David Carner, age 15, of Santa Cruz, Calif., for his question:

WHO DISCOVERED STREPTOMYCIN?

Streptomycin is a drug that fights the bacteria that causes many diseases. It is the first drug that has found extensive application in the treatment of tuberculosis. Credit for finding the drug goes to Selman Waksman of Rutgers University.

In 1939, Waksman began to test microscopic growths to find a substance that could be used against disease germs. The best substance he found was formed by a microbe belonging to the group of antinomycetes, of the genus Streptomyces. It was named streptomycin.

Doctors can give streptomycin by injecting it into the muscles or under the skin. It can also be taken by mouth or sprayed into the lungs.

Streptomycin acts by interfering with the growth of the microbes. This effect is bacteriostatic. It kills bacteria, a bactericidal action.

Streptomycin is effective in the treatment of tuberculosis, infections of the urinary passage, typhoid fever, pneumonia, dysentery, undulant fever and such wound infection as gas gangrene.