ▁bath - h ouses ▁were ▁called ▁Volks bad , ▁and ▁in ▁Austria - ▁Tr ö p fer l bad . ▁In ▁ 1 8 9 9 , ▁L ass ar ▁was ▁founder ▁of ▁the ▁German ▁Society ▁for ▁Volks b ä dern . ▁One ▁of ▁his ▁s log ans ▁was ▁" a ▁week ly ▁bath ▁for ▁every ▁German ." ▁ ▁He ▁was ▁very ▁social , ▁and ▁he ▁invited ▁phys icians ▁who ▁made