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.