of the limbs of the pear do, moreover a dark fluid exudes (as the circulation is arrested where a patch occurs) in both cases alike, consequently if the remedy in both cases is based on the same principles, and is demonstrated to be equally effectual, the cause and the disease are similar. I have seen dry gangrene in the human subject originate apparently from an old "frost bite;" which means merely chronic debility of the capillaries of the foot or shin. Thus the extremities of the pear, or the weakest part, always succumb first, and the most vigorous trees never manifest it until they are weakened by their first crop of fruit. All are familiar with the fact that an old frost bite will swell or succumb to a temperature which will be innocuous to any other part of the body. The microscope may invariably reveal fungi in the patch of pear blight precisely as the housewife discovers the mold plant in her preserves and canned fruit, and even in the eggs of fowls, the mycelium (or spawn) penetrating the fruit or preserve though it be covered while boiling hot. If so, the reason why all parts of the tree are not attacked at the same time, is not because the fungus is not ubiquitous. We first notice the action of strychnia in the legs, or in paralyzed limbs exclusively, because they are weaker and become subject to its influence more easily; so also the same tree may escape for a long time after the limb which has succumbed is removed. Moreover the grafts, however numerous, may all be blighted, but the standard seedling on which so many varieties were grafted has survived more than fifty winters, and it fruited last year. DAVID STEWART, M. D. PORT PENN, DEL. TREATMENT OF TREE WOUNDS. Valuable trees that have been wounded or mutilated are often sacrificed for lack of the discreet surgery which would repair the injury they have suffered; and Professor C. A. Sargent, of the Bussey Institution, has done good service to farmers, fruit-raisers, and landscape-gardeners, by translating from the French the following practical hints, which we give with slight abridgment: