How marijuana affects the mind. Marijuana reaches the same pleasure centers in the brain that are targeted by heroin, cocaine and alcohol. Depending on the quantity, quality and method of consumption, marijuana can produce a feeling of euphoria â or high â by stimulating brain cells to release the chemical dopamine.
In 1928, Alexander Fleming made one of the most important contributions to the field of antibiotics. In an experiment, he found that a strain of green Penicillium mold inhibited the growth of bacteria on an agar plate. This led to the development of the first modern era antibiotic, penicillin.
It was by these means that Penicillium chrysogenum was discovered, on a cantaloupe from a grocery store in Peoria, Illinois. The fungus isolated from this cantaloupe produced several hundred times as much penicillin as Fleming's original cultures.