"I am going to return home now," said St. John presently, when the storm seemed to be clearing away. "If I don't get back, my mother will be wondering what has become of me."
"All right," answered the doctor. "But let me hear from you by to-morrow night, sure."
"I will."
"And don't mention my name to Colonel Stanton."
"But if I have him arrested you will furnish those witnesses to the fact that he is a spy?"
"I will, rest assured on the point."
A little later St. John hurried off in the darkness. Dr. Mackey watched him go, and then began to pace the floor nervously.
Jack touched Old Ben on the shoulder.
"Wot am it, Massah Jack?" whispered the faithful old negro.
"Ben, we must make the surgeon a prisoner."