344 LEGUMINOS.E PRODUCING TANNING MATTERS AND DYES 



(3) Keersal, a cr>-stalline substance which has been found deposited 

 in the wood. 



Tlae black catechu is prepared in the following manner : The wood 

 is cut up into pieces and allowed to boil for twelve hours ; the wood 

 is then removed and the liquid evaporated till it is of the consistency 

 of syrup, it is then poured into wooden frames resembling brick 

 moulds. After cooling, the blocks are cut into pieces weighing from 

 36 lb. to 44 lb. A ton of wood is usually reckoned to give 250 lb. to 

 300 lb. of black catechu. 



This substance is chiefly used in the tanning and dyeing industries. 



Pale catechu is prepared in a different way. In the north of India 

 the method is as follows : A concentrated decoction of the wood is 

 made and twigs are added till the cooling is complete. The twigs are 

 then withdrawn and the crystalline substance which has been deposited 

 is removed; it is then pressed into large irregular cubes. It is used in 

 medicine as an astringent and the natives eat it. 



Keersal is a crystalline substance occasionally found in the wood. 

 Dr. Dymock says that the Keersal or catechuic acid occurs in small 

 irregular fragments resembling small pieces of very pale catechu 

 mixed with shavings of reddish wood. It occurs in the forest trees of 

 Bariya and Gujerat, and is used as a remedy for coughs, for which 

 it is very efficacious. 



The three varieties Acacia Catechu ^ A. Sinidra, A. catecluioides all 

 produce it. 



These acacias occur in India, especially in Burma, Ceylon, and on 

 the West Coast of Africa. In Mysore, Bengal, and Gujerat catechu 

 is also extracted from Acacia Sitina. 



India exports on an average 10,000 tons of catechu per annum, 

 chiefly to England. The French colonies do not produce any. 



We append some figures, the averages of thirty-one analyses : — 



I00"0 



The difference between the extremes is thus large enough to justify 

 our saying that the ciuality depends on the locality where the catechu 

 is manufactured. The figures for the Indian catechu are taken from 

 twenty-six analyses of samples from different localities. 



Acacia sarmentosa (Shrub). — The bark of the fruit may be used for 

 dyeing black and for tanning. 



Acacia ruguta (Tree). — The bark is astringent, and is used in 

 dyeing and tanning. 



Acacia Sundra (Tree). — Shavings boiled in water yield a dyc^tnff 

 of a beautiful purple black- 



