NITROGEN SCARCITY--"Nitrogen tantalizes mankind with the paradox of poverty in the midst of plenty. All living things on this planet--animal and vegetable--must have nitrogen in their food. Yet the free nitrogen in the air is so difficult to incorporate into foodstuffs that man must engage in back-breaking toil to conserve the comparatively small amount that nature captures and fixes in the soil. However, since 1949 a flurry of discovery has turned up undreamed numbers of micro-organisms that fix nitrogen. We can look forward to the possibility that we may some day be able to exploit the power of these organisms, and so help nature's nitrogen cycle to enrich our earth."