The Pacific Spaceport was not likely to run short of this useful substance.

The only useful substance she could find was a vial of asinolyathin.

Animals are being genetically transformed so that they can produce drugs and other useful substances in their milk.

Using similar procedures it is now possible to engineer organisms that can produce relatively large quantities of useful substances.

But that may change in a few years, especially if other useful substances can be derived from guayule.

The conversion of wood into charcoal may have been the first chemical process developed by human beings for the production of a useful substance.

Sodium chloride, or common salt, is one of the most useful and sought-after substances on earth.

By their effects on the body we may distinguish between good and useful substances and poisons.

Insects also produce useful substances such as honey, wax, lacquer and silk.

Chemists are constantly working to find new and useful substances.