Thomas A. Bailey and David M. Kennedy, The American Pageant: A History of the Republic, 10th ed., (Lexington, Massachusetts: D.C. Heath and Company, 1994), 407.
So savage was this 'Man-stealing Law' [Fugitive Slave Act] that it touched off an explosive chain reaction in the North. Many Shocked moderates, hitherto passive, were driven into the swelling ranks of the antislaveryites. When a runaway slave from Virginia was captured in Boston in 1854, he had to be removed from the city under heavy federal guard through streets lined with sullen Yankees and shadowed by black-draped buildings festooned with flags flying upside dow. One prominent Bostonian who witnessed this grim spectacle wrote that 'we went to bed one night old-fashioned, conservative, Compromise Union Whigs and waked up stark mad Abolitionists.'