Changes in materials
Changes in materials: an important factor in the evolution of laboratory instruments.
When the evolution of equipment and laboratory tools is studied, we readily notice changes in the materials used in their manufacture.
Laboratory instruments made of wood were widely used in laboratories from the 1920s until the 1970s. They are no longer used, because this material cannot be cleaned correctly or sterilized to prevent bacterial contamination, for example. Nowadays, the use of metal or plastic is favored.
The Petri dish is an invention of Richard Petri, the assistant to Robert Koch who discovered the pathogenic agent for tuberculosis, Mycobactérium tuberculosis, as well as the cholera bacillus. In 1905, Koch received the Nobel prize in medicine for the whole body of his work, which included numerous discoveries that contributed greatly to the evolution of microbiology study techniques.
These reusable glass Petri dishes were filled with agar, a nutritional medium favorable for the multiplication of microorganisms.
Petri dishes nowadays are made of plastic and are for single use, such as the model shown here. Their function, however, has remained the same: they contain a gelatinous nutritional medium for the culture of microorganisms.