(Synonym: Croton-chloral hydrate, wrongly so called.)

Characters. - It forms white pearly crystalline scales, with a pungent smell, and acrid, disagreeable taste.

Solubility. - It is sparingly soluble in water (1 in 100), but is readily soluble in glycerine (1 in 4).

Preparation. - By acting on cold dry aldehyd at 14° F., with chlorine, separating the butyl-chloral by fractional distillation, and converting it into solid hydrous butyl-chloral by the addition of water.

Dose. - To lessen pain, 1 1/2-5 gr. (0.1-0.3 gm.); as hypnotic, 5-15 gr. (0.3-1.0 gm.).

Action. - It acts much like chloral, though less powerfully, and has a less depressing effect on the heart, and is much less poisonous than chloral. It is said by Liebreich to affect the fifth nerve especially, and cause anaesthesia in the parts supplied by it before general anaesthesia is produced.

Uses. - It has been used especially in facial neuralgia and migraine and paroxysmal toothache. It has been used also as a hypnotic instead of chloral in cases of weak heart.

Administration. - The disagreeable taste is best covered by syrup of tolu, and it may be suspended in almond mixture or mucilage.

Bromal Hydrate. C2Br3OH. Not officinal.

Characters. - An oily colourless substance, with a strong smell and burning taste.

Preparation. - It is prepared in the same way as chloral hydrate, bromine vapour being employed in place of chlorine.

Action. - It irritates the eyes and produces running at the nose. It has a narcotic action like chloral, but causes more excitement and less profound sleep. It has a more powerful paralysing action on the heart, and is poisonous in smaller doses than chloral. It generally causes salivation, and profuse secretion from the bronchial mucous membrane accompanied by congestion. In toxic doses it produces cyanosis, dyspnoea, and death with convulsions, which are probably due, in great measure at least, to clogging of the respiratory passages.

Use. - It is said to have been of use in epilepsy.

Bichloride of Methylene. CH2C12. Not officinal.

Characters. - A colourless volatile liquid, with a smell like chloroform. Sp. gr. 1.344. Boiling point, 40° C (104° F.).

Preparation. - By acting on chloroform with nascent hydrogen, CHC13 + H2 = CH2C12 + HC1.

Action. - Like that of chloroform but more rapid, though a larger quantity is required. It is said to depress the action of the heart more than chloroform, but it has been found a very satisfactory anaesthetic in ovariotomy.

It is very doubtful whether the substance sold as bichloride of methylene is anything but a mixture of chloroform and alco-hol, as the pure substance is expensive.

Chloroformum, B.P.; Chloroformum Venale, U.S.P. Chloroform. CHC13; 119.2.

Characters. - A limpid colourless liquid, of an agreeable ethereal odour, and sweet taste. Specific gravity 1.497.

Solubility. - Dissolves in alcohol and ether in all proportions; and in water to the extent of 1 volume in 200, communicating to it a sweetish taste.

Reactions. - It is not coloured by agitation with sulphuric acid, leaves no residue and no unpleasant odour after evaporation.

Preparation. - By distilling alcohol with chlorinated lime and slaked lime, washing the distillate with sulphuric acid, and redistilling from slaked lime and calcium chloride.

In this process the alcohol probably first becomes reduced to aldehyd. From the aldehyd, chloral is formed, and this is broken up by the caustic lime into formate of calcium and chloroform.

Aldehyd.

Chloral.

C2H4O +

3C12 = C2HC13O

+ 3HC1.

Formate of Calcium.

Chloroform.

2C2HC13O

+ Ca(HO)2 =

Ca(CO.OH)2 +

2CHC13.

Or, disregarding the intermediate steps, the reaction may be represented thus: -

Alcohol.

Calcium hypochlorite.

4C2H6O

+ 8CaCl2O2 =

2CHC13 + 3Ca(CO.OH)2 + 5CaCl2 + 8H2O.

Impurities. - Hydrochloric acid, chlorine, hydrocarbons, alcohol. Tests. - The same as those of purified chloroform.

Dose. - 3 to 10 min.

U.S.P. Chloroformum Purificatum. Purified Chloroform. CHC13; 119.2.

Preparation. - By mixing chloroform (200) with sulphuric acid (60) and allowing them to stand, with occasional shaking, for twenty-four hours; then separating the lighter liquid and adding to it carbonate of sodium (10) previously dissolved in water (20). The mixture is then agitated thoroughly for half an hour and set aside. The chloroform is then separated from the supernatant layer, mixed with alcohol (2), transferred to a dry retort, and lime (1) is added, and the liquid distilled, taking care that the temperature does not rise above 67.2° C. (153° F.), into a well-cooled receiver, until the residue in the retort is reduced to 2 parts.

Tests. - If 5 c.c. of purified chloroform be thoroughly agitated with 10 c.c. of distilled water, the latter when separated should not affect blue litmus-paper (absence of acids), nor test-solution of nitrate of silver (chloride), nor test-solution of iodide of potassium (free chlorine). If a portion be digested warm with a solution of potassa, the latter should not become dark-coloured (absence of aldehyd). On shaking 10 c.c. of the chloroform with 5 c.c. of sulphuric acid, in a glass-stoppered bottle, and allowing them to remain in contact for twenty-four hours, no colour should be imparted to either liquid. If a few c.c. be permitted to evaporate from blotting-paper, no foreign odour should be perceptible after the odour of chloroform ceases to be recognised.

Preparations

B.P.

Dose.

Aqua Chloroformi.........................................................1 volume in

200...1/2-2 fl. oz.

Linimentura Chloroformi (vide p. 516) ...................1 ,,

2.

Spiritus Chloroformi..................................................... 1 ,,

20...20-60 min.

Tinctura Chloroformi Composita.................................1 ,,

10...20-60 min.

„ „ et Morphinae.....................1 „

8...5-10 min.

U.S.P.

Linimentum Chloroformi (vide p. 517)...............................................

40 per cent.

Mistura Chloroformi...........................................................................

8 ,, ,,

Spiritus Chloroformi..........................................................................

10 „ „

U.S.P. Mistura Chloroformi. Chloroform Mixture. Purified chloroform 8, camphor 2, fresh yolk of egg 10, water 80.

Dose. - 1 to 2 tablespoonfuls.