s a field open for
experiment; but the operator must not lose sight of the fact that he is
"playing with edged tools." We will now state what has been proved to be
beneficial when carefully carried out. Those who grow batches of the
showy Dendrobiums such as _D. nobile_, _D. Wardianum_, _D. Phalaenopsis_,
and others of the class, and who, at the growing season, place them in a
warm, moist house, suspended from the roof for preference, frequently
give them weak doses of liquid manure during the season of growth, and
the plants make very fine growth.

[Illustration: PLATE IV

CATTLEYA TRIANAE

VAR. "HYDRA"

(The plant bore 88 flowers.)]

The liquid from farm-yard manure, or from a stable, should be avoided,
as its strength cannot be known; sometimes it is very weak, and at
others fatally strong. A large tub with liquid manure made of cow-dung,
and in which a coarse bag of soot has been sunk, is a safe manure for
any plant, and if properly diluted can do no harm to plants requiring
such a stimulant.

Terrestrial Orchids such as Calanthes and Phaius can scarcely be grown
to their best without a liberal application of this, or some other
manure known to the operator to be safe, during their season of growth.
Cymbidiums, Zygopetalums, Peristerias, and other strong-growing Orchids
have also been treated to weak liquid manure from the commencement of
growth until the flowers expanded, with advantage so far as evidence is
available.

An occasional watering of liquid manure, or slight sprinkling of guano,
may be given beneath the staging in the evenings during the growing
season.

The structure of the roots of Orchids does not favour the idea that
they are suited for taking up stimulating liquid in the manner common to
fibrous-rooted plants.

On the general question of the use of stimulants in Orchid culture many
clever men have carried out experiments. The late Dr. A. H. Smee went
into the question, basing his experiments on the chemical constituents
of the plants themselves, which is not an infallible guide.

The late Norman C. Cookson carefully studied the subject, and he
recommended for experiment the following formula:--

Potassium nitrate (saltpetre), 3 oz.
Ammonium phosphate, 2 oz.

Dissolve in a three-gallon jar of soft water, and when watering growing
Orchids, or those perfecting their flowers, add one ounce of the
solution to each gallon of water.

Again it must be urged that th