Fanny Hesse
[3] Shortly afterwards, the couple began to reside in the Erzgebirge mountain range due to Walther Hesse's work in nearby uranium mines as a doctor.
[1] In addition to her housekeeping duties, Hesse worked in an unpaid capacity to assist her husband by preparing bacterial growth media, cleaning equipment, and producing illustrations for scientific publications.
In addition to these technical duties, she used her artistic abilities to draw pictures of bacterial colonies as viewed under a microscope in the different phases of bacteria growth to use in her husband's journal publications.
[6] In 1881, while her husband was working in the laboratory of German physician and microbiologist Robert Koch, he struggled with performing experiments on gelatin medium that liquified due to gelatin-liquefying organisms and temperature increases during incubation.
[3][10] Hesse's suggestion of using agar also proved to be central to her husband's success in analyzing microbial counts in air, as he initially ran into problems with summertime temperatures liquefying the gelatin.
Subsequent experiments following her suggestion of using agar as an alternative gelling agent revealed its advantages in thermal stability, resistance to liquifying bacterial enzymes, ability to maintain sterility, and benefits for long term storage, which rectified many of the problems associated with gelatin.
Agar-based mediums were capable of providing a firmer media at higher temperatures, which allowed for better plating and isolation of bacterial colonies in the conditions Walther and Koch performed their experiments in.
In his paper on the etiology of tuberculosis, Robert Koch wrote: “The tubercle bacilli can also be cultured on other nutrient substrates, if the latter possess similar properties to the solidified serum.
They are able to grow on a solidified gel which remains solid at incubator temperature, prepared by adding agar-agar to a meat infusion or peptone medium.”[10] Although Koch mentioned in an 1882 paper on tuberculosis bacilli that he used agar, he did not credit either Hesse.
