Paul Ritchie, age 13, of Indianapolis, Ind., for his question:
WHAT IS PENICILLIN?
Penicillin is a germ killer that is produced by molds belonging to the genus Penicillium. It was the first substance from molds to be used for treating infectious diseases in man. Penicillin is a powerful germ killer or germicide that can kill bacteria and other microorganisms. Nearly all germicides kill equally well the cells that make up the body, and for this reason are poisonous and cannot be used. But penicillin and other antibiotics are more harmful to certain germs than to body cells.
If an infection occurs on the surface of the body, doctors can put penicillin directly on it. But when the disease is within the body, the penicillin must reach the infected part by way of the bloodstream.
Since the stomach and intestines will destroy penicillin before it can reach the bloodstream, doctors usually inject a solution containing the drug into the muscles of the body. There is one type, however, that can be given by mouth.
A scientist named Alexander Fleming discovered penicillin in London in 1928. In 1940, Howard Florey of Australia and Ernst Chain of Great Britain found a way to purify penicillin for use.
Penicillin is not a germ killer that can be used for every infection. It is not at all effective against diseases that are not caused by germs, such as cancer. But most of the bacteria that cause common infections, such as those of the blood, are very sensitive to it.
A few people can become allergic to penicillin. For these people, even a small amount of the drug can cause discomfort.
Penicillin is used extensively in treating pneumonia, staphylococcal and streptococcal infections, pleurisy, ear infections and many other diseases.
Penicillin is used by doctors to treat many infections when the popular sulfa drugs do not kill the bacterial growth. Penicillin can be given as an injection and is also available in powder and in aerosol cans, making it possible to spray the drug directly on diseased tissues, or inhale it.
Penicillin was first produced by growing Penicillium on broth or culture fluid in bottles or pans. Now a better culture fluid is used, and the mold is grown in the depths of the fluid, which is constantly stirred by a stream of air. Tanks holding up to 15,000 gallons are used.
In the United States today, hundreds of tons of penicillin are made each year. Although chemists have made penicillin in a laboratory without the mold, it is cheaper to let the mold do the work.