Julius Richard Petri (31 May 1852 – 20 December 1921) was a German microbiologist who is generally credited with inventing the device known as the Petri dish, which is named after him, while working as assistant to bacteriologist Robert Koch.
Friedrich Carl Duisberg (29 September 1861 – 19 March 1935) was a German chemist and industrialist.
Friedrich Bayer (born Friedrich Beyer, 6 June 1825 in Barmen now Wuppertal – 6 May 1880 in Würzburg) was the founder of what would become Bayer, a German chemical and pharmaceutical company. He founded the dyestuff factory Friedrich Bayer along with Johann Friedrich Weskott in 1863 in Elberfeld, a flourishing city in the early industrialised region of the Wuppertal or Wupper Valley.
Friedrich Bayer changed the spelling of his surname from Beyer in his early twenties, due to the publicity gained by a fraudulent merchant from Leipzig bearing the same name. Friedrich Beyer from Barmen feared that the bad reputation of his namesake could damage his business and consequently changed his surname to Bayer.