Cobalto-Ultramarine. A fine blue pigment, prepared by mixing freshly precipitated alumina, 8 parts, with phosphate or arseniate of cobalt, 1 part; drying the mixture, and then slowly heating it to redness. By daylight the colour is pure blue, but by artificial light it is violet. See Blue pigments.
COCA. Erythroxylon Coca. This plant is grown largely in Peru and Bolivia. The Bolivian coca is said to be much superior to the Peruvian. The best kind is believed to come from the province of Yungas, and the most inferior description from Peru. The consumption of Coca in Peru, Bolivia, and in some of the provinces of the Argentine Confederation
is enormous. In small doses it is supposed to act as a stimulant and to aid digestion; in large ones it is said to possess dangerous narcotic properties. The mountaineers in South America state they are enabled to reach high elevations without difficulty of respiration, and to stave off the feeling of hunger by chewing the leaves during their ascents. “Good quality coca should have its leaves unbroken, of a medium size, bright green in colour, and of an odour somewhat combining that of hay and chocolate. The taste is bitter, and when masticated, coca is said to yield easily to the teeth. Infused in hot water, it has a beautiful green colour, which, however, is much darker from inferior leaves. An infinite number of varieties are recognised between the best and the lowest quality, which has a disagreeable smell and a colour resembling roasted coffee. The leaves are also bent and broken, scarcely a whole leaf being found amongst them.”[249] The statements as to the effects of coca are conflicting, as will be seen from what follows:—Sir R. Christison, writing to the ‘British Medical Journal,’ April 29th, 1876, states he was hardly sensible of the fatigue of two mountain descents made from Ben Vorlich after chewing coca leaves. That, as a consequence of his doing so, hunger and thirst were suspended for a long time, but that eventually appetite and digestion were unaffected. He made trial during the first descent of 60 grains, and of the second, undertaken eight days after, of 90 grains of coca.
[249] ‘Pharmaceutical Journal.’
Mr Dowdeswell, in a communication to the ‘Lancet,’ May 6th, 1876, says that, contrary to the experience of Sir R. Christison, he found no decided effects produced after consuming nearly a pound of the leaves, which were taken in all forms and at all hours for nearly a month. They failed to produce the slightest excitement, not giving rise even to the feeling of buoyancy and exhilaration which is experienced from mountain air or a draught of spring water.
In the ‘Canadian Pharmaceutical Journal’ for August, 1877, there is a paper by Mr Shuttleworth, wherein results the opposite to those of the last-named gentlemen are recorded. Mr Shuttleworth states that the members of a club established at Toronto for the purpose of playing at La Crosse, a very violent and fatiguing pastime, were almost unanimous in ascribing their invariable success over their numerous adversaries to the use of coca leaves during their contests; their opponents not employing the plant. The antagonists of the club were men of stronger build and physique as well as more accustomed to out-of-door pursuits, and were besides trained players.
The same writer says that in South America care is taken to procure the leaves in as fresh a state as possible, and that many writers have ascribed the want of effect to old leaves.
The ‘British Medical Journal’ of March 10th, 1877, contains a communication from Dr T. McBean, who states that he has found the administration of coca leaves useful in typhoid fever, as well as in other febrile diseases.
CO′COA (kō′-ko). Syn. Caca′o. An alimentary substance formed of the roasted seeds of the Theobroma Cacao, a tree belonging to the natural order Byttneriaceæ. This definition is equally applicable to chocolate, but we commonly class the preparations containing sugar and flavouring substances under that head, and the unsweetened and cheap preparations under COCOA. The cocoa-seed or berry must not be confounded with the cocoa-nut, which is the fruit of a palm (Cocus nucifera). The cocoa tree is a native of Mexico, and is now more or less extensively grown throughout Central America, Brazil, Peru, Venezuela, Caraccas, Ecuador, Grenada, Demerara, Essequibo, Guayaquil, and Surinam; with some of the West India Islands, foremost among which stands Trinidad. It has also been introduced with more or less success into Africa, the Mauritius, Madagascar, Bourbon, the East Indies, Australia, and the Philippine Islands. The following is a list of the principal kinds of cocoa, in the order of their commercial value:—Caraccas, Surinam, Trinidad, Grenada, Jamaica, Dominica, Guayaquil, Venezuela, Bahia, Brazil, St. Lucia. It seems probable that some of the highest kinds of cocoa do not find their way into this country, but are consumed by the inhabitants of Spain.
Prep. The pods containing the seeds are gathered when ripe, and after having lain for a day and a night are opened, and the seeds, which are taken out by hand, are submitted to what is termed the sweating process. They are first placed on a sloping floor or in baskets, so that the chief part of the pulp in which they are enveloped may drain off, and are then shut up in a close box, and left for 24 to 48 hours, according to the season and weather, after which they are turned out in the sun to dry. Upon a nice performance of the sweating process, which may be likened to malting, the value of the cocoa greatly depends. When quite dry, the seeds are packed in barrels or bags, and are ready for shipment. The process of roasting is effected in a metal cylinder, with holes at each end, through which the vapour generated is allowed to escape. When the aroma is sufficiently developed the seeds are cooled, and then passed to a ‘kibling mill,’ which removes the husks and skins from the ‘nibs’ (see below).