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.
In the February number, Mr. C. W. Seeyle in reply to my article on this subject asks if by what I say, I mean to convey the idea that the Dionaea is not carnivorous. I reply to this, that the results of my experiments went to confirm that impression, not only as regarding the shell snails of Mr. Smith, but also our own fly "feeding" of them, for as I have clearly stated, the result showed that no improvement was discern-able in those that had been "fed," over those that had not been "fed." Mr. Seeyle further ! says that from my remarks he is left in doubt, "whether the plants did in any sense assimilate or feed on the insects." I too am left in doubt in this matter except to believe that if they did "assimilate food " their digestive apparatus was in some way defective, for the "food" certainly did not add to their size or beauty. Mr. Seeyle mis-quotes me when he says I said "each plant was fed daily for three months" if he will look again he will see I did not say so, I said the 100 plants - meaning such of them of course as showed to be in condition to receive it were fed almost daily, the point with us being to place the insect in the trap when its indications 'showed it to be in the proper condition to close on it.
Any one who has seen the Dionaea growing in a healthy condition knows that each plant in the course of three months would develope from ten to twenty of these leaf traps, but developed of course, as the plant grows, - not all at once.
That being the case in our experiment, there was never at any time any "accumulation " of the insects, as Mr. Seeyle from his mis-reading of my article assumes there was. Then he triumphantly says: "If the insects remained upon and about the plants unappropriated by them, this ends the whole question." But unfortunately for the "ending of the question" the insects did not remain, they "dissolved," but whether their dissolution was due to one of nature's laws that we know something of - decomposition - or whether they were "assimilated" as Mr. Darwin would say, leaves the question, as far as my judgment goes, yet an open one. All that has been said yet by our experiments is only to flatly contradict those made by Mr. Francis Darwin as regards any improvement shown by such "feeding".
It would be edifying to know to enable comparison to be made, what means Mr. Darwin had for making his experiments, or how they were conducted. We have some knowledge of how such experiments are usually conducted by amateurs, and we have rarely seen them to be such as to give professional horticulturists much respect for the deductions they draw.
The question whether these plants thrive better with such "food " is not a subordinate one as Mr. Seeyle says it is. Darwin gives it as proof of bis extraordinary theory, and if experiments fairly made will show that such treatment improves their growth, over those not so treated, then he has gained a strong point. Our experiments made, we think under the most favorable conditions, and in the most careful manner showed conclusively that no change or improvement took place. Mr. Darwin had asserted that his "meat fed" plants were much better than those "unfed," and our trial was made solely in the interest of science and with the sole desire to get at the truth; and for that reason not wishing to place my single experiment against such an authority as Mr. Darwin, as having settled the question, I offered then, as I offer now. to send without charge, a sufficient number of plants of the Dionaea to any one who wishes to test the question, having the proper means to try the experiment.
Professor Beal, your other correspondent on this subject, raises what seems to me to be a very trifling objection to our experiment in saying that Mr. Francis Darwin's trial was with the Drosera rotundifolia, while ours was made with the Dionaea muscipula. But Mr. Darwin says that both these plants are insect eaters, and inasmuch as they are near relatives of the same family (Droseraceae), surely if one improved by being "meat fed" it was fair to presume the other would. Professor Beal further says that though he tried to feed his tomatoes through their glandular hairs with beef soup, but damaged them thereby, it probably having been too strong, he does not think that such failure has overthrown Mr. Darwin's theory. In this I entirely agree with him. Such an experiment would never be likely to overthrow or confirm anything.
The question whether or not certain plants are insect-eating is not yet settled; that the wondrous rat-trap like structure of the Dionaea leaf should make men jump to the conclusion that nature designed them to eat the insect that they caught is not to be wondered at; but that it is certain that after catching their prey they devour them, we do not think has been proved by Mr. Darwin or any one else. Nature shows many such instances where insect life is " trapped " by plants. The gummy exudations from scores of different species of plants are covered with insects, the butterfly and bumble bee are found impaled on the spines of the thistle and the burdock; the pond lily, Nymphea alba, spreads its petals in the sun light, and when night comes and closes them, scores of insects are often found imprisoned in a single flower. The Physianthus albens, which Professor Thurber has well named the "cruel plant," catches almost every unfortunate moth or but-terfty that tries to sip the nectar from its flower cup, and dozens may be seen dangling dead and dying from a single plant; but are these trapped for the purpose of being "assimilated" by the plants? Certainly not, yet when we find the Diona?a closing on a fly and holding him there, (it will close on and hold a wad of moist paper or cotton exactly the same), it is said that it kills to eat.