Seventy years ago today, on March 11, 1955 (February 18, 1955), the British bacteriologist Fleming passed away. The invention of penicillin (1928) Since ancient times, infectious diseases have been the enemy of mankind. Generations of scientists have made unremitting efforts in the prevention and treatment of infectious diseases. Later studies found that bacteria are the culprit of infectious diseases, so people tried every means to find new drugs to kill infectious bacteria. Until the discovery of penicillin, the era when infectious diseases were almost untreatable was gone, and the average life expectancy of human beings was extended. It was the British bacteriologist Alexander Fleming who discovered penicillin. In 1928, when Fleming inspected the petri dishes, he found that the staphylococcus in the petri dishes had grown a large cloud of mold due to contamination, and the staphylococcus around the mold was killed. Staphylococcus grew only in places farther away from the mold. He inoculated the mold into sterile agar medium and broth medium, and found that in the broth, the mold grew rapidly, forming one after another white and dark green mold clusters. Through identification, Fleming knew that the mold belonged to a type of penicillium, so he called the filtered liquid containing the mold secretions "penicillin". Then Fleming inoculated the mold into the petri dishes of various bacteria and found that staphylococcus, streptococcus and diphtheria bacteria could be inhibited by it. This greatly encouraged Fleming, who was eager to find a drug to treat purulent infections. After a series of experiments and studies, Fleming believed that penicillin could become an antibacterial drug that could be applied throughout the body. In 1929, Fleming published a paper reporting his findings. But the purification problem of cyanotoxin has not been solved, which makes it difficult to produce the drug in large quantities. In 1935, British pathologist Flory and German biochemist Qian En, who lived in England, collaborated to re-study the properties, isolation and chemical structure of penicillin, and finally solved the problem of penicillin concentration. At that time, during World War II, the development and production of penicillin was transferred to the United States. The mass production of penicillin saved millions of wounded and sick, and became one of the three major inventions in World War II, along with the atomic bomb and radar. This contribution to the benefit of mankind won Fleming, Qian En and Flory the Nobel Prize in Physiology and Medicine in 1945. The discovery of penicillin was a milestone in the history of human development of antibiotics. To this day, it is still the most popular and widely used antibiotic. Penicillin can kill all kinds of bacteria and treat all kinds of inflammation. And it is almost non-toxic to the human body. Therefore, except for a very small number of people who are allergic to penicillin, most patients can recover their health with the help of penicillin. It was the discovery of penicillin that triggered the climax of the medical community's search for new antibiotics, and humans entered the era of synthetic new drugs. On March 11, 1955, Fleming died. Antibiotics (1928)