I must take this opportunity of expressing my gratitude to many friends for valuable {viii} assistance, and especially to my friend and colleague, Mr R. Marett, to whose comprehensive knowledge of the religious thought and ritual of savage races I owe many important clues. L. R. FARNELL. _August_, 1905. Contents {ix} LECTURES I. AND II. THE COMPARATIVE STUDY OF RELIGIONS: ITS METHOD AND PROBLEMS LECTURE III. THE RITUAL OF PURIFICATION AND THE CONCEPTION OF PURITY: THEIR INFLUENCE ON RELIGION, MORALITY, AND SOCIAL CUSTOM LECTURE IV. THE EVOLUTION OF PRAYER FROM LOWER TO HIGHER FORMS INDEX ENDNOTES The Evolution of Religion {1} LECTURES I. AND II. THE COMPARATIVE STUDY OF RELIGIONS: ITS METHOD AND PROBLEMS The reasonable and sympathetic study of the various religions of mankind, which are perhaps the clearest mirror we possess of human feeling, aspiration, and thought in its highest and lowest forms, is only possible for the individual or for the age that feels no constraining call to suppress and obliterate all save one cherished creed. Such study began, as we should expect, in the earlier Hellenic period, the Hellenic religion throwing few or no obstacles in the way of undogmatic investigation; and the first anthropologist of religion is Herodotus. Then among Hellenistic {2} scholars and those of pre-Christian Rome there were some who devoted themselves to the collection and exposition of the religious institutions of foreign races. But save a few short treatises, such as Plutarch’s _De Iside et Osiride_, Sallustius’ _De Diis et Mundo_, Lucian’s _De Dea Syria_, nothing has survived beyond the titles and the fragments of their works; and by an irony of fortune we owe much of our knowledge of Hellenic and other religions of the Mediterranean area to the Christian controversialists, who reveal many of the essential features of the various pagan creeds in order to expose them to obloquy: they could not anticipate that we should gather as the fruit of their labours a better appreciation than we could otherwise have gained of the religions which they strove to destroy, and possibly of Christianity itself. If I were attempting, as I do not propose to attempt, to give a complete survey of the growth and development of the study which we are considering, I should probably be able to cull {3} but little material for the narrative from Byzantine and mediæval sources. We may note that the spirit of these ages was, on the whole, alien to our present interest; and that it is not till after the Renaissance and the discovery of America that systematic work in this field begins again. To two Spaniards of Peruvian and Mexican descent,[3.1] we owe our knowledge of the religions of the Incas and the Aztecs, that of the latter at least being of prime importance for the student of the higher religions of mankind. A Polish nobleman of