Bark-bursting

- This occurs on thrifty young api)le trees near the ground, and is often a souree of serions loss and sore chagrín to the nurseryinan who lias taken pride in the f ree and liandsouu! growth of his trees throngh the season, when, near the close of the egpecially ln-atitii'ul. insectCree second growth, he ïimis on aome soft and balmy Septemher inorning that liis very thriftiest and flnest specimens have their bark split and detached. It used to he thouglit that freezing of the abundant liquid sap oecasióned this. lint tlien it occurs as frequently liefore the first autunm frost as alter it. The sim lias been supposed to cause it, because it is oftner seen on the southerly side oi the stem than on the north. Bui sometimes; like the tides, H oceurs on both sides at once. The useful Collie Quarterly prints a theuryof explanation given by sonie Germán observéis who luive made this phenomerion a special subject of study. They say that the protoplasm tn the cells of "the newly formed wood and bark is extremely hyo-rosropie, imbibing water and sweiling like a sponge. The aggregate force of expansión of tliousands Of cclls is siiiliciont, certainly, to account for the disruption. The editor adds the remark tliat some ssrts of trees, more liable to Imrst in this way, seem to have an open hark whie'h linbibes water ironi w itliout readily. Some èrial inlluence is implicated, lor we always lind the injury at or just ahpve the surface. sudden ehangeóftemperatui-e. probáWy deterssmes the actual crisis oí the