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448                                               MEDICAL JURISPRUDENCE

1.   Petroleum ether to extract picric acid, salicylic acid, benzoic acid,
camphor, ethereal oils, capsicin, piperine and the esters of salicylic and
benzoic acids with guaiacol, naphthol and cresol.

2.   Benzene to extract caffeine, veratrine, hydrastine, piperine, cantha-
ridin, santonin, colocynthin, digitalin, absinthin, elaterin and resorcin.

3.   Chloroform to extract theobromine, colchicine, papaverine, narceine,
hydrastine, cinchonine, cinchonidine, jervine, acetanilide, picrotoxin, gelsemic
acid, helleborin, etc.

The acid solution is now shaken up with petroleum ether to remove
traces of chloroform. It is then rendered slightly alkaline by the cautious
addition of ammonia, and the following solvents are added successively to
separate the undermentioned substances : — -

1.   Petroleum ether to dissolve out volatile alkaloids and aniline, as also
strychnine, brucine, coniine, nicotine, lobeline, quinine, veratrine, pyridine,
aconitine/gelsemine, etc.

2.   Benzene   to   dissolve   out  strychnine,   brucine,   cocaine,   atropine,
hyoscyamine, hyoscine, veratrine, codeine, narcotine, thebaine, apomorphine,
physostigmine, etc.

3.   Chloroform to dissolve out berberine, cinchonine, narceine, papa-
verine, and traces of morphine.

4.   Amyl alcohol to dissolve out morphine, solanine, salicin and traces
of saponin, narceine, etc., that may have been still left in the alkaline


5.   The remaining portion of the  alkaline  solution is evaporated to
dryness with the addition of powdered glass and the residue is extracted
with chloroform, when curarine will separate out.

In order to obtain quicker and better results Webster 12 recommends the
use of a perforator instead of shaking out with the immiscible solvents. The
solvent is automatically and continuously carried through the aqueous liquid
contained in the perforator, which is of two forms — one to be used with
liquids, such as ether, which are lighter than water, and another to be
employed with liquids, such as chloroform, which are heavier than water.

General Tests for Alkaloids. — 1. Wagner's Reagent. — Iodine dissolved in
a solution of iodide of potassium gives a reddish-brown precipitate, if added
to most alkaloids.

2.   Mayer's Reagent. — Biniodide  of mercury  gives   a yellowish-white
crystalline precipitate with an acid solution of most alkaloids.   Biniodide of
mercury is prepared by adding a solution of iodide of potassium to one of
mercuric chloride, when a scarlet precipitate is f ormedy which is just dis-
•solved by a further addition of either of the two.                            '    f

3.   Sonnenschein's   Reagent— Phosphoinolybdic   acid   giyesr   a   yeUow
amorphous precipitate with most Alkaloids.

4.    Scheibler*$ Reagent — Ph<i«photpngstic acid has the same reaction
as No. 3.

5.   Pldttnte CMorick.^-A solution of platiBfe Chloride gives a brown
precipitate with alkaloids.         *

6.   Tannin, Picric Acid or Mercuric .Chloride.— :E?tch. of these, when
added to alkaloids, precipitates them,

Metallic P^^s^Ew» methods, „ viz^ wet and ctcy^ %£& emplo^eelior
extracting metalM^pois«s from orgai^TfiiSdioi^.                            V   ,

Batpk W. Webster, Legal MeA <md Toxw3©i<w, B3^ & 346.