Which metaphor does Crane Brinton employ in The Anatomy of Revolution?

Brinton summarizes in his book the revolutionary process as moving from "financial breakdown, [to] organization of the discontented to remedy this breakdown ... revolutionary demands on the part of these organized discontented, demands which if granted would mean the virtual abdication of those governing, attempted use of force by the government, its failure, and the attainment of power by the revolutionists.