63 
NON-ASTRINGENT ARABIN GUMS. 
380. White Cedar. 
. -mucilage of commercial arabic gum. It differs from the arabin of this 
Hein coagulated from a dilute solution on addition of ferric 
Chi 
KOH. 
Lead acetate does not make any precipitate, but alcohol throws 
the arabin down without addition of acid or alkali, and the precipitate 
_ redissolved in aleohol by a very small quantity of HCl.. Borax does 
ot gelatinise the watery gum solution, but silicate of soda gelatinises 
by degrees, : 
The gum of the white cedar is a very good substitute for arabic 
| ANALYSIs— 
cs ny ee 
Arabin oI aay el Pe + wei’ 
100°0 
__, Cedrela Toona, Roxb. The gum of the red cedar contains arabin 
| = metarabin in variable quantities. The specimen examined by 
ie. Maiden contained 68 per cent. of arabin and 6 per cent. of 
metarabin, J always found a much higher amount of metarabin. 
The arabin is gelatinised only slowly and imperfectly by ferric 
rd ay and borax. It is precipitated out of its watery solution by 
ry 4 greenish-yellow colour, a reaction which is very character- 
‘ oy Or 
mor 
pe not produce any colouration in a watery solution of 
ia , metarabin gets dissolved in water on prolonged - boiling. 
he tee the dissolved gum and acquires a greenish-yellow 
Cy . e * 
a . 
ustic potash solution dissolves only a small fet of it, and on 
y dis 
“tin metarabin is stained brown but it gets 0 solved after 
oC; 
‘eS ANALYsts— 
se bin é 45°0 
- M B ene ove Sax Pre rom 2 36° 
oS ae se ee 
100°0 
siitdersa maculosa, Li .d-tree), and 
7 . , Lindl. (Leopardwood or Spotte : 
Suppl, Fiana, B. vy. M. iciseeeey See Syn. Ql. Fi. 1st 
“Gs for bot. description. The gum of the a 
ed M Macs (1890). Tt gives a colourless, 
aj geacting solution with water, in which a i - 
i tates arte Chloride only if the solution is very thick. A - 0 
coh’, the ‘arabin without any addition, and this precipitate 1s 
in aleohol on addition of a small quantity of HCl. Borax 
