One thing to be remembered is, don't brush too hard or too deep.

There is an old saying and a good one, "You can't brush the scalp too little, or the hair too much." Wetting the hair for the purpose of "slicking" it or combing it, is about as bad a thing as could be done; for the moisture sets up a sort of rancid fermentation in the natural oil of the scalp, giving the well-known sour smell to hair that is combed instead of brushed, and furnishing a splendid soil for germs and bugs of all sorts to breed in.
There is no objection to boys' and men's wetting their hair in cold water as often as they wish, provided that they rub it thoroughly dry afterward and give it a brisk currying with the brush.
Hair oils and greases of all sorts are sanitary nuisances, and mere half-civilized and lazy substitutes for proper brushing and washing.
There is no drug known to medicine which will cause hair to grow, or make it thicker or curlier.

All "hair tonics" claiming to do this are frauds.
Corns, Calluses, and Warts.

Our skin not only made our hair, teeth, and nails, but still retains in every part a trace of its nail-making powers, so that under pressure or irritation, it can thicken up into a heavy leather-like substance which we call _callus_.

This is naturally and healthfully present in the soles of the feet and the palms of the hands.