It is not many years since Mr Ward first drew the attention of
botanists to the cultivation of plants in closely-glazed cases; but
the most sanguine dreams of the discoverer could not then have
foretold the many useful purposes to which the Wardian Case has become
applicable, nor the important influence which it was destined to
obtain in promoting the pleasant pursuits of gardening and botany. The
Wardian Case has been instrumental in diffusing a love of these
pursuits among all classes of society. It has opened up to those whose
pursuits confine them within the limits of the city's smoke-cloud, a
means whereby they may obtain 'a peep at nature, if they can no more.'
Far removed from green fields and leafy woods, they may, for instance,
enjoy their leisure mornings in watching one of the most beautiful
phenomena of vegetable development--the evolution of the circinate
fronds of the fern; a plant in every respect associated with elegance
and beauty. This kind of gardening has, therefore, become of late
years one of the most fashionable, while at the same time one of the
most pleasant sources of domestic amusement.
An interesting companion to the Wardian Case has lately been presented
in the Aquatic Plant Case, or Parlour Aquarium, due to the ingenuity
of Mr Warington, and which has for its object, as its name indicates,
the cultivation of aquatic or water plants. It may be described as a
combination of the Wardian Case and the gold-fish globe, the object
being to illustrate the mutual dependence of animal and vegetable
life. Mr Warington has lately detailed his experiments. 'The small
gold-fish were placed in a glass-receiver of about twelve gallons'
capacity, having a cover of thin muslin stretched over a stout copper
wire, bent into a circle, placed over its mouth, so as to exclude as
much as possible the sooty dust of the London atmosphere, without, at
the same time, impeding the free passage of the atmospheric air. This
receiver was about half-filled with ordinary spring-water, and
supplied at the bottom with sand and mud, together with loose stones
of limestone tufa from Matlock, and of sandstone: these were arranged
so that the fish could get below.... A small plant of _Vallisneria
spiralis_ was introduced, its roots being inserted in the mud and
sand, and covered by one of the loose stones, so as to retain the
plant in its position.... The materials being thus arranged, all
appeared to go on well for a short time, until circumstances occurred
which indicated that another and very material agent was required to
perfect the adjustment.' The decaying leaves of the vallisneria
produced a slime which began to affect the fish injuriously: this it
was necessary to get quit of. Mr Warington introduced five or six
snails (_Limnea stagnalis_), 'which soon removed the nuisance, and
restored the fish to a healthy state; thus perfecting the balance
between the animal and vegetable inhabitants, and enabling both to
perform their functions with health and energy. So luxuriant was the
growth of the vallisneria under these circumstances, that by the
autumn the one solitary plant originally introduced had thrown out
very numerous offshoots and suckers, thus multiplying to the extent of
upwards of thirty-five strong plants, and these threw up their long
spiral flower-stems in all directions, so that at one time more than
forty blossoms were counted lying on the surface of the water. The
fish have been lively, bright in colour, and appear very healthy; and
the snails also--judging from the enormous quantities of gelatinous
masses of eggs which they have deposited on all parts of the receiver,
as well as on the fragments of stone--appear to thrive wonderfully,
affording a large quantity of food to the fish in the form of the
young snails, which are devoured as soon as they exhibit signs of
vitality and locomotion, and before their shell has become hardened.'
In remarking upon the result of his experiments, Mr Warington
observes: 'Thus we have that admirable balance sustained between the
animal and vegetable kingdoms, and that in a liquid element. The fish,
in its respiration, consumes the oxygen held in solution by the water
as atmospheric air, furnishes carbonic acid, feeds on the insects and
young snails, and excretes material well adapted as a rich food to the
plant, and well fitted for its luxuriant growth. The plant, by its
respiration, consumes the carbonic acid produced by the fish,
appropriating the carbon to the construction of its tissues and
fibres, and liberates the oxygen in its gaseous state to sustain the
healthy functions of the animal life; at the same time that it feeds
on the rejected matter, which has fulfilled its purposes in the
nourishment of the fish and snail, and preserves the water constantly
in a clean and healthy condition. While the slimy snail, finding its
proper nutriment in the decomposing vegetable matter and minute
confervoid growth, prevents their accumulation by removing them; and
by its vital powers converts what would otherwise act as a poison into
a rich and fruitful nutriment, again to constitute a pabulum for the
vegetable growth, while it also acts the important part of a purveyor
to its finny neighbours.'[5] This perfect adjustment in the economy of
the animal and vegetable kingdoms, whereby the vital functions of each
are permanently maintained, is one of the most beautiful phenomena of
organic nature.
The Parlour Aquarium affords valuable, we might say invaluable,
facilities to the naturalist in the prosecution of his researches. The
botanist can now conveniently watch the development of aquatic plants
under conditions _not_ unnatural, throughout the entire period of
their existence, from their germination to the production of flowers
and the perfection of seeds; and we are in hopes that much of the
obscurity that invests many aquatic vegetables will in consequence be
cleared up. The zoologist is perhaps even more indebted to the
invention. The habits, not only of the fishes, but of the mollusca,
can be accurately studied under natural conditions, and many important
facts of their history ascertained and illustrated. The water-beetles
and other aquatic insects will also come in for a share of attention.
In concluding his paper in the _Garden Companion_ (i. p. 7), Mr
Warington states, that he is at present attempting a similar
arrangement with a confined portion of sea-water, employing some of
the green sea-weeds as the vegetable members of the circle, and the
common winkle or whelk to represent the water-snails. In a Report of
the Yorkshire Naturalist's Club, November 5, 1851,[6] we observe it
stated, that Mr Charlesworth read an extract from a letter from a
gentleman in America, detailing some successful experiments on keeping
marine molluscs alive in sea-water for months; but our inquiries have
not been successful in eliciting any further information on the
subject.
Experiments of our own have led to the conclusion, that some families
of aquatic plants are altogether unsuitable for the Parlour
Aquarium--such as, potamogeton, chara, &c., which very soon
communicate a putrescent odour to the water in which they are grown,
rendering it highly disagreeable in a sitting-room.