Chris Jones, age 12, of Memphis, Tenn., for his question:

WHAT IS LANOLIN?

Lanolin is a common name for wool wax, which is made from a greasy coating found on sheep's wool. The name is used especially when the wax is purified and mixed with water. Lanolin is a yellowish, sticky substance, as thick as ordinary wax. It does not react readily with acids or alkalies. It will absorb from 25 to 30 percent of its own mass in water.

When lanolin is mixed with water, it breaks up easily into tiny droplets. This forms an emulsion known as hydrous lanolin. Hydrous lanolin is widely used in medicines such as salves and ointments, and in cosmetics, because it is easily absorbed by the skin.

Lanolin is also used as a dressing for leather goods, as a protective coating for metals and as a base in grease paints and shoe polishes.