DOMESTIC GARDENING. 
351 
use precautionary measures, even when these 
" signs " are not to be observed. 
Air. — Leaving out of question all specu- 
lative notions respecting the action of the 
atmosphere on the vegetable economy, the 
amateur may regard its application as being 
useful to him for two obvious purposes ; first, 
to purify the confined internal air of his 
green-house, by carrying it outwards in its 
currents, and supplying its place by that which 
has not been submitted to circumstances likely 
to contaminate it : to effect this purpose, he 
may take advantage of every favourable oppor- 
tunity during the winter and spring months to 
admit as large a portion as will be consistent 
with the exclusion of frost, and the excessive 
external humidity which sometimes prevails 
at this season. The other application of the 
admission of air, which is useful to the amateur, 
is to lower and modify the temperature of his 
confined atmosphere during hot weather and 
bright sunshine, which the opening of his 
structure will accomplish, by causing an obvi- 
ous circulation and interchange of the internal 
and external air. The medium degree of heat 
which should be maintained in winter, may be 
taken at 45°; that of the spring months at 
55°; and when this temperature is indicated 
by the thermometer, recourse should be had 
to the means we have just noticed, of reducing 
it, more or less, according to existing circum- 
stances. During summer, a confined heat of 
more than 60° should not, on any account, 
be allowed. 
General Eemarks. — From what has been 
advanced, it will have incidentally appeared, 
that all plants require a seasonal arrangement 
of their treatment ; or, in other words, an 
alternate period of rest and of excitement, 
varying, indeed, according to their particular 
constitution, but ever constant and necessary 
in its appropriate degree. In some plants 
this principle will be evinced by the death of 
one series of vital organs, viz. the leaves, and 
the return of vitality within the root or stem ; 
and in the case of these, the seasonal treat- 
ment, which is naturally indicated, must be 
particularly and obviously attended to. In 
other plants, the leaves remain for a greater 
length of time, but their action during a 
portion of this is feeble, or even totally 
arrested for a period; and in cultivating these, 
it is needful to withhold stimulants whilst this 
condition remains, and reserve their appli- 
cation for a more favourable opportunity. The 
stimulants of vegetable growth are heat and 
moisture combined, and applied with pro- 
portionate reference to the individual cha- 
racter of the plants. The means of affording 
rest is obviously the converse of this — the 
conjoint reduction of the supply of heat and 
moisture in a palpable degree. Among the 
plants which will be recommended for this kind 
of structure, some few require rather minute 
attention with reference to the point just 
named ; thus, for example, the Azaleas form 
their new growth immediately after flowering ; 
consequently, at this period, the stimulants 
ought to be applied, and then again withheld 
gradually when the growth is maturing. 
Camellias, too, grow in the same manner, and 
therefore require similar treatment : after 
this growth is completed, and become partially 
firm or ripened, both Camellias and Azaleas 
are benefited by being placed for a period in 
the open air, in order that it may become 
more perfectly matured. 
We have not yet referred particularly to 
the operation of pruning, and mention it here, 
rather to caution against indulging too freely 
in the practice, than to recommend its adop- 
tion. It is by no means a natural process 
when carried to the extent which is frequently 
recommended ; and the only cases in which 
we can heartily speak favourable of its adop- 
tion, with reference to shrubby plants, is in 
the case of long, straggling, and rampant 
shoots, whose presence would be unfavourable 
to a neat and orderly appearance. Epacris, 
and Genista, in our list, may be referred to as 
examples of those which require such an 
occasional reduction of their branches : the 
majority, however, of those named, require 
little or no interference with their regular and 
natural form of growth. "While, however, in 
the case of hard-wooded, shrubby plants, we 
repudiate an extensive interference with their 
natural form of growth, there are others 
among those called soft-wooded plants, which 
are improved in their appearance by their 
being sometimes (generally annually) con- 
siderably reduced. Thus, Geraniums should 
be cut down to a stump, a few inches only 
from the pots, after they have done blooming, 
in order to secure compact and bushy plants 
for the following season. Fuchsias require to be 
pruned in, close to a single upright stem, or 
their branches become crowded together and 
confused, and the blossoms are not exhibited 
to advantage. Aloysia (the Lemon-plant) 
requires to be cut quite back, or it will become 
straggling. Roses generally require some 
pruning, or they become too large for their 
situations, and this should generally consist in 
the removal of an entire branch when they 
are liable to become crowded. In these, and 
many other cases, pruning may be resorted to 
as an expedient for the sake of securing 
certain desirable qualities which would not 
otherwise be obtained. 
We have appended a list of creeping plants, 
which are adapted to extend over the rafters, 
and thus ornament the roof of the green-house; 
and we consider the proper introduction of 
