37 



Tanning Substances. 



ZANZIBAR 



was examined at the Imperial Institute, and the results, which were given 

 fully in the Bulletin of the Imperial Institute, 1901, Vol. ii., p. 165, showed that 

 the "Msinzi" bark of Zanzibar contained 85 '8 per cent, of tannin, and the 

 "Magomi" and "Mkomafi" barks of Pemba, 32*8 and 23 - 8 per cent, of tannin 

 respectively. These East African barks seem, on the whole, to be richer than 

 those of 



INDIA AND THE EAST INDIES. 



A series of mangrove barks and extracts prepared in India was examined 

 at the Imperial Institute in 1899, and the results are given in Technical Reports 

 and Scientific Papers, Part 1, p. 186. For the present purpose it is, perhaps, 

 sufficient to recapitulate briefly the amounts of tannin found in the various barks 

 —Rhizophora mucronata, 4 to 27"29 per cent. ; Bruguiera gymnorrhiza, 12-77 per 

 cent.; Ceriops Candolleana, 13*23 to 21 -54 percent.; Ceriops Roxburghiana, 23" 54 

 per cent. ; and Kandelia Rheedii, 11 '99 per ceut. 



CEYLON, BORNEO AND THE STRAITS. 



Some attention has also from time to time been paid to the utilisation of 

 mangrove barks in Ceylon, Borneo and the Straits Settlements, and recently a 

 considerable export trade in mangrove barks, and so-called " mangrove cutch," 

 has arisen in Sarawak and British North Borneo. In the Federated Malay States 

 considerable quantities of mangrove timber are used at present, but the bai-k seems 

 generally to be thrown away, though in the Dingdings, according to the District 

 Officer, some "Tengah bark" (Ceriops candolleana) and " bukan bark," derived 

 from a Rhizophora or Bruguiera, is vised locally, and exported for tanning purposes 

 (Agricultural Bulletin, Straits Settlements, Vol. iv., pp. 3 and 124). Barks derived 

 from a Bruguiera or Rhizophora species, and containing from 19 to 24'3 per cent, 

 of tannin, are also used locally in Indo-China (Feuille de Renseignments, 1904, 58, 

 p. 2). Perhaps the most recent addition to the countries exploiting the mangrove 

 for bark is 



QUEENSLAND. 



A short description of the conditions under which it is collected in this 

 Colony is given in the Bulletin of the Imperial Institute, 1904, Vol. ii-, p. 276, where 

 it is shown that the Queensland bark contains 39-5 per cent, of tannin. A region 

 celebrated for the extent of its mangrove swamps is 



WEST AFRICA, 



but so far no serious attempt seems to have been made to collect this product for 

 export in any of the West African Colonies. Possibly the reason of this is that 

 the oil palm (Elaeis guineensis) is so plentiful and its prodticts are in such demand 

 at remunerative prices, that there is no incentive to collect less valuable products 

 such as mangrove barks. 



Some years ago this industry was started in Senegal by a French firm, but 

 after a short time the collection of the bark was prohibited by the Government, 

 for the reason that the mangrove trees were cut down with the result that rapid 

 erosion of the foreshore took place. Recently, however, M. E- Baillaud has again 

 directed attention to this subject (Journal d Agriculture Tropicale, 1904, Vol. 

 p. 200) and has given an account of some preliminary experiments made in th e 

 collection of the bark by natives in French Guinea. 



COLLECTION AND EXPORT OP MANGROVE BARK. 



Tn German and Portuguese East Africa, where mangrove bark has, perhaps, 

 been more systematically worked than elsewhere, the mangroves were at first 



