Cats have the credit of being more worldly wise than dogs—of looking more after their own interests and being less blindly devoted to those of their friends. And we men and women are naturally shocked at such selfishness.
 Jerome K. Jerome, Idle Thoughts of an Idle Fellow (1886). copy citation

Context

“But there, the clever people are such a very insignificant minority that it really doesn't much matter if they are unhappy. So long as the foolish people can be made comfortable the world, as a whole, will get on tolerably well.
Cats have the credit of being more worldly wise than dogs—of looking more after their own interests and being less blindly devoted to those of their friends. And we men and women are naturally shocked at such selfishness. Cats certainly do love a family that has a carpet in the kitchen more than a family that has not; and if there are many children about, they prefer to spend their leisure time next door. But, taken altogether, cats are libeled.” source