Page:The American Cyclopædia (1879) Volume IV.djvu/805

 OOCLES COCOA 789 considerable rapidity into their holes. Eat- ables which they cannot devour are often ren- dered unfit for use by the disagreeable smell communicated to them by their excrements. Cockroach. 1. Male. 2. Female. In old houses they swarm in great numbers, and the usual way to get rid of them is by poison. A mixture of red lead, Indian meal, and molasses, in a thick batter, placed at night near their haunts, will be eagerly eaten, and will soon exterminate them. Another more dangerous preparation is a mixture of a tea- spoonful of powdered arsenic with a table- spoonful of mashed potato, which may be crumbled about the hearth at bedtime; this requires great caution in its use. Phosphorus mixed in a paste will kill them, and they are often driven away by borax, to which they have a great antipathy. The females lay one or two oval capsular bodies about as thick as one half their body, each containing 16 eggs. The cockroach is terrestrial in all its states, and equally omnivorous and voracious in all. COCLES, Horatius, a hero of the old Roman lays, who defended the Sublician bridge, in conjunction with Spurius Lartius and Titus Herminius, against the whole Etruscan army under Porsena, while the retreating Eomans broke down the bridge behind them. When the work of destruction was nearly accom- plished, Horatius sent back his two comrades, and as soon as the bridge was altogether de- stroyed, he himself plunged into the Tiber and swam across to the city in safety, amid showers of arrows from the enemy. Rome raised a statue to his honor in the comitium, and granted him as much land as he could plough around in one day. COCOA, a preparation of the seeds of the tree called by Linnaeus tJieobroma cacao. (See CAOAO.) Several varieties of the tree have been since described, which produce beans, or seeds, varying somewhat in their size and pro- perties. Their use is for the manufacture of chocolate. The article was unknown in Eu- rope till it was introduced from Mexico in 1520 by the Spaniards ; with them its prepara- tion was long afterward kept secret. The seeds are prepared for use by roasting in the same way as coffee is roasted. When the aroma is well developed, the beans are turned out into shallow wooden vessels and stirred till cool. Those which have been fermented now lose the shells readily, and split open into several lobes like split beans. The shells, amounting to about 12 per cent, of the whole weight, are separated by winnowing, and form an inferior quality of cocoa known as shells. The split seeds thus prepared may be used for food by long boiling ; but for making chocolate they are ground, and mixed with other sub- stances. (See CHOCOLATE.) Their average com- position, according to Johnston, is nearly as follows : water, 5 per cent. ; starch, gum, &c., 22 ; gluten, &c., 20 ; oil, 51 ; theobromine, 2. The theobromine is a white, crystallizable sub- stance, similar to the theine in tea, but con- tains more nitrogen. The other constituents, as starch, gum, gluten, and the large propor- tion of fat, give to cocoa the variety of nutri- tive qualities possessed by milk, and like this it contains every ingredient necessary to the growth and sustenance of the body. A volatile aromatic oil and a bitter and an astringent principle are present, which affect the taste and qualities of the cocoa, though they are not detected in the analyses. The former is de- veloped in the roasting, and is the cause of the aroma which is then exhaled. The fatty oil, called cocoa butter, resembles tallow in white- ness and consistence ; it melts at 122 F., and in this condition may be separated by express- ing it from the other ingredients. It has a mild and agreeable flavor, and is not apt to turn rancid. Neither tea nor coffee possesses the nutritive oily matter of cocoa, and of the gluten which is contained so largely in tea a considerable proportion remains in the leaves when the infusion is prepared. The shells contain but little theobromine and fat, a small portion of mucilage, no starch, but much vege- table tissue or lignine. Their infusion in boil- ing water is much used as a substitute for tea and coffee. Its taste is somewhat like that of chocolate, but weaker. The irregular-shaped, angular pieces into which the seeds separate by pressure after the shell is removed, are called nibs ; they are the purest form in which cocoa can be purchased, being the kernel de- prived of its husk and unadulterated. Then- structure, exposed by the microscope, is seen to be that of minute rounded cells, which are filled with starch corpuscles and fatty matter. The fragments of the cells and the starch cor- puscles may still be detected in the finely ground powder of the cocoa prepared for chocolate; and in this way the presence of undue proportions of the shells is exposed, as also of the numerous other matters used as adulterants. Cocoa should properly be the pure paste prepared by grinding the nibs be- tween heated stones, and rolling into a flaky mass the oily product which flows out. This, when moulded and cooled, is called flake or rock cocoa; but the name of cocoa is often applied to compositions of the pure article with