you use liquid manure for your plants. That is entirely a matter for your own 
judgment. I can only say that I am fully satisfied with the results that I have 
obtained from its use. 
Although Orchids, like other plants, obtain a large portion of their nourish- 
ment from the salts absorbed from their compost, they also obtain some very 
essential elements directly from the atmosphere which surrounds them. Their 
respiratory processes have much in common with those of animals. Both ani- 
mals and plants breathe air and both have internal cells or cavities into which the 
air may enter and be modified. In the case of the animal, however, its lungs 
extract oxygen from the air, and expel the carbon-dioxide; in plants the oxygen 
is thrown off and the carbon-dioxide is retained to supply the carbohydrates that 
are used to build up plant tissues and to help supply the sugars, starches, etc., 
which it needs. If you examine the leaf of an Orchid under a very powerful glass 
you will find that its whole surface is covered with tiny pores, and through these 
the air enters into the internal air chambers. Packed closely round these air cham- 
bers are myriads of tiny cells which contain the green chlorophyll grains giving 
the leaf its typical colour. These chlorophyll cells absorb sunshine, and use it to 
break down the carbon-dioxide, and extract from it the carbon for the use of the 
plant. The chlorophyll cells can work only in comparatively bright light, and, 
during the night or under cloudy or dark conditions, the guard cells, which nature 
has provided about the breathing pores, change their form, and by shutting out 
the atmosphere and shutting in the water of the plant, prevent useless evapo- 
ration. 
You will remember that I mentioned, in regard to the equatorial band in 
which Orchids grow naturally, that one of the characteristics of the climates 
there, was strong sunlight for the greater part of the year. This implies a very 
high activity on the part of the respiratory organs of the plant, and, having regard 
to the pithy, firm nature of the stems or pseudobulbs of the great majority of our 
epiphytical Orchids, we know that this must be the case. It follows from this 
that in order that our plants may be able to obtain a sufficiency of carbon to build 
up strong, vigorous, floribundant pseudobulbs or stems, we must give them ample 
air and light. Orchids grown under dark, stuffy conditions will be puny and 
weak, and will lack strength to resist the attacks of disease and parasites, or to 
produce flowers in the quantity and quality characteristic of the species. In many 
cases, I believe that light is of greater importance than temperature for the suc- 
cessful growing of a plant. 
I have endeavoured to give you some idea of the natural laws 
underlying the nutrition of plants, and to show you how to use these laws to im- 
prove your Orchids. I know that quite a number of Orchid growers are rather 
sceptical as to the advantages of the application of science to their hobby. But if 
they will compare the results obtained from present-day methods with those of 
older days, I am sure that they will find out that the passing years have brought a 
greater understanding of the needs of Orchids, with the result that losses have been 
reduced to a fraction of what they were, and that the plants of to-day are, for 
the most part, stronger and healthier, and flower more regularly than ever before. 
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