TWO OR MORE HOUSES TO CULTIVATE ORCHIDACEOUS PLANTS. 85 
with moisture, and of course every individual plant inhales, according to its 
capabilities, an equal proportion of that moisture. It is scarcely necessary to state 
that some plants imbibe that moisture in an undue and unnecessary degree, and 
that where such is the case, it invariably proves to the same extent injurious. 
This can only be obviated by dividing the collection into at least two parts ; for 
it is notorious, that those plants of this tribe which require but little heat, also need 
little or no atmospheric moisture ; and on the contrary, such plants as thrive best 
in a high temperature, require a great degree of moisture to counteract the 
influence of the heat, and maintain the vital principle in full vigour. Therefore, if 
plants from temperate climates are kept in a house by themselves, there will be no 
danger of any of them being injured by excessive moisture ; and if those which are 
known to inhabit tropical regions are likewise placed in a house or a department of 
a house where others of opposite habits are not admitted, they may receive the 
requisite supply of humidity without suffering from the aridity of the atmosphere, 
maintained on account of the other sorts with which they are intermingled. By 
this system, likewise, the necessity of varying the degree of shading will be almost 
entirely precluded ; for it is obvious that those plants which require but little heat 
and a very slight degree of atmospheric moisture, will likewise generally be capable 
of enduring the full extent of the sun's influences, or at least will need less shading 
than such as are constantly and largely supplied with atmospheric humidity, and 
thus the whole of the plants in each house may be equally shaded, or nearly so. 
Nor is atmospheric moisture — by which term we mean the evaporation arising from 
water thrown on the flues or floor of the house, or, what is much better, from hot 
water kept in a cistern or boiler — alone to be considered here. Most, indeed all, 
cultivators of orchidacese, are accustomed to syringe their plants with water occa- 
sionally, some practising it to a great extent, and others applying it cautiously and 
sparingly. We do not, however, here intend to discuss the quantity in which it 
should be administered ; we only wish to deprecate the practice of applying it 
indiscriminately in this manner ; for to some species it is highly injurious, and not 
unfrequently does the injudicious application of it cause many of these plants to 
damp off and die. In this particular, again, the advantage of possessing two 
houses for the cultivation of these plants must at once be obvious ; for to some 
species the administration of water in this way is absolutely necessary, while, as 
we have above observed, the practice is highly detrimental, and even fatal to others. 
Indeed, where this division is effected, and the plants are arranged in two separate 
houses, according to their habits, it is necessary to use great discrimination with 
regard to the application of water by a syringe, as many plants require a much 
greater quantity of water administered to them in this way than others which may 
probably bear a great resemblance to them in habit. In short, it is incumbent on 
every individual who imports or receives plants of this tribe from foreign parts, to 
make strict inquiries whether they abound most in tropical or temperate regions ; 
whether they are found growing in shaded or exposed situations ; whether they 
