Boredom gives birth to innovation. This is the burden of a great mind: that it analyzes and perceives too quickly for long-term occupation with any subject. When the mind lacks adequate stimulation, it snatches and grasps at any means of alleviating the near madness of its situation. Perhaps this, at least in part, explains Holmes' fascination with bees.
In his young adulthood he had delved into the human race, and within 20 years felt he had seen all the wonders and terrors it had to offer. As his retirement drew near, he took none but the most puzzling cases, until he had quite enough of petty human troubles and turned instead to the monarchy of apis mellifera. Although the honey bees manages to capture his attention for nearly a decade, I grew more anxious with the passage of time as I watched my old friend revert to his old symptoms of boredom—irritableness and emaciation to the point that Mrs. Hudson sent a note begging me to visit and convince the impossible man to eat.
I had all but given up on his recovery when I received a visit from a surprisingly fleshier Holmes, who spoke, more enthusiastically than I had heard him in years, of a refreshing, new acquaintance—a girl of all people! I was quite dumbfounded until I met dear Mary, an intelligent, capable young woman, who was quite as lovely as Holmes described. I comforted myself with the knowledge that she would care for Holmes (and he for her) in a way that I never could.
Years passed, the pair traveled here there and yonder, falling in and out of dangerous situations, which they have yet to relay to me (I suspect Holmes would rather not find them in The Strand, although I can't see why not), and Mary managed to keep Holmes occupied enough to keep him from dabbling in narcotics. They had just returned from a tour of the world when an unexpected visitor thrust a role—two roles, in fact—upon Holmes that should keep him occupied for the rest of his life. I have yet to meet this bohemian son of Holmes', but I feel certain the presence of offspring and, no doubt, the addition of a grandchild shall, as Mary says, 'throw him for a loop." They will do wonders for his health.