CHLOROFORM. A most valuable agent to the physician in producing tem porary insensibility to pain : and a still more useful aid in the arts, where it has taken its place as a solvent for many resins, &c. It is obtained by distilling alcohol, woodspirit, or acetone with a so lution of chloride of lime. One part of hydrate of lime is suspended in four parts of cold water, and chlorine passed through the mixture until nearly the whole lime is dissolved. A little more hydrate is then added to restore the al kaline reaction, the clear liquid mixed with one part of alcohol or woodspirit, and, after an interval of 24 hours, cau tiously distilled in a very spacious vessel.
A watery liquid containing a little spirit, and a heavy oil collect in the receiver ; the latter, in which is the chloroform, is agitated with water, digested with chlo ride of calcium, and rectified in a water bath. It is a thin, colorless liquid of agreeable ethereal odor, much resembling that of Dutch-liquid, and sweetish taste. Its density is and it boils at 141°; the density of its vapor is 4.116. Chloro form is with difficulty kindled, and burns with a greenish flame. It is nearly in soluble in water, and is not affected by concentrated sulphuric acid. Alcoholic
solution of potash quickly decomposes it with production of chloride of potassium and formiate of potash.
ChloroforM contains H • it is changed to formic acid by the substitu tion of three eq. of oxygen for the three eq. of chlorine removed by the alkaline metal.
It is difficult to obtain pure chloro form. Gregory directs it to be agitated with oil of vitriol and filtered subse quently through oxide of manganese : it will then be free from impurity and keep better.
Chloroform has already been applied to many uses ; it is a valuable test for iodine and other bodies in the hand of the chemist : gutta percha dissolved in it, constitutes the collodion or artificial skin used by the surgeon in dressing abraded surfaces. It dissolves bro mine and the essential oils, gun cotton, caoutehouc, copal and gum lac ; and if produced sufficiently cheap, would be a valuable substance in the manufacture of varnishes. The credit of first using sub stances for producing insensibility, of which ether and chloroform are the chief, belong to this country—having been first applied by Dr. Jackson of Boston, and Mr. Morton.