Then more dirt gets into the cracks just formed, and more scrubbing with bristles and hot water and soap is indulged in to get it out.

This opens the cracks still further, and the next layer of dirt is worked in still deeper.

Wash frequently with cold or cool water, occasionally with hot water, and sparingly with soap; and limit the use of brushes to the nails and the hair.
CARE OF THE NAILS Importance of Clean Nails.

On account of their constant use, your hands are brought in contact with dusty or dirty substances in your work and in your play; and it is very easy for some of this dirt, and such germs as it may contain, to lodge in the little chink under the free edge of the nail, between it and the rounded end of the finger.

It is of great importance that this nail chink should be kept clean, not only because it looks both ugly and untidy to have the ends of your fingers "in mourning," with black bands across them, but also because the germs lodged under your nails may get onto your food the next time that you eat, and set up irritation and fermentation in your stomach.