2,28 PLANTS PRODUCING GUMS AND RESINS 



Acacia Jacquemontii. — Some years ago the gum from this acacia 

 was the basis of a large trade, being exported from Karachi. 



In the opinion of some it is inferior to gum arabic, but it is 

 nevertheless used in medicine, in printing cottons, and in the manu- 

 facture of paper. Messrs. Rowntree and Co., of York, say that it is 

 the best gum for confectionery, and Watt confirms this statement. 

 It is strongly mucilaginous, and when lo per cent, of water is added 

 forms a thin jelly. The solution is brownish m colour and devoid of 

 sediment; the flavour is sweet. In Amritsar 1,750 kilos of this gum 

 are produced annually. 



Acacia tortilis. — This gum occurs in hard fragments, variously 

 coloured and glassy in appearance, with a bitter taste and slight odour. 

 The fragments are resinous and certain portions of their surface are 

 covered with an opaque yellow film. The gum swells up in water 

 without forming a mucilage and the quality is very inferior. 



Acacia modesta. — This tree yields very little gum. It occurs in 

 the form of small round tears or angular fragments. 



Prebble says that it is transparent and yellowish in colour, very 

 soluble in water, and forms a good pale-coloured mucilage. Under 

 the action of basic acetate of lead and ferric chloride it is converted 

 into jelly, whilst borax has no action ; with neutral acetate of lead 

 a slight precipitate or cloudiness is formed. It slightly reduces 

 Fehling's solution. The gum is sent from Bombay to the North of 

 India, and is classed as Amritsar gum. It is largely used in medicine. 



Acacia leucophloea. — A shrub which has been introduced into India 

 from Asiatic Turkey. It produces the Bassora gum, which occurs in 

 small irregular fragments, more or less twisted, white or yellowish, less 

 transparent than the Arabian and Senegal gums, and has a slight 

 acetic odour. 



This gum is composed of bassorin united with a small quantity of 

 arabin, and forms in water a loosely combined mucilage which tends 

 to limit its uses. It is gelatinized by borax, whilst ether, basic acetate, 

 and neutral acetate of lead have no action upon it. It is probably used 

 to adulterate the best ciualities of gJiati. 



Acacia Adansonii — A shrub, 6 to S metres high, with erect whitish 

 spines and yellow flowers arranged in globular fashion and situated at 

 the axils of the leaves. It occurs fairly widely throughout the whole 

 of the Senegal Plain, the Middle Niger, &c. It yields gum which 

 collects in tears; the gum contains a large proportion of tannin, which 

 gives it its red colour and renders it astringent. It is less valuable than 

 the Verek gum. 



Acacia tomentosa — This acacia occurs in the plains of the Senegal. 

 Like the foregoing, it is a variety of Acacia arabica. The gum which it 

 produces is mixed with those of A. Adansonii and A. alhida and sold as 

 a gum of second quality. 



In Acacia tomentosa the herbaceous portions and the ripe fruit are 

 covered with a cottonv down. 



