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Gums and Resins 



347 



Wattle Gums 



The wattles are a group of acacias indigenous to Australia, where they are largely exploited 

 for their barks, which are rich in tannin (see p. 352), and for their soluble gums. Several of 

 the wattles have been introduced into South Africa, where they are cultivated for bark, gum 

 being collected from them as a bye-product. The principal Australian species yielding gum 

 in notable quantities is Acacia dealbata. Cape gum is obtained from Acacia horrida. 



Indian Gums 

 Two varieties of gum are exported from India, viz., " East Indian gum," already alluded 

 to, which consists essentially of Somaliland gum mixed with true Indian gums, and Ghati gum, 

 so named because it is collected spasmodically by the natives inhabiting the western Ghats. 

 The Ghati gum which reaches this country is tolerably uniform and is probably collected, 

 principally from Anogeissus latifolia. It is usually of pale colour and possesses special properties, 

 which have secured for it a prominent place as a substitute for Sudanese and Senegal gums, 

 especially in the United Kingdom. 



RESINS 



The commercially valuable resins are, as explained in the article dealing with gums, known 

 in commerce as gums, e.g., " gum copal," " gum dammar." They are readily distinguishable 

 from true gums by being 

 soluble in spirit or oils, but ^ " 

 not in water. They also 

 differ from gums in their 

 mode of formation in plants 

 thus, whilst true gums 

 are apparently decomposition 

 products of cellulose, resins 

 appear to be elaborated by 

 plants from certain constit- 

 uents of the essential oils. 

 It follows from this mode of 

 formation that resins usually 

 occur in plants associated 

 with essential oils, thus 

 " common rosin " occurs in 

 special ducts in pine trees 

 dissolved in oil of turpentine, 

 and similarly fresh copal and 

 dammar usually contain 

 small quantities of the essen- 

 tial oils from which they 

 were probably originally 

 formed. The resins of com- 

 merce may conveniently be 

 divided into four classes : — 

 1. Varnish resins. These 

 are usually hard substances 

 containing either no essential 

 oil or very small quantities of 

 such volatile products. Ex- 



amDleS * CODal dammar San- From Stereograph Copyright, Underwood & Underwood, London and New York 



darac, mastic. 2.0leo-resins. the resin market, savannah, Georgia 



