124 MANGROVE SWAMPS 
Concerning the manufacture of cutch from Philippine mate- 
rials Bacon and Gana * write as follows: 
There are three large cutch factories in Borneo using tan barks from 
the same species of mangrove as those found in the Philippines. These 
factories regard the process of manufacturing cutch as a trade secret, but 
we can not believe that these so-called trade secrets are of a very formidable 
nature, as we have succeeded in preparing very good grades of cutch with- 
out any complicated processes in this laboratory. Our cutch is a dry, 
brown solid with a brilliant, almost metallic, fracture. It is easily and 
completely soluble in water and the analysis shows the following con- 


stituents: 
| In parts per 100 
| | of water-free 
5 material. 
| Constituent. | 
<=: 
| | Le 
| 
Per cent.) Per cent. 
| "Moisture®-225-= esos. =o oe Se ed he ee eee 2.6 5.7 
Maisolu Dies 2 at ae ee SS Se ee es oe Ee ee 1.9 1.3 
Seles PR ase es eas, SS As Og ee BOs ee | 98.1] = 98.7 
Non-bannin == 22-328 25S sc escn obs asda set sae ee See eet eae ease aes see 28.8 26.1 | 
Weenie soe Oe Ss eS a ee ee ee 69.3 72.6 
_ - —— = 

The following was the method used to prepare the cutch: 
The finely ground bark was leached with cold water, and this solution 
evaporated to dryness in vacuo. Hot water extracts too much of the 
coloring matter, and no more tannin than cold water. The evaporation, 
at least the latter stages, must always be made in vacuo to avoid burning 
the cutch. It is sufficiently obvious that the extraction on a large scale 
would be carried out in such a manner that strong solutions would be 
employed to leach fresh bark while weak ones would be used to extract 
the last percentages of the tannin from the partly exhausted bark. All 
the parts of the factory, except the vacuum dryers, could be built on the 
ground, and it is evident that the fuel for the boilers and for the dryers 
would cost very little, so that it would appear that if the cutch manufacture 
were taken up in connection with the lumbering or firewood industry that 
it would be exceedingly profitable. 
The chief objection to the use of cutch as a tanning material 
seems to be that it produces a reddish-brown leather which is 
somewhat harsh and thick-grained, due to the high astringency 
of the tannin; but when mixed with other materials it gives a 
very satisfactory tannage.+ 

* Bacon, R. F. and Gana, V. Q., The economic possibilities of the man- 
grove swamps of the Philippines, Philippine Journal of Science, Sec. A, 
Vol. 4 (1909), pages 206 and 207. 
+ Williams, R. R., The economic possibilities of the mangrove swamps 
of the Philippines, Philippine Journal of Science, Sec. A, Vol. 6 (1911), 
page 56. 
