Jim Erwin, age 14, of Utica, N.Y., for his question:

HOW DO YOU GET A BOIL?

A boil is a hard, round abcess or infection of the skin and tissue under the skin. Most boils are caused by a type of staphylocoocal bacteria. The bacteria can enter an oil gland, sweat gland, hair follicle or small, shallow wound.

The bacteria multiply and grow in the tissues and give off poisons. Blood vessels in the area expand to bring blood serum and white blood cells to the infected tissues. At first the boil looks like a small, red point. It gradually becomes hard and painful.

The tissue in the core or center of the boil is destroyed and the boil then softens. Pus usually drains from the core but it can sometimes be absorbed.

A doctor should open a painful boil and let the pus out. Since there is a danger of spreading the infection into the bloodstream or to other parts of the body, it is important to have medical assistance.

When the pus is drained, the pain ceases and the boil heals. Hot applications and soaking in boric acid solution often cause the pus to discharnge more readily.

Boils can often be prevented by keeping the skin clean and avoiding all skin irritations.