Colored people of boston, one & all, you are hereby respectfully cautioned and adrised, to avoid conversing win the watchmen and police officers of boston, kidnappers slave catchers, for since the recent order of the max alderen, they are empowered to set and they have atrendy been actually employed in loidnapping, catiming, and keeping slaves. therefore, if you valve your liberty, and the w are of the uglies among you, san them in every possible manner, as so many wounds on the track of the most unfortunate of your race. keep a sharp look out for kidnappers, and have top eye open. april 24, 1851, source: library of congress, the american timo capsule: three centuries of broadsides and other printed ephomora 18. this poster from the 1850s appeared in response to the (1) passage of the fugitive slave law (2) start of the civil war (3) issuance of the emancipation proclamation (4) enactment of the 13th amendment