Collyrium, Unct′uous. See Ointments (Eye).
COL′OCYNTH (sĭnth). Syn. Colocynth pulp., Colocynthidis pulpa, B. P. Bit′ter ap′ple, Bitter gourd, Bitter cu′cumber, Peeled colocynth; Coloquint′ida, Colocynth′is (B. P.), L. The decorticated fruit or pulp of the Citrellus Colocynthis (Schrad.—Ph. L.), or Cucumis Colocynthis (Linn.—Ph. E. & D.). It is an acrid, drastic purge and hydragogue, and cannot be given alone with safety; but, in combination with other substances, it forms some of our most useful cathartic medicines.
COLOCYNTH′IN. Syn. Colocynth′ium, L. The bitter, purgative principle of colocynth.
COL′OPHENE. Formed by distilling oil of turpentine with concentrated sulphuric acid. A colourless, viscid, oily liquid; with a high boiling-point; and exhibiting a bluish tint by reflected light.
COL′OPHONY. See Resin.
COLORADO BEETLE. Syn. Doryphera decemlineata. The Colorado potato beetle belongs to the family Chrysomelidæ, and is a native of the eastern slopes of the Rocky Mountains. It measures nearly half an inch in length, and has a tawny or yellowish cream-coloured body, darkly spotted; with wing cases which are marked with ten black longitudinal stripes. It has been gradually migrating eastward toward the more cultivated lands of the Northern states, until it has reached the Atlantic coast. It is now found over all the central and northern parts of the United States east of the Rocky Mountains, as well as throughout Canada, on the potato crops of all of which regions it has committed incalculable ravages. The leaves and stalks are the parts of the potato plant principally attacked; the depredators being, for the most part, the larvæ, of which three broods are said to be produced annually.
In America, we believe, the only means of destroying these insects as well as their eggs and larvæ consists in the application to the plant of the highly poisonous and dangerous pigment, Scheele’s green, a hydrated arsenite of copper. M. Girard recommends in preference to the arsenical salt a liberal use of sulpho-carbonate of potash.
COLOUR BLINDNESS. Syn. Dal′tonism. A curious defect of vision, from which the eye is incapable of distinguishing colours. It is of three kinds:—1. An inability to distinguish any colour properly so called, the person being only able to distinguish white and black, light and shade. 2. An inability to distinguish between the primary colours, red, blue, and yellow, or between these and the secondary or tertiary hues, such as green, purple, orange, and brown. 3. An inability to distinguish nicer shades and hues, as greys and neutral tints. The first form is rare; the second and third are common. Dr George Wilson found that of 1154 persons examined by him in Edinburgh, 65, or 1 in 177, were colour blind; of these, 21 confounded red with green, 19 brown with green, and 25 blue with green.
COL′OURING. Syn. Brandy colouring, Brewer’s c., Spirit c. Car′amel; Essen′tia bi′na, L. Prep. Brown sugar is melted in an iron vessel over the fire until it grows black and bitter, stirring it well all the time, after which water is added, and it is boiled to a syrup. In the making of brandy colouring white sugar is more frequently used.
Obs. Some persons use lime-water to dissolve the burnt sugar. Care must be taken not to overburn it, as a greater quantity is