436 
REPORT OF CHEMICAL LABORATORY 
Gum of Acacia 
arabica 
Kuk gum from 
. IraciavefUi^ea 
“ Natural exudation ” 
From tapped trees 
Laboratory number 
944 
943 
Moisture, per cent. 
10-6 
9-30 
Acidity (ecpiivalent to milligrams KHO) 
3-37 
•2-89 
Ash, per cent. 
3'.35 
3-in 
Viscosity of j Degrees of retard.atiou . . 
■2U per cent. 
solution [ Mugar equivalent, grammes per lOd c.c. of solution ... 
44 
39 
G4 
G3'l 
Taste .■ . 
Bitter 
No marked taste 
Colour and behaviour of *20 per cent, solution ... 
Very dark, becoming 
darker on standing, 
and depositing a 
dark coloured ppt. 
Amber. Darkens 
only very slightly on 
exjiosure. 
OF ACACIA ARABICA 
The (.-I. rern, Willd), known in the Sudan as “sunt,” was the original 
source of true gum arabic. It exists in fair amount, hut is employed rather as a timber and 
as firewood. The native method of tapping the tree differs from that einjiloyed in the 
case of vl. verek. It consists in chopping out a section, say two or three inches in 
diameter, of the hark and bruising the tree by a number of rather heavy blows around 
the cut. Except that it is, on the whole, rather darker than hashab gum, sunt gum is 
usually of very good quality. The following may he taken as an average sample :— 
Laboratory Number 
Source 
425 
Rennar 
IMoisture, per cent_ 
11-G,5 
A.sh, per cent. 
2 -(l2 
Acidity (milligrams KHO re(]uired for 1 gramme) 
2-(l9 
Viseosity of j Degrees of retardation . . 
40-7U 
20 per cent. ^ 
solution [ Rugar ccpiivalent (grammes per 100 c.c. of solution) ... 
G-33 
The gum was completely soluble and its solution of light yellow colour and practically 
tasteless. 
Some results of examination of gums from less known sources, kindly supplied us, in 
most cases, by the Director of Woods and Forests, are given below. These results should be 
regarded as suggestive only, since a relialile judgment as to the character of the gum which 
a tree is capalsle of furnishing can probably only be formed by a consideration of results of 
examinations extending over an entire gum-producing season. Single samples may give 
results altogether misleading. 
■tCACIA VERUGEA. Schwft. Anih. — Kuk. 
A sample of this gum was found to be mainly dark in colour and in more irregular 
masses than the tears of ordinary hashab gum. 
On treatment with water the gum does not form a true solution, except in part, 
glairy, somewhat gelatinous mass separates, as sometimes occurs in the early collections 
of ordinary gum. 
