Dear Sir: A Washington letter-writer in the Traveller, comparing the Chinese sugar-cane with that grown in our Southern States, and referring to the mode of propagating the latter (by cuttings), says: "In the case of all plants propagated by cuttings, there is a constant deterioration; so that, in many parts of the South, the growth of cane is not over two-thirds what it was some years ago, and that on an equally fertile soil." Is this principle correct? If so, what is to become of our quinces, and some other trees propagated mainly by cuttings? R. J. B.

The principle is not correct. Some years ago, it was supposed so by some physiologists, because some kinds of plants were showing signs of decay that had mostly been propagated that way. We might with as much reason say, " all the American buttonwood that we have seen diseased were seedlings; therefore there is a deterioration in all plants raised from seeds." Is the deterioration noticed in western districts once famous for their wheat crops, to be attributed to its being always a seed crop? We sometimes jump at conclusions when it would be safer to travel slower.

Saint Catharines, C. W., Deo. 15,1856. Sib: A great number of fruit-trees have been destroyed in our port of the country, during the past year, by mice. I bare planted an orchard, this fall, of peach and apple-trees, and find the mice commencing their depredations. Can yon inform me of a remedy f And also, if what I hare done is likely to prove one, viz: smearing the stem, with tar from gas-works, from the ground to about one foot up? Is the gas tar an injury to trees?

Yours, obediently, James Taylor.

There is a singular difference of opinion amongst practical men as to whether gas tar does or does not injure trees applied in the way you suggest. We have applied it to prevent the attacks of the peach and apple borers, smearing the stems below, and two inches above the ground, achieving our object, and without the slightest perceptible injury to the tree. Yet we know cultivators whose opinions and statements we place full reliance in, who say that their experiments with it have injured their trees. It is an excellent means of preserving trees from mice, and, to be on the safe side, tie coarse paper or leather round the stem, and tar that. Scatter, besides, as our friend - Alan Corson - recommends, a few prunings under the trees. They will eat these when the desperation of hunger might otherwise, perhaps, encourage them to brave the tar.

(Brevitas.) We are afraid we hardly comprehend your question. A "list of the principal vegetables, with the soil and manure suited to each," would go far to exhaust a complete treatise on kitchen gardening. If we understand your want correctly, we could not do better than recommend you to procure Buist's Kitchen Garden Directory, You will probably succeed very well with your melons - provided you do not get them too weak by keeping them too long in your hotbed, or too far from the glass.