In- order to be successful in the ordinary routine of a garden, or in the culture of either fruits, flowers, or vegetables, there are certain natural laws relating to light, heat, air, soils, and moisture, which must be fulfilled. These laws, or axioms of vegetable physiology, are either directly or indirectly understood by most of our practical horticulturists; but, at the same time, I have often thought that our present subject has not been studied or worked out in practice so much as it, from its importance to mankind in general, deserves. Our success in the cultivation of fruits, flowers, or vegetables, depends in a great measure on the selection of good varieties, according to the particular season of the year at which the crop is required. To illustrate more fully the results of careful selection, we need only point to the magnificent new Grapes of a Thompson, a Pearson, or a Standish; the beautiful Fuchsias of Cannel or Smith; the zonal Pelargoniums of Turner, Grieve, or Wills; or the Peas of Laxton, - to say nothing of other horticulturists whom we could name by the dozen did our space permit, and who equally deserve our admiration and respect.

The improvement of races is one of the most noble of all pursuits; and by devoting some portion of our lives to this laudable object, we not only reap in many cases a rich harvest ourselves, but we leave a goodly heritage to posterity - a monument more durable than either gilded marble or burnished brass. To come to a practical argument, the improvement of existing forms or races depends in a great measure on the judicious selection of the pollen and seed-bearing parents, added to a careful weeding out of the seedlings themselves, so as to insure as far as possible constitutional vigour. It often occurs that the most lanky and debilitated seedlings will produce the finest or richest-coloured flowers; but seedling cross-breds, or hybrids that have a bad habit of growth, should never be tolerated, except to cross with plants of a better habit and better constitution. A plant of any kind, to be perfect in its class, must have the best habit of growth as well as the finest flower or noblest fruit; for to obtain a fine flower or fruit at the expense of a neat habit, or of constitutional health and vigour, is at the best only a questionable improvement.

Florists' flowers afford us familiar examples; but if we look at either stove or greenhouse plants, Orchids or Ferns, we often find extreme variability in the habits of different individuals of the same species, or in the relative size, colour, period, or profusion of their flowers. It is these distinctions that give us the opportunity of exercising our judicial powers of selection, and the practical result is the propagation of those marked forms best suited to our tastes or requirements, as the case may be. The best varieties of plants give no more trouble to the cultivator than do inferior forms of the same species, often much less; hence we may reasonably infer that by growing carefully-selected varieties we shall be amply repaid by a better return for our time and capital than would be the case were the plants we have to grow taken without any, or but slight, discrimination. The variability of species is not confined to our plant-houses or gardens, but extends to the lawn and shrubberies - nay, to the primeval forest itself.

The observant cultivator may everywhere note nature's "masks and faces;" and if wise, will turn this specific variation to good and useful-account.

Those interested in Coniferse must often observe the variation of such beautiful species as Abies Canadensis, Cedrus deodara, or the Chilian Pine, Araucaria imbricata. While inspecting the rich collection at' Elvaston Castle some little time ago, the head-gardener, Mr M'Kellar, pointed out some striking forms or varieties of the above and other species. This variation, with regard to the last-named species, we have also observed in the collection of Lord Poltimore, near Exeter, South Devon.

In the improvement of races great care and attention must be paid to the condition of the seed-bearing plant. The state of fruition in the vegetable as in the animal kingdom demands the highest possible state of. health and vigour; and it may not be out of place to remark that debilitated or unhealthy plants, or such as by local causes are dwarfed or stunted in their growth, frequently produce enormous crops of fruit or seed. This is in many cases the last effort of expiring nature to reproduce, herself, although the seed borne by exhausted plants seldom produces a healthy progeny: indeed, it is as reasonable to infer that a debilitated plant can never produce a vigorous progeny, as that consumptive parents never produce healthy offspring. This last remark will of course apply with equal force to cuttings and grafts taken from diseased or cankered plants or trees.

Many of our finest varieties of Camellias, Azaleas, and Chrysanthemums have been obtained from what are technically called "sports;" and in the first-named genera it is common to meet with bud-variation fully illustrated by white flowers being borne on coloured varieties, or vice versa. When these bud-variations are exceptionally fine, they may be in some degree fixed by grafting the portion of the branch affected, and thus perpetuating what, if left to itself, would in all probability have reverted to its original form. When we come to the aristocratic Orchids, we find this protean variability illustrated in the superlative degree; and it is here that the cultivator has full scope for his judicial powers of selection. Cattleyas are almost proverbial for their dissimilarity, and C. Mossise and C. Trianiae of all others sport into the most beautiful varieties imaginable. These, like the forms of some Dendrobiums, vary greatly, not only in the relative size, form, and colouring of their sepals and petals, but also in constitutional vigour and their season of blooming.

This last interesting fact enables us to use our selective faculties judiciously in order to prolong the natural blooming season of each species; for if we select the extreme forms, or those which flower a month earlier or later than the common variety, then we have that species in bloom three months instead of only one - a result well worth attempting. Our desultory remarks are intended to be suggestive rather than directly instructive to the practical horticulturist, and the ideas here thrown out may form a nucleus around which those of others may cluster like the richly-laden Vine to the bare trellis, or refined gold to the earthen crucible.

F. W. Burbridge. Fairfield Nurseries, Manchester.