"Before a nature so fearless, and so fertile in expedients, obstacles speedily vanish, and young Crosby found himself in possession of a large and responsible practice, even before taking his medical degree, and at the early age of twenty-three years. The following year (1824) he graduated in Medicine at Dartmouth (having passed his examination in November preceding), and for ten years remained in Gilmanton, in practice with his father. He then removed to Meredith Bridge, now Laconia, N. H., where he practiced for three years; and in 1838 was called to the chair of Surgery in Dartmouth College, then recently made vacant by the resignation of the late Dr. Mussey. In this field Dr. Crosby found at once full exercise for all his large resources of head and heart and hand. As an instructor he was clear, direct, and definite,--imparting, to his pupils his own zeal, and teaching them his own self-reliance. 'Depend upon yourselves, young gentlemen,' he invariably said. 'Take no man's diagnosis, but see with your own eyes, feel with your own fingers, judge with your own judgment, and be the disciple of no man.' "In his class, he was courteous without familiarity, patient with dulness, but quick to punish impertinence; always kind, always dignified, always genial. The practical view of a subject was the view which he delighted to take; and the dry humor with which he never failed to emphasize his point, at once fixed it in the memory of the class, and made it available for future use. With his office-students, Dr. Crosby was the very soul of geniality and confidence. He saw and measured men at a glance, and was rarely wrong in his estimate of character. Strong in his own convictions, he was yet tender of the infirmities and the prejudices of others, and his generous instincts lost no opportunity for their daily exercise. "His love of nature was as instinctive and as thorough as his knowledge of men. He transferred the treasures of the woods to his own garden. He studied the habits of birds and insects, and his parlors were adorned with a cabinet of American birds more complete than is often found in the museum of a professed naturalist. He reveled in the 'pomp of groves and garniture of fields,' and his daily drives through the picturesque scenery of the Connecticut valley fed his æsthetic taste, and proved a compensation for fatigue.