While no single person invented the agar plate as we know it today, its development was a collaborative effort involving several key individuals. The story involves the development of agar as a solidifying agent and the design of the Petri dish.
The Role of Agar
The use of agar as a solidifying agent in microbiological culture media was a pivotal step. While the exact discovery of agar's use is debated, the popular story centers on Fanny Hesse, the wife of Walther Hesse, an assistant to Robert Koch. Fanny Hesse, while working at home making growth medium, is credited with suggesting the use of agar, which she learned was used to solidify jellies. Fanny Hesse, the Woman Who Introduced Agar to Microbiology ... This happened around 1881 or 1882. Before agar, gelatin was used, but it had limitations due to its susceptibility to bacterial degradation. Agar's heat stability and resistance to microbial degradation made it far superior. A Brief History Of Agar – Asian Scientist Magazine
The Petri Dish
The invention of the Petri dish is attributed to Julius Richard Petri, another assistant to Robert Koch. Petri designed a shallow, lidded dish to improve on existing techniques. This design, patented in 1887, allowed for easier handling and prevented contamination. This made the cultivation of pure microbial colonies significantly easier. Why do we use Agar plates and how should you best handle them? Department of Pathology - Agar — A Growth Medium For Germ Theory The combination of agar and the Petri dish created the modern agar plate.
Early Development
It's important to note that the development of microbiological techniques was incremental. Even before the widespread use of agar and the Petri dish, scientists experimented with different methods of cultivating microorganisms. For example, History of the agar plate | Laboratory News mentions that in 1888, Martinus Beijerinck developed elective media, a step toward the diagnostic media we use today.
In summary, while Fanny Hesse's suggestion of agar and Julius Richard Petri's invention of the dish were crucial, the development of the agar plate was a collective achievement building on previous microbiological advancements.
