Coccus (U. S. P.)—Cochineal.

Fig. 79. Coccus cacti. Preparation: Tincture of Cochineal - Cochineal color

The dried female of Coccus cacti, Linné"—(U. S. P).
Class: Insecta. Order: Hemiptera"—(U. S. P.).

Source.—The cochineal insect, Coccus cacti, belongs to the class Insecta, order Hemiptera; the general characters are: Tarsi, with one joint, terminated by a single hook. The male is destitute of a rostrum, and has two wings covering the body horizontally; the abdomen is terminated by 2 setae. The female is apterous, and furnished with a rostrum. The antennae are of 11 joints, filiform, and setaceous. The males are very small, with antennae shorter than the body, which is elongated, deep-red, and terminated by 2 long, diverging setae. The 2 wings are beautifully snow-white, large, and crossed above the abdomen. The females are nearly twice as large as the males, wingless, bluish-red, covered with a white farina, have the antennae short, and the body convex and 3 flattened below, with short feet.

History.—The Cochineal insects inhabit Mexico, and other parts of tropical America, where they feed on the Opuntia and Cactus families of plants. They are also cultivated extensively in the Canary Islands, and to some extent in the West Indies, and have been introduced into southern Spain, though their cultivation in the latter country is said to have been unprofitable. They are collected at various seasons. The best are the product of the first collection, which consists of the impregnated females; the males not being gathered. Those killed by the heat of a stove are said to be superior to those destroyed by boiling water and sun-dried.

The insects are protected during the rainy season by coverings placed over the cactus plants on which they are feeding. After pleasant weather has returned they are taken out and planted or sown on the different species of Opuntia, particularly the Opuntia cochinillifera of Miller, known to the Mexican natives as nopal. The male insect, which is very rapid in its movements, flies to the female, and, after the act of fecundation, the female attaches itself to the plant and remains stationary, rapidly enlarging from the development of an immense number of eggs within the body, and, in this distorted condition is knocked off the plant with feathers and dull knives, and either dipped into hot water and afterwards sun-dried, or killed by being placed in heated ovens. A few are left, however, to deposit their eggs, shortly after which they die. The eggs, hatching in the sun, give an innumerable supply of young insects, which at once distribute themselves over the plant, and begin feeding, In this manner 3 crops are gathered yearly from the nopal plantations. For a full and instructive account of the cultivation of cochineal in Central America, see Amer. Jour. Pharm., 1873, p. 30.

Description.—The U. S. P. thus describes cochineal: "About 5 Mm. (⅕ inch, long; of a purplish-gray or purplish-black color; somewhat oblong and angular in outline; flat or concave beneath; convex above; transversely wrinkled; easily pulverizable, yielding a dark-red powder. Odor faint; taste slightly bitterish. Cochineal contains a red coloring matter soluble in water, alcohol, or water of ammonia, slightly soluble in ether, insoluble in fixed and volatile oils. On macerating cochineal in water it swells up, but no insoluble powder should be separated. When completely incinerated, cochineal should leave not more than 5 per cent of ash"—(U. S. P.). As met in commerce, cochineal is sometimes covered with a white bloom, which, if not due to adulteration, consists of a wax-like body (see below). When properly kept it is not liable to deteriorate. There are two varieties, silver grains (silver, or Honduras cochineal) and black grains (zaccatilla cochineal). The silver cochineal, of a reddish ash-color, is said to be procured by destroying the female insect previous to laying its eggs, and is the most esteemed; the black cochineal, of nearly a black color, is obtained, by killing the female after the eggs have been laid (Amer. Jour. Pharm., Vol. XVIII, p. 47). According to other statements the silver grains are the product of oven-killed insects, or those allowed to perish by sun-heat, while the black grains are produced by immersion of the live insect in boiling water. There are also inferior grades, consisting chiefly of uncultivated young insects, called granilla (grana sylvestra). Dr. Jas. Stark, in 1855, directed attention to a commercial form, called "cake cochineal," imported from Cordova, Argentine Republic. However, it possessed only ⅙ of the coloring strength of ordinary cochineal.

Chemical Composition.—Cochineal imparts a violet-red tinge to the saliva. It was first analyzed by Pelletier and Caventou, in 1818, and according to Hager (Handbuch, 1886), was found by subsequent analyses to contain moisture (about 6 per cent), fatty matter (15 to 18 per cent), red coloring matter (40 to 45 per cent), ash (3.5 to 5 per cent), and insoluble matter (7 to 11 per cent). The red coloring matter, first investigated closely by Warren de la Rue, in 1847, has been called carminic acid, and, following the later researches of Grabowski and Hlasiwetz, was believed to be a glucosid capable of being resolved by the action of diluted sulphuric acid, into carmine-red and sugar. Von Miller and Rohde (1893), however, established the non-glucosidal character of this substance. Pure carminic acid, by treatment with boiling dilute sulphuric acid, remained on the whole unaffected, although partial decomposition took place, yielding formic acid and a strongly reducing substance of unknown composition (Amer. Jour. Pharm., 1894; from Berichte, 1893). According to Liebermann and Voswinckel (1897), carminic acid yields upon oxidation cochenillic acid (C10H8O7) and coccinic acid (C9H8O5) which are (tri- and dicarboxyl) derivatives of meta kresol (C6H4.CH3.OH). The exact structural formula of carminic acid is not exactly established.

Carminic acid (carmine-red) usually occurs as a brown-purple body, but may be obtained in large, garnet-red crystals by treating good commercial cochineal with 5 times its weight of water, filtering, agitating with 20 times its weight of glacial acetic acid, filtering again, and allowing the solution to crystallize over sulphuric acid (v. Muller and Rohde). Carminic acid is soluble in alkalies, warm water, and alcohol; not soluble in oils and fats; aluminum salts precipitate it in the form of a purple-lake. Will and Leymann obtained from 5 kilograms of the silver-gray variety of cochineal, 400 to 500 grammes of pure carmine-red. These investigators also obtained two bromine compounds (C10H4Br4O3) and C11H5Br3O4), which are mainly of theoretical interest (see Amer. Jour. Pharm., 1886, p. 91). The whitish material covering the insect was investigated by Liebermann (1885), who found it to be a peculiar wax, soluble in benzol, which he named coccerin, the constituents of which are coccerylic acid (C31H62O3), melting at about 92° C. (197.6° F.), and cocceryl alcohol (C30H62O2), melting at about 104° C. (239.2° F.). Besides, he found in cochineal myristin (1.5 to 2 per cent), and liquid fatty oil (4 to 6 per cent). Liebermann observed 1 to 2 per cent of coccerin in the silver variety, 0.5 to 1 per cent in the black variety, while from granilla (the inferior kind) he obtained 4.2 per cent (Amer. Jour. Pharm., 1886).

Adulterations.—Carmine has been adulterated largely with starch, vermilion, dichromate of lead, talcum, etc. These additions, however, may be readily detected by dissolving the cochineal coloring matter with aqua ammoniae, and examining the residue for the substances named. E. Donath, in Chem. Ztg., 1891, reports on a sample of commercial "ordinary" carmine, which consisted of lead oxide and alumina lakes of eosine, and contained much lead sulphate. Another specimen ("carmin antik") of good appearance was the barium compound of red corallin (related to rosolic acid and rosanilin), leaving, upon ignition, 75 per cent of barium carbonate (Amer. Jour. Pharm.).

Cochineal, especially in powder form, has been adulterated with French chalks, plumbago, soapstone, carbonate of lead, manganese dioxide, barium and iron salts, etc., to increase the weight, and the grains have even been imitated. The U. S. P., as stated before, fixes the upper limit of ash at 5 per cent. We, however, have found the majority of commercial specimens (both powdered and whole cochineal) to exceed this limit by far, the ash often running as high as 25 and 32 per cent. A species of Coccus (Coccus ilicis, Fabricius), feeding upon a Mediterranean oak (Quercus coccifera, Linné), has been occasionally met as an adulteration. It is known as chermes, kermes, or alkermes, and, when dried in the sun after having been treated with acetic acid, becomes colored a brown-red, and yields a carmine powder, producing with tin salt (SnCl2+2H2O) a bright scarlet-red color, similar to that derived from true coccus. They are nearly spherical and quite smooth.

Action, Medical Uses, and Dosage.—Anodyne and antispasmodic. Formerly used in whooping-cough and neuralgic affections. Also used to color tinctures and ointments, imparting a beautiful carmine hue. Webster (Dynam. Therap., p. 431) declares that coccus specifically influences the entire urinary tract and directs small doses in renal colic, copious voidings of clear, limpid urine, due to renal capillary relaxation, and in vesical tenesmus and urinal retention. He suggests that 10 to 15 drops of mother tincture be added to 4 fluid ounces of water, and a teaspoonful administered every 2 hours. Dose, from 5 to 10 grains, 3 or 4 times a day.

Specific Indications and Uses.—"Colica renalis, with dark-colored urine and pain extending down ureters to bladder" (Watkins' Comp. of Ec. Med.).

Derivative.—CARMINE (derived from cochineal) is not a definite principle, but contains a mixture of nitrogenous compounds, ash, wax, and coloring matter to the extent of as high as 60 per cent. It may be prepared by precipitating a filtered cochineal decoction with bitartrate of potassium or alum, and collecting and drying the precipitate at about 30° C. (86° F.).

RED INK.—Red ink may be made as follows: Take of cochineal in powder, 160 grains; carbonate of potassium, 320 grains; distilled water, 8 fluid ounces., mix together and boil; then add of alum, 80 grains; bitartrate of potassium, 2 ounces; let them stand for 24 hours, filter, and add ½ ounce of powdered gum Arabic.

King's American Dispensatory, 1898, was written by Harvey Wickes Felter, M.D., and John Uri Lloyd, Phr. M., Ph. D.