such. He must be
physically strong; he must be untiring in his search after truth; he
must be able to scent a mystery as a hound does a fox, to follow up
the trail with energy unflagging, and seize opportunities without
hesitation; he must possess a cool presence of mind, and above all be
able to calmly distinguish the facts which are of importance in the
strengthening of the clue from those that are merely superfluous. All
these, besides other qualities, are necessary for the successful
penetration of criminal mysteries; hence it is that the average
amateur, who takes up the hobby without any natural instinct, is
invariably a blunderer.

Ambler Jevons, blender of teas and investigator of mysteries, was
lolling back in my armchair, his dreamy eyes half-closed, smoking on
in silence.

Myself, I was thirty-three, and I fear not much of an ornament to the
medical profession. True, at Edinburgh I had taken my M.B. and C.M.
with highest honours, and three years later had graduated M.D., but my
friends thought a good deal more of my success than I did, for they
overlooked my shortcomings and magnified my talents.

I suppose it was because my father had represented a county
constituency in the House of Commons, and therefore I possessed that
very useful advantage which is vaguely termed family influence, that I
had been appointed assistant physician at Guy's. My own practice was
very small, therefore I devilled, as the lawyers would term it, for my
chief, Sir Bernard Eyton, knight, the consulting physician to my
hospital.

Sir Bernard, whom all the smart world of London knew as the first
specialist in nervous disorders, had his professional headquarters in
Harley Street, but lived down at Hove, in order to avoid night work or
the calls which Society made upon him. I lived a stone's-throw away
from his house in Harley Street, just round the corner in Harley
Place, and it was my duty to take charge of his extensive practice
during his absence at night or while on holidays.

I must here declare that my own position was not at all disagreeable.
True, I sometimes had night work, which is never very pleasant, but
being one of the evils of the life of every medical man he accepts it
as such. I had very comfortable bachelor quarters in an ancient and
rather grimy house, with an old fashioned dark-panelled sitting-room,
a dining-room, bedroom and dressing-room, and, save for the fact that
I was compelled to be on duty after fou