A very serious question has been agitated since a great many years: that of the extinction of varieties by time. About twenty years ago, it was discussed in our horticultural papers, and then the great majority was in favor of the belief that all varieties would be rendered perpetual by grafting, or any other mode of propagation.

I have always been of opinion, that all living beings have received from nature a certain longevity, and must, at its expiration, cease to exist. But I am not quite convinced, that that limit cannot be extended by grafting, or any other mode of multiplication. It was discussed Sunday last, at my table, by four eminent horticulturists. They are all of opinion that the extinction must take place some day or other, but they are divided as to the possibility of prolonging the existence of plants by artificial means.

As it is a very important question, particularly for fruit treees, I call your attention, and that of your readers, to the subject, and should like to see it discussed seriously to obtain a conclusion. I am of opinion, that if fruits were not renewed by sowing, we should, after a while, be deprived of those we now possess; and that, if since the beginning of this century, some people had not addicted themselves to sowing, we should not possess the excellent varieties of apples and pears now existing.

If the question is settled about the extinction by time, it is necessary to encourage sowing by selection. I suppose that no one knows the medium existence (life-time) of fruit trees, and I suppose that it has not been studied. We know, and everyone knows, the duration of annuals and bi-annuals; but no one, I suppose, that of the so-called perennials. Can it be done? If so, I think that the study ought to be undertaken as soon as possible.

Notwithstanding what precedes, I am of opinion that grafting has been a splendid discovery, and must be largely practiced; and also that the influence of the stock on the graft, must be carefully studied and not neglected, because till now a great many propagators have overlooked it, and have sown the seed for stocks at random> without attention to the natural and universal law of variability.

Monplaisir, Lyons, France, July 8th, 1886.

[When our correspondent states that "no one has been able to fix the medium of existence or life-time of a fruit tree," he hits on the real essence of the question. Unless we settle this question at the beginning, the discussion may never end.

The advocates of limit say, that a tree cannot live beyond the life-time fixed by nature; and hence grafts or cuttings taken from trees that have passed this life-time, will give only diseased trees, which will soon die.

If the advocates of persistency point to a Red Dutch currant that has been reproduced by cuttings for centuries, or the Bergamotte d'automne, or some other old pear that has been grafted for hundreds of years, still as healthy and as sound as ever; or Jerusalem artichokes or sweet potatoes, that year in and year out have been propagated by sets, without once getting a renovation from seed, and still going on as if they would do it forever, the limitationists simply shrug the shoulder and say: "Oh, yes! they have probably not reached the life-term allotted to them".

There is therefore no use in arguing till we decide what is "the life term?" So far as we know, there is no such thing so far as plants are concerned.

If we are to take the question in a general way, as put here, " Is it possible to prolong the existence of plants by artificial means," as involving the whole question in dispute, every-day experience in gardening shows we can. There is nothing more perfectly an annual than the sunflower, Helianthus annuus. A year is its "natural life." But the writer of this well remembers that when a boy, his father delighting in a very dwarf and very double sunflower, and wishing to keep just that kind, kept it for years by cuttings; and we have no hesitation in saying that any one may keep a plant of an annual sunflower going on in this way for his whole lifetime, and his grandchildren or great-grandchildren may continue from where he ceased. Florists continually propagate annuals from cuttings, and keep the variety for years without limit in that way.

We do not wish to cut off the discussion invited by our friend. We would rather welcome it, but as "our attention," as well as that of our readers, is called to the subject, we unhesitatingly record our sentiments as wholly against the limitationists, though perfectly willing to be converted should good evidence be adducced. - Ed. G. M].