444 ANNUAL REPORT SMITHSONIAN INSTITUTION, 194 5 



rate of bacteria showed that pathogenic organisms die out rapidly 

 in the soil, due to some unknown factor present in soil. 



The potentialities of antagonistic mechanisms among the micro- 

 organisms were appreciated by Cantani, who in 1885 endeavored to 

 treat certain diseases by means of known cultures of saprophytic 

 organisms. 



PYOCYANASE 



Later, many other antibiotics were discovered, including extracts 

 from Bacillus pyocyaneus. Pyocyanase has been known since the 

 early nineties, although it was never deemed very effective. It was 

 never obtained in crystalline form, and was employed chiefly in ex- 

 perimental studies, although in Germany since 1930 a pyocyanase 

 ointment has been available for local application on skin lesions 

 resulting from anthrax. 



The last step in the series of basic researches which preceded the 

 advent of the recent antibiotic studies was when Vaudremer at- 

 tempted to treat tuberculosis with Aspergillus fumigatus cultures. 

 His unsuccessful work followed preliminary laboratory in vitro tests 

 which had given great promise. 



ACCIDENTAL DISCOVERY 



Our story really begins, however, in 1928 in the bacteriology labora- 

 tory of St. Mary's Hospital, in London. During the routine exam- 

 ination of some culture plates Prof. Alexander Fleming observed en- 

 tirely by accident a contaminating mold which caused lysis of the 

 staphylococcus organisms nearby. He had observed a phenomenon 

 which had been ignored by countless bacteriologists before and since. 

 Fleming subcultured the mold in broth and found that a strong anti- 

 biotic, nontoxic to animals, passed into the broth from the mold. The 

 broth apparently possessed marked inhibitory, bactericidal, and bac- 

 teriolytic properties. Fleming coined the name "penicillin" to des- 

 ignate a filtrate of the broth culture of the particular organism which 

 he incorrectly identified as Penicillium rubrum. The term "penicil- 

 lin" has been retained, and while medical dictionaries recommend the 

 pronounciation as "pen'-iss-lin," the majority of scientific workers 

 prefer to use "pen-i-sill-in." 



After a year's study, Fleming established the specific activity of 

 penicillin against various gram-positive micro-organisms highly 

 pathogenic to man, including the streptococci, staphylococci, gon- 

 ococci, pneumococci, and meningococci. He had also discovered that 

 the filtrate was ineffective against many gram-negative cocci and 

 bacilli. 



