h 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