CHLOROFORM. 
§ I95-] 
§ 195. Simple distillation of tissues or stomach contents will not 
recover all the chloroform present, for chloroform forms additive com¬ 
pounds with many substances, which are not broken up by ordinary 
distillation. One of the best methods is that of Nicloux. 1 20 c.c. 
of blood or finely divided organic matters are treated with 95 c.c. of 
alcohol and 5 c.c. of 5 per cent, alcoholic solution of tartaric acid; this 
mixture is distilled into 10 c.c. of alcohol, the end of the tube dipping 
into the alcohol; when the distillate and receiving alcohol measure 
50 c.c. ; it is transferred to a flask, and the recipient washed with 
10 c.c. of alcohol; the 60 c.c. is now mixed with 10 c.c. of 10 per 
cent, alcoholic solution of potash (chlorine free) and boiled gently for 
an hour under a reflux condenser. According to the reaction 
CHC1 3 + 4KHO = HCOOK+ 3KC1+ 2N 2 0, 
the w'hole of the chlorine is split off, and a milligramme of chlorine equals 
1-13 chloroform. The chlorine in the distillate may be conveniently 
titrated by d.n. nitrate of silver solution (after careful neutralisation), 
using potassium chromate as indicator. 
Schmiedeberg's method ?—A combustion tube of 24 to 26 cm. long, 
and 11 to 12 mm. in diameter, open at both ends, is furnished at the 
one end with a plug of asbestos, while the middle part, to within 
5-6 cm. of the other end, is filled with pieces of caustic lime, 
from the size of a lentil to that of half a pea. The lime must be 
pure, and is made by heating a carbonate which has been precipitated 
from calcic nitrate. The other end of the tube is closed by a 
cork, carrying a silver tube, 16-18 cm. long, and 4 mm. thick. The 
end containing the asbestos plug is fitted by a cork to a glass tube. 
The combustion tube thus prepared is placed in the ordinary combustion 
furnace ; the flask containing the chloroform is adapted, and the dis¬ 
tillation slowly proceeded with. It is best to add a tube, bent at right 
angles and going to the bottom of the flask, to draw air continuously 
through the apparatus. During the whole process, the tube containing 
the lime is kept at a red heat. The chloroform is decomposed, and the 
chlorine combines with the lime. The resulting calcic chloride, mixed 
with much unchanged lime, is, at the end of the operation, cooled, dis¬ 
solved in dilute nitric acid, and precipitated with silver nitrate. Any 
silver chloride is collected and weighed and calculated into chloroform. 3 
1 Compt. Rend. Soc. de Biol., 1906. 
2 Ueber die quantitative Bestimmung des Chloroforms im Blute. Inaug. Dissert., 
Dorpat, 1866. 
3 S. Vidali has made the ingenious suggestion of developing hydrogen in the 
usual way, by means of zinc and sulphuric acid, in the liquid supposed to contain 
chloroform, to ignite the hydrogen, as in Marsh’s test, when it issues from the tube, 
and then to hold in the flame a clean copper wire. Since any chloroform is burnt up 
in the hydrogen flame to hydrochloric acid, the chloride of copper immediately 
volatilises and colours the flame green. 
