Even after my marriage, I still spent time at the residence I previously shared with Holmes, as you may have gathered from my writings. I visited Holmes not only when he called on me to accompany him on cases, but also, occasionally, when I had other business in the vicinity.
Particularly in the days shortly after I moved out, I felt a need to check on him, out of concern that he might rely too heavily on his vices to stave his ennui when he could not find fulfilling work. The image of him clutching that morocco case of his after I announced my engagement was fresh in my mind.
One day, I stopped by on my way back from a house call.
"Thank goodness you're here, Doctor. Mr Holmes is ill," said Mrs Hudson, as she ushered me upstairs.
When I entered his rooms, I saw a pile of clothes on the floor, topped by a wig and a false beard. It was Holmes' sea-captain disguise. Holmes himself was lying face-down on the settee, in his purple dressing gown. His head was pressed against a cushion, and one of his arms dangled limply, touching the floor.
"Holmes!" I said, turning his head to the side and noting the film of sweat on his skin, "you might suffocate!"
"I'm fine, Watson," he murmured, looking up at me with barely-opened eyes.
"What have you been up to?" I asked, gesturing at the clothes, and at him.
"Reconnaissance," he said as proudly as his tired voice could manage, which was not very much.
I sighed. Effectively, I had come from one house call to another.
After I had examined him and noted his symptoms, I provided him with a bottle of sleeping draught and advised him to not to exert himself until he had recovered.
"What am I to do, then?" he said. "I am on the trail of the Napoleon of Crime! I cannot lose the scent!"
"If this Napoleon of Crime is as you say he is, surely he will still be around when you are well," I said.
"I must strike while the..." he trailed off.
"While the...?"
"I must strike," he said, lamely.
"Holmes," I said, "clearly your faculties are not at their best."
"I cannot concentrate on anything but this," he said.
"Perhaps you could do some reading, in the meantime."
"I have nothing to read!" he protested.
"Though I doubt that, I have a book here for you to read," I said, rummaging through my bag.
"Not one of your yellow-backed novels!" he said.
"No, it's not." I pulled out the book my patient had given me as a token of appreciation.
He took the hefty tome and examined it. "What use would I have for this information?" he said, annoyed.
"That is for you to find out, after you read it," I said. In truth, I had not read the book myself, having just received it that day, and had no intention of reading it, for it was rather out of the scope of my understanding.
Holmes accepted the book, albeit reluctantly.
When I next visited Baker Street, Holmes was in good health and good spirits.
"I found it!" he said, after greeting me, "The proof I need to corner the Napoleon of Crime!
"It was in plain sight, but not a soul saw it until now, because none had gone far enough to see it!"
"Wonderful!" I said. "And you were able to do it without camping in parts unknown for days on end?"
"Oh, I followed your advice, my dear Watson," he said, "I rested at home all this while."
I nodded approvingly. "It shows. So, how did you find this missing piece of the puzzle?"
"He confessed," he said, smugly.
"No doubt out of pity when he saw the state you were in, trying to find him," I said.
Holmes laughed. "Of course not. But I would not have found him, were I not in that state."
"What do you mean?"
"He confessed," said Holmes, "on page 598 of The Dynamics of an Asteroid."