I saw in the lamplight the vicious gleam in the American's eye and the twitch of his hand to his pocket.

That decided me to interfere and I got in front of him.
This brought the second jock into the fray.

He was a broad, thickset fellow, of the adorable bandy-legged stocky type that I had seen go through the Railway Triangle at Arras as though it were blotting-paper.
He had some notion of fighting, too, and gave me a rough time, for I had to keep edging the other fellow off Gresson.
'Go home, you fool,' I shouted.

'Let this gentleman alone.

I don't want to hurt you.' The only answer was a hook-hit which I just managed to guard, followed by a mighty drive with his right which I dodged so that he barked his knuckles on the wall.