Mr. Ludgrove smiled, and even the Professor’s set features relaxed a little. “I am not afraid to walk to Praed Street, especially in your company, Mr. Ludgrove,” he replied.

“And coming back?” persisted the herbalist. “I fear I have no telephone, and it may take me some minutes to find you a cab. I should be happy to walk back here with you.”

The Professor made an impatient gesture. “Believe me, Mr. Ludgrove, I am no more afraid of Praed Street than you are. If you insist upon walking home with me, I shall be very glad of your company. If not, I am perfectly capable of taking care of myself.”