The stamping may be performed by a hand stamper (Fig. 24), a screw press
(Fig. 25), or by a steam stamper. The screw press works very
satisfactorily for toilet soaps.

There are two kinds of moulds in use for milled soaps:--

(_a_) _Pin Moulds_ in which tablets of one size and shape only can be
produced (Fig. 25). The edges of the mould meet very exactly, the upper
part of the die carries two pins attached to the shoulder, and these are
received into two holes in the shoulder of the bottom plate. The
superfluous soap is forced out as the dies meet.

(_b_) _Band or Collar Moulds._--In this form (Fig, 27) the mould may be
adjusted to stamp various sized tablets, say from 2 ozs. to 5-1/3 ozs.
and different impressions given by means of removable die plates. The
band or collar prevents the soap squeezing out sideways. We are indebted
to R. Forehaw & Son, Ltd., for the loan of this illustration.

It is usual to moisten the soap or mould with a dilute solution of
glycerine if it should have a tendency to stick to the die plates.

The soap is then ready for final trimming, wrapping, and boxing.

[Illustration: FIG. 27--Band Mould.]

MEDICATED SOAPS.

The inherent cleansing power of soap renders it invaluable in combating
disease, while it also has distinct germicidal properties, a 2 per cent.
solution proving fatal to B. coli communis in less than six hours, and
even a 1 per cent. solution having a marked action on germs in fifteen
minutes.

Many makers, however, seek more or less successfully to still further
increase the value of soap in this direction by the incorporation of
various drugs and chemicals; and the number of medicated soaps on the
market is now very large. Such soaps may consist of either hard or soft
soaps to which certain medicaments have been added, and can be roughly
divided into two classes, (_a_) those which contain a specific for
various definite diseases, the intention being that the remedy should be
absorbed by the pores of the skin and thus penetrate the system, and
(_b_) those impregnated with chemicals intended to act as antiseptics or
germicides, or, generally, as disinfectants.

The preparation of medicinal soaps appears to have been first taken up
in a scientific manner by Unna of Hamburg in 1886, who advocated the use
of soap in preference to plasters as a vehicle for the application of
certain remedies.

Theoretically, he considered a soap-stock made entirely from beef tallow