102 



MATERIA. MEDICA. 



CLASS XVIII^—EMOLLIENTS. 



" Medicines which soften and relax the skin, when externally ap- 

 plied." They diminish the pain and tension of inflamed parts, 

 often assisting in producing resolution ; or if too far advanced for 

 that, they aid the suppurative process. Their action is believed to 

 be purely mechanical. They all owe their efficacy to moisture; in 

 fact, ivater is, by some, considered the only emollient ; a tempera- 

 ture above 62° F. is requisite; aqueous vapour still more emollient 

 than warm water. The usual method of applying emollients is by 

 cataplasm, of which the best is that made from flaxseed meal. 

 Nearly all the demulcents have an emollient effect when externally 

 applied. 



CLASS XIX. — DEMULCENTS. 



" Substances of a bland unirritating nature, capable of forming a 

 viscid solution with water." They are closely allied to emollients; 

 in fact they produce the same eflfect upon the internal passages as 

 the latter do upon the skin. They consist chiefly of gum, sugar, 

 oil, or starch, and are useful both as adjuvants to other acrid or irri- 

 tating medicines, and also, when given alone, to defend inflamed or 

 irritated surfaces, with which they come into direct contact, as the 

 stomach and bowels, — when they may be given either by the mouth, 

 or by enema. Also very much used in inflammations and irritations 

 of parts on which their action must be indirect, as in bronchitis and 

 urinary disorders ; in the latter instances, they probably act by being 

 absorbed. Several of the demulcents are much used as articles of 

 diet for the sick. 



Gum Arabic. — (Acacia, U. S.) 



Product of several species of Acacia^ especially the A. vera, A. 

 Senegal, and A. Arabica. They are 

 thorny shrubs, or trees, growing in the 

 deserts of Arabia, Africa and India. 

 The gum exudes spontaneously and by 

 incisions. The varieties are as follows : 

 — 1. Turkey gum, im'^onedi from the Le- 

 vant ; comes in small irregular frag- 

 ments, either whitish, or very light yel- 

 lowish red: among these are larger 

 round pieces with numerous cracks ; brit- 

 tle, and completely soluble in water. 2, 

 Gum Senegal, from the western coast of 

 Africa; larger fragments, darker colour, 

 less brittle, of a conchiodal fracture. 

 3. Gum Barhary, from the northern 



Fig. 27. 



