Deep cavities caused by rot are cleaned out, disinfected with bordeaux mixture, gas-tar, or other material, and the place filled completely with cement. In some cases, new wood is added in the form of cions of last year's twigs. Such cions may be set around the edge of a stub, thrust between the bark and the wood, to start new branches where an important one was broken off. The cions are cut wedge-shape (much as those in Fig. 18) and a bandage is tied around the stub to hold them in place; the exposed parts are covered with grafting-wax. The operation is performed in spring. Sometimes cions are used to bridge a girdle. Usually a girdle heals itself if the injury does not extend into the wood, and if it is bound up to prevent drying out; but when the injury is deep and the exposed wood has become dry and hard, the cions may be used. The cions are somewhat longer than the width of the girdle. The edges of the girdle are trimmed to fresh tight bark; cions are cut wedge-shape at either end; the ends are inserted underneath the bark at bottom and top of the wound; edges of the wound are securely bandaged; entire work is covered with wax. The cions are many, so close that they nearly touch. The buds on the cions are not allowed to produce branches. This process is known as bridge-grafting. With some experience, the cultivator soon learns to make many deft applications of ingrafting. Sometimes a piece of bark may be used as a patch. In the bracing of crotches in young trees, the two trunks may be joined by uniting a small branch from either one, twisting them together to form a bridge like a bolt; they can be made to grow together, forming a solid union. Bolting the parts with iron rods, or holding them together by means of chains, is the usual and commonly the better method. The iron is not to go around a limb, however, for girdling results; the rods or chains should be secured by bolts bored through the wood and pulling against large heads or washers. The usual repairs are easily made. When trees are badly injured, and particularly when the tree is low in vitality, it may not be worth while to engage in surgery. It may be better to plant a new tree. Saving very old trees by the mending processes is not likely to be satisfactory. The grower should transfer his affection to a young tree. If the tree has had good care throughout its life, it probably will not need much surgery in old age. The grower will be willing, when the time comes, to take a photograph for memory's sake and to let the tree come to a timely and artistic end. XIV CITIZENS OF THE APPLE-TREE Many years ago, my old friend, the late Dr. J. A. Lintner, State Entomologist of New York, compiled a list of 356 insects that feed on the apple-tree. Later authorities place the number at nearly five hundred species. It must be a good plant that has such a host of denizens. The number of fungi is also large; and the tree often supports lichens, algae, and other forms of life.