In reality, the first and most famous antibiotic had been discovered in 1928 by Sir Alexander Fleming, but penicillin was not generally available until it was mass produced just before the second world war. Now we worry about the effects of over use of penicillin and other antibiotics, but at that time penicillin's discovery meant that doctors could finally cure infectious diseases caused by bacteria. One conservative estimate is that 90 million lives have been saved by penicillin. Eventually , it became available in topical, injectable and tablet form, so yes, Robert would certainly have carried penicillin in his medical bag by the end of the 1930's.
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