The theory of some horticultural writers, that in the most of our cultivated fruits the fruit is but a swollen capsule, inclosing the true fruit, the seeds, always seemed to me sufficiently reasonable to be accepted without much investigation; and the occasional occurrence of a variety of which the seeds are generally abortive, did not appear worthy of being received as aught but an exception. This season, my adherence to the theory has been severely shaken by the circumstance which I am about to relate.

It may not have escaped your memory, Mr. Editor, that in June last (1859) a frost of terrible severity devastated orchards and gardens to an extent rarely experienced. I at first was not alarmed for my fruit, a cursory examination satisfying me that the most of the crop was safe; but being incited to a more thorough investigation by the fearful reports of my neighbors, I was appalled by the conclusion which forced itself upon me. Upon cutting transversely through the cores of a large number of apples and pears, I found a very small proportion apparently sound - on some trees, scarcely any; of the remainder, the core was blackened, and the seeds, to all appearances, quite destroyed.

I at once gave up for lost the greater part of my crop, and expected to see the young fruits shortly dropping from the trees, leaving but an occasional specimen. Many did so fall, but I was surprised at the quantity which remained, although I did not fairly allow myself to be convinced that they were safe, until the season was far advanced.

The summer varieties were shortly approaching ripeness, and I found a large number of pears, when fully mature, wonderfully gritty at the core: so woody were they, that to cut one across was nearly as difficult as to sever a branch.

Attributing this, of course, to the action of the frost, I expected to find the later varieties similarly affected; but in this I was pleasantly disappointed. Pears, as a general thing were rarely finer, and even on trees where I had scarcely found any sound specimens, there was a fair crop. Even many of the fragments left attached to the tree after amputating the larger portion, swelled to a fair size and ripened well, although there was but the vestige of a core, no entire seeds (usually none at all) remaining. These specimens bore some resemblance to an obtuse fig, the dissected portion cicatrizing with a brown scar, and the cut edges closing over with a rounded lip.

This fact seems to me to conflict with the theory before mentioned, and would appear to indicate that a fruit is a fruit after all, and not a capsule, fleshy or not fleshy. If the existence of the fruit is secondary to that of the seed, why should the former swell and ripen, without the presence of the latter?

Grapes, when the seed fails to set, rarely swell to any extent; I had many bunches spoiled for this reason by the frost. And I had sent me a most beautifully formed miniature bunch of Hamburgh, in which there was not a seed, nor was there a berry much larger than duck shot, yet all perfectly colored and ripened.

These injuries were undoubtedly the result of cold acting upon the flowers, when about setting, and I do not see why the pear fragments should swell and the grapes not do so, except for the reason that the pears were injured after, and the grapes before setting.

I should like to see the opinions of yourself, Mr. Editor, and any of your correspondents who have investigated these points, for I do not remember any authority which quite covers the case.

[A "Young Pomologist" has opened an interesting question, which some of our readers may feel disposed to discuss, especially in its botanical bearings, which we may refer to again. Pomologically, we do not consider the seed a necessary part of the fruit, though generally present; for we have seedless Grapes, Oranges, Persimmons, etc, and it may not have escaped the notice of our young friend, that the effect of high culture and hybridizing is to reduce the number and the size of seed in fruit generally. We think the influence of the frost will sufficiently account for the small size of his grapes, without recurring to the absence of seed. We have now before us some samples of Black Hamburgh Grapes from Mr. Ellis, in all respects beautiful; bunches weighing two pounds, berries large, well colored, with a very handsome bloom, all indicating a high degree of culture; but not one berry in six has a seed in it; and this fact we have often noticed in the best grown grapes. If a "Young Pomologist" will direct his observation to points like these, we think he will find additional testimony that " the seed is not a necessary part of the fruit." We hope he will do so, and let us know the result. - Ed].