Winter slowly assimilated this description.  Then he inquired: 

“Why did you say just now that you came away from Middle Street a few minutes too soon?”

“Where did Mrs. Capella go when she left the hotel?”

“If she went to visit the man you met, then she is acting in collision with her brother’s murderer, and she knows it.”

“That is a hard thing to say, Winter.”

“It is a harder thing to credit, sir; but one cannot reject all evidence, merely because It happens to be straightforward and not hypothetical.”

“Winter, you are sneering at me.”

“No; I am only trying to make you admit the tendency of facts discovered by yourself.  There is a period in all criminal investigation when deductive reasoning becomes inductive.”

“Now I have got you,” cried Brett “I thought I recognised the source of your new-born philosophy in the first postulate.  The second convinces me.  You have been reading ‘The Murders in the Rue Morgue.’”

“The book is in my pocket,” admitted Winter.

“I recommend you to transfer it to your head.  It should be issued departmentally as a supplement to the Police Code.  But let us waste no more time.  To-morrow we have much to accomplish.”

“I am all attention.”

“In the first place, Mrs. Capella is leaving London for the North.  She must not be regarded in our operations.  The woman is weighted with a secret.  I am sorry for her.  I prefer to allow events as supplied by others to unravel the skein.  Secondly, Jiro and his wife, and all who visit them, or whom they visit, must be watched incessantly.  Get all the force required for this operation in its fullest sense.  You, with one trusted associate, must keep a close eye on No. 37 Middle Street.  On no account obtrude yourself personally into affairs there.  Rather miss twenty opportunities than scare that man by one false move.  Do you understand me thoroughly?”

“I am to see and not be seen.  If I cannot do the one without the other, I must do neither.”

“Exactly.  What a holiday you are having!  You will return to the Yard with an expanded brain.  When you buy a new hat you will be astounded and gratified.  But beware of the fate of the frog in the fable.  He inflated himself until he emulated the size of the bull.”

“And then?”

“Oh, then he burst.”

The detective changed the conversation abruptly.

“What do you propose doing, Mr. Brett?”

“I purpose reading a chapter in ‘The Stowmarket Mystery,’ written by your friend, Mr. Holden.”

They heard a loud rat-tat on the outer door.

“Probably,” continued Brett, “this is its title.”

Smith entered with a telegram.  It was in the typed capitals usually associated with Continental messages.  It read: 

    “Johnson leaves Naples to-night with others, I travel same
    train.—­HOLDEN.”