therefore
impracticable for general employment. The following are those in more
common use:--

The _gelatin dressing_, as originally ordered, is made by melting over a
water-bath one part of gelatin in two parts of water--quickly painting
it over the diseased area; it dries rapidly, and to prevent cracking
glycerine is brushed over the surface. Or the glycerine may be
incorporated with the gelatin and water in the following proportion:
glycerine, one part; gelatin, four parts, and water eight parts.
Medicinal substances may be incorporated with the gelatin mixture.

A good formula is the following:--

[Rx] Gelatin, ............................. [Oz]j
Zinci oxidi, ......................... [Oz]ss
Glycerini, ........................... [Oz]iss
Aquae, ................................ [Oz]ii-[Oz]iij.

This should be prepared over a water-bath, and two per cent. ichthyol
added. A thin gauze bandage can be applied to the parts over which this
dressing is painted, before it is completely dry; it makes a comfortable
fixed dressing and may remain on several days.

_Plaster-mull_ and _gutta-percha plaster_. The plaster-mull, consisting
of muslin incorporated with a layer of stiff ointment, and the
gutta-percha plaster, consisting of muslin faced with a thin layer of
India-rubber, the medication being spread upon the rubber coating.

_Rubber plasters._ These are medicated with the various drugs used in
the external treatment of skin diseases, and are often of service in
chronic patches.

Two new excipients for fixed dressings have recently been
introduced--bassorin and plasment; the former is made from gum
tragacanth, and the latter from Irish moss.

The following is a satisfactory formula for a tragacanth dressing:

[Rx] Tragacanth, .......................... gr. lxxv
Glycerini, ........................... [minim] xxx
Ac. carbolici, ....................... gr. x-xx
Zinci oxidi, ......................... [dram]iss-[dram]iiss. M.

This is painted over the parts and allowed to dry, and a mild dusting
powder sprinkled over. It cannot be used in warm weather or in folds, as
it is apt to get sticky. The following is a bassorin paste which may be
variously medicated.

[Rx] Bassorin, ............................ [dram]x
Dextrin, ............................. [dram]vj
Glycerini, ........................... [Oz]ij.
Aquae, ....................... q.s. ad