From the diary of John H. Watson MD, 2nd September 1884
I don't know why I was so surprised to find that he had a brother. Certainly, he had been evasive about his past, but in truth his reticence on such matters had been no greater than my own. Still, I was shocked when Holmes had suddenly brought this hitherto unknown brother into the conversation. Perhaps my disbelief stemmed from an inability to see that the extraordinary man who was Sherlock Holmes possessed the mere humanity to allow him to have such a simple thing as a sibling; I fancy I would have felt less discomfited to learn that my friend had been hatched.
Now I sat in an opulent anti-room of the building housing possibly the queerest club in existence, the Diogenes, a club in which talking was forbidden: why, it was absurd! I could have pondered this peculiar setting for an age, and no doubt I would have if my current bemused and awed state would have allowed me to consider anything but the scene being played out by the brothers in front of me. Standing in the bay window the two men- as different in stance and stature as two brothers could possibly be- discussed the intricacies of the people below with all the enthusiasm of the ethnologist in a foreign land.
I was not quite immune to my friend's seeming omnipotence but I was at least used to it after the many times he had peered into the souls of the populace in my presence, however, to have two of them doing it… It was all I could do to keep my mouth from gaping open. I was reminded strangely of watching a game of lawn tennis as my head swerved left and right from brother to brother- "an old soldier, I perceive" my friend made the first serve. "And very recently discharged" Mycroft met with a volley, and so it continued, until Sherlock parried "…with a child." The older Holmes' eyes lit up as he made his return "children, my dear boy, children." I winced on my companion's behalf: advantage, Mycroft.
"Come" I said, dispelling the competitive tension from the room with a laugh, "this really is too much." Both heads turned to me and, although both brothers proceeded to spend several minutes highlighting my comparative ineptitude in the art of deduction, I felt relieved that the brothers' attention had at least been diverted away from each other. For all my lack of deductive prowess I was well aware of the strain in the relationship between these two great individuals. I might not have been able to tell that the stranger outside the window was a widowed army officer with two children but I could tell that my friend in this room was as taut as the E string on his violin. Mycroft had been incorrect with one observation; when he had stated that the greatest spot for the examination of mankind was from that window he was truly looking at things from the wrong side of the glass.
We were joined shortly after by Mr. Melas and The Case of the Greek Interpreter began, but that, dear reader, is for another tome entirely. While my friend and his brother examined and cross-examined both witness and evidence and I wrote notes with an outward display of diligence, I was inwardly using Holmes' own methods to gather data of an all together different nature. I noticed that at several points when Mycroft's intellect was excited he would reach out as though to touch his brother, but each time he did this, his rationality seemed to kick in and he occupied himself in another pursuit such as pouring or consuming another glass full of sherry. I also noticed the tension in every line of his brother's face every time Mycroft neared him and the relaxation that came when he moved away again. To a casual observer, such unrest would not have been observed- I daresay Mr. Melas did not notice a thing- but one cannot spend years in the company of a man and fail to sense his distress, even if that man is as skilled in the art of disguise as Sherlock Holmes.
Soon our interview came to an end and the Greek gentleman made his nervous way home. I finished my notes and stretched myself and Mycroft unconsciously reached into his pocket for a silver snuff box. As soon as he saw it, Sherlock's eyes snapped up and he looked to Mycroft with an expression even I couldn't place. "Father's case" he stated, his tone casual and giving nothing away but still Mycroft paled, shuffling the case back into its hiding place an expression which suddenly reminded me very much of his brother when I found him with his syringes and seven per cent solutions. But how could the expose of a fondness for snuff, which paled in comparison to some of Sherlock's vices, make the older Holmes so uncomfortable? My companion rose with some parting words on the subject of the case and made for the door and I too bade my goodbyes and followed him.
It was not until I stepped into the hall that I realised another part of this complex puzzle that had been niggling at me from the moment I had first seen the brothers together. Not once during the entire meeting had Mycroft Holmes looked his brother in the eye.