- Writer:
- Nesta Pain
- Producer:
- Nesta Pain
- Layman:
- Alan Wheatley
- David Bruce:
- John Laurie
- Mrs Bruce:
- Molly Rankin
- Woman of Today:
- Dorothy Smith
- Entomologist 1:
- Laidman Browne
- Entomologist 2:
- Roger Snowdon
- Laywoman:
- Grizelda Hervey
- Irishman:
- Charles Maunsell
- Sir Alexander Fleming:
- Frank Partington
- Advertiser:
- Ellinore Stuart
- Protozoologist:
- Carleton Hobbs
- Dr Spurway:
- Muriel Davidson