The chief value of the potato as an article of diet consists in
the starch it contains, and to a less extent in the potash and other
salts. The quantity of nitrogen in its composition is small,
and hence it should not be relied on to constitute the staple
article of diet. Letheby gives the following as the average
composition of the potato—
| Nitrogenous matters | 2.1 | Saline matter | 0.7 |
| Starch, &c. | 18.8 | Water | 75.0 |
| Sugar | 3.2 | ||
| Fat | 0.2 | 100.0 |
—a result which approximates closely to the average of nineteen analyses cited in How Crops Grow from Grouven. In some analyses, however, the starch is put as low as 13-30, and the nitrogenous matter as o-92 (Dehérain, Cours de chimie agricola, p. 159). Boussingault gives 25.2% of starch and 3% of nitrogenous matter. W arington states that the proportion of nitrogenous to non-nitrogenous matter in the digestible part of potatoes is as 1 to 10.6. The composition of the tubers evidently varies according to season, soils, manuring, the variety grown, &c., but the figures cited will give a sufficiently accurate idea of it. The “ash” contains on the average of thirty-one analyses as much as 59.8% of potash, and 19.1% of phosphoric acid, the other ingredients being in very minute proportion. Where, as in some parts of northern Germany, the potato is grown for the purpose of manufacturing spirit great attention is necessarily paid to the quantitative analysis of the starchy and saccharine matters, which are found to vary much in particular varieties, irrespective of the conditions under which they are grown.
It is to the Spaniards that we owe this valuable esculent. The Spaniards met with it in the neighbourhood of Quito, where it was cultivated by the natives. In the Cronica de Pern of Pedro Cieca (Seville, 1553), as well as in other Spanish books of about the same date, the potato is mentioned under the name “battata” or “papa.” Hieronymus Cardan, a monk, is supposed to have been the first to introduce it from Peru into Spain, from which country it passed into Italy and thence into Belgium. Carl Sprengel, cited by Professor Edward Morren in his biographical sketch entitled Charles de l'Escluse, sa vie et ses œuvres, states that the potato was introduced from Santa Fé into England by John Hawkins in 1563 (Garten Zeitung, 1805, p. 346). If this be so, it is a question whether the English and not the Spaniards are not entitled to the credit of the first introduction; but, according to Sir Joseph Banks, the plant brought by Drake and Hawkins was not the common English potato but the sweet potato.
In 1587 or 1588 De l'Escluse (Clusius) received the plant from Philippe de Sivry, lord of Waldheim and governor of Mons, who in his turn received it from some member of the suite of the papal legate. At the discovery of America, we are told by Humboldt, the plant was cultivated in all the temperate parts of the continent from Chile to Colombia, but not in Mexico. In 1585 or 1586, potato tubers were brought from what is now North Carolina to Ireland on the return of the colonists sent out by Sir Walter Raleigh, and were first cultivated on Sir Walter's estate near Cork. The tubers introduced under the auspices of Raleigh were thus imported a few ye'axs'later than those mentioned by Clusius in 1588, which must have been in cultivation in Italy and Spainfor some years prior to that time. The earliest representation of the plant is to be found in Gera1d's Herbal, published in 1597. The plant is mentioned under the name Papus orbiculalus in the first edition of the Catalogns of the same author, published in 1596, and again in the second edition, which was dedicated to Sir Walter Raleigh (1599). It is, however, in the Herbal that we find the first description of the potato, accompanied by a woodcut sufficiently correct to leave no doubt whatever as to the identity of the plant. In this work (p. 781) it is called “ Battata virginiana sive Virginianorum, et Pappus, Potatoes of Virginia.” 1 The “common potatoes” of which Gerard speaks are the tubers of Ipomoea Balatas, the sweet potato, which nowadays would not in Great Britain be spoken of as common. A second edition of the Herbal was published in 1636 by Thomas Johnson, with a different illustration from that given in the first edition, and one which in some respects, as in showing the true nature of the tuber, is superior to the first. The phenomenon of growing out or “ super-tube ration ” is shown in this cut. Previous to this (in 1629) Parkinson, the friend and associate of Johnson, had published his Paradisus, in which (p. 517) he gives an indifferent figure of the potato under the name of Papas sen Ballalas Virginianormn, and adds details as to the method of cooking the tubers which seem to indicate that they were still luxuries. Chabraeus, who wrote in 1666, tells us that the Peruvians made bread from the tubers, which they called “ chunno." He further tells us that by the natives Virginieae insulae the plant was called “ openauk, ” and that it is now known in European gardens, but he makes no mention of its use as an esculent vegetable, and, indeed, includes it among “ plantae malignae et venenatae.” Heriot (De Bry's Collection of Voyages), in his report on Virginia, describes a plant under the same name “ with roots as large as a walnut and others much larger; they grow in damp soil, many hanging together as if fixed on ropes; they are good food either boiled or roasted.” The plant (which is not a native of Virginia) was probably introduced there in consequence of the intercourse of the early settlers with the Spaniards. The cultivation of the potato in England made but little progress, even though it was strongly urged by the Royal Society in 166 3; and not much more than a century has elapsed since its cultivation on a large scale became general.
Botanists are agreed that the only species in general cultivation in Great Britain is the one which Bauhin, in his Phytopinax, p. 89 (1596), called Solanum tuberosum esculentum, a name adopted by Linnaeus (omitting the last epithet), and employed by all botanical writers. This species is probably native in Chile, but it is very doubtful if it is truly wild farther north. Baker (Journ. Linn. Soc., 1884, xx. 489), has reviewed the tuber-bearing species of Solanum from a systematic point of View as well as from that of geographical distribution. Out of twenty so-called species he considers six to be really distinct, while the others are merely synonymous or trifling variations. The six admitted tuber-bearing species are S. tuberosum, S. Maglia, S. Commersoni, S. cardiophyllum, S. Jamesii and S. oxycarpum.
S. tuberosum is, according to Mr Baker, a native not only of the Andes of Chile but also of those of Peru, Bolivia, Ecuador and Colombia, also of the mountains of Costa Rica, Mexico and the south-western United States. It seems most probable, however, that some at least of the plants mentioned in the northern part of America are the descendants of cultivated forms. S. Maglia is a native of the Chilean coast as far sou th as the Chonos Archipelago, and was cultivated in the garden of the Horticultural Society at Chiswick in 1822, being considered by Sabine, in his paper on the native country of the wild potato, to be the true S. tuberosum and the origin of the cultivated forms. This species was also found by Darwin in Chile, and was considered by him, as by Sabine before him, to be the wild potato. Baker refers to the plants figured by Sabine (Trans. Hart. Soc. Lond. v. 249) (fig. 1) as being without doubt S. Maglia, but A. de Candolle (Origins des Plantes cultivées, p. 40) is equally emphatic in the opinion that it is S. tuberosum. S. Commersoni occurs in Uruguay, Buenos Aires and the Argentine Republic, in rocky situations at a low level. Under the name of S. Ohrondii it has been introduced into western France, where it is not only hardy but produces abundance of tubers, which are palatable, but have a slightly acid taste. S. cardiophyllum, described by Lindley in the Journ. Hort. Soc. is a native of the mountains of central Mexico at elevations of 8000 to 9000 ft. S. Jamesii is a well-defined species occurring in the mountains of Colorado, New Mexico and Arizona, and also in Mexico. In a wild state the tubers are not larger than marbles. S. oxycarpurn is a
- (From Sabine's figure in the Trans. Hort. Soc. Lond., 1824, vol. v. pl. ii. See text.)
Fig. 1.—Wild Potato-plant in bloom. (14 nat. size.)
