metarabin

Therefore the 84 per cent. of soluble matter contains 58 parts of metarabin, and the total metarabin in this gum is 58 + 16 = 74 per cent, on the dry gum.

Scientific American Supplement, No. 821, September 26, 1891 Various

For, let it be conceded that the solution of any Ghatti leaving an insoluble residue is a mixture of arabin and metarabin in the same ratio as our "maximum" solution, only more diluted with water, then from the found viscosity we obtain a point on the curve for dilution, which gives the percentage of dissolved matter.

Scientific American Supplement, No. 821, September 26, 1891 Various

Therefore those gum arabics which are low in viscosity consist of nearly pure arabin, while as the viscosity increases so does the amount of metarabin, until we come to

Scientific American Supplement, No. 821, September 26, 1891 Various

Ghattis which contain more metarabin than their arabin can hold in solution, when their viscosity goes down again.

Scientific American Supplement, No. 821, September 26, 1891 Various

From observation of the general nature of the solutions of Ghatti gums, and from the fact that when allowed to stand portions of the apparently insoluble matter passed into solution, the hypothesis suggested itself that metarabin was soluble in arabin, although insoluble in cold water.

Scientific American Supplement, No. 821, September 26, 1891 Various

Besides obtaining this curve for change in viscosity from maximum amount of metarabin to no metarabin at all, we also traced the decrease in viscosity of the "maximum" solution by dilution with water.

Scientific American Supplement, No. 821, September 26, 1891 Various

But the new hypothesis, and the experiments undertaken to confirm it, showed clearly that if the viscosity of a gum solution depends on the ratio of metarabin to arabin, then there is no absolute line of demarkation between a Ghatti and a gum arabic.

Scientific American Supplement, No. 821, September 26, 1891 Various

In other words, there is a constant gradation between gum arabic and Ghattis, down to such gums as cherry gum, consisting wholly of metarabin and quite insoluble in water.

Scientific American Supplement, No. 821, September 26, 1891 Various

Moreover, the solutions yielded by various Ghattis leaving insoluble matter behind would _be all of the same kind_, viz., a saturated solution of metarabin in arabin more or less diluted by water.

Scientific American Supplement, No. 821, September 26, 1891 Various

Still further, if the insoluble residue of a Ghatti be the residual metarabin over and above that required to saturate the arabin, then it will be possible to dissolve this by the addition of more arabin in the form of ordinary gum arabic.

Scientific American Supplement, No. 821, September 26, 1891 Various