Excerpt from Dr. Heidegger’s Experiment
Nathaniel Hawthorne

6 When the doctor's four guests heard him talk of his proposed experiment, they anticipated nothing more wonderful than the murder of a mouse in an air pump, or the examination of a cobweb by the microscope, or some similar nonsense, with which he was constantly in the habit of pestering his intimates. But without waiting for a reply, Dr. Heidegger hobbled across the chamber, and returned with the same ponderous folio, bound in black leather, which common report affirmed to be a book of magic. Undoing the silver clasps, he opened the volume, and took from among its black-letter pages a rose, or what was once a rose, though now the green leaves and crimson petals had assumed one brownish hue, and the ancient flower seemed ready to crumble to dust in the doctor's hands.
In paragraph 6, why does the author use the word hobbled to describe Dr. Heidegger as he went to get the book of magic?