Lord Florey ( Howard Walter Florey , 29 November 1898 â `` 21 February 1968 ) was an Australian pathologist who shared the Nobel Prize in Physiology or Medicine for 1945 , for his study into penicillin . Howard Walter Florey , Baron Florey OM FRS ( 24 September 1898 â `` 21 February 1968 ) was an Australian pharmacologist and pathologist who shared the Nobel Prize in Physiology or Medicine in 1945 with Sir Ernst Boris Chain and Sir Alexander Fleming for his role in the extraction of penicillin .