“I have not,” said the doctor promptly, looking up.  “Why do you ask?”

His glance carried conviction, and interrogation also.  But it was Barrant’s province to ask questions, not to answer them.  He ignored Dr. Ravenshaw’s.

“There’s another matter, doctor,” he continued.  “One of the coast fishermen has a story that when Robert Turold was out on the moors he used to hasten home with great strides, like a man who feared pursuit.  Did you ever observe this peculiarity in him?”

“I have observed that he used to walk at a quick pace.”

“This was more than a quick pace—­it was almost a run, according to the fisherman—­looking backward over his shoulder as he went.”

“I did not notice that, but I should not be surprised if it were true, with a man of Robert Turold’s temperament.”

“He feared pursuit—­some unknown danger, then?”

“I cannot say.  He may have suffered from agoraphobia.”

“What is that?” asked Barrant.

“The dread of open spaces.”

“I have heard of claustrophobia—­the dread of closed spaces—­but not of this.”

“It is common enough—­an absurd but insurmountable aversion to open spaces.  The victims are oppressed by a terrible anxiety when crossing a field.  I have known a man who would be terrified at the idea of crossing Trafalgar Square.”

“What is the cause of agoraphobia?” asked Barrant.

“It is a nervous disorder—­one of the symptoms of advanced neurasthenia.”

“Did Robert Turold suffer from neurasthenia?”

“His nervous system was in a state of irritable weakness through the monomania of a fixed idea,” was the reply—­“too much seclusion and concentration on one object, to the exclusion of all other human interests.”

“How’s your patient?” said Barrant, giving the conversation an abrupt turn.

“What patient do you mean—­Mrs. Thalassa?” asked Dr. Ravenshaw in some surprise.

“Yes.  I gathered from what I overheard you say to Thalassa that you have been attending her.”

“I have been attending her since Mr. Turold’s death.”

“She is in a strange condition,” observed Barrant reflectively.  “I was questioning her the other night, but I could get nothing out of her.  She seems almost imbecile.”

“She is not a woman of strong mind, and she is now suffering from a severe shock.  She should be looked after or taken away from here altogether, but her husband seems quite indifferent.”

“Do you think she will recover?”

“It is impossible to say.”

“How do you think the shock was caused?”

“I should not like to hazard an opinion on that point, either,” replied Dr. Ravenshaw gravely.  He glanced at his watch as he spoke.  “I must be going,” he said.

They left the house together, but branched off at the gate—­Dr. Ravenshaw to visit a fisherman’s dying wife, and Barrant to seek the Three Jolly Wreckers for supper before returning to Penzance.