theory of some arm-chair lounger who evolves all these neat little paradoxes in

the seclusion of his own study. It is not practical. I should like to see him

clapped down in a third class carriage on the Underground, and asked to give the

trades of all his fellow-travellers. I would lay a thousand to one against him.”

 

“You would lose your money,” Sherlock Holmes remarked calmly. “As for the

article, I wrote it myself.”

 

“You!”

 

“Yes, I have a turn both for observation and for deduction. The theories which I

have expressed there, and which appear to you to be so chimerical are really

extremely practical—so practical that I depend upon them for my bread and

cheese.”

 

“And how?” I asked involuntarily.

 

“Well, I have a trade of my own. I suppose I am the only one in the world. I’m a

consulting detective, if you can understand what that is.

 

Here in London we have lots of Government detectives and lots of private ones.

When these fellows are at fault they come to me, and I manage to put them on the

right scent. They lay all the evidence before me, and I am generally able, by

the help of my knowledge of the history of crime, to set them straight. There is

a strong family resemblance about misdeeds, and if you have all the details of a