POTATO 



355 



Hnmboldt calculates that the same extent of 

 ground which would produce thirty pounds of wheat 

 would produce one thousand pounds of potatoes. 

 But potatoes are not nearly so nutritious as wheat, 

 and the constant employment of them as the chief 

 article of food is not favourahle to the development 

 of the physical powers, and is consequently in 

 its protracted influence unfavourable to mental 

 energy. All this is too well illustrated in Ireland 

 and the Highlands of Scotland, in a race capable 

 of the highest development. It is calculated that 

 100 parts of good wheat-Hour, or 107 parts of the 

 grain, contain as much actual nutriment as 613 

 parts of potatoes. The inferiority of the potato in 

 nutritious power is very much owing to the com- 

 paratively small quantity of nitrogenous substances 

 which it contains, in consequence of which it is 

 most advantageously used along with some very 

 nitrogenous article of food, in Britain generally with 

 animal food, in some parts of Europe with curds or 

 with cheese. The potato tuber, in a fresh state, 

 contains about 71 to 80 per cent, of water ; 15 to 20 

 of starch, 3 to 7 of fibre or woody matter, 3 to 4 of 

 gum, dextrine, and sugar, and '2 of albumen, gluten, 

 and casein. There are considerable differences, 

 however, in different varieties, in different stages 

 of maturity, and in different soils and seasons. 



Potatoes are used, both raw and boiled, for the 

 feeding of cattle. For human food they are 

 variously prepared by roasting or boiling, but 

 now chiefly by boiling, a process by which they are 

 freed from all that is narcotic and noxious in their 

 juice. The water in which potatoes have been 

 boiled is not wholesome. 



The herbage or haulm of the potato has been 

 used for making paper, but the results were not 

 encouraging. Potato pulp produces a kind of cel- 

 luloid or vegetable ivory, and from potato- leaves 

 passable or even excellent cigarettes m;iy be 

 manufactured. The berries yield by distillation a 

 tolerable spirit. 



The varieties of the potato in cultivation are 

 extremely numerous 500 were exhibited at the 

 Westminster Tercentenary Exhibition ( 1886). Any 

 enumeration or classification of them is impossible. 

 New ones are continually appearing, and old ones 

 passing away. Those most advantageously cul- 

 tivated in particular soils and climates are often 

 found to degenerate when removed to a small dis- 

 tance. Potatoes differ considerably in the char- 

 acter of their herbage which is sometimes erect, 

 sometimes straggling and in the size and colour 

 of their flowers, but are more generally dis- 

 tinguished by the size, form, and colour of their 

 tubers, which are round, long, or kidney-shaped, 

 white, red, dark purple, variegated, &c. 



New varieties of potato are produced from seed ; 

 but potatoes are ordinarily propagated by planting 

 the tubers, or cuttings of the tubers, each contain- 

 ing an eye or bud. Much has been written by 

 gardeners and agriculturists on the comparative 

 advantages of planting whole tubers or cuttings ; 

 but the latter method generally prevails. 



Potatoes are 

 spade or 

 made by 



of potatoes are covered over with earth dug out of 

 the alleys. The alleys serve, although imperfectly, 

 for drains in undrained land. The cultivation of 

 potatoes as a field-crop seems to have lieen first 

 attempted in lazy beds. They are still common in 

 many parts of Ireland, hut are now scarcely ever 

 een in England or Scotland. They are very suit- 

 able for strong, heavy, and somewhat moist land, 

 and are profitably used in reducing some kinds of 

 soil to cultivation, but are generally unsuitable for 

 field-culture, owing to the expense of labour re- 

 quired. In strong, heavy land potatoes are culti- 



vated in raised drills ; in lighter and drier soils the 

 raising of the drills is unnecessary. Manure is 

 invariably given, consisting generally of farmyard 

 dung and artificial manures. Common dressings 

 consist of from fifteen to twenty-five tons of duns 

 per acre, with from five to ten cwt. of artificial 

 manure, such as guano, dissolved bones, super- 

 phosphate, a little potash, and perhaps nitrate of 

 soda or salts of ammonia instead of guano. The 

 cultivation of potatoes, after they are planted, 

 whether in the field or garden, consists chiefly in 

 keeping the ground clear of weeds, and in earthing 

 up the plants, to promote the formation of tubers. 

 Potatoes are taken up by the fork, by turning over 

 the drills with the plough, or by an implement 

 specially designed for the purpose, known as a 

 potato-raiser. Where the crop is grown exten- 

 sively this implement is now almost universally 

 used, and performs its. work expeditiously and 

 thoroughly. Garden potatoes are generally used 

 long before they are really ripe, forming a favourite 

 dish in a very unripe state, when they are far from 

 being a safe article of food, and contribute not a 

 little to the prevalence of cholera and kindred 

 diseases in summer. In recent years the growing 

 of early |M>tatoes for use in the large towns has 

 been prosecuted to a large extent and with much 

 success on the coast of Ayrshire and other similar 

 parts favoured with a Denial climate. To facilitate 

 this the seed is forced in small taxes in which it is 

 placed over winter, and from which it is taken in 

 spring when the shoots are 2 to 4 inches long and 

 planted in well-manured drills. Potatoes from 

 seed thus prepared may !>< dug about three weeks 

 earlier than if the seed had not been sprouted. 

 The main field-crop is allowed to ripen thoroughly, 

 and is capable of being stored for winter and spring 

 use. The planting of potatoes in the open air can- 

 not be successfully practised in most parts of 

 Britain before February or March, and in many 

 seasons the later-planted are found as early as the 

 earlier-planted, and more productive. The storing 

 of potatoes is variously accomplished in dry lofts 

 or sheds, in airy cellars or bams, and in pits, which 

 are sometimes holes excavated to a small depth in 

 the earth, with the potatoes piled up al>ove the sur- 

 face of the ground, in a conical, or in a roof-like 

 form, sometimes mere heaps of one or other of. 

 these forms upon the surface of the ground, and 

 covered with straw and earth to keep out light and 

 frost. Potato-pits should always be well venti- 

 lated by means of pipes or otherwise, as without 

 ventilation the potatoes are apt to heat and sprout. 

 Potatoes taken from the ground liefore they are 

 quite ripe are extremely apt to heat and sprout. 



The potato crop is now an important one in 

 almost all the rotations practised in Britain, al- 

 though its cultivation is in most districts not quite 

 so extensive as before its failure from the potato 

 disease in 1845 and subsequent years, and farmers 

 are more careful not to depend too much upon it. 

 It very commonly succeeds a grain-crop, but some- 

 times is advantageously planted on land newly 

 broken up from grass. 



But, besides its value as a culinary vegetable, the 

 potato is important in other respects. Its starch is 

 very easily separated, and is in large proportions ; 

 hence it is cheaper than any other kind. It is manu- 

 factured on a very large scale. It is chiefly used in 

 textile manufactories under the name of farina, 

 which is converted into dextrine or British gum 

 (see STARCH). In Holland and in Russia, where 

 there is much difficulty in keeping potatoes through 

 the winter, and there is consequently a necessity 

 for using the crop quickly, large quantities of starch 

 are made, and this is converted into sugar or syrup 

 ( see SUGAR ). The refuse of the starch-manufactories 

 is all utilised ; it is pressed out from the water, 



