These two prove excellent foils for the stronger personages of the story, and afford much amusement. "A Mortal Antipathy" is less of a romance than the others. The reader will be interested in the description of a boat race which is exquisitely done. In biographical writing, we have two books from Dr. Holmes, one a short life of Emerson, and the other a memoir of Motley. Though capable of writing a great biography like Trevelyan's Macaulay or Lockhart's Scott, the doctor has not yet done so. Of the two which he has written, the Motley is the better one. In neither, however, has the author arrived at his own standard of what a biography should be. Mechanism in thought and morals,--a Phi-Beta-Kappa address, delivered at Harvard in 1870,--is one of Dr. Holmes' most luminous contributions to popular science. It is ample in the way of suggestion and the presentation of facts, and though scientific in treatment, the captivating style of the essayist relieves the paper of all heaviness. A brief extract from this fine, thoughtful work may be given here:-- "We wish to remember something in the course of conversation. No effort of the will can reach it; but we say, 'wait a minute, and it will come to me,' and go on talking. Presently, perhaps some minutes later, the idea we are in search of comes all at once into the mind, delivered like a prepaid bundle, laid at the door of consciousness like a foundling in a basket. How it came there we know not. The mind must have been at work groping and feeling for it in the dark; it cannot have come of itself. Yet all the while, our consciousness was busy with other thoughts."