Chapter XXII: Section V: Roots and Tubers

The important part which the so-called root crops play in the modern systems of agriculture, has secured for them a large share of the attention of the chemist, so that our knowledge of their composition and relative nutritive value is very extensive. As compared with most other articles of food, the roots, as they are popularly called, of potatoes, turnips, mangels, carrots, and such like plants, contain a high proportion of water, and are not very nutritious; indeed, with the exception of the potato, none of them contain 20 per cent. of solid matter, and some not more than five per cent. They are, however, easily produced in great quantities, which compensates for their low nutritive value. I shall consider each of the more important roots separately.

_The Turnip._--There are numerous varieties of this plant, which differ from each other in the relative proportions and total amount of their constituents, and even in different individuals of the same variety there is considerable variation in composition; hence the difficulty which has been felt by those who have endeavored to assign to this plant its relative nutritive value. From the average results of a great number of experiments, conducted both in the laboratory and the feeding-house, it is concluded that turnips are the most inferior roots produced in the field. The Swedish turnips are the most valuable kind: they contain a higher proportion of solid matter than the other varieties, and they are firmer and store better. The average composition of five varieties of turnips, as deduced from the results of the analyses of Anderson and Voelcker, is shown in the following table:--

ANALYSES OF TURNIPS.

----------------------------+-------+-------+--------+---------+-------
|Swedish| White |Aberdeen|Purpletop|Norfolk
|Turnip.| Globe.|Yellows.|Yellows. |Bell.
+-------+-------+--------+---------+-------
Water | 89.460| 90.430| 90.578| 91.200 | 92.280
Albuminous, or | | | | |
flesh-forming substances | 1.443| 1.143| 1.802| 1.117 | 1.737
Non-nitrogenous, or | | | | |
fat-forming substances | | | | |
(fat, gum, sugar, &c.) | 5.932| 5.457| 4.622| 4.436 | 2.962
Woody fibre | 2.542| 2.342| 2.349| 2.607 | 2.000
Mineral matter (ash) | 0.623| 0.628| 0.649| 0.640 | 1.021
+-------+-------+--------+---------+-------
|100.000|100.000| 100.000| 100.000 |100.000
----------------------------+-------+-------+--------+---------+-------

The _Greystone Turnip_ is a variety which has only quite recently been introduced. It is stated to be an uncommonly productive crop, usually yielding returns from 30 to 50 per cent. greater than those obtained from other varieties of the turnip. The composition of the Greystone turnip appears to be inferior, so that probably it is not, after all, a more economical plant than the ordinary kinds of turnips.

DR. ANDERSON'S ANALYSIS OF THE GREYSTONE TURNIP.

No. 1. No. 2.
Grown on Clay. Grown on Sand.

Water 93.84 94.12
Oil 0.26 0.34
Soluble albuminous matters 0.35 0.56
Insoluble ditto 0.20 0.18
Soluble respiratory matters 2.99 2.32
Insoluble ditto (chiefly fibre) 1.73 1.85
Ash 0.63 0.63
------ ------
100.00 100.00

It was at one time the fashion--not yet become quite obsolete--to regard the proportion of nitrogen in the turnip as the measure of the nutritive value of the bulb; but the fallacy of this opinion has been shown by several late investigators, and more particularly by the results of one of the numerous series of feeding experiments conducted by Mr. Lawes. Many bulbs exceedingly rich in nitrogen are very deficient in nutritive power--partly from a deficiency in the other elements of nutrition--partly because most of their nitrogen is in so low a degree of elaboration as to be incapable of assimilation by animals. The value of a food-substance does not merely depend upon the amount and the relative proportion of its constituents, but also, and to a very great extent, upon their easy assimilability. There is but little doubt that the nutritive matters contained in the Swedish turnip when the bulb is fresh are very crude. By storing, certain chemical changes take place in the bulb, which render it more nutritious and palatable. A large proportion of the non-nitrogenous matters exist in the fresh root as pectin; but this substance, if the bulb be preserved for a couple of months, becomes in great part converted into sugar, which is one of the most palatable and fattening ingredients of cattle-food. By storing, too, the bulbs lose a portion of their excessive amount of water, and become less bulky, which is unquestionably a desideratum. These facts suggest the necessity for cultivating the earlier varieties of the turnip, for it may be fairly doubted if a late-grown crop, left for consumption in the field, ever, even under the most favorable circumstances, attains its perfect development. At the same time it must not be forgotten that turnips _fully matured_ in the field rather deteriorate than otherwise after a few weeks' storage.

Many agriculturists consider that there is a strict relation between the specific gravity, or comparative weight of the bulb, and its nutritive value; others believe that a very large turnip must necessarily be inferior in feeding qualities to a small one; whilst not a few maintain that neither its size nor its specific gravity is an indication of its feeding qualities. Dr. Anderson, who has specially investigated a portion of this subject, states that "the specific gravity of the whole turnip cannot be accepted as indicating its real nutritive value, the proportion of air in the cells being the determining element in such results; that there is no constant relation between the specific gravity of, and the nitrogen compounds in, the bulb; and that such relation does exist between the specific gravity of the expressed juice and the nitrogen compounds and solid constituents." Dr. Anderson allows, however, that the best varieties of the turnip have the highest specific gravity; which admission--coupled with the fact admitted by all experimenters that the heavy roots store best--lead me to adopt the opinions of those who consider great specific gravity as one of the favorable indications of its nutritive value. With respect to size, I prefer bulbs of moderate dimensions; the monsters that win the prizes at our agricultural shows--and which, in general, are _forced_--are inferior in feeding qualities, are always _spongy_, and almost invariably rot when stored.

The composition of the turnip is influenced not only by the nature of the soil on which it is grown, but also by that of the manure applied to it. The most reliable authorities are agreed that turnips raised on Peruvian guano are watery, and do not keep well; but that with a mixture of Peruvian guano and superphosphate of lime, with phospho-guano, or with farmyard manure supplemented with a moderate amount of guano, the most nutritious and firm bulbs are produced.

Turnip-tops have been analysed by Voelcker, with the following results:--

ONE HUNDRED PARTS CONTAIN--

White. Swedish.

Water 91.284 88.367
Nitrogen compounds 2.456 2.087
Non-nitrogenous matters (gum, sugar, &c.) 0.648 1.612
Ditto, as woody fibre 4.092 5.638
Mineral matter 1.520 2.296
------- -------
100.000 100.000

These figures apparently show that the tops of turnips are more valuable than their bulbs; but, in the absence of any feeding experiments made to determine the point, we believe they are less so, as a very large proportion of the solid matter in the tops of turnips is in too low a degree of elaboration to be assimilable. Their high proportions of nitrogen and mineral matter constitute them, however, a very useful manure--nearly twice as valuable as the bulbs; this fact should be borne in mind when turnips are sold off the land.

_The Mangel-wurtzel_ is one of the most valuable of our green crops. Its root is more nutritious than the turnip, occupying a position in the scale of food equivalents midway between that bulb and the parsnip. Mangels, when fresh, possess a somewhat acrid taste, and act as a laxative when given to stock; but after a few months' storing they become sweet and palatable, and their _scouring_ property completely disappears.

Although the mangel is one of the most nutritious articles of food which can be given to cattle, yet it is stated on the best authority that sheep do not thrive upon it. Voelcker, who has investigated this subject, informs us that a lot of sheep which he fed on a limited quantity of hay and an unlimited quantity of mangels, did not, during a period of four months, increase in weight, whilst another lot of sheep supplied with a small quantity of hay, and Swedish turnips _ad libitum_ increased on an average 2-1/2 lbs. weekly. I believe the experience of the greater number of feeders agrees with the results of Dr. Voelcker's experiment.

The chemistry of the mangel-wurtzel has been thoroughly studied by Way and Ogston, Fromberg, Wolff, Anderson, and Voelcker. According to the last-named chemist, its average composition is as follows:--

Water 87.78
Flesh-forming matters 1.54
Sugar 6.10
Gum, pectin, &c. 2.50
Woody fibre 1.12
Mineral matter (ash) 0.96
------
100.00

It is difficult to accurately determine by a comparative trial the relative feeding properties of mangels and turnips, for the former are only in a fit state to be given to the animals when the latter are deteriorating. However, by comparing the composition of the two substances, and the results obtained from numerous feeding experiments, it would appear, that on the average 75 lbs. weight of mangels are equal to 100 lbs. weight of turnips. Of the different varieties of the mangel the long yellow appears to be the most nutritious, and the long red the least so.

The leaves of the mangel--some of which are occasionally pulled and used for feeding purposes, during the growth of the bulb--are an excellent feeding substance: their composition indicates a nutritive value but little inferior to that of the root; but as their constituents cannot be in a highly elaborated condition, it is probable they are not more than equal to half their weight of the bulbs.

One _questio vexata_ of the many which at present occupy the attention of the agricultural world is, whether or not the leaves of mangels may be removed with advantage during the latter part of the development of the plants. This practice prevailed rather extensively a few years since, but latterly it has fallen somewhat into disuse.

Those who adopt this plan urge, as its advantages, that a large quantity of food is obtained at a time when it is urgently needed, and that instead of the removal of the leaves exercising an injurious influence on the development of the roots, the latter are actually increased in size.

In 1859 an experimental investigation was carried out at the Glasnevin Model Farm, with the view of throwing new light on the question. The outside leaves were very gradually removed on different occasions--from the 12th August to the 15th October. In this way five tons of leaves per statute acre were removed, and subsequently made use of for feeding purposes. The experiment was conducted on a field of four acres, of which the produce of 12 drills, each 200 yards in length, was left untouched. The result was that the produce of the roots of the untouched plants was only 40 tons 8 cwt. 6 qrs. per acre, whilst the roots of the plants which had been partly denuded of their leaves weighed at the rate of 45 tons 1 cwt. This experiment afforded results which are apparently favorable to the practice of stripping the leaves; but it is to be regretted that it was not rendered more complete by an analysis of the roots, as a great bulk of roots does not necessarily imply a great weight of dry food, and it is just possible, though not very probable, that the roots of the stripped mangels contained a larger proportion of water than those of the untouched plants.

The results of the experiments of Buckman, and of Professor Wolff, of the Royal Agricultural College at Hohenheim, are at direct variance with those obtained at Glasnevin. Both of these experimenters found that the removal of the leaves occasioned a diminution in the produce of the roots to the amount of 20 per cent. Nor was this the only loss, for it was found by the German professor that the roots of the untouched plants possessed a far higher nutritive value than those of the stripped mangels.

When doctors differ, who is to decide? Here we have high authorities in the agricultural world at direct variance on a matter of fact. The names of Buckman and Wolff are a sufficient guarantee that the experimental results which they announce are trustworthy, and I can testify, from observation, that no field experiments could be more carefully conducted than those carried out at the Albert Model Farm. We can only, then, under the circumstances, admit that both Mr. Boyle, on the one side, and Professors Buckman and Wolff on the other, are correct in their statements of fact; but as it is evident both cannot be right in the general inferences therefrom, it is desirable that the subject should be still further investigated, and the truth be placed beyond doubt. It is a question which appears so simple that one is at a loss to account for the discrepant opinions in relation to it which prevail. "Let nothing induce the growers," says Mr. Paget, in a paper on the cultivation of the mangel, "to strip the leaves from the plant before taking up the root. A series of careful experiments has convinced me that by so doing we borrow food at a most usurious interest." "Although," says Mr. Boyle, "the practice of stripping has been followed for many years on the farm without any perceptible injury to the crop, these results, showing so considerable an addition to the crop from taking off the leaves, were hardly anticipated." It certainly does appear somewhat at variance with our notion of the functions of the leaves of plants, that their partial removal could possibly cause an increase in the weight of the roots; but granting such to be the fact, it is not altogether _theoretically_ inexplicable. We know that highly nitrogenous manure has a tendency to increase the development of the leaves of turnips at the _expense_ of the roots. Gardeners, too, not unfrequently remove some of the buds from their fruit trees, lest the excessive development of foliage should retard or check the _growth_ of the fruit. _Theoretically_ an excessive development of the leaves of the mangel may be inimical to the growth of the root. Probably, too, it may be urged, the outer leaves, which soon become partially disorganised and incapable of elaborating mineral matter into vegetable products, prevent the access of light to the more vigorous inner leaves. In conclusion, I may say of this subject that it is worthy of further elucidation; and I would suggest to my readers, and more especially to the managers of the various model farms, the desirability of fully testing the matter.

The _White Beet_ is a congener of the mangel. It is largely grown on the continent as a sugar-producing plant, but is seldom cultivated in these countries. It produces about 15 tons of roots per acre, and its roots on the average contain--

Water 83.0
Sugar 10.0
Flesh-formers 2.5
Fat-formers 1.5
Fibre 2.0
Ash 1.0
-----
100.0

This plant is deserving of more extensive growth in Great Britain.

The _Parsnip_ is, after the potato, the most valuable of roots. It differs from the turnip and the mangel in containing a high proportion of starch, and but little sugar; and its flesh-forming constituents are largely made up of casein, instead of, as in the case of the turnip, albumen.

The average composition of the parsnip is as follows:--

Water 82.00
Flesh-forming principles 1.30
Fat-formers (starch, sugar, &c.) 7.75
Woody fibre 8.00
Mineral matter (ash) 0.95
------
100.00

The parsnip is extensively grown in many foreign countries, on account of its valuable feeding properties. As a field-crop it is but little cultivated in Great Britain, and its use is--if we except the table--almost restricted to pigs. Its food equivalent is about double that of the turnip; that is, one pound of parsnips is equal to two pounds of turnips.

The _Carrot_ bears a close resemblance to the parsnip, from which, however, it differs, containing no starch, and being somewhat inferior in nutritive value. According to Voelcker, its average composition is as follows:--

Water 88.50
Flesh-formers 0.60
Fat-formers (including woody fibre) 10.18
Mineral matter (ash) 0.72
------
100.00

As carrots contain a high proportion of fat-forming matters, and a low per-centage of flesh-forming substances, they are better adapted for fattening purposes. Dairy stock greedily eat them; and they are given with great advantage to horses out of condition.

_Kohl-Rabi._--This plant, though early introduced into the agriculture of these countries, has made but little progress in the estimation of the farmer. It belongs to the order and genus which include the turnip, but differs widely from that plant in its mode of growth. Its bulb--which is formed by an enormous development of the overground stem--is, according to some authorities, less liable than the turnip to injury from frost. It is subject to no diseases, save anbury and clubbing; and, owing to its position above the soil, it can be readily eaten off by sheep. The bulbs store better than Swedes, and, according to some farmers, keep even better than mangels. With respect to the flavor of this bulb, there is some difference of opinion. Professor Wilson, of Edinburgh, quotes several eminent feeders to prove that "whether in the fold for sheep, in the yard for cattle, or in the stables for horses, it will generally be preferred to the other descriptions of homegrown keep." Mr. Baldwin, on the contrary, states that although good food for sheep, it is too hard-fleshed for old ewes, and that carrots are better food for horses, and Swedish turnips for cattle.

An accurately conducted comparative trial to test the nutritive value of the Kohl-rabi, was conducted at the Glasnevin Model Farm, under the direction of Mr. Baldwin. The experiment was commenced in January, 1863. Four oxen were selected, and divided into two lots. Nos. 1 and 2 (Lot 1) were fed on Kohl-rabi, oil-cake, and hay, and Nos. 3 and 4 (Lot 2) on Swedish turnips, oil-cake, and hay. As the animals supplied with the Kohl-rabi did not appear to relish it, and as it was desirable to gradually accustom them to the change of food, the experiment did not really commence till the 12th January. On that date the weights of the animals were as follows:--

cwt. st. | cwt. st.
|
Lot 1. {No. 1. 10 1 | Lot 2. {No. 3. 7 5
{No. 2. 7 4 | {No. 4. 10 2
------- | -------
17 5 | 17 7

The lots, therefore, counterpoised each other pretty fairly. From the 12th to the 28th January they received the following quantities of food per diem:--

1. 2. 3. 4.

Roots stones 7-1/2 6 6 7-1/2
Oil cake pounds 4-1/2 3 3 4-1/2
Hay pounds 10-1/2 10-1/2 10-1/2 10-1/2

The animals fed upon the Kohl-rabi evinced from the first a disinclination to it, but they nevertheless ate it before their meal of oil-cake was supplied to them. On the morning of the 28th January they were put upon the dietary shown in the table, and which induced them to eat the Kohl-rabi more quickly.

1. 2. 3. 4.

At 6.30 a.m. {Roots, Stones 3 2-1/2 2-1/2 3-1/2
{Cake, lbs. 1-1/2 1 1 1

At 12.30 a.m. {Roots, Stones 3 2-1/2 2-1/2 3-1/2
{Cake, lbs. 1-1/2 1 1 1

At 6.30 p.m. {Roots, Stones 3 2-1/2 2-1/2 3-1/2
{Cake, lbs. 1-1/2 1 1 1

At 9.30 p.m. Hay, lbs. 7 7 7 7

On the 11th February the cattle were again weighed, when their increase was found to be as follows:--

Weight on Weight on Increase in
Jan. 12. Feb. 11. 30 days.

cwt. st. cwt. st. st.

1} Lot 1, fed on Kohl-rabi,} 10 1 10 4 3
2} &c. } 7 4 7 6 2
---
Total 5

3} Lot 2, fed on Swedes, } 7 5 8 3 6
4} &c. } 10 2 10 7-1/4 5-1/2
------
Total 11-1/2

The results of this experiment show that the animals fed upon Swedish turnips, hay, and oil-cake, increased in weight at a rate more than 100 per cent. greater than the lot supplied with equal quantities of Kohl-rabi, hay, and oil-cake. The superiority of the Swedish turnips was rendered more evident by the results of subsequent experiments. Nos. 1 and 4 were not tried after the 11th February; but Nos. 2 and 3 were kept under experiment. No. 2 was put on Swedes, and No. 3 on mangel-wurtzel, and after an interval of a fortnight No. 2 had increased much more than they had done on Kohl-rabi.

Specimens of the Kohl-rabi and Swedish turnips employed in this experiment were submitted to me for analysis by Mr. Baldwin, and yielded the following results:--

Swedish
Kohl-rabi. Turnip.

Water 87.62 88.84
Nitrogenous, or flesh-forming principles 2.24 1.66
Non-nitrogenous, or fat-forming principles 7.78 6.07
Woody fibre 1.34 2.73
Mineral matter (ash) 1.22 0.70
------ ------
100.00 100.00

These results show a slight superiority of the Kohl-rabi over the Swedish turnip; the great difference in their nutritive power, as shown by Mr. Baldwin's experimental results, must therefore be due to the superior flavor and digestibility of the turnip.

Dr. Anderson's analysis of Kohl-rabi afforded results more favorable to the highly nutritive character assigned by some feeders to that bulb than those arrived at by me. The bulbs, it should however be remarked, were grown, no doubt with great care, by Messrs. Lawson and Son, the well-known seedsmen:--

ANALYSIS OF KOHL-RABI, BY DR. ANDERSON.

Bulbs. Tops.

Water 86.74 86.68
Flesh-forming principles 2.75 2.37
Fat-forming principles 8.62 8.29
Woody fibre 0.77 1.21
Mineral matter 1.12 1.45
------ ------
100.00 100.00

The _Radish_ is a plant which deserves a place amongst our field crops, though hitherto its cultivation has been restricted to the garden. At one time its leaves were boiled and eaten, but in these latter days they are subjected to neither of these processes. The root, however, in its raw state, is, as every one is aware, considered one of the dainties of the table.

Many of those who devote themselves to the important study of dietetics, consider the use of raw vegetables to be objectionable; but be their objections groundless, or the reverse, it is certain that a vegetable which, like the radish, may be eaten raw with apparently good results, cannot be otherwise than a good article of food when cooked. I once tried the experiment of eating matured radishes, not as a salad, but cooked like any other boiled vegetable, and I must say that I found their flavor rather agreeable than otherwise. Boiled radishes--roots and tops--form excellent feeding for pigs. How could it be otherwise? for what is good for the family of man must surely be a luxury to the swine tribe. I have known horses to eat radishes greedily, and I am certain that they would prove acceptable to all the animals of the farm. But it may be asked, why it is that I recommend the use of radishes as food for stock, when there are already so many more nutritious roots at our disposal--turnips, mangels, and potatoes. Simply for this reason:--Between the departure of the roots and the advent of the grasses, there is a kind of interregnum.[33] Now we want a good tuberous, bulbous, or tap-rooted plant to fill up this interregnum. Such a plant we have in the radish. The root is certainly a small one, but then it grows so rapidly that a good supply can be had within thirty days from the sowing of the seed, and a crop can be matured before the time for sowing turnips. Two crops may be easily obtained from land under potatoes--one before the tops cover the ground, the other after the tubers have been dug out. The yield of radishes, judging from the produce in the garden, would be at least six tons of roots and three tons of tops. I would suggest, then, that the radish should at once get a fair chance as a stolen crop. If it succeed as such, it will not be the first gift of the gardener to the husbandman. Was not the mangel-wurtzel once known only as the produce of the garden?

The composition of the radish indicates a nutritive value less than that of the white turnip. I have analysed both the root and the tops, and obtained the following results:--

ANALYSIS OF THE RADISH.

Root. Tops.

Water 95.09 94.30
Flesh-forming principles 0.52 0.75
Fat-formers (starch, gum, fat, &c.) 1.06 1.16
Woody fibre 2.22 2.36
Mineral matter (ash) 1.11 1.43
------ ------
100.00 100.00

The _Jerusalem Artichoke_ has long been cultivated as a field-crop on the Continent, and in certain localities the breadth occupied by it is very considerable. The French term the tuberous root of this plant _poitre de terre_, or _topin ambour_; and although they expose it for sale in the markets, it is not much relished by our lively neighbours, who are so remarkable for their _cuisiniere_. As food for cattle, however, the French agricultural writers state it to be excellent. It is much relished by horses, dairy cows, and pigs; store horned-stock also eat it when seasoned with a little salt, and appear to enjoy it amazingly when permitted to pull up the roots from the soil. The green tops are also given to sheep and cattle, and, it is stated, are readily eaten by those animals.

The Jerusalem artichoke (_Helianthus Tuberoses_) differs from its half namesake, the common artichoke, and resembles the potato in being valuable chiefly for its tubers. It is perennial, and attains on the Continent a height varying from 7 to 10 feet. In this country its dimensions are less. The stem is erect, thick, coarse, and covered with hairs. It is a native of Mexico, and although introduced 200 years ago into Europe, it can hardly be said to be acclimatised, since it very seldom flowers, and never develops seed. The plant is therefore propagated by cuttings from its tubers, each containing one or two eyes; or if the tubers be very small, which is often the case, a whole one is planted. The tubers possess great vitality, and remain in the ground during the most severe frosts, without sustaining the slightest injury. For this reason it is usual to devote a corner of the garden to the cultivation of the Jerusalem artichoke; for, no matter how completely the crop may appear to have been removed from the soil, portions of the tubers will remain and shoot up into plants during the following season. This peculiarity of the plant it is likely may prove an obstacle to its having a place assigned to it in the rotation system.

The question now presents itself--What are the peculiar advantages which the crop possesses which should commend it to the notice of the British farmer? I shall try to answer the question.

1st. No green crop (except furze) can be grown in so great a variety of soils; except marshy or wet lands, there is no soil in which it refuses to grow.

2nd. It does not suffer from disease, is very little affected by the ravages of insects, is completely beyond the influence of cold, and may remain either above or below ground for a long time without undergoing any injurious changes in composition.

3rd. It gives a good return, when we consider that it requires very little manure, and but little labor in its management.

At Bechelbronn, the farm of the celebrated Boussingault, the average yield is nearly eleven tons per acre, but occasionally over fourteen tons is obtained. Donoil, a farmer of Bailiere, in the department of Haut-loire, states that he fed sheep exclusively on the tops and tubers of this plant, and that he estimated his profits at L23 per hectare (L9 3s. 4d. per acre). The soil was very inferior. Donoil terms it third-rate, and it does not appear to have been manured even once during the fifteen years it was under Jerusalem artichoke. I fear our artificial manure manufacturers will hardly look with a favorable eye on the advent of a crop into our agriculture which can get on so well without the intervention of any fertilising agents. Indeed, several of the French writers state that little or no manure is necessary for this plant. But this can hardly be the case; for it is evident that a crop which, according to Way and Ogston, removes 35 lbs. of mineral matter per ton from the soil, or three times as much potash as turnips do, must certainly be greatly benefited by the application of manure. And I have no doubt but that the Jerusalem artichoke, if well manured and grown in moderately fertile soil, would produce a much heavier crop than our Continental neighbors appear to get from it.

4th. The Jerusalem artichoke may be cultivated with advantage in places where ordinary root-crops either fail or thrive badly. In such cases the ground should be permanently devoted to this crop. Kade gives an instance where a piece of indifferent ground had for thirty-three years produced heavy crops of this plant, although during that time neither manure nor labor had been applied to it. In Ireland the potato has been grown under similar circumstances.

The nutritive constituents of tubers of the Jerusalem artichoke bear a close resemblance in every respect, save one, to those of the potato. Both contain about 75 per cent. of water, about 2 per cent. of flesh-forming substances, and 20 per cent. of non-nitrogenous, or fat-forming and heat-giving elements. In one respect there is a great difference--namely, that sugar makes up from 8 to 12 per cent. of the Jerusalem artichoke, whilst there is but a small proportion of that substance in the potato.

The large quantity of sugar contained in this root is no doubt the cause of its remarkable keeping properties in winter, and it also readily accounts for the avidity with which most of the domesticated animals eat it.

On the whole, then, I think that the facts I have brought forward relative to the advantages which the Jerusalem artichoke presents as a farm crop, justify the recommendation that it should get a fair trial from the British farmer, who is now so much interested in the production of suitable forage for stock.

COMPOSITION OF (DRY) JERUSALEM ARTICHOKE

Albuminous matters 4.6
Fatty matters 0.4
Starch, gum, &c. 19.8
Sugar 69.5
Fibre and ash 5.7
-----
100.0

The _Potato_, regarded from every point of view, is by far the most important of the plants which are cultivated for the sake of their roots. Its tubers form the chief--almost sole--pabulum of many millions of men, enter more or less into the dietary of most civilised peoples, and constitute a large proportion of the food of the domesticated animals. The great importance of this plant, arising from its enormous consumption, has caused its composition to be very minutely studied by many British, Continental, and American chemists. With respect to its nutritive properties, the least favorable results were obtained by the American chemists, Hardy and Henry, and the most by the European chemists.

The flesh-forming principles vary from 1 per cent., as found by Hardy, to 2.41 per cent., the mean results of the analyses of Krocker and Horsford. The proportion of starch in different varieties of the potato also varies, but not to the same degree as the nitrogenous principles. In new potatoes, only 5 per cent. has been found; in ash-leaved kidneys, 9.50 per cent.; and in different kinds of cups, from 15 to 24 per cent. The amount of starch is also influenced by the soil, the manure, the climate, and the various other conditions under which the plant is developed. The proportion of starch increases during the growth, and diminishes during the storage of the tubers.

Dr. Anderson is the most recent investigator into the composition of the potato; the chief results of his inquiries are given in the following table:--

ANALYSIS OF THE POTATO BY DR. ANDERSON.

--------------+--------+----------+-------------+-------+-------+-------
|Regents.|Dalmahoys.|Skerry-blues.|White |Orkney |Flukes.
| | | |Rocks. |Reds. |
+--------+----------+-------------+-------+-------+-------
Water | 76.32 | 75.91 | 76.60 | 75.93 | 78.57 | 74.41
Starch | 12.21 | 12.58 | 11.79 | 12.77 | 10.85 | 12.55
Sugar, &c. | 2.75 | 2.93 | 3.09 | 2.17 | 2.78 | 2.89
Flesh-formers | | | | | |
soluble | 2.16 | 2.10 | 1.90 | 1.88 | 1.48 | 1.98
insoluble | 0.21 | 0.15 | 0.16 | 0.24 | 0.21 | 0.20
Fibre | 5.53 | 5.21 | 5.41 | 5.55 | 5.93 | 6.71
Ash | 0.88 | 0.81 | 0.94 | 1.04 | 0.98 | 0.98
+--------+----------+-------------+-------+-------+-------
| 100.06 | 99.69 | 99.89 | 99.58 |100.80 | 99.72
--------------+--------+----------+-------------+-------+-------+-------

The potato is relatively deficient in flesh-forming matters, and contains the respiratory elements in exceedingly high proportions; hence it is well adapted for fattening purposes, and in this respect is equal to double its weight of the best kind of turnips. When used as food for man, it should be supplemented by some more fatty or nitrogenous substance--such, for example, as flesh, oatmeal, or peas. Buttermilk, a fluid which is rich in nitrogen, is an excellent supplement to potatoes, and compensates to a great extent for the deficiency of those tubers in muscle-forming matters. If, then, the potato is destined to retain its place as the "national esculent" of the Irish, I trust their national beverage may be--so far at least as the masses of the people are concerned--buttermilk, and _not_ whiskey.

Potatoes so far diseased as to be unsuited for use as food for man, may be given with advantage to stock. They may be used either in a raw or uncooked state, but the latter is the preferable form. Sheep do not like them at first, but on being deprived of turnips they acquire a taste for them; on a daily allowance, composed of 1 lb. of oil-cake or corn, and an unlimited quantity of potatoes, they fatten rapidly. Cattle thrive well on a diet composed of equal parts of turnips and diseased potatoes, and do not require oil-cake. The evening feed of horses may advantageously be composed of potatoes and turnips. If raw, the potatoes should be given in a very limited quantity--four or five pounds; in the cooked state, however, they may be given in abundance, but the animals should not, after their meal, be permitted to drink water for some hours. As a feeding substance, diseased potatoes, unless they be very much injured, are equal to twice their weight of white turnips; it is certain that they do not injure the health or impair the condition of the animals which feed upon them.