I had as an eager reader of memoirs on biological subjects become acquainted with Metchnikoff's earliest publications in 1865, when he was twenty years of age and I two years younger. I wrote short accounts of them, as they appeared, for a chronicle of progress in the _Quarterly Journal of Microscopical Science_, then edited by my father. Those on a European Land Planarian, on the development of Myzostomum (the parasite of the Feather-Star), on Apsilus, a strange new kind of wheel-animalcule, and his protest against Rudolf Leuckart's treatment of him in the matter of his important discoveries concerning the Frog's lung-worm--_Ascaris nigrovenosa_--remain in my memory, and later, in 1872, I was especially struck by his important demonstration of the true mode of development of the gastrula of the calcareous sponges in correction of Professor Ernst Haeckel. Many other papers of his became known to me, until in 1881 he published his first observations on _Intracellular Digestion in Lower Animals_, which was the starting-point of his life's work on "Phagocytosis," to which all his subsequent researches--during thirty-five years--were exclusively dedicated. In 1888 I was introduced by my friend Lauder Brunton to the great Pasteur, and called on him at his laboratory in the rue d'Ulm. There I met Metchnikoff, only lately arrived from Russia, and welcomed as one of his staff by Pasteur. The next year, 1889, Pasteur was installed in the new "Institut Pasteur" in the rue Dutot, and I met Metchnikoff there in his new quarters. Pasteur's assistants were carrying on daily his system of inoculation against rabies, and many British subjects were amongst those treated. I persuaded the Lord Mayor of that year, Sir James Whitehead, to visit the Pasteur Institute with a view to taking steps to make some recognition of the services rendered by Pasteur to our fellow-countrymen in treating over two hundred of them threatened with hydrophobia. Sir James called a meeting on July 1, 1889, at the Mansion House, and placed the management of it in my hands. As a result we obtained subscriptions to a fund which enabled us to assist many poor British subjects to visit Paris for the purpose of undergoing M. Pasteur's treatment, to make a donation of 30,000 francs to the Pasteur Institute, and to initiate with a sum of £300 the formation of a fund for the purpose of establishing an Institute in London similar in purpose and character to the Institut Pasteur. That initial fund has step by step received generous additions and given us the "Lister Institute" on Chelsea Embankment possessed of buildings, site, and capital valued at more than £300,000.