Page:EB1911 - Volume 06.djvu/273

 Piedmont; also as large plates at West Chester in Pennsylvania and at other American localities. Crystals of penninite are found in serpentine at Zermatt in Switzerland and in the green schists of the Zillerthal in Tirol.

Closely allied to the chlorites is another group of micaceous minerals known as the vermiculites, which have resulted by the alteration of the micas, particularly biotite and phlogopite. The name is from the Latin vermiculor, “to breed worms,” because when heated before the blowpipe these minerals exfoliate into long worm-like threads. They have the same chemical constituents as the chlorites, but the composition is variable and indefinite, varying with that of the original mineral and the extent of its alteration. Several indistinct varieties have been named, the most important of which is jeffersonite.

CHLOROFORM (trichlor-methane), CHCl3, a valuable anaesthetic, a colourless liquid, possessing an agreeable smell and a pleasant taste. It may be prepared by the action of bleaching powder on many carbon compounds, such, for example, as ethyl alcohol and acetone (E. Soubeiran, Ann. chim. phys., 1831 [2], 48, p. 131; J.v. Liebig, Ann., 1832, I, p. 199), by heating chloral with alkalis (Liebig), CCl3CHO + NaHO = CHCl3 + NaHCO2, or by heating trichloracetic acid with ammonia (J. Dumas, Ann., 1839, 32, p. 113). In the preparation of chloroform by the action of bleaching powder on ethyl alcohol it is probable that the alcohol is first oxidized to acetaldehyde, which is subsequently chlorinated and then decomposed. Chloroform solidifies in the cold and then melts at −62° C.; it boils at 61·2° C., and has a specific gravity 1·52637 (0°/4°) (T. E. Thorpe). It is an exceedingly good solvent, especially for fats, alkaloids and iodine. It is not inflammable. The vapour of chloroform when passed through a red-hot tube yields hexachlorbenzene C6Cl6, perchlorethane C2Cl6, and some perchlorethylene C2Cl4 (W. Ramsay and S. Young, Jahresberichte, 1886, p. 628). Chromic acid converts it into phosgene (carbonyl chloride, COCl2). It reacts with sodium ethylate to form ortho-formic ester, CH(OC2H5)3, and when heated with aqueous ammonia for some hours at 200-220° C. gives carbon monoxide and ammonium formate, 2CHCl3 + 7NH3 + 3H2O = NH4·HCO2 + CO + 6NH4Cl (G. André, Jahresb., 1886, p. 627). When digested with phenols and caustic soda it forms oxyaldehydes (K. Reimer, Ber., 1876, 9, p. 423); and when heated with alcoholic potash it is converted into potassium formate, CHCl3 + 4KHO = KHCO2 + 3KCl + 2H2O. It combines with acetoacetic ester to form the aromatic compound meta-oxyuvitic acid, C6H2·CH3·OH·(COOH)2. A hydrate, of composition CHCl3·18H2O, has been described (G. Chancel, Fresenius Zeitschrift f. anal. Chemie, 1886, 25, p. 118); it forms hexagonal crystals which melt at 1·6° C.

Chloroform may be readily detected by the production of an isonitrile when it is heated with alcoholic potash and a primary amine; thus with aniline, phenyl isocyanide (recognized by its nauseating smell) is produced,

CHCl3 + C6H5NH2 + 3KHO = C6H5NC + 3KCl + 3H2O.

For the action and use of chloroform as an anaesthetic, see . Chloroform may be given internally in doses of from one to five drops. The British Pharmacopoeia contains a watery solution—the Aqua Chloroformi—which is useful in disguising the taste of nauseous drugs; a liniment which consists of equal parts of camphor liniment and chloroform, and is a useful counter-irritant; the Spiritus Chloroformi (erroneously known as “chloric ether”), which is a useful anodyne in doses of from five to forty drops; and the Tinctura Chloroformi et Morphinae Composita, which is the equivalent of a proprietary drug called chlorodyne. This tincture contains chloroform, morphine and prussic acid, and must be used with the greatest care.

Externally chloroform is an antiseptic, a local anaesthetic if allowed to evaporate, and a rubefacient, causing the vessels of the skin to dilate, if rubbed in. Its action on the stomach is practically identical with that of (q.v.), though in very much smaller doses. The uses of chloroform which fall to be mentioned here are:—as a counter-irritant; as a local anaesthetic for toothache due to caries, it being applied on a cotton-wool plug which is inserted into the carious cavity; as an antispasmodic in tetanus and hydrophobia; and as the best and most immediate and effective antidote in cases of strychnine poisoning.

 CHLOROPHYLL (from Gr. , green,  , a leaf), the green colouring matter of leaves. It is universally present in growing vegetable cells. The pigment of leaves is a complex mixture of substances; of these one is green, and to this the name, originally given in 1817 by Pelletier and Caventou, is sometimes restricted; xanthophyll (Gr. , yellow) is dark brown; carotin is copper-coloured. Chlorophyll is related chemically to the proteids; a decomposition product, phylloporphyrin, being very closely related to haematoporphyrin, which is a decomposition product of haemoglobin, the red colouring matter of the blood. Chlorophyll is neutral in reaction, insoluble in water, but soluble in alcohol, ether, &c., the solutions exhibiting a green colour and a vivid red fluorescence. Magnesium is a necessary constituent. (See S. B. Schryver, Science Progress, 1909, 3, p. 425.)

 CHLOROSIS (Gr. , pale green), the botanical term for loss of colour in a plant-organ, a sign of disease; also in medicine, a form of anaemia (see : Pathology).

 CHLORPICRIN (Nitrochloroform), C·NO2·Cl3, the product of the distillation of many nitro compounds (picric acid, nitromethane, &c.) with bleaching powder; it can also be prepared by the action of concentrated nitric acid on chloral or chloroform. A. W. von Hofmann (Annalen, 1866, 139, p. 111) mixed 10 parts of bleaching powder into a paste with cold water and added a solution (saturated at 30° C.) of 1 part of picric acid. A violent reaction is set up and the chlorpicrin distils over, generally without the necessity for any external heating. It is a colourless liquid of boiling-point 112° C., and of specific gravity 1·692. It is almost insoluble in water, but is readily soluble in alcohol; it has a sharp smell, and its vapour affects the eyes very powerfully. Iron filings and acetic acid reduce it to trimethylamine, whilst alcoholic ammonia converts it into guanidine, HN:C(NH2)2, and sodium ethylate into ortho-carbonic ester, C(OC2H5)4. The corresponding brompicrin is also known.

 CHMIELNICKI, BOGDAN (c. 1593–1657), hetman of the Cossacks, son of Michael Chmielnicki, was born at Subatow, near Chigirin in the Ukraine, an estate given to the elder Chmielnicki for his lifelong services to the Polish crown. Bogdan, after learning to read and write, a rare accomplishment in those days, entered the Cossack ranks, was dangerously wounded and taken prisoner in his first battle against the Turks, and found leisure during his two years’ captivity at Constantinople to acquire the rudiments of Turkish and French. On returning to the Ukraine he settled down quietly on his paternal estate, and in all probability history would never have known his name if the intolerable persecution of a neighbouring Polish squire, who stole his hayricks and flogged his infant son to death, had not converted the thrifty and acquisitive Cossack husbandman into one of the most striking and sinister figures of modern times. Failing to get redress nearer home, he determined to seek for justice at Warsaw, whither he had been summoned with other Cossack delegates to assist Wladislaus IV. in his long-projected war against the Turks. The king, perceiving him to be a man of some education and intelligence, appointed him pisarz or secretary of the registered Cossacks, and he subsequently served under Koniecpolski in the Ukraine campaign of 1646. His hopes of distinction were, however, cut short by a decree of the Polish diet, which, in order to vex the king, refused to sanction the continuance of the war. Chmielnicki, now doubly hateful to the Poles as being both a royalist and a Cossack, was again maltreated and chicaned, and only escaped from gaol by bribing his gaolers. Thirsting for vengeance, he fled to the Cossack settlements on the Lower Dnieper and thence sent messages to the khan of the Crimea, urging a simultaneous invasion of Poland by the Tatars and the Cossacks (1647).

On the 11th of April 1648, at an assembly of the Zaporozhians (see : History), he openly declared his intention of proceeding against the Poles, and was elected ataman by acclamation.