Mangrove Tannin. 



By Prof. Henry Trimble, Ph.M. 



(WITH PLATE VII.) 



[The following interesting paper by Professor Henry Trimble on Man- 

 grove Bark needs no word of introduction from anyone. It may, however, 

 not be out of place to call attention to the illustration of a mangrove thicket 

 near Port Morant, Jamaica, and to add that, if the extraction of tannin 

 from mangrove bark can be made a commercial success, the new 

 industry so created must react most favorably upon our hemlock forests. 

 For the hemlock trees, there are so many uses, that it seems unwise to 

 cut them down, as has often been done solely to obtain the bark. This 

 is especially so, when one remembers that our supply is by no means inex- 

 haustible, and that the rate of reproduction is extremely slow. The man- 

 grove (Rhizophora Mangle, L.) is a common inhabitant of tropical sea- 

 boards around the world, and save for the possible tannin producing ca- 

 pacity of its bark gives promise of no great commercial value to us.] 



J. T. Rothrock. 



AA ANGROVE bark from Rhizophora Mangle, L. has 

 / \ been frequently mentioned as a possibility in the 

 i V tannin industry. Probably the first reference to it 

 was made by Dr. James Howison * in 1804, when he received a 

 gold medal from the Society of Arts, for his description, and a 

 sample of the extract made in India from 400 pounds of the 

 bark. The method of preparing this extract, however, was 

 not such as to give the largest yield or the most satisfactory 

 product, since the extraction was carried on without the aid 

 of heat, and the resulting liquor was evaporated by exposure 

 to the sun until quite concentrated, when it was finished by 

 the application of heat. There must have been considerable 

 deterioration of the product by fermentation. This sample 

 of fifty-four pounds cost eight shillings in Bengal, and the 



1 " Preparation of Tan made in the East Indies from the Bark of the Mangrove Tree." 

 Transactions of the Society of Arts, 22, 201. 



