Page:Collier's New Encyclopedia v. 02.djvu/546

CHLORAL tice were wonderfully different. Chivalry declined and fell with the feudal system, of which it was a normal growth. The institution of the military orders, the Knights Templar, the Knights of St, John, and the Teutonic Knights, was an interesting development of mediæval chivalry.

CHLORAL (C2HCI3O or CCUCO.H=trichloraldehyde), a colorless, odorous, oily liquid, boiling at 94°. It is obtained by passing chlorine gas through absolute alcohol. With water it forms a crystalline compound called hydrate of chloral, CCl3.HC(0H)2.

CHLORAL HYDRATE, a white crystalline substance, forming a neutral aqueous solution if free from HCl. It produces sleep, but only acts as an anodyne during sleep, the pain returning as soon as the patient wakes. The habitual use of this drug is followed by profound melancholy and enfeeblement of will, and muscular lassitude and suicidal insanity. It was discovered by Dr. 0. Liebreich.

CHLORINE, a monatomic element; symbol CI; at. wt. 35.5. Discovered by Scheele in 1774. It was thought by Berthollet to contain oxygen, and was called by him oxymuriatic acid. It was found to be an element by Davy in 1810. Chlorine is a yellow-green incombustible gas. It has a powerful irritating smell, and attacks violently the mucous membranes and the lungs. It is very soluble in water, acts strongly on metals, and is best collected by displacement. Sp. gr. 2.47. At the pressure of five atmospheres it is condensed into a heavy yellow liquid. It is obtained by heating common salt, sodium chloride, with sulphuric acid and black oxide of manganese. It combines with hydrogen to form hydrochloric acid, with an explosion in direct sunlight or when fire is applied to a mixture of the two gases, but slowly in diffused daylight. A solution of it in water is gradually converted in the sunlight into HCl with liberation of oxygen. A lighted candle burns in CI with a smoky flame. Phosphorus, antimony, arsenic, and turpentine take fire in chlorine. Chlorine destroys animal and vege- table matter; and forms addition and substitution compounds with organic compounds ; an aqueous solution of it has powerful bleaching properties. It is also a powerful disinfectant. It occurs in nature in the form of metallic chlorides. Three oxides of Chlorine are known, Cl2O; Cl2O3; Cl2O4. Chlorine was extensively used during the World War in connection with the manufacture of Asphyxiating Gas (q. v.).

CHLORITE, a mineral of a grass-green color, opaque, usually friable or easily pulverized, composed of little spangles, scales, prisms, or shining small grains, and consisting of silica, alumina, magnesia, and protoxide of iron. It is closely allied in character to mica and talc.

CHLOROFORM (CHCl3, trichloro-methane), is formed by the action of the sun's rays on a mixture of chlorine and marsh gas; also by the action of caustic potash on chloral or chloracetic acid, or by the action of nascent hydrogen on tetrachloride of carbon. It is prepared on a large scale by distilling water and alcohol with bleaching powder. Chloroform is a colorless, mobile, heavy, ethereal liquid. Specific gravity, 1.5. It boils at 62°; its vapor density is four times that of air; it is nearly insoluble in water, but dissolves readily in alcohol. It has a sweet taste. It dissolves caoutchouc, resins, fats, alkaloids, etc. It should not be exposed to the light, as it may decompose, hydrochloric acid and chlorine being set free.

Chloroform is used in medicine, dissolved in alcohol, under the name of chloric ether, as a stimulant. Chloroform taken internally acts as a narcotic, sedative, and antispasmodic, and is given in cases of asthma, colic, and cholera, also for neuralgia. Linimentum Chloroformi, equal parts of Chloroform and camphor liniment, is used externally to allay pain and irritation in neuralgia and itching.

The vapor of Chloroform, when inhaled for some time, produces a temporary insensibility to pain. Inhaled in small doses it produces pleasurable inebriation, followed by drowsiness; in larger doses it causes loss of voluntary motion, suspension of mental faculties, with slight contraction of the muscles and rigidity of the limbs; then if the inhalation is continued a complete relaxation of the voluntary muscles takes place, but if carried too far it causes dangerous symptoms of apncea or of syncope, and the patient must be restored by artificial respiration. Chloroform should not be administered to persons suffering from cerebral disease or organic cardiac affection. Dr. Simpson, of Edinburgh, in 1847, began to employ the vapor as a means of producing anaesthesia or insensibility, partial or complete,

CHLOROSIS, one of the most formidable diseases to which plants are liable, and often admitting of no remedy. It consists of a pallid condition of the plant, in which the tissues are weak and unable to contend against severe