In 1838 he read Malthus' _Essay on the Principle of Population_, which showed how great and rapid, without checks like war and disease, the increase in number of the human race would be. He had seen something in his travels of rivalry for the means of subsistence. He now perceived "that under these circumstances favorable variations would tend to be preserved, and unfavorable ones to be destroyed. The results of this would be the formation of a new species." As special breeds are developed by artificial selection, so new species evolve by a process of natural selection. Those genera survive which give rise to species adapted to new conditions of existence. In 1858, before Darwin had published his theory, he received from another great traveler, Alfred Russel Wallace, then at Ternate in the Moluccas, a manuscript essay, setting forth an almost identical view of the development of new species through the survival of the fittest in the struggle for existence. REFERENCES Charles Darwin, _A Naturalist's Journal_. Francis Darwin, _The Life and Letters of Charles Darwin_. W. A. Locy, _Biology and its Makers_ (third revised edition), chap. XIX. G. J. Romanes, _Darwin and After Darwin_, vol. I. A. R. Wallace, _Darwinism_. See also John W. Judd, _The Coming of Evolution_ (The Cambridge Manuals of Science and Literature). CHAPTER XVI SCIENCE AND WAR--PASTEUR, LISTER In the history of science war is no mere interruption, but a great stimulating influence, promoting directly or indirectly the liberties of the people, calling into play the energy of artisan and manufacturer, and increasing the demand for useful and practical studies. In the activities of naval and military equipment and organization this influence is obvious enough; it is no less real in the reaction from war which impels all to turn with new zest to the arts and industries of peace and to cherish whatever may tend to culture and civil progress. Not infrequently war gives rise, not only to new educational ideals, but to new institutions and to new types of institution favorable to the advancement of science. As we have already seen, the Royal Society and Milton's Academies owed their origin to the Great Rebellion. Similarly the Ecole Polytechnique, mother of many scientific discoveries, rose in answer to the needs of the French Revolution. No less noteworthy was the reconstruction of education under the practical genius of Napoleon I, the division of France into académies, the founding of the lycées, the reëstablishment of the great Ecole Normale, and the organization of the Imperial University with new science courses and new provincial Faculties at Rennes, Lille, and elsewhere. With all these different forms in which the influence of war makes itself felt in the progress of science the life and career of Louis Pasteur (1822-1895), the founder of bacteriology, stood intimately associated.