An old colored man.
A soiled red dress.
107. Use the comma to set off non-emphatic introductory words or phrases, and participial phrases.
John, come here.
By the way, did you see Mary?
After having done this, Cæsar crossed the Rubicon.
Cæsar crossed the Rubicon, thus taking a decisive step.
108. Use the comma to set off appositive expression (see §29, Note 1), or a geographical name that limits a preceding name.
He was told to see Dr. Morton, the principal of the school.
Muncy, Pennsylvania, is not spelled the same as Muncie, Indiana.