"Veena, do you know what a microorganism is?"
"Benevolent or malignant?"
"Malignant. A plague."
She pursed her lips. "Organic or cultural?"
"Organic of course."
"Bacteria." Veena shrugged. "Quite a few of the first generation died immediately after the landing. Until they adapted. Until they analyzed the basic metabolism of the planet's dominant life-forms, and constructed a neutralizer."
"A neutralizer?"
"A protective shell of ionized particles," she said patiently, "keyed to the individual body-chemistry."
"Classified information," Mentor droned.
Saxon licked his lips. "You mentioned cultural microorganisms?"