This section is from the book "The Gardener's Monthly And Horticulturist V21", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
You sometimes have your say about the English journals discussing matters easy of solution, self-evident, and long ago proven to the satisfaction of every one on this continent at all interested, etc. Now I find you devoting considerable space to a question of little practical importance to anybody, viz., whether leaves absorb moisture - which they sometimes do, of course - or whether the presence of moisture in the atmosphere checks evaporation - which is equally a matter of course.
I agree in the main with Peter Henderson's logic, but think the absorption question could have been more practically settled by his taking a well-wilted plant, weighing it after divesting it of every particle of soil, immersing the leaves alone in water, and then weighing it again after recovery by such immersion. A gain in weight will be found in the case of nearly all plants except aquatics, whose leaves frequently repel moisture.
As for the question whether such moisture enters the circulation, that is not so easily answered; the professors interested must use water colored by some very finely triturated pigment if they wish to settle that question. The Brom-eliad business settles something. Their structure enables them to withstand severe droughts, as does that of Cacteae, and even of many Or-chideae, Nepentheae, Cycadeae, Filices, etc., etc. They can wait quite a time without either roots or leaves for the moisture which will encourage them to put forth what stands for both, and they will unquestionably absorb it through their pores without any roots at all in the soil, and often without any discernible ones out of it. I need give no instance beyond the cutting of a Den-drobe, the stem of a Cycad or an Oleander, any of which will begin to grow suspended in an atmosphere constantly at the point of saturation. Nay, I cannot omit a more remarkable instance. I have frequently seen that pest of the coffee estate, Ageratum Mexicanum, grow for weeks when accidentally thrown by the weeders among the branches of the shrubs during the monsoons.