I know things. I know a lotta things. For instance: I know it's fun to punch dogs. Lots of people know this, but they may be unaware that dog punching was considered a worthy sport among the emerging middle class in nineteenth century England, along the lines of bull fighting, fox hunting and chicken kicking.
One of the major class conflicts in Victorian England involved people who adopted dogs as pets instead of punching targets. Releases by these zealots as well as unlicensed breeding programs resulted in strays infesting the city streets and the countryside. Soon every municipality employed professionals to round up the packs of animals to be placed in buildings where the middle class could view animals in cages before selecting specimens to be punched.
And it's from this practice we get the word 'pound'.