given in table (232) is based entirely upon analyses made prior to 1890. It is probable that much of the silage at the present time contains seventy per cent or less of water. Silage at the Wisconsin Station1 in 1893 contained 64.3, and in 1894, 70.7 per cent of water. In an experimental sample the per cent of water in the maize plant when it was put into the silo was 68.9, while when taken out it was 71.2 per cent. It thus appears that the loss of dry matter in silage is greater than the loss of water. 234. Ash.-The maize grain is characterized by a comparatively low percentage of ash. The ash appears to be principally phosphates of potassium and magnesium. The ash contains approximately fifty per cent of phosphoric acid (P2OË), thirty per cent of potash (K,O), and fifteen per cent of magnesia (MgO). The extremely small amount of lime (CaO) present, about two per cent, has an important bearing upon the feeding value of maize when fed to growing pigs exclusively or only in connection with milk. Schweitzer found that the maize plant removed from an acre of land 219 pounds of ash and 135 pounds of nitrogen. One-fourth the ash and one-half the nitrogen was removed by the ear.3 2 The Massachusetts Station has found the fertilizing constittents in air-dry substance to be as follows: 235. Protein.-In the analyses of the 208 air-dry samples including all varieties, the protein (N x 6.25) was found to vary from seven to 15.3 per cent. The usual limit of variation lies between eight and twelve per cent.1 Osborne' has studied the proteids of the maize grain and has distinguished them according to their solubilities as follows: "a Proteid, soluble in pure water, having some of the properties of proteose. ' Globulins, insoluble in pure water, but soluble in salt solutions. "c Proteid, insoluble in water and salt solutions, but soluble in alcohol of 60 to 99 per cent. "d Proteid matter, insoluble in water, salt solutions and alcohol, but soluble in dilute alkalies and acids." The most important of these compounds, both on account of its quantity and because it is a characteristic of the maize grain, is the proteid soluble in dilute alcohol, called zein. No proteids are found in the maize grain which give to its meal the properties which gluten (mixture of gliadin and glutenin) gives to wheat flour. Zein in maize corresponds in some of its chemical properties to gliadin in wheat, but it is neither sticky nor plastic. 236. Carbohydrates.-The chief constituent of the carbohydrates of the maize grain is starch, which may constitute sixty-five per cent of the total dry substance. In the manufac ture of starch, fifty-five per cent of commercial starch may be obtained from the water-free grain. Besides the starch, the carbohydrates consist of two per cent of fiber, five per cent of gum (pentosans), and small quantities of sugar (sucrose and dextrine). 237. Fat.-The fat of maize is fluid at ordinary temperatures, solidifying at 36° F., and is hence known in commerce as corn oil. It is composed principally of linolin and olein and has a specific gravity of about .925.3 1 U. S. Dept. of Agr., Yearbook 1901, p. 304. 2 Conn. Rpt. 1896, p. 391. 3 Ill. Bul. 53 (1898), p. 170. X. MAIZE. CLASSIFICATION AND VARIETIES 238. Species. No wild species belonging to the genus Zea having with certainty been identified, all the knowledge we have of maize is obtained from its cultivated types, all of which have been considered as coming from one species (Zea mays L.). Apart from pod maize, there are five types or classes which are readily recognizable and when kept pure breed true to type. Although the different types cross readily, intermediate types The difference in these types is due primarily to the arrangement and character of the endosperm, although accompanied with and resulting therefrom are marked variations in the shape of the grain. (226) are not common. If a dent maize grain is split through its two longest diameters, the endosperm will appear to consist of two parts. In the central part the endosperm will appear white, while on either side it is glossy or corneous (horny). Sturtevant first pointed out the relation between the character of the endosperm and the five types of maize. The several types he has called agricultural species and proposed Latin names for them as follows: I. Pod maize (Zea tunicata). 6. Sweet maize (Zea saccharata). In this book these proposed species will be referred to as the types of maize, and variations within these types will be called varieties. 239. Pod Maize.-In this type of maize each grain is covered with a husk in addition to the ear itself being so covered. The plant is excessively leafy, the tassels usually heavy and inclined to produce grains. The plant suckers abundantly.. The grains may be of any of the types of maize hereafter described, suggesting that this was the prim itive type from which they have been derived, and also, that the differentiation into these types occurred Pod maize: one-third natural size. before the podded character became abortive. Reversion is now occasionally seen in cultivated forms. Pod maize is rarely grown even as a curiosity. 240. Pop Maize is that type in which all or almost all of the endosperm is glossy or corneous. Sometimes, perhaps usually, there is a thin layer of white or soft endosperm around the embryo. The grain is usually an elongated oval in outline and extremely hard. The only type with which it can be confused is the flint. The small size of the grain and its property of "popping" makes iden Flint maize: ear one-third natural size; grain about natural size. tification certain. When the dry grain is exposed for a short time to a high temperature, it explodes into a snow-white fluffy palatable mass, the endosperm being everted about the embryo and hull. This property of popping is connected with the density of the endosperm. A small amount of white endosperm does not unfavorably affect popping, but if the white portion is in excess, as in flint maize, the corneous portion explodes without everting the endosperm. The varieties of pop maize may be divided into two groups, rice and pearl, with the golden as a rather distinct type of the pearl. The rice pop has a very pointed grain at the top, with a tendency to have the grains imbricated instead of side by side and to have the ears cone-shaped. In the pearl pop the top of the grain is smooth and rounded; the grains are compactly arranged upon the cob and are very dense and lustrous in appearance. The ears are cylindrical. pearl variety, about natural The plant of pop maize is said to vary with variety, climate and soil from eighteen inches to twelve feet; the usual variation Pop maize: ear rice variety, being from five to seven feet. The tenone-third natural size; grain dency to bear many ears is strongly marked and the plant is much subject to sports. The ears vary from one to eight and a half inches; usually from four to six inches in length and from one to one and a half inches in diameter. Variations from eight to thirty rows are reported, with twelve to sixteen rows the most common. An ordinary weight is from three to four ounces per ear. The following table gives weight and dimensions of the grain A of four varieties of pop maize: |