Penicillin

Penicillin, often abbreviated by PCN, is a group of antibiotics that came from penicillium fungi. PCN was an early antibiotic then was very affective against diseases such as Syphilis and staphylococci. PCN is still widely used in todays society but some diseases have adapted and PCN is not affective on them. 

 Penicillin was invented by Alexander Flemming in 1928. Flemming was a Scottish scientist who conducuted an expirement that included penicllium fungi. The results he produced were suprising, producing one of the first antibiotics. To produce the Penicillin flemming had to keep the Peniciilin fungi cells under stress, thus causing them to produce the antibiotic we still use today. 

In 1946 some U.S. scientists conducted an expirement to make sure the Penicillin was still in effect. They had prositutes, that were infected with Syphillis, see prision inmates in Guatemala. These inmates then were treated with the Penicillin antibiotics. 1300 inmates were infected with the STD and all were treated with Penicillin. Out of the 1300, 48 died. The article says that it is unclear of the deaths were realted to the STD or not. 

http://en.wikipedia.org/wiki/Penicillin