Agar as a microbial culture medium (Hesse and Koch)
Agar como medio de cultivo microbiano (Hesse y Koch)
- Date
- 1881-1882 · confidence high
- Place
- Imperial Health Office, Berlin, Germany
- Credited to
- Fanny and Walther Hesse; Robert Koch
- Field
- Life & health
What it is
Fanny Hesse suggested to her husband Walther, a collaborator of Koch, replacing gelatine with agar, which does not liquefy at 37 °C and is not digested by most bacteria. With the Petri dish (1887) it allowed pure cultures to be isolated and has been the standard medium ever since.
Fanny Hesse, originally from New York, was not named in the publications; her contribution is recorded in Walther Hesse's testimony (1884) and laboratory tradition. By tradition, she knew agar from a Dutch neighbour who had used it in Java.
What it led to
- isolation of pathogenic bacilli (tuberculosis, cholera) in pure culture
- strain collections and plate antibiograms
- technical basis of genetic engineering (colonies, selection, cloning)