has not got over
the Afghan campaign yet. I cannot afford to throw any extra strain
upon it."

He smiled at my vehemence. "Perhaps you are right, Watson," he said.
"I suppose that its influence is physically a bad one. I find it,
however, so transcendently stimulating and clarifying to the mind that
its secondary action is a matter of small moment."

"But consider!" I said, earnestly. "Count the cost! Your brain may,
as you say, be roused and excited, but it is a pathological and morbid
process, which involves increased tissue-change and may at last leave a
permanent weakness. You know, too, what a black reaction comes upon
you. Surely the game is hardly worth the candle. Why should you, for
a mere passing pleasure, risk the loss of those great powers with which
you have been endowed? Remember that I speak not only as one comrade to
another, but as a medical man to one for whose constitution he is to
some extent answerable."

He did not seem offended. On the contrary, he put his finger-tips
together and leaned his elbows on the arms of his chair, like one who
has a relish for conversation.

"My mind," he said, "rebels at stagnation. Give me problems, give me
work, give me the most abstruse cryptogram or the most intricate
analysis, and I am in my own proper atmosphere. I can dispense then
with artificial stimulants. But I abhor the dull routine of existence.
I crave for mental exaltation. That is why I have chosen my own
particular profession,--or rather created it, for I am the only one in
the world."

"The only unofficial detective?" I said, raising my eyebrows.

"The only unofficial consulting detective," he answered. "I am the
last and highest court of appeal in detection. When Gregson or
Lestrade or Athelney Jones are out of their depths--which, by the way,
is their normal state--the matter is laid before me. I examine the
data, as an expert, and pronounce a specialist's opinion. I claim no
credit in such cases. My name figures in no newspaper. The work
itself, the pleasure of finding a field for my peculiar powers, is my
highest reward. But you have yourself had some experience of my
methods of work in the Jefferson Hope case."

"Yes, indeed," said I, cordially. "I was never so struck by anything
in my life. I even embodied it in a small brochure with the somewhat
fantastic title of 'A Study in Scarlet.'"

He shook his head sadly. "I glanced over it," said he. "Honestly, I
cannot