OFFICINAL GITAIACUM.
1211
g ^ Tan ^ e s -Analysis.stance sui generissUaiacim, properly sr. called) .
•fc-Xtra
Buchner's Analysis.
Ure's Analysis.
79 8
67'88
TWt ( Woody fibre ...
16-5
Hydrogen..
7 05
91
9
„q.| j Tasteless gum .
1 Extractive.
1-5
2.1
Oxygen ....
2507
100
Guaiacum .
999
Guaiacum ..
100 00
al Co V ^uaiacic Acid; Guaiacin. Is insoluble in water, but is readily dissolved bya c i(i s ° ’ ail( J is precipitated from its alcoholic solution by water, sulphuric and nitrictirii, s ’ aa A chlorine. Ether dissolves the resin, but not so readily as alcohol. Solu-cj t es i A' e caustic alkalies (potash and soda) dissolve it, funning alkaline guaia-its „w3aaiacum soaps; sapones guaiacini). The mineral acids precipitate it fromlead . lle solution. Various salts (as acetate of baryta, acetate of lime, acetate of■d|( a |j tlUrate of silver, and chloride of gold) occasion precipitates ( guaiacates ) with thedero 0 ne solution. Guaiacic acid is remarkable for the changes of colour it un-"ith h S t * le influence of various agents. Thus its powder, and paper moistenedchan™ 8 Ancture, become green in air or oxygen gas, but not in carbonic acid gas. This'" ,e ns V ' dl ' tdl seems connected with the absorption of oxygen, is influenced by the^ ar *A colour of the light. Various substances give a blue tint to guaiacumbee n ln contact with air: thus gluten, but not starch. Hence powdered guaiacum hasof t| )( ! )ro t lose A as a test of the goodness of wheaten flour (which contains gluten), andSW Punty starc h. Gum Arabic, dissolved in cold water, has the same effect as«ten, s If ut tragacanth gum has not. Milk, and various fresh roots and undergroundSess th ° r exam pie> those of the horseradish, potato, carrot, colchicum, &c.), also pos-bliie a s ,P ro Pcrty. Certain agents change the colour of guaiacum successively to green ,"A brown thus, nitric acid and chlorine. Nitric acid colours the tincture of•he (j 01 S r een, then blue, and afterwards brown. If a piece of paper moistened withc ‘ u >; e be exposed to the fumes of the acid, its colour is immediately changed toP. 2lm ‘’!. r it of nitric ether usually gives a blue colour to tincture of guaiacum (seeAitf,. re ," "It- Brande has conjectured, and I think with great probability, that these>Po„„a 0 . loure . d compounds are combinations of oxygen with guaiacum,—the greenJob|| U,| A containing the least, the brown the most, while the blue is intermediate. Mr.Go ( Proceed. of the Royal Soc. June 18, 1840) says guaiacum resin consists ofSiiai ac ^!° J its equivalent, therefore, is 343. According to Unverdorben the resin of" , hi ( .| 1 ? rn * s of two kinds: one readily soluble in a solution of ammonia,—and another°f RB .»"ns with ammonia a tarry compound. Pagenstecher has shown that tinctureC °l°Ur / acum with hydrocyanic acid and sulphate of copper produces an intense blue2. P-241).
P»rti 0 Active. This is extracted from guaiacum by the agency of water. The pro-°* it present is liable to variation. It is a brown acrid substance.
' r txi n ese observations, then, show that guaiacum is essentially a peculiarUv e ’ If j ec hanically mixed with variable but small quantities of extrac-Ai) 0 ^ °^ ler impurities.
bsed Gl ‘ TERATI0N '— 1 Various adulterations are described as being prac-tlii s 011 guaiacum. Though I have found this substance in the shops of$u S p untry of unequal degrees of impurity, I have never had reason totesip C . bat sophistication had been practised on it. The presence ofheight be suspected by the peculiar odour evolved when the sus-res in is heated. Another mode of detecting this fraud is to addi° alcoholic solution of the suspected guaiacum, and to theb»e ]; Q * u bl thus formed a solution of caustic potash is to be added until^te, ^ 0r becomes clear. If now an excess of potash cause no precipi-' v ate r ?, res in is present; for while guaiacate of potash is soluble inPletely * e salt produced by the union of potash and resin is not com-
4b
UYsi,
acrid
°logical Effects. —1. Of the Resin. Guaiacum resin isstimulant. Its acridity depends in a great measure on the ex-