Happy Birthday, Julius Petri!
The last day of May is the birthday of Julius Richard Petri (1852-1921), who is generally acknowledged as the inventor of the Petri dish. This little device enabled microbiologists to easily culture and subculture microorganisms in the laboratory, which in turn allowed microorganisms to be easily isolated in pure culture for the purposes of identification. Petri was trained as a physician, and while on active duty as a military physician, was assigned to the Imperial Health Office in Berlin to work as an assistant to Robert Koch. Just prior to this, the Koch laboratory had begun to culture bacteria on solid media containing the solidifying agent agar. Petri’s innovative dishes allowed microbiologists to utilize aseptic technique during the transfer of microorganisms, greatly decreasing the chances of contamination of samples and thereby making the process much more effective. Petri’s original dishes were made out of glass, and were decontaminated by autoclaving after use and carefully cleaned for reuse. In the disposable BIO230 generation, our Petri dishes are made out of plastic and go out with the trash after decontamination. Although students might be able to save tens of dollars on their college tuition by going back to the reusable glass Petri dishes, I suspect that the busy life of the college student would make it a difficult proposition to require them to wash all of their own dishware to save a buck.