Every year when the lilac buds begin to burst their sheaths and until the full-blown clusters have spent themselves in the early summer air, the remembrance of Longfellow-something of his presence-wakes with us in the morning and recurs with every fragrant breeze. "Now is the time to come to Cambridge," he would say; "the lilacs are getting ready to receive you." It was the most natural thing in the world that he should care for this common flower,...