P. 15.—“32 deg. F.” 32 degrees on the Fahrenheit thermometer. This scale, invented in 1714, by Fahrenheit, is commonly used in England and America, although the centigrade scale (where the distance between the boiling point and zero is divided into one hundred parts) takes its place largely on the continent, and in most scientific works. P. 18.—“Amœba,” a-mœˈba. Readers who live in warm climates will have no trouble in finding the _amœba_ attached to the stems of plants or floating in pools of stagnant water. To find a specimen in December in temperate latitudes will be more difficult, but by collecting grass and stems of water plants, with water from a pool, and keeping them in a warm room for a time, specimens may be obtained. P. 22.—“Cinchona,” cin-chōˈna. The tree from which the well known drug, Peruvian bark, is obtained. “Quinine.” Kwiˈnīn is Webster’s preferred pronunciation, kwe-nīnˈ, Worcester’s. Quinine is an alkaloid obtained from the cinchona bark. P. 28.—“Nucleus.” The nucleus may be easily seen in a thin section from an apple or potato, placed under a microscope. “Mucilaginous,” mū-ci-lăgˈi-noŭs. Like mucilage. P. 29.—“Silica,” sĭlˈi-ca. Flint or quartz. P. 31.—“Tannin,” tănˈnin, or tannic acid. An astringent principle found in nut-galls and the bark of many trees. If treated with ether a solid is obtained which is soluble in water. It is used in tanning leather. “Starch.” The grains of starch are easily found. Wheat, oats, arrow-root, sage and tapioca all furnish excellent examples. “Crystals.” Răphˈi-des is the name given by botanists to the little crystals found in the tissues. A section of an onion will reveal them. Also, the juice of the hyacinth. P. 34.—“Cochineal Cactus,” cŏchˈi-nēal. The cactus from which the cochineal insects, whose bodies are sold in the shops for a red dye, are obtained. The plant is also called cochineal fig, and is raised with as great care for food for the insect, as is the mulberry tree for the silk worm. P. 35.—“Vessels.” The “dotted” vessel, or duct, is a long, open tube whose sides are marked by pores, or dots. A transverse section of a radish will furnish an example. A fern will furnish an example of “reticulated” cell; almost any common plant contains the “annular” and “spiral” cells. P. 36.—“Epidermis.” All varieties of cells will be found in the epidermis together with the mouths, or stomata. For examination a layer should be carefully removed with a razor or knife, a little water put on it to prevent too rapid drying, and the whole covered by a thin glass. P. 37.—“Volatile oil.” That which wastes away when exposed to the atmosphere; as musk.