The color rose in his cheeks and he glanced into the fire. "I'm not sure he'll agree with you, once he recalls what happened." He swallowed hard, and added softly, "Although I'm not sure that his memory shall ever return, since that chase after Jonathan Small down to the same reaches of the river has not shaken it free."

"You meant it to!" I realized. "You took him on the river at night again deliberately."

Holmes nodded. "Yes," he admitted. "He had you to turn to. Between the river and the treasure I thought to make it a clean break. I should lose him in any case."

The light from the flames showed up the lines on his face and the smudges under his eyes more clearly and I realized that a good part of Holmes' distress must come from exhaustion, and no wonder, if he had had no one with whom he could share his fears. But this fear at least could be dispelled. "In thinking so, you do him the only wrong in all this coil. You saved his life, and risked your own to do so. I cannot imagine him to be so monstrous as to be ungrateful. The promise you made in Yorkshire was for that time, and place only. Last June the danger was closer and driven by a force far less beneficent than Providence."

"I could have given him the cocaine," Holmes countered, turning again to face me, and then he made a rueful moue. "Theoretically, at least. I have read of it being used as an anesthetic, although not as an analgesic."

It was my turn to brush the consideration aside. "Better to use the drug you knew would work."

"I could have stayed awake and kept us from going aground."

I dismissed that as well. "If you could have, you would have."

"I could have told him what happened." His chin was up, his eyes defiant. Having owned his faults he was ready to defend them.

But I only smiled. "Ah, now there you have me." But I could see why he had not. I reached over to touch his arm. "Now, tell me what happened last night."

"How do you know anything happened last night?" he said, not as a delay, I think, but because he wished to know how I was thinking.

"Something precipitated this visit," I told him. "Something which prevented you from getting the sleep you clearly needed even yesterday, and given that you felt a need to come and tell me of your concerns I think it must be that you saw Dr. Watson attempt to use morphine again."

He shook his head. "Nothing quite that desperate," he said. "But desperate enough."

"Tell me."

"Watson was quiet at dinner," he said, folding his legs and resting his elbows on his knees so that he could rest his chin on his hands once more. "And after dinner he spent some time at his desk going over his bank accounts until I drove him to his room by engaging in a particularly malodorous chemical investigation. I reminded him, as we said goodnight, of his promise to you that he would sleep, but your name only made him pensive -- whereas before he has brightened at it. There was nothing more that could be done at that hour, though, and I thought that sleep would ease him. Still, I stayed busy in the sitting room, feeling restless myself and hoping to be distracted by a hunt through my books for a quotation I'd half remembered. I fell asleep on the couch.

"I woke to find Watson, barefoot and in his nightshirt, standing by the mantelpiece, which is where that case --" he indicated the one lying on the table with a gesture, "lives when it is not in my pocket. He was staring at it, holding quite still, like a man frozen in a block of ice. I said his name, meaning to tell him of the mislabelled phial. He jumped back and his foot came down on one of the books I'd left on the floor. It went out from under him and he fell onto the cane chair, which was also stacked with books, and he, the chair, and the books all went to the floor with a tremendous crash."

"I went to pick him up of course, although he didn't want the help, and had just finished mumbling something about how I must despise him for being a water of the first hypocrite when Mrs. Hudson came in, alerted by the crash. Fortunately, he will accept from her what would seem like falsity in me, and she soon had him back in bed and was berating him for going about without his slippers or dressing gown. His temperature was up, and he'd strained his leg in the fall, but between brandy and a course of headache powders we got him settled again. That was just before dawn."

"So he'd confused his words again?" I asked. Holmes would not have mentioned the mistake if it were not pertinent. "You said earlier that that did not fit the pattern," I recalled.

"Nor did it," Holmes said. "Until recently." The puzzle was clearly gnawing at Holmes, so I set to asking him questions, as I do when I help the children with their schoolwork.

"Did anything else fit the pattern you would expect? Was he trembling, or were his legs restless? Did he need his handkerchief?"

"No, none of those things. But these past weeks all of my expectations have been awry." Holmes tapped his fingers against each other. "It's possible that Sir Julian is right."

"And it's possible that he is wrong. I should think you know John better than any man alive."

Holmes snorted. "I didn't even know he'd had a brother until ten minutes before you came to our door." His shook his head. "But that's a mystery for another day. Watson never speaks of his family, not even when he is delirious. Even Murray knew little more than that his father had died at Capetown some few weeks before Maiwand."

I made a quiet resolution to find out what I could, but Holmes was right. The other question pressed harder. "And you are certain of the symptoms of the craving?" I asked.

"Even if I had not seen them confirmed in Watson's medical magazines I have seen them often enough in the man himself," Holmes said.

"Since June?"

"Several times, but with decreasing frequency as the months have passed. That's what I saw in the spring and summer of '83 as well. Eventually the spasms must have passed entirely, for I saw nothing of the sort between his return and the fresh injury."

I felt an idea dancing just out of my reach. "And the pattern you see in the confusions of speech... you said it was to do with the old wound, not the new..."

Holmes' eyes widened. "And this morning, he caught himself as he fell with both hands. And I know it hurt his shoulder by the way he carried his arm afterwards." But then his face fell. "Still that does not explain why he was at the mantel in the first place -- nor what happened on the night of our rendezvous with Thaddeus Sholto."

"One thing at a time," I said and bit my lip, trying to remember every small detail I had noticed about John during that strange and terrible excursion. There was a clue there, if only I could think of it. "Does he often carry the ebony stick with the silver handle?" I asked. "The one he had that night?" I hadn't seen him carry it since.

"He brings it whenever we're on a case at night," Holmes said. "There's a lead weight in it to give it better balance in case it must be used in a fight."

"So it's much heavier than his usual stick," said I, thinking out loud. "And he was carrying it in his left hand at first." I was certain of that. I could still feel the warmth of his right hand where it had rested in mine in the garden of Pondicherry Lodge. "But later..." I closed my eyes, the better to recall what he had looked like as he went back to the cab after he'd dropped me off at home. The light had fallen out of the hall, illuminating his silhouette, and I'd thought even then that his steps were lighter. And the stick he'd raised to the cabman... I moved my own hand in imitation. "Later he was carrying it in his right. You were not there to see, but I assure you it was true."

"I did see," said Holmes. "He carried it in his right as we followed Toby."

"But that was only so after he brought me home. And after we had seen him off, and turned to go inside again Mrs. Forrester said that the next day would be fair, and I looked and the barometer was rising. But it had been so cold and damp all the day before then -- could not John's leg have been bothering him? And when he leaned upon the stick with his bad arm he overtired it?"

Holmes gave me such a look of approval that I blushed. "Excellent! But you have not yet explained why he was at the mantelpiece before he fell this morning."

By the light in his eye I think he had gone before me, but faced with the challenge I could not ignore it. "You said the stumbling in his speech has only seemed connected with the morphine recently. Since the weather turned?" I guessed, and at Holmes' nod had the answer. "That's why then. He was at the mantel this morning because the fog was rolling in and it made his wounds ache. He wanted morphine, not because of any fiendish craving, but because he was hurting, and in his half-awake state was only looking for some means to alleviate the pain."

"I knew you had the right instincts!" Holmes exclaimed, bringing his hands together with a sharp clap. "Yes, that explanation fits the facts."

"It doesn't explain why overstraining his arm would make him confused," I felt constrained to point out.

"No," Holmes said. "But Watson might know, once it's pointed out to him. Some difficulty with circulation, perhaps. His left hand is often paler than the right." He had a bright, fierce look upon his face. "It explains why the amnesia has seemed to worsen since the rains have come as well. Watson insists on going out to walk every day, regardless of the weather -- says he must use the leg lest it atrophy -- but when his leg wound pains him he moves his stick to the left hand and so strains the bad arm. Once you have eliminated the occasions when he has only seem confused it's clear that the periods of morphine craving are diminishing, rather than increasing in frequency, just as they did the first time. Given time he could practice medicine again, just as he did before, without so great a risk of lapsing back into his addiction."

"And if he knows that a tired arm might make him confused he can be particularly careful about any instructions he gives when he is tired," I said with satisfaction. "I can sell my pearls -- they ought to bring enough to purchase a practice."

"Won't you need the money for other things?" Holmes asked. "I have a few cases I could take on -- not terribly interesting, but the clients are wealthy. With a little effort I could gift you two enough of a wedding present to meet the price of a modest practice."

"Yes, but would he take the money?" I said, feeling a sudden doubt. "How shall you get around his stiff neck?"

"I'll think of something," Holmes said. "Perhaps I'll send him as my agent off to the country while I do work in town. He can't refuse a share of the fee if he's the one did most the work." He rose to his feet and held out a hand to me. "It would mean holding off your wedding a while."

I took his aid gratefully. "The children don't want me to go before Christmas in any case. And I'll need to do something about my trousseau."

"Yes, but most of all you need to come to Baker Street tomorrow, and set his fears to rest." Holmes took my other hand in his. "I told Watson that I could not congratulate him when he announced his engagement to you -- a churlish sentiment I confess to now so that you will know the worst of me. But I felicitate you, Miss Morstan. You have chosen the truest, most honorable man in London as your husband. Do not let him slip between your fingers."

"I do not mean to," I promised him, meaning not to let this other bright knight slip away from us either.

Holmes began to put himself together. He took his case from the table and tucked it in his pocket again, sweeping his eye around the room for any other thing that he might have otherwise forgotten. I rang for the girl, who brought his hat and coat and gloves. He pulled them on quickly, trembling like a racing horse ready for the gate, so anxious was he to return to Baker Street and expound his new insight to his friend.

"Are you sure you want me to come by?" I asked. "I did mean for you both to have some respite, and you have been driving yourself quite hard."

Holmes patted the pocket with the morocco case. "Oh, I can manage for a while longer," he said gaily. "And Mrs. Hudson shines her brightest when she means to tempt our appetites. Besides, Watson will be delighted to see you."

"Shall I be there for luncheon, then?" I asked. "One o'clock? The children will have finished their schoolwork by noon."

"That should do. I'll wire you if he's not up to company." But as he reached the door he stopped and turned, sudden doubt in his eye. "Miss Morstan. This conversation..."

"Is yours to tell John of or not." I overrode him. "I am a governess to eight children Mr. Holmes, and as such I am the keeper of many secrets. This one I shall hold closer to my heart than all the rest, until you give me leave to speak."

"Thank you," he said, and was gone.

--break--

This story was inspired by mention of an essay called "John H. Watson and the Subclavian Steal" by Van Liere, and further nudged into being by an essay called "Sherlock Holmes' Cocaine Habit by Thomas Dalby, over at the bakerstreetdozen website. Ian Hart's performance in the BBC Hound can probably take some of the blame too. The medical ideas I had vetted by Surgical Steel, and any errors which remain are my own.

Subclavian steal is a condition where the subclavian artery is narrowed by an injury (or more usually artheriosclerosis) between the place where it arises from the aorta and the place where several arteries branch off from it in the direction of the brain. The subclavian artery continues after the branching on into the arm, changing it's name, but still providing all the circulation going down to the fingers. Because of the way fluids seek the easiest path, if a person with subclavian steal uses the arm very vigorously, the blood will be diverted from its usual circulation and the brain will lose some of the blood flow it normally requires, causing temporary confusion. I haven't actually read Van Liere's essay, mind you. But the idea does have its attractions. Ian Hart, by remembering to "protect" that left arm fed the already nibbling plotbunny that suggested that Watson did not return to work as a surgeon because he'd permanently lost some motion in the arm. If the top of the scapula is what shattered, and the shoulder had been held immobile in the vague hope of healing, a long term disability would result, but careful use over time might give the circulation at least a chance to rebuild somewhat, eventually easing away the symptoms of subclavian steal.

Dalby's essay I'll let you hunt out for yourselves.

Thanks to Surgical Steel for the medical beta (and telling me about subclavian steal), Cuthalion for the title, and both of them as well as Pompey, KMC and clevertoad for encouragement, beta comments, and helping me get this actually finished.