A spot of red spread on Roger’s cheekbones.  In spite of his apparent demureness he had a pugnacious spirit and a quick fist.

“By the bones of Charles Lamb!” he said.  “Young man, your manners need mending.  If you’re looking for display advertising, I’ll give you one on each eye.”

Aubrey had expected to find a cringing culprit, and this back talk infuriated him beyond control.

“You damned little bolshevik,” he said, “if you were my size I’d give you a hiding.  You tell me what you and your pro-German pals are up to or I’ll put the police on you!”

Roger stiffened.  His beard bristled, and his blue eyes glittered.

“You impudent dog,” he said quietly, “you come round the corner where these people can’t see us and I’ll give you some private tutoring.”

He led the way round the corner of the alley.  In this narrow channel, between blank walls, they confronted each other.

“In the name of Gutenberg,” said Roger, calling upon his patron saint, “explain yourself or I’ll hit you.”

“Who’s he?” sneered Aubrey.  “Another one of your Huns?”

That instant he received a smart blow on the chin, which would have been much harder but that Roger misgauged his footing on the uneven cobbles, and hardly reached the face of his opponent, who topped him by many inches.

Aubrey forgot his resolution not to hit a smaller man, and also calling upon his patron saints—­the Associated Advertising Clubs of the World—­ he delivered a smashing slog which hit the bookseller in the chest and jolted him half across the alley.

Both men were furiously angry—­Aubrey with the accumulated bitterness of several days’ anxiety and suspicion, and Roger with the quick-flaming indignation of a hot-tempered man unwarrantably outraged.  Aubrey had the better of the encounter in height, weight, and more than twenty years juniority, but fortune played for the bookseller.  Aubrey’s terrific punch sent the latter staggering across the alley onto the opposite curb.  Aubrey followed him up with a rush, intending to crush the other with one fearful smite.  But Roger, keeping cool, now had the advantage of position.  Standing on the curb, he had a little the better in height.  As Aubrey leaped at him, his face grim with hatred, Roger met him with a savage buffet on the jaw.  Aubrey’s foot struck against the curb, and he fell backward onto the stones.  His head crashed violently on the cobbles, and the old cut on his scalp broke out afresh.  Dazed and shaken, there was, for the moment, no more fight in him.

“You insolent pup,” panted Roger, “do you want any more?” Then he saw that Aubrey was really hurt.  With horror he observed a trickle of blood run down the side of the young man’s face.

“Good Lord,” he said.  “Maybe I’ve killed him!”

In a panic he ran round the corner to get Leary’s outside man, who stands in a little sentry box at the front angle of the store and sells the outdoor books.