52 Improvements in Physical Science (Jan. 
grain is always more or less contaminated. He fell upon the follow- 
ing method of separating this gluten, which succeeded perfectly : 
3 Ib. of potash are dissolved in 100 lb. of water, and the solution 
mixed with 4 Ib. of good slacked quick-lime. The mixture is fre- 
quently agitated during three hours, and then the clear liquid is 
drawn off, and kept for use in close vessels. For every pound of 
starch to be purified, a pound of this alkaline ley must be taken. 
It must be poured on the starch, and allowed to remain in contact 
with it at a moderate temperature for two or three days. It acquires 
a brown colour from the gluten, which it dissolves, and the starch 
becomes much whiter and purer. (Schweigger’s Journal, xiv. 385.) 
4. Malamlbo Bark.—This is the bark of an unknown tree in 
South America, which has been long used in medicine, and is con- 
sidered as an effectual cure of locked jaw. From the accounts of 
MM. Bonpland and Zea, there is reason to consider the plant as 
belonging to the family ef magnolia, and very probably to the genus 
wintera. A chemical examination of this bark has been published, 
both by M. Cadet, in the Journal de Pharmacie, and by M. Vau- 
quelin, in the Ann. de Chim. Its principal ingredients are three 
in number, namely, 
(1.) A volatile Oil, obtained by distilling a mixture of one part 
of bark and 19 parts of water. It has a yellow colour, and a smell 
intermediate between that of pepper and thyme. Its taste is acrid. 
It is very soluble in alcohol, and a little so in water. It is specifi- 
cally lighter than water. 
(2.) A Resin, obtained by macerating the bark in alcohol, and 
evaporating that liquid. This resin is very abundant. Its colour is 
brown. It is brittle, and has the usual resinous fracture. When 
put into the mouth, it appears at first to have no flavour, but an in- 
tensely bitter taste gradually developes itself. It is very soluble in 
alcohol, and is again precipitated by the addition of water. It is 
insoluble in alkalies. When thrown upon a hot body, it is almost 
entirely dissipated in smoke, which has the odour of frankincense. 
(3.) An Extract, which is obtained by macerating the bark in 
water. Its colour is yellowish brown. It is brittle when dry; but 
attracts moisture when exposed to the atmosphere. When properly 
washed in alcohol, it has no bitter taste. When heated in close 
vessels, it yields a brown oil, and a liquid which reddens the infu- 
sion of litmus; but from which potash disengages a sensible quan- 
tity of ammonia. The residual charcoal, when burnt, leaves a 
notable quantity of carbonate of potash, coloured green by man- 
ganese. (See Ann. de Chim. xevi. 113.) 
5. Cork.—Chevreul has published a very elaborate set of experi- 
ments on this substance, which, from its yielding suberie acid 
when treated with alcohol, is considered by chemists as consisting 
chiefly of a peculiar vegetable priaciple, to which the name of suber 
has been given. Chevreul has contrived a new apparatus for the 
analysis of vegetable bodies. It consists of a small Papin’s digester, 
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