This section is from the "A Complete Dictionary of Dry Goods" book, by George S. Cole. Also available from Amazon: A complete dictionary of dry goods and history of silk, cotton, linen, wool and other fibrous substances,: Including a full explanation of the modern processes ... together with various useful tables.
Cochineal (Kotch'-I-Neal). A dyestuff consisting of the dried bodies of a species of insects. It colors a brilliant crimson, which can be changed by acids to an orange-red, and by alkalis to violet; a beautiful scarlet dye is also prepared from it. The cochineal insect is extensively cultivated in the tropical countries of America, in Algeria, Java and the Canary Islands, especially the island of Teneriffe, from whence about five million pounds are exported annually. The female only are valuable for their color, and are collected twice a year. They are killed by baking them in rude ovens or immersing them in boiling water. The cochineal is a fat, dark, spherical little body, looking like a black currant, and with neither head, legs, nor tad to the casual observer. In fact, he is so inanimate that one may crush him between finger and thumb without any qualm of conscience. He is nothing but a black currant sure enough and the ancient Greeks held the idea that they were a sort of berry, though the bright carmine from his body which serves him for blood and the dyer for dye, is a better color than the juice of the currant. A cochineal plantation has a singular aspect. The larva;, like that of the silk-worm, being very delicate have to be tied upon cactus plants, which is to be their nursery and their nourishment at the same time. Thus may be seen hundreds of the shoots of the cactus all bandaged with white linen, as if they had the toothache. In this way the insects are kept warm and dry during the winter, and induced to adhere to the plant itself. When they are full grown, they are ruthlessly swept away from their prickly quarters, baked or boiled to death and dried in the sun. The shriveled anatomies are then packed in bags, and sold for about $25 per hundredweight.