#TBT: Fanny Hesse: Agar Superstar technician

Thanks to Fanny, we use agar to study microbes - critical in the fight against disease 

Name: Fanny Angelina Hesse (also known as ‘Lina’)

DOB: June 22, 1850

DOD: December 1, 1934 (aged 84)

From: New York, USA

Area of work: Bacteriology

What they did

Potato, polenta, gelatin, and cooked egg white. No, not a school dinner menu from hell, but some of the materials used as solid surfaces on which to grow and study bacteria in the early days of bacteriology. All of these had had their problems, so when laboratory technician Fanny Hesse suggested using agar, it revolutionized this new area of science. Even the great Louis Pasteur exclaimed, “C'est un grand progrès!”

Fanny was born in 1850 in New York, the daughter of a successful Dutch immigrant. Little is known of her early life but in 1872, Fanny met her future husband Walther, then serving as a ship’s surgeon on a German passenger liner. The couple were married on 16th May 1874 and Fanny moved to Dresden to be with her husband.

Walther was a country doctor who was passionate about hygiene and public health for workers, particularly the conditions of workers in the local mines. In 1881 he took a sabbatical to study in the Berlin labs of Robert Koch, the ‘father of bacteriology’, to investigate airborne microbes.

On top of her duties running the household and teaching their sons, Fanny became Walther’s assistant. She worked as an unpaid technician, preparing  the environment for bacteria to grow in (normally beef broth which is known as a growth media), cleaning equipment, and using her considerable artistic talents to produce beautiful watercolour illustrations for his publications.

To study airborne microbes, Walther was using tubes lined with the growth media made by Fanny. Unfortunately, the gelatin in this media melted at 37°C, transforming from a solid to a liquid on warm days. Similarly, some bacteria broke down the gelatin to liquid. These issues plagued their experiments and were a source of great frustration.

Fanny suggested replacing gelatine with the seaweed extract agar. She had been using agar for years to make fruit and vegetable jellies using recipes from her mother, who had in turn learnt about agar from some Dutch friends who had lived in Java, Indonesia.

Agar solved their problems: solid up to 90°C, transparent, indigestible by microorganisms, and sterilizable, it was perfect for growing and studying bacteria.

For her husband’s last publication in 1908, on culturing intestinal bacteria from typhoid patients, Fanny painted beautiful and highly accurate watercolour images of the magnified colonies on agar plates during different growth phases using work that was only possible with a thorough understanding of both bacteriology and microscopy. Despite her contribution to this and many more of Walther’s papers she was never included as an author or acknowledged in his work.

Agar has become almost as important to bacteriology as the petri dish, which would be invented just a few years later. Despite this, when Fanny died in 1934, few bacteriologists knew of her death. In their 1939 paper on Fanny’s life, Hitchens and Leikind suggested that "plain agar" be referred to as "Frau Hesse's medium" to acknowledge her forgotten "service to science and to humanity." This is yet to happen, but it is never too late.

Without them… 

The understanding of disease, and even the clinical diagnosis of disease would not have made the rapid progress we have seen in the last hundred years.

To learn more, please visit: Andy Connelly's #technicianjourney Blog

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