He probably would have been in his fifties.
Was he still with Holmes? Was he married?
The publication date of this story is 1903. It is believed Watson was once again married in 1902. So it would seem he was happily sequestered in his home study when he recorded it.
Holmes at the time of this tale is recently back from his great hiatus. Watson has moved back in to Baker St., at Holmes' request. Holmes is however bored with the lack work for his singular talents. At one point he remarks how London once was the European capital of high crime, and he longs for those more active days.
It would be interesting, if records had been kept, to compare crime statistics for major European cities at this time.
Holmes has trouble hiding his glee when McFarlane shows up with what seems to be a case worthy of Holmes' abilities.
The following line reminds one of a small child trying to restrain his emotions after receiving good news; “Arrest you!” said Holmes. “This is really most grati—most interesting. On what charge do you expect to be arrested?”
As this summers reading has suggested (as does Bill Cochrans book), Holmes appears to have come back from his travels a much more easily satisfied man.
Another incident on the first few pages of the story that I found interesting was how Holmes offered an asthmatic a cigarette. Although definitely a no-no now a days, in Holmes time was it thought a cigarette would help ones breathing. The following advertisements may suggest that that was indeed the case. (And Watson doesn't admonish Holmes in any way for this suggestion.)
(But don't give it to kids under six.)
The mystery itself is good, with a very good plot along with very good detective work. Lestrade is, as always, Lestrade.
And once again we get a fine example of how far forensics had or had no come at this time in Holmes life.
It is not uncommon in modern forensic science for the police to determine the types of bones found at a site by DNA, bone measurement and probably any number of other ways to tell one bone from another.
And it also is the case with the examination of the blood samples. It doesn't appear that there was a method yet that could determine the nature of the blood.
There were probably many naturalist in Europe at the time of this story that could identify different types of bones, but it doesn't seem to be the police forces practice to involve experts from other fields yet.
Watson may have been able to help, but he did not visit the bone site during the story.
I would have been a little worried about starting a fire in the house, but, after all, it was a fairly modern villa so probably it met up to some better fire standards than . . let's say. . . something built during. . . Victorian times.
So. next time you are feeling under the weather. . . .
But make mine a Guinness!