THE COCHINEAL INSECT. (Coccus cacti.)
The Cochineal Insect is of the same genus as the scale insect on the vine, which looks like a little bit of wool attached to the branch, but which, when pressed, stains the fingers with a red liquid. The Cochineal Insect in the like manner affixes itself to the leafy stems of the nopal-tree, a kind of opuntia, or prickly-pear, common in Mexico and South America, whence the Cochineal used in Europe is principally imported.
When the Mexicans have gathered the Cochineal Insects, they put them into holes in the ground, where they kill them with boiling water, and afterwards dry them in the sun; or they kill them by putting them into an oven, or laying them upon hot plates. From the various methods of killing them arise the different colours in which they appear when brought to us. While they are living, they seem to be sprinkled over with a white powder, which they lose when the boiling water is poured upon them, but preserve when killed in an oven. Those dried upon hot plates are the best.
The quantity of Cochineal annually exported from Mexico and South America is said to be worth more than five hundred thousand pounds sterling—a vast sum to arise from so minute an insect; and the present annual consumption of Cochineal in England has been estimated at about one hundred and fifty thousand pounds weight. The Mexicans think so highly of their trade in this insect, that the republic has adopted the nopal-tree as part of its arms.
It is for dyeing scarlet that Cochineal is chiefly in demand; but, although a peculiarly brilliant dye is now obtained from it, this substance gave only a dull crimson colour until a chemist of the name of Kuster, who lived at Bow, near London, about the middle of the seventeenth century, discovered the art of preparing it with a solution of tin. Cochineal, if kept in a dry place, may be preserved without injury for a great length of time. An instance has been mentioned of some of this dye, one hundred and thirty years old, having been found to produce the same effect as though it had been perfectly fresh.
