If a man were attacked by a group of ruffians and he had a club he might lay about himself with it.

"Lay about him or himself" is an idiom. It means to strike out in all directions. Suppose a man were attacked by ruffians and he had (or picked up) a weapon such as a long piece of wood, iron bar, etc, he might then defend himself by striking ("laying") with the weapon at his attackers who are around (about) him.

When the dogs cornered the old man, he laid about him (or himself) with his cane.