At breakfast Sir Nathaniel noticed that Adam was put out about something, but he said nothing. The lesson of silence is better remembered in age than in youth. When they were both in the study, where Sir Nathaniel followed him, Adam at once began to tell his companion of what had happened. Sir Nathaniel looked graver and graver as the narration proceeded, and when Adam had stopped he remained silent for several minutes, before speaking.

"This is very grave. I have not formed any opinion yet; but it seems to me at first impression that this is worse than anything I had expected."

"Why, sir?" said Adam. "Is the killing of a mongoose--no matter by whom--so serious a thing as all that?"

His companion smoked on quietly for quite another few minutes before he spoke.

"When I have properly thought it over I may moderate my opinion, but in the meantime it seems to me that there is something dreadful behind all this--something that may affect all our lives--that may mean the issue of life or death to any of us."

Adam sat up quickly.

"Do tell me, sir, what is in your mind--if, of course, you have no objection, or do not think it better to withhold it."

"I have no objection, Adam--in fact, if I had, I should have to overcome it. I fear there can be no more reserved thoughts between us."

"Indeed, sir, that sounds serious, worse than serious!"

"Adam, I greatly fear that the time has come for us--for you and me, at all events--to speak out plainly to one another. Does not there seem something very mysterious about this?"

"I have thought so, sir, all along. The only difficulty one has is what one is to think and where to begin."

"Let us begin with what you have told me. First take the conduct of the mongoose. He was quiet, even friendly and affectionate with you. He only attacked the snakes, which is, after all, his business in life."

"That is so!"

"Then we must try to find some reason why he attacked Lady Arabella."

"May it not be that a mongoose may have merely the instinct to attack, that nature does not allow or provide him with the fine reasoning powers to discriminate who he is to attack?"

"Of course that may be so. But, on the other hand, should we not satisfy ourselves why he does wish to attack anything? If for centuries, this particular animal is known to attack only one kind of other animal, are we not justified in assuming that when one of them attacks a hitherto unclassed animal, he recognises in that animal some quality which it has in common with the hereditary enemy?"

"That is a good argument, sir," Adam went on, "but a dangerous one. If we followed it out, it would lead us to believe that Lady Arabella is a snake."

"We must be sure, before going to such an end, that there is no point as yet unconsidered which would account for the unknown thing which puzzles us."

"In what way?"

"Well, suppose the instinct works on some physical basis--for instance, smell. If there were anything in recent juxtaposition to the attacked which would carry the scent, surely that would supply the missing cause."

"Of course!" Adam spoke with conviction.

"Now, from what you tell me, the negro had just come from the direction of Diana's Grove, carrying the dead snakes which the mongoose had killed the previous morning. Might not the scent have been carried that way?"

"Of course it might, and probably was. I never thought of that. Is there any possible way of guessing approximately how long a scent will remain? You see, this is a natural scent, and may derive from a place where it has been effective for thousands of years. Then, does a scent of any kind carry with it any form or quality of another kind, either good or evil? I ask you because one ancient name of the house lived in by the lady who was attacked by the mongoose was 'The Lair of the White Worm.' If any of these things be so, our difficulties have multiplied indefinitely. They may even change in kind. We may get into moral entanglements; before we know it, we may be in the midst of a struggle between good and evil."

Sir Nathaniel smiled gravely.

"With regard to the first question--so far as I know, there are no fixed periods for which a scent may be active--I think we may take it that that period does not run into thousands of years. As to whether any moral change accompanies a physical one, I can only say that I have met no proof of the fact. At the same time, we must remember that 'good' and 'evil' are terms so wide as to take in the whole scheme of creation, and all that is implied by them and by their mutual action and reaction. Generally, I would say that in the scheme of a First Cause anything is possible. So long as the inherent forces or tendencies of any one thing are veiled from us we must expect mystery."

"There is one other question on which I should like to ask your opinion. Suppose that there are any permanent forces appertaining to the past, what we may call 'survivals,' do these belong to good as well as to evil? For instance, if the scent of the primaeval monster can so remain in proportion to the original strength, can the same be true of things of good import?"

Sir Nathaniel thought for a while before he answered.

"We must be careful not to confuse the physical and the moral. I can see that already you have switched on the moral entirely, so perhaps we had better follow it up first. On the side of the moral, we have certain justification for belief in the utterances of revealed religion. For instance, 'the effectual fervent prayer of a righteous man availeth much' is altogether for good. We have nothing of a similar kind on the side of evil. But if we accept this dictum we need have no more fear of 'mysteries': these become thenceforth merely obstacles."

Adam suddenly changed to another phase of the subject.

"And now, sir, may I turn for a few minutes to purely practical things, or rather to matters of historical fact?"

Sir Nathaniel bowed acquiescence.

"We have already spoken of the history, so far as it is known, of some of the places round us--'Castra Regis,' 'Diana's Grove,' and 'The Lair of the White Worm.' I would like to ask if there is anything not necessarily of evil import about any of the places?"

"Which?" asked Sir Nathaniel shrewdly.

"Well, for instance, this house and Mercy Farm?"

"Here we turn," said Sir Nathaniel, "to the other side, the light side of things. Let us take Mercy Farm first. When Augustine was sent by Pope Gregory to Christianise England, in the time of the Romans, he was received and protected by Ethelbert, King of Kent, whose wife, daughter of Charibert, King of Paris, was a Christian, and did much for Augustine. She founded a nunnery in memory of Columba, which was named SEDES MISERICORDIOE, the House of Mercy, and, as the region was Mercian, the two names became involved. As Columba is the Latin for dove, the dove became a sort of signification of the nunnery. She seized on the idea and made the newly-founded nunnery a house of doves. Someone sent her a freshly- discovered dove, a sort of carrier, but which had in the white feathers of its head and neck the form of a religious cowl. The nunnery flourished for more than a century, when, in the time of Penda, who was the reactionary of heathendom, it fell into decay. In the meantime the doves, protected by religious feeling, had increased mightily, and were known in all Catholic communities. When King Offa ruled in Mercia, about a hundred and fifty years later, he restored Christianity, and under its protection the nunnery of St. Columba was restored and its doves flourished again. In process of time this religious house again fell into desuetude; but before it disappeared it had achieved a great name for good works, and in especial for the piety of its members. If deeds and prayers and hopes and earnest thinking leave anywhere any moral effect, Mercy Farm and all around it have almost the right to be considered holy ground."

"Thank you, sir," said Adam earnestly, and was silent. Sir Nathaniel understood.

After lunch that day, Adam casually asked Sir Nathaniel to come for a walk with him. The keen-witted old diplomatist guessed that there must be some motive behind the suggestion, and he at once agreed.

As soon as they were free from observation, Adam began.

"I am afraid, sir, that there is more going on in this neighbourhood than most people imagine. I was out this morning, and on the edge of the small wood, I came upon the body of a child by the roadside. At first, I thought she was dead, and while examining her, I noticed on her neck some marks that looked like those of teeth."

"Some wild dog, perhaps?" put in Sir Nathaniel.

"Possibly, sir, though I think not--but listen to the rest of my news. I glanced around, and to my surprise, I noticed something white moving among the trees. I placed the child down carefully, and followed, but I could not find any further traces. So I returned to the child and resumed my examination, and, to my delight, I discovered that she was still alive. I chafed her hands and gradually she revived, but to my disappointment she remembered nothing--except that something had crept up quietly from behind, and had gripped her round the throat. Then, apparently, she fainted."

"Gripped her round the throat! Then it cannot have been a dog."

"No, sir, that is my difficulty, and explains why I brought you out here, where we cannot possibly be overheard. You have noticed, of course, the peculiar sinuous way in which Lady Arabella moves--well, I feel certain that the white thing that I saw in the wood was the mistress of Diana's Grove!"

"Good God, boy, be careful what you say."

"Yes, sir, I fully realise the gravity of my accusation, but I feel convinced that the marks on the child's throat were human--and made by a woman."

Adam's companion remained silent for some time, deep in thought.

"Adam, my boy," he said at last, "this matter appears to me to be far more serious even than you think. It forces me to break confidence with my old friend, your uncle--but, in order to spare him, I must do so. For some time now, things have been happening in this district that have been worrying him dreadfully--several people have disappeared, without leaving the slightest trace; a dead child was found by the roadside, with no visible or ascertainable cause of death--sheep and other animals have been found in the fields, bleeding from open wounds. There have been other matters--many of them apparently trivial in themselves. Some sinister influence has been at work, and I admit that I have suspected Lady Arabella--that is why I questioned you so closely about the mongoose and its strange attack upon Lady Arabella. You will think it strange that I should suspect the mistress of Diana's Grove, a beautiful woman of aristocratic birth. Let me explain--the family seat is near my own place, Doom Tower, and at one time I knew the family well. When still a young girl, Lady Arabella wandered into a small wood near her home, and did not return. She was found unconscious and in a high fever--the doctor said that she had received a poisonous bite, and the girl being at a delicate and critical age, the result was serious--so much so that she was not expected to recover. A great London physician came down but could do nothing--indeed, he said that the girl would not survive the night. All hope had been abandoned, when, to everyone's surprise, Lady Arabella made a sudden and startling recovery. Within a couple of days she was going about as usual! But to the horror of her people, she developed a terrible craving for cruelty, maiming and injuring birds and small animals-- even killing them. This was put down to a nervous disturbance due to her age, and it was hoped that her marriage to Captain March would put this right. However, it was not a happy marriage, and eventually her husband was found shot through the head. I have always suspected suicide, though no pistol was found near the body. He may have discovered something--God knows what!--so possibly Lady Arabella may herself have killed him. Putting together many small matters that have come to my knowledge, I have come to the conclusion that the foul White Worm obtained control of her body, just as her soul was leaving its earthly tenement--that would explain the sudden revival of energy, the strange and inexplicable craving for maiming and killing, as well as many other matters with which I need not trouble you now, Adam. As I said just now, God alone knows what poor Captain March discovered--it must have been something too ghastly for human endurance, if my theory is correct that the once beautiful human body of Lady Arabella is under the control of this ghastly White Worm."

Adam nodded.

"But what can we do, sir--it seems a most difficult problem."

"We can do nothing, my boy--that is the important part of it. It would be impossible to take action--all we can do is to keep careful watch, especially as regards Lady Arabella, and be ready to act, promptly and decisively, if the opportunity occurs."

Adam agreed, and the two men returned to Lesser Hill.