33. Zea Mays, Linn.—Indian Corn; Maize.
Tribe II. Phalarideae.
History.—Frumentum Indicum Mays dictum, Casp. Bauhin, Pinax; Frumentum vel Triticum Turcirum; Turkish Corn or Wheat. The first undoubted notice of this plant occurs in the works of Tragus [De Stirpium Historia, p. 651, 1532. (Sprengel, Hist. Rei Herb. t. i. p. 320, 1807).], who died in 1554; though by some writers it is thought to be referred to both in the Bible [Genesis, ch. xli. ver. 5; Leviticus, ch. ii. ver. 13, ch. xxiii. ver. 14; Matthew, ch. xii. ver. 1, &c. See Cobbett's Treatise on Cobbett's Corn, ch. ii. 13, 1828.] and in the works of Greek and Roman authors [Both Theophrastus (Hist. Plant. lib. viii. cap. iv.) and Pliny (lib. xviii. cap. xiii.) mention a Bactrian corn of remarkably large size. Theophrastys says the grains were as large as olive stones; and Pliny states that they were as large as the ears of our corn. Fraas (Synopsis Plant. Florae Class. p. 312, 1845) suggests that the βίσμορον of Strabo (lib. xv.) may be our maize.].
Botany.—Stem 2 to 10 feet high. Leaves broad, flat, entire with a short ligula. Flowers monoecious; males terminal, racemose; females axillary, densely spiked. Stamens 3. Ovary sessile ovate. Style 1, long, capillary. Stigma ciliated. Caryopsides roundish or reniform, arranged on a large cylindrical receptacle or rachis, popularly called the cobb.—An annual plant, indigenous in tropical America, but cultivated in various parts of the world.
The ordinary colour of the ripe grains or caryopsides is yellow; but they are frequently met with white, party-coloured, red, purple, or even black.
Maize meal is sold in the shops under the name of polenta.
Composition.—Maize has been analyzed by Dr. Gorham [Quarterly Journal of Science, vol. xi. p. 206, 1821.], by Bizio [L. Gmelin, Handb. d. Chem. ii. 1340.], and more recently by Payen, whose analysis may be considered to have superseded his predecessors (see ante, p. 106).
1. Maize starch is not at present an article of commerce [The substance usually sold in the shops as Indian corn starch is potato starch.]; though a patent [Repertory of Patent Inventions, N. S. vol. xviii. p. 163, 1942.] has been taken out for its manufacture by fermentation as well as by the action of caustic and carbonated alkalies. The quantity of starch contained in dried maize is, in round numbers, about 67 per cent, (see ante, p. 106, and vol. i. p. 119).
When examined by the microscope, the particles of maize starch are seen to be more or less rounded or ovoid, with a very distinct either circular or slit hilum; but with no visible rings or laminae. Their shape is mostly somewhat irregular and knobby; some mullar shaped. Owing to their mutual compression, many of the particles are angular or polyhedric: this is especially the case with those contained in the outer or horny portion of the albumen; while those found in the interior or farinaceous portion are more rounded. Occasionally, particles are seen with a projection like a stalk. The particles of maize starch are mostly of the medium size [The following measurements of seven (including the largest and smallest) grains of maize starch were made by Mr. George Jackson:—1. 0.0010 of an English inch. 2. 0.0006. 3. 0.0005. 4. 0.0004. 5. 0.0003. 6. 0.0002. 7. 0.0001.] (.0005 to .0007 of an inch). By polarized light they show very distinct crosses.
2. Proteine matters.—The quantity of gluten and other azotized constituents in maize is smaller than in wheat. Horsford [Ann. d. Chem. u. Pharm. Bd. xlviii. 1846.] obtained 13.65 per cent. from maize meal, and 14.66 per cent. from maize grains. But Payen (see ante, p. 106,) found only 12.5 per cent. Partly in consequence of this smaller proportion of gluten, and partly from some difference in the quality of this substance [M. Guibourt (Hist. Nat. des Drog. simpl. t. ii. p. 129, 4me éd. 1849) says that the gluten of maize contains less nigrogen than that of other grasses.], maize is less adapted for making bread than wheat.
3. Fatty matters.—Of all the cereal grains, maize appears be richest in fatty matter. MM. Dumas and Payen procured 9 per cent. of yellow oil from maize [Comptes rendus, Oct. 24, 1842.]; but Liebig [Annalen der Chemie und Pharmacie, Bd. xlv. S. 126, 1843.] was able to obtain only 4.25 per cent. This oil consists, according to Fresenius, of carbon 79.68, hydrogen 11.53, and oxygen 8.79. More recently, Payen [Précis de Chim. Industrielle, p. 394, 1849.] has given 8.80 per cent. as the proportion of oil found in maize.
Effects.—Maize agrees generally with the other cereal grains in its nutritive properties (see ante, p. 107). It is remarkable for its fattening quality, and which probably depends on the larger amount of fatty matter contained in it than in other cereal grains. In those unaccustomed to its use, it is considered apt to excite or keep up a tendency to diarrhoea.
Uses.—It is exclusively employed as an article of food.