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Full text of "Medical Jurisprudence And Toxicology"

-    CHEMICAL  ANALYSIS   -                                              445

(a.) The acid solution is extracted with ether and on separation of ether
and evaporation the residue will contain such substances as caffeine, acetani-
lide, phenaeetin, antipyrin, salicylic acid, veronal, picric acid, colchicine,
mercuric cyanide and narcotine.

(b)  The acid aqueous residue from the above is treated with sodium
hydroxide solution to render it strongly alkaline and is again extracted with
ether.   On separating and evaporating the extract most of the  alkaloids
except morphine, apomorphine and narceine are obtained.   H small globules
with a strong odour are visible, an attempt should be made to search for
coniine and nicotine.

(c)   Ammonium chloride  is  added to  the remaining alkaline residue
which, when extracted with ether, will yield apomorphine  and traces of

(d)  Extraction of the  ammoniacal solution with hot chloroform will
remove  morphine,  narceine,  colchicine,  caffeine,   antipyrin and  traces  of
others.10         ,

Several important modifications of the Stas-Otto process depending
upon the use of absorption and chromatographic methods and upon the use
of other solvents, such as trichloracetic acid, acetone, saturated ammonium
sulphate solution, tannin in glycerin, etc. in place of absolute alcohol have
been devised, but these discoveries are still in the experimental stage "and
need not be discussed here.

B. Dragendorffs Process as modified by Haines.  This is specially
intended for the separation of alkaloids, glucosides and vegetable principles
from each other, when the Chemical Examiner has no idea as to the type of
-vegetable poison used. It n consists in dissolving about 100 grammes of the
mixture containing the suspected material in three times its volume of 50
per cent alcohol in a distilling flask of a capacity of 500 cc. to which a reflux
condenser is attached. The solution is acidified by adding a small quantity
of acetic or tartaric acid and is digested on a water bath to a tempera-
ture not exceeding 50C. for an hour or two. The mixture is allowed to
cool and filtered. The solid material on the filter is washed thoroughly with
dilute alcohol, and the washings are added to the rest of the filtrate. The
residue is again acidulated and extracted. This process is repeated a third
time to ensure complete extraction. , The various filtrates _$nd washings are
combined in a large evaporating dish, are heated on a water bath and aye
evaporated at a moderate temperature not exceeding 60C. to the consist-
ence of a syrup, and, while it is still warm, three or four volumes of 90
per cent alcohol are added slowly while stirring it. The mixture is allowed
-to starxd in a warm place with frequent agitation for at least an hour and is
then* filtered. The insoluble residue on the filter is extracted several times
.with slightly acidulated absolute alcohol The filtrates. and washings, thus
collected, are combined, evaporated to a syrupy consistence, and the process
is repeated using absolute alcohol as an extracting fluid in order to free the
-solution of all * coagulable material. The final filtrate and washings are
evaporated to a syrupy consistence, which, when cold, is mixed with two or
three; volumes of watefv apidulated* with a few drops of sulphuric acid. The
precipitate which is formed is filtered and washed with water. The result-
juag scid filtrat^ and washings are collected, are placed in a separating funnel
aiid are shaken oiit successively with the following immiscible solvents to
i extract the undermentioned substances1 '. 

10.   Autemieth, Laboratory Mamtxd 'fdr the* Detection of Poisons and Powerful Drugs,
Transl ..to

,^ _____     ____        _____

11.   Peterson, Haines and Websters, Legal Med. and Toxicol., Vol. IIr Ed. IE, p.