There are three different qualities of extract; the first and best is white, brittle, and has an earthy appearance when rubbed between the fingers (which earthy appearance gave it the name of Terra Japonica, being supposed, at first also, to come from Japan), and is formed into very small round cakes.  This is the dearest sort, and most refined, but it is not unfrequently adulterated with sago; this kind is brought in the greatest quantity from the island of Sumatra.  The second quality is of a brownish yellow color, is formed into oblong cakes, and, when broken, has a light brown earthy appearance; it is also made into a solid cube form; it is sold in the bazars in small packets, each containing five or six.  The third quality contains more impurities than the preceding, is formed into small circular cakes, and is sold in packages of five or six in the bazar.

The method employed in preparing the extract is thus correctly related by Finlayson:—­“The leaves are collected three or four times a year; they are thrown into a large cauldron, the bottom of which is formed of iron, the upper part of bark, and boiled for five or six hours, until a strong decoction is obtained; the leaves are then withdrawn, and allowed to strain over the vessel, which is kept boiling for as many hours more, until the decoction is inspissated; it is then allowed to cool, when the catechu subsides, The water is drawn off; a soft soapy substance remains, which is cut into large masses; these are further divided by a knife into small cubes, about an inch square, or into still smaller pieces, which are laid in frames to dry.  This catechu has more of a granular, uniform appearance than that of Bengal; it is, perhaps, also less pure.”

The younger leaves of the shrub are said to produce the whitest and best gambier; the older, a brown and inferior sort.  There are other species of Nauclea indigenous to Singapore, but they do not produce any extract.

Dr. Bennett has particularised four qualities of gambier:—­

1.  Small round cakes, about the size of a small lozenge.  Color pale, purplish, yellowish, white.

2.  Cubes, in which shape it is principally imported into England, and square prisms, or oblong pieces.

3.  Circular discs, or short cylindrical pieces.

4.  Cubical amylaceous pieces, of a darker brown than the other kinds.

Gambier is one of the most powerful of the pure astringents.

The chief places of manufacture are Saik, Malacca, Singapore, and Rhio or Bintang.  Bennett, in his “Wanderings,” says there are 60,000 plantations of gambier on this island.  After that of Rhio, the next best gambier is that of Lingin.  That used by the Malays, with the leaves of betel, in the same manner as cutch in other parts of India, is the finest and whitest; the red being stronger tasted and rank, is exported to Batavia, China, and England, for the purposes of tanning and dyeing.  It is frequently adulterated with sago powder, but it may be detected by solution in water.