Ledyard stared thoughtfully at the table for a few seconds. He looked up quickly, dark eyes full of surmise. “With those symptoms? They could well have been the onset of grand mal.”
Darwin clapped his hands together. “Exactly. They could indeed have been caused by an epileptic seizure, a convulsive fit. Now that, as we well know, can be carried for many generations. It is a disease with a strong tendency to perpetuate itself through a family line. Charles Alderton, as you had already told me, died of a seizure. He had been alone in the pit when it happened. A severe convulsion, with no medical help nearby, could well be fatal to one of advancing years, who was already in failing health. The strain to the system is great in a case of grand mal.”
“But Philip is not an epileptic,” cried Alice. “His health has always been good. I have known him for over a year, and he has never been sick in all that time.”
“And what does the pit have to do with all this?” objected Ledyard. “If Alderton were to suffer a seizure, why should it be only when he was in a hole in the ground?”
Darwin had picked up the same meat pie and was again sniffing at it suspiciously. “I hope that the cook has not been foolish enough to omit the cloves from a squab pie,” he said in a worried voice. “I can smell mutton, onions and apples—but where are the cloves? I must have a word with her tomorrow.”
He again replaced the pie on the table. “Why in a hole in the ground? Yes, indeed. That was a most difficult question. Accept that Philip killed Barton and the hounds, when he had no control over his actions. Remember, too, his look of the Viking, and recall the berserker, who showed tremendous strength when the killing rage was on him in Norse battles. Recall that Philip’s clothes showed that he had been in some desperate fray at the bottom of the pit. It still left the question: why in the pit? And what had Gerald Alderton’s old warning about the moon, the wind and the mill to do with all this? That was when I decided that I had to look at this pit, when the conditions were right for the appearance of the Beast.”
“I wish you had told me more of this at the time, Erasmus,” grumbled Pole. “I don’t know anything about your grand mal, but the idea of being down there with the Lambeth Immortal was quite a grand enough mal to frighten me. ‘Wind strong on the Mill’ was quite right—you could hear my bowels churning with it from twenty paces.”
“You surprise me, Jacob,” Darwin said. He smiled his gap-toothed smile. “Are you not the man who tells of the midnight ascent of a Shiraz temple, guarded by the spirits of a thousand years of dead priests? You told me that on that occasion you did not turn a hair.”
“Nor did I.” Pole sniffed. “But there were rubies promised at the end of that climb. And a collection of heathen spirits are not half so alarming as a giant hound, ready to rip my backside off while I’m trying to scramble out of the pit.”
“There is a legend of gold near the pit, also,” said Ledyard. “A Viking treasure that was buried somewhere near here.”
“Now, you should never have said that.” Darwin swore heartily. “I’ll never get him away from here now. Jacob, I’m leaving the day after tomorrow, with or without you.” He turned again to Ledyard. “Did you ever read any of the works of Fracastoro of Verona? It is no idle question,” he added, seeing Ledyard’s puzzled look.
Ledyard shook his head.
“You should do so,” went on Darwin. “His book on the methods of infection, De Contagione, sets a new direction for the analysis of disease propagation. He was an acute observer, and an ingenious experimenter. I thought of him when we were in the pit the other night. In one of his works, there is a brief discussion of epilepsy. He asserted, without further comment, that seizures can in some cases be induced artificially in a patient. He talked of exposing the sufferer to a regular, flickering light, as might be accomplished by a rotating wheel that intercepts a beam of sunlight entering a darkened room.”
The others looked again at the instrument that stood at the far end of the table, the fan motionless on its front.
“The sweeps of the mill,” Alice said suddenly. “We saw them tonight, cutting across the moon’s face.”
Darwin nodded. “If James Ledyard had not come tonight, you might not now be a living woman. When you are at the bottom of the pit, the rising moon strikes behind the mill. A strong wind turns the sweeps at their highest rate. The latticework in the rotating arms makes that flickering pattern to the eyes. I noticed it, thought of Fracastoro’s remarks, and tried to time the period of the light. That device”—he pointed along the table—“achieves the same effect, independent of mill, moon, and wind. I had to have a way of varying the pace, since I was not sure of the exact frequency that would affect Philip Alderton.”
“And Charles Alderton was similarly affected?” asked Ledyard.
“And Gerald Alderton also.” Darwin nodded. “Gerald somehow discovered the circumstances that led to his seizures, and he tried to warn his descendants, while not revealing the family’s misfortune to the world. It is ironic to think that it was his message that lured Charles and Philip to the pit, and assured the new appearance of the Immortal.”
Bretherton entered the room as Darwin was speaking. “Mister Philip is awake. He seems very tired, but otherwise in no discomfort. He is bewildered to again be in his bed, when his last memory was of sitting in the dining room. I have told him nothing.”
Ledyard stood up. “I will go to him. He is still my patient, regardless of tonight’s events.”
Alice did not speak, but she rose to her feet and left the room with Ledyard and Bretherton.
“She’s had a terrible shock,” said Pole. He was looking at Darwin shrewdly. “Her fiancй is a murderer. How will she react to that?”
Darwin shook his head. “I cannot tell. Alderton is not a pleasant man, and he is overbearing and graceless with the servants. But he must be pitied.”
“James Ledyard is very fond of Alice,” probed Pole. “And I think that you are very well disposed toward Ledyard. Do you now propose to have Alderton arrested as a murderer, for the killing of Tom Barton?”
Darwin sighed. His grey, patient eyes were troubled and weary. “Don’t bait me, Jacob. You know the answer to that question very well. I am a doctor. My task is to save life, not to take it.”
“And you think that James Ledyard has the same view?”
“His feelings for Alice make his decision harder, but I think he will reach the same conclusion. Our concern must be only to make sure that nothing like this can happen again. The Alderton epilepsy is a rare form, apparently called forth only by that special stimulus of a flickering light. When Alderton finds out what he did, I hope that he will offer himself for treatment or restraint.”
“And if he does not choose to do so?”
Darwin sighed, and shrugged his heavy shoulders. “Then he must be forced to accept medical help, or placed where he can do no further harm. Remember, he must not be blamed for the sickness itself. He cannot help that disease, any more than you are to be blamed for your malaria. But he must accept responsibility for its control. Gerald Alderton faced a similar problem, and when he found out the truth he gave his life to religious works. But he already had children. Philip may decide, faced with the facts, that the Alderton line must end with him. That is not our decision.”
He looked across at the remains of the food. In an absentminded way, he had slowly disposed of most of it, even the despised cloveless squab pie. He pushed his chair away from the table.