To answer the questions proposed at the end of the last lecture would be to write a book in many volumes. The task of measuring the actual movement of civilization becomes manageable only by a division of labour. I have attempted elsewhere to deal with it from the point of view of ethics – a point of view which necessarily involves something of the development of religion and something of the development of jurisprudence within its scope. Recently Dr Müller Lyer, in his Phasen der Kultur, has applied a similar treatment to the development of industry. Enough has been done to indicate some of the difficulties that beset this method of treatment, and also to suggest certain results. These I will endeavour to indicate to you by taking one side of social life, and tracing development on this side as we pass from the simplest to the most advanced modern societies. As some compensation for the limitations of the enquiry, I will take one of the fundamental problems. I will ask you to consider the nature of the social bond, to examine what is common to all societies and what is distinctive, and I shall try to show that what is distinctive in the nature of the social bond forms a fundamental principle of classification in any social morphology, and serves as one of the measuring rods which helps us to determine the nature of the movement which has made modern civilization what it is.