The Structures of the Hydrogen Molecule and the Hydrogen Ion.

ON this mmorable and, beautiful occasion I bave the cherished honor of having been chosen to perform, as it were, the duties of chronicler, in order that we may all be led to review in our minds the successive steps by which our great leader and master rose to such high distinction and wrought the miracle of giving to medicine a new birth in this country; and in order, also, that our successors, lighting their lamps at the shrine of Pathology and studying the treasures which these precious volumes enclose, may catch a gleam of what mnanner of man he was who produced them, and by the vigor of his living example and the charm of a rare personality, as well as by the ,power of his spoken and written word, in the short span of a lifetime raised medicine in the United States from a beneficent art to an expanding science. William Henry Welch was born in Norfolk, Connecticut, April 8, 1850. He was the son of William and Emeline (Collin) Welch. His father was a practising physician, as were four of his father's brothers. Moreover, a great grandfather and grandfather were also physicians., When about one year of age, William Henry',s mother died; thereafter he was