Former Display Label: 'Measuring penicillin'
The strength of penicillin preparations was determined by measuring the extent to which it prevented bacterial growth. The pencillin was placed in small cylinders in a culture dish  and the size of the clear circular inhibited zone gave an indication of strength. Simple apparatus turned this measurement into a routine procedure . The Oxford group defined a standard unit of potency and was able to produce and distribute samples to calibrate research elsewhere .
- Special Exhibition Label: 'Back from the Dead: Demystifying Antibioics' 04.11.2016 - 21.05.2017. Dunn School Case. Shelf 1.
- Former Display Label: Cylinder-Plate Assay of Penicillin
- Former Display Label: Science at Oxford