most likely, is found in the smaller kinds when wild. Under artificial
cultivation there are, however, many conditions more or less
unfavourable to the health of plants, and, in the case of Cactuses, very
large specimens, when imported from their native haunts to be placed in
our glass houses, soon perish. At Kew, there have been, at various
times, very fine specimens of some of the largest-growing ones, but they
have never lived longer than a year or so, always gradually shrinking in
size till, finally, owing to the absence of proper nourishment, and to
other untoward conditions, they have broken down and rotted. This
rotting of the tissue, or flesh, of these plants is the great enemy to
their cultivation in England. When it appears, it should be carefully
cut out with a sharp knife, and exposed to the influence of a perfectly
dry atmosphere for a few days till the wound has dried, when the plant
should be potted in a sandy compost and treated as for cuttings.
Sometimes the decay begins in the side of the stem of the plant, in
which case it should be cut away, and the wound exposed to a dry air.
The cause of this decay at the base or in the side of the stems of
Cactuses is no doubt debility, which is the result of the absence of
some necessary condition when the plants are cultivated in houses or
windows in this country.

Grafted plants, especially Epiphyllums, when worked on to Pereskia
stocks, are apt to grow weak and flabby through the stem wearing out, or
through the presence of mealy bug or insects in the crevices of the part
where the stock and scion join, in which case it is best to prepare
fresh stocks of Pereskia, and graft on to them the best of the pieces of
Epiphyllum from the old, debilitated plant. It is no use trying to get
such plants to recover, as, when once this disease or weakness begins,
it cannot easily be stopped.