1899  C. Smith didn't "mush on" when requested by the police to do so, and showed his objection to the introduction of the new order for keeping the sidewalks clear by using abusive language.
1910  "Mush on, there," he repeated truculently; "you're not wanted 'round here' Mush! Pretty darned smart."
1938  After his death it was easy to round up the members of his gang, who were either imprisoned or told to "Mush on!"