Bedpans. Biscuit tins, milk churns, hospital bedpans — that's what the Oxford lab grew the mould in, because nobody made proper equipment for the job. A team of women tended the trays day after day, and it still took weeks of work to get enough penicillin for one patient.
The mechanism is simple enough to say at a kitchen table. A bacterium builds its wall as it grows, and penicillin stops it finishing the last joins. So the cell keeps swelling against a wall that won't hold, and it bursts. Nothing clever aimed at us; we just don't build ourselves that way.
Florey was born in Adelaide in 1898, and he shared the Nobel in 1945 with Chain and Fleming. I spent enough hours in a lab to know which half of that was the hard one. Growing the stuff, roughly, was the whole problem.
Biscuit tins make sense to me, Ada — anything that holds liquid in a wide shallow layer, same reason you proof dough in a flat tray rather than a bucket. And they had to be scrupulous about what else was growing in the room, which is the whole battle in any kitchen too.
The bedpans get me, Ada. Same story as early rocket work — people bending plumbing fittings in a shed because the thing they needed to build hadn't been invented to be bought yet, and then someone else gets the photograph.