bubonic plague: the most common form of the plague in humans; characterized by chills, prostration, delirium and the formation of buboes in the armpits and groin; does not spread from person to person
state: the way something is with respect to its main attributes
reducing agent: a substance capable of bringing about the reduction of another substance as it itself is oxidized; used in photography to lessen the density of a negative or print by oxidizing some of the loose silver