In these early years in London Huxley's work was most varied. A large number of anonymous articles by him appeared in the _Literary Gazette_, and in other periodicals. He assisted to remove the insular narrowness from English scientific work by translating many foreign memoirs. With the collaboration of Mr. Henfrey, he edited a series of scientific memoirs, all of which were translated from foreign languages, and many by his own pen. With the assistance of Mr. George Busk he made a translation of Kölliker's _Histology_, a great treatise on microscopic anatomy which played a large part in the development of the modern English schools of anatomy and physiology. He made some valuable contributions to Todd and Bowman's _Cyclopædia of Anatomy_, an elaborate publication now nearly forgotten and practically superseded, but which was the standard anatomical work of the middle of this century. He was unable to progress rapidly with his work upon oceanic Medusæ, as he was uncertain how to have it published; the Admiralty refused to assist, and it was too lengthy for publication in the volumes of the learned Societies. As a matter of fact, he did not publish it until 1858, when it appeared as a separate memoir. To the _Quarterly Journal of Microscopical Science_ and to the _Transactions of the Royal and Linnæan Societies_ he contributed a large number of memoirs dealing with the microscopic anatomy and relationships of invertebrates, and, lastly, he gave a series of addresses at the Royal Institution, which had been founded as a means by which leading men of science might give accounts of their work to London society. Abstracts of these lectures are published in the early volumes of the _Proceedings of the Royal Institution_ and are interesting as shewing the kinds of zoölogical subjects which were attracting the attention of Huxley and which he considered of sufficient interest and importance to bring to the notice of the general public. The first of these lectures, and probably the first given in public by Huxley, occurred on April 30, 1852, and was entitled "Animal Individuality." The problem as to what is meant by an individual had been raised in his mind by consideration of many of the forms of marine life, notably compound structures like the Portuguese man-of-war, and creatures like the salps, which form floating chains often many yards in length. He explained that the word _individual_ covers at least three quite different kinds of conceptions. There is, first, what he described as arbitrary individuality, an individuality which is given by the mind of the observer and does not actually exist in the thing considered. Thus a landscape is in a sense an individual thing, but only so far as it is a particular part of the surface of the earth, isolated for the time in the mind of the person looking at it. If the observer shift his position, the range of the landscape alters and becomes something else. Next there are material, or practically