15-4 POISONS : THEIR EFFECTS AND DETECTION. [§ l8o. 
is’ adapted an upright tube about 2 feet long, which may be of small 
diameter, and must be surrounded by a freezing mixture of ice and salt. 
The upper end of this tube is closed by a thistle-head funnel with syphon, 
and in the bend of the syphon a little mercury serves as a valve. Heat 
is now applied to the flask by means of a water-bath, and continued 
for several hours ; the liquid which has distilled over is then treated 
with dry calcic chloride and redistilled exactly in the same way. To 
this distillate again a similar process may be used, substituting dry 
potassic carbonate for the calcic chloride. It is only by operating on 
these principles that the expert can recover in an approximate state of 
anhydrous purity such a volatile liquid. Having thus obtained it pure, 
it may be identified (1) by its smell, (2) by its boiling-point, (3) by its 
inflammability, and (4) by its reducing chromic acid. The latter test 
may be applied to the vapour. An asbestos fibre is soaked in a mixture 
of strong sulphuric acid and potassic dichromate, and then placed in the 
tube connected with the flask—the ethereal (or alcoholic) vapour passing 
over the fibre immediately reduces the chromic acid to chromic oxide, 
with the production of a green colour. 
V.—Chloroform. 
CHLOROFORM, TRICHLOROMETHANE OR METHYL CHLORIDE 
(CHC1 3 ). 
§ 180. Chloroform appears to have been discovered independently by 
Soubeyran and Liebig, about 1830. It was first employed in medicine 
by Simpson, of Edinburgh, as an anaesthetic. Pure chloroform has a 
density of 1-491 at 17°, and boils at 60*8° ; the chloroform of the B.P. 
contains 2 per cent, alcohol and should have a specific gravity of 
1-483-1-487. It is a colourless liquid, strongly refracting light ; it 
cannot be ignited by itself, but, when mixed with alcohol, burns with 
a smoky flame edged with green. Its odour is heavy, but rather 
pleasant ; the taste is sweet and burning. 
Chloroform sinks in water, and is only slightly soluble in that fluid 
(-44 in 100 c.c.) ; it is perfectly neutral in reaction, and very volatile. 
When rubbed on the skin, it should completely evaporate, leaving no 
odour. Pure absolute chloroform gives an opaline mixture if mixed 
with from 1 to 5 volumes of alcohol, but with any quantity above 
5 volumes the mixture is clear ; it mixes in all proportions with ether. 
Chloroform coagulates albumen, and is an excellent solvent for most 
organic bases—camphor, caoutchouc, amber, opal, and all common 
resins. It dissolves phosphorus and sulphur slightly—more freely iodine 
and bromine. It floats on hydric sulphate, which only attacks it at a 
boiling heat. 
