Julius Richard Petri

Julius Richard Petri (; 31 May 185220 December 1921) was a German microbiologist who is generally credited with inventing the device known as the Petri dish, which is named after him, while working as assistant to bacteriologist Robert Koch.

Life and career Petri was born in the town of Barmen (now a district of the city of Wuppertal), Germany, on 31 May 1852. He came from a distinguished family of scholars, and was the eldest son of Philipp Ulrich Martin Petri (18171864), a professor in Berlin, and Louise Petri. and further developed the technique of agar culture to purify or clone bacterial colonies derived from single cells. This advance made it possible to rigorously identify the bacteria responsible for diseases.

Petri's first wife, Anna Riesch, died in 1894 during childbirth. In 1897, he married Elizabeth Turk.

Petri plates can be incubated upside down (agar on top), which can help lessen the risk of contamination from airborne particles containing microbes settling and to decrease and prevent the chance of condensation from water accumulating and disturbing the microbes being cultured.

Scientists had long been growing cells in natural and synthetic matrix environments to elicit phenotypes that are not expressed on conventionally rigid substrates. Unfortunately, growing cells either on or within soft matrices can be an expensive, labour-intensive, and impractical undertaking.

The basic design of the Petri dish has not changed since being created by Petri in 1887. It was a challenge to keep dishes free of dust and extra bacteria that could collect and alter samples; heavy bell jars used for this purpose having proved ineffective, six years later Petri created a transparent plate slightly larger than the dish, which served as a transparent lid. After running the Göbersdorf sanatorium, he became the director of the Museum of Hygiene in Berlin in the year 1886.

Works Attempts at the chemistry of proteins. 1876. Methods of modern bacteria research (in: Collection Exoteric Scientific Lectures). 1887. The danger of carbon soda furnaces. 1889. Industrial hygiene. 1890. Experiments on the spread of contagious diseases, especially tuberculosis, by the railway and on measures to be taken. 1893. The microscope. From its beginnings to the present perfection. 1896. A judgment of highpressure Pasteurising apparatus 1897. Towards quality testing in butter and milk. 1897. Apparatus for determination of water content in milk by distillation in a vacuum.