Q. I often hear plumbers speak of finding stains on marble wash-stands or toilet-stands which they cannot remove or give a suitable explanation for. I have been told the cause in some instances is from ladies using a certain kind of perfumed tooth-powder which contains quinine, but I am not chemist enough to say if such a compound would create a permanent stain. Please suggest a remedy.

A. Marble, especially that which is called statuary marble, is porous and absorbent, consequently it retains any moist foreign matter which comes in contact with it, and stains are easily seen. The best Italian marble is less likely to show stains than the white, and is much better for plumbing purposes.