Is there any connection, either in cause or effect, between blight in pear-trees and the substance called honey dew? We have had both here, to an unusual extent, and the latter more largely on pear-trees than any other, though found on almost all kind of trees. I have two large pear-trees, planted more than thirty years ago (one a wilding), brought in from the fields when small, and planted in the orchard. This has grown freely, and was never affected with blight till this season, and now, large upper limbs, near two inches in diameter, are dead; two of the branches grafted, of late years, with the Bergamot and White Doyenne, are somewhat affected, but not so badly. The other tree was an ordinary fall pear, grafted on the root of a white thorn, and is probably now mostly on its own roots, as the graft was inserted beneath the surface of the ground, and the tree has grown freely but not rapidly. This is scarcely touched with the blight, except some of its upper branches that have been grafted latterly with other varieties, to bring them into early bearing.

This tree exhibited the substance called honey dew, to a greater extent than I ever noticed before; the young shoots of the present year, the stems of the leaves, and the surface of the leaves themselves, in many places were literally covered with it, and it fell in drops to the ground. We have about one hundred varieties of pear now planted within the last ten years, and all exhibited this substance more or less. Even the forest-trees showed it on their leaves to an unusual extent, this season.

But what is honey dew? and has the cause of its production anything in common with what we may suppose to be the cause of the pear blight? Without assuming the affirmative, it might be well to examine the subject a little, and obtain what light we can on this or any other subject connected with vegetable growth. The most plausible theory that has occurred to me, is this: We know that in almost, if not quite all trees, the first flow of sap, in the spring, contains saccharine matter; this appears to be elaborated in the pores of the wood, from the matter brought up by the sap previous to the suspension of the circulation by cold. A long, regular cold winter, is most favorable for its production; hence the region 2° or 3° north of us, is better for sugar making from the maple than this latitude. But this winter here, has been, for length and for cold, more severe than they often have there, thus producing more saccharine matter here, in trees, than usual. The past winter has been one remarkable for sugar making in the Northern States. This saccharine matter, in the sap particularly, when abundant, might be supposed to obstruct the circulation, and even if not sufficiently to produce the blight, it at least does so enough to cause the leaves, to fall off.

The observance of this fact first led me to examine the cause, when I found the young shoots with the stems ami much of the surface of the leaves coated with this adhesive substance, which appeared plain to me must obstruct the evaporation of the sap from the leaves, and, at the same time, prevent the absorption of the carbonic acid gas of the atmosphere, thus producing a weakness in growth that caused many of the leaves to fall.* Perhaps the week or ten days of mild weather we had in the midst of winter, was favorable for the production of sugar in the sap, as it is well known that such weather after cold weather, is favorable for sugar making.

The wood of the pear-tree is hard and compact, and the pores small; and may it not be possible that, under certain circumstances favorable to a large production of saccharine matter in the sap, the sap may be so thickened by it as to stop the circulation entirely, and then putrefy?. Large numbers of the small spurs on our apple-trees are affected the same way this year, disfiguring our trees very much and very generally. There must be a cause for this; and may not this be the reason why our fruit set so badly this year? Trees that were heavily loaded with bloom, scarcely set any fruit; indeed, I have seldom known so general a failure, except from late severe frosts; but, this season, we had none after blooming. Some suppose the failure was caused by rainy weather; but that does not appear satisfactory to me. We had rain, also, when our grape-vines were in bloom, and we have seldom had them to set so freely. I should like to hear, through the columns of the Horticulturist, whether the effect has occurred in other places.

It has very generally been supposed to be favorable to the blight, when, after a dry summer, a wet fall, favorable to late growth, occurs, and then an early and severe winter; but this was not the case the past season. We had both a dry summer and fall, no late growth encouraged, and the wood certainly was well ripened generally; the winter, it is true, set in early and pretty severe.

The following varieties of pear have suffered badly with us, this year: Messire Jean and Glout Morceau, Hacon's Incomparable, Easter Beurre, Doyenne Oris Jaune de hivre nouveau, Ananas d'Ete, Beurre d'Esperen, on pear roots; and Swan's Orange, Belle Lucrative, Ananas d'Et6, Beurre de Ranz, on quince. Slightly affected: Louise Bonne de Jersey, Napoleon, Bergamot, Urbaniste, Jargonelle, Bartlett, Heathcot, Surpass Vergalieu, Beurre d'Aremburg, and Ott; the remainder (amounting to upwards of ninety varieties) of those most recommended in the books, are uninjured. Our grounds are rolling, and naturally well underdrained.