ospheric
changes--mode of admitting air--atmospheric influence on
vegetation--nitrogen--carbon 50

CHAP. IX.

Growth of Persian Melons in summer--peculiarities of
treatment--soil--watering--solar heat--light 56

CHAP. X.

Conclusion 59

TREATISE.

CHAP. I.

INTRODUCTORY REMARKS.

The Cucumber, _Cucumis sativa_, is supposed to be a native of the East
Indies; but like many other of our culinary plants, the real stations
which it naturally has occupied, are involved in obscurity: in habit it is
a trailing herb, with thick fleshy stems, broadly palmate leaves, and
yellow axillary monaecious flowers. In the natural arrangement of the
vegetable kingdom, the genus of which it forms part, ranks in the first
grand class, _Vasculares_, or those plants which are furnished with
vessels, and woody fibre; in the sub-class _Calyciflorae_, or those in
which the stamens are perigynous; and in the order _Cucurbitaceae_, or that
group, of which the genus _Cucurbita_, or Gourd family is the type.

The affinities of this order, are chiefly with _Loasaceae_, and
_Onagraceae_; with the former it agrees in its inferior unilocular fruit,
having a parietal placentae, and with the latter, in its definite
perigynous stamens, single style, and exalbuminous seeds. It has also some
affinity with _Passifloraceae_, and _Papayaceae_, in the nature of the
fruit, and with _Aristolochiaceae_, in its twining habit, and inferior
ovarium. M. Auguste St. Hiliare, also regards it as being related to
_Campanulaceae_, in the perigynous insertion of the stamens, the single
style with several stigmas, the inferior ovarium, and in the quinary
division of the floral envelope, in connection with the ternary division
of the fruit.

The properties of the plants comprised in this natural family, are not
numerous; a bitter laxative quality pervades many of them, a familiar
example of which is the resinous substance called Colycinthine, the
production of the Colocynth gourd, in which the active purgative principle
is concentrated, rendering it drastic, and irritating. Among our native
plants the roots of _Bryonia dioica_, in common with the perennial roots
of all the plants in the order, possess these purgative properties. On the
other hand, the seeds are sweet, yielding an abundant supply of oil; and
it may be