"'When a growing branch,'" read Miss Harson, "'is broken off, the remaining portion becomes charged with resin,' which is deposited by the resin-bearing sap of the tree, 'forming what is called a pitch-knot, extending sometimes to the heart. The same thing takes place through the whole heart of a tree when, full of juice, its life is suddenly destroyed.' 'Resin' is another name for turpentine, but is used of it commonly when hardened into a solid form. The tar is obtained by slowly burning splintered pine, both trunk and root, with a smothered flame, and collecting the black liquid, which is expelled by the heat and caught in cavities beneath the burning pile. Pitch is thickened tar, and is used in calking ships and for like purposes."