“I won’t.”

“Then I’ll force my way in!”

“If you try it, I shall infallibly bust you one on the jaw.”

The stout young man drew back a pace.

“You can’t do that sort of thing, you know.”

“I know I can’t,” said George, “but I shall.  In this life, my dear sir, we must be prepared for every emergency.  We must distinguish between the unusual and the impossible.  It would be unusual for a comparative stranger to lean out of a cab window and sock you one, but you appear to have laid your plans on the assumption that it would be impossible.  Let this be a lesson to you!”

“I tell you what it is—­”

“The advice I give to every young man starting life is ’Never confuse the unusual with the impossible!’ Take the present case, for instance.  If you had only realized the possibility of somebody some day busting you on the jaw when you tried to get into a cab, you might have thought out dozens of crafty schemes for dealing with the matter.  As it is, you are unprepared.  The thing comes on you as a surprise.  The whisper flies around the clubs:  ’Poor old What’s-his-name has been taken unawares.  He cannot cope with the situation!’”

The man with the collar-studs made another diagnosis.  He was seeing clearer and clearer into the thing every minute.

“Looney!” he decided.  “This ‘ere one’s bin moppin’ of it up, and the one in the keb’s orf ‘is bloomin’ onion.  That’s why ’e ’s standin’ up instead of settin’.  ’E won’t set down ’cept you bring ‘im a bit o’ toast, ’cos he thinks ’e ’s a poached egg.”

George beamed upon the intelligent fellow.

“Your reasoning is admirable, but—­”

He broke off here, not because he had not more to say, but for the reason that the stout young man, now in quite a Berserk frame of mind, made a sudden spring at the cab door and clutched the handle, which he was about to wrench when George acted with all the promptitude and decision which had marked his behaviour from the start.

It was a situation which called for the nicest judgment.  To allow the assailant free play with the handle or even to wrestle with him for its possession entailed the risk that the door might open and reveal the girl.  To bust the young man on the jaw, as promised, on the other hand, was not in George’s eyes a practical policy.  Excellent a deterrent as the threat of such a proceeding might be, its actual accomplishment was not to be thought of.  Gaols yawn and actions for assault lie in wait for those who go about the place busting their fellows on the jaw.  No.  Something swift, something decided and immediate was indicated, but something that stopped short of technical battery.

George brought his hand round with a sweep and knocked the stout young man’s silk hat off.