Trimble. — Mangrove Tannin. 51 



author thought it could be prepared for ten shillings per hun- 

 dred weight. 



More recently, in 1846, we find a description of mangrove 

 by W. Hamilton, 1 in which he gives an interesting account of 

 its manner of growth and possible uses. 



It appears, however, not to have come into use, except in 

 the localities where it grows. The probable reasons for this 

 are (1) the fact that almost all parts of the world are able to 

 supply tanning material for home consumption, and (2) that 

 the mangrove produces a leather of a bad color and a spongy 

 texture. It is, therefore, of interest chiefly as a possibility, 

 for, in the event of its being needed, the color, and spongy 

 character which it imparts, could, no doubt, be corrected. It 

 has been thought that an investigation of the constituents of 

 the bark as well as a study of its peculiar tannin might be of 

 interest. For, if not for immediate use, it would, by giving 

 us a knowledge of the individual tannin, increase our infor- 

 mation on the whole class of tannins, of which we at present 

 know so little. 



The material for this investigation was supplied to me by 

 Professor J. T. Rothrock, who collected it during his southern 

 scientific expedition in the winter of 1890-91. 



The bark, after powdering, was found to contain 12.04 P er 

 cent, of moisture, and 6.10 per cent, of ash. Sodium salts 

 predominated in the ash, chiefly as the chloride. 



Only insignificant amounts of fat, wax, and compounds of 

 that nature were found. 



Stronger ether removed 0.40 per cent, of a substance insol- 

 uble in water, but which caused a green color with ferric chlo- 

 ride. Gallic acid was proved to be absent. 



Absolute alcohol extracted 20.32 per cent, of a very astrin- 

 gent substance with a narcotic odor. Of this an amount equal 

 to 13.42 per cent, of the bark was soluble in cold water, and 

 the remainder was almost completely soluble in hot water. 

 The alcoholic extract was found to consist largely of tannin, 

 red coloring matter, and a small quantity of glucose. 



1 " On the medical and economic properties of the Rhizophora Mangle, or Mangrove 

 Tree." 



Pharmaceutical Journal and Transactions, 6, n. 



