over the earth’s surface. Still more important, however, is the fact that among the peoples who use the classificatory system there is an infinitely greater variety of social institution, and especially of forms of marriage, than exist among civilised peoples whose main social unit, the family, is not one which is capable of any extended range of variation. The result of the complete survey has been to justify my use of the classificatory system as the means whereby to demonstrate the dependence of the terminology of relationship upon social conditions. It is the great variability of this mode of denoting relatives which makes it so valuable an instrument for the study of the laws which have governed the history of that department of language by which mankind has denoted those who stand in social relations to himself. * * * * * You may have been wondering whether I am going to say anything about the merits of the controversy which has till now given to systems of relationship their chief interest among students of sociology. I have so far left on one side the subjects which have been the main ground of controversy ever since the time of Morgan. You will have gathered that I regard it as a grave misfortune for the science of sociology that the topics of promiscuity and group-marriage should have been thrust by Morgan into the prominent place which they have ever since occupied in the theoretical study of relationship. Even now I should have liked to leave them on one side on the ground that the evidence is as yet insufficient to make them profitable subjects for such exact inquiry as I believe to be the proper business of sociology. Their very prominence, however, makes it impossible to leave them wholly unconsidered, but I propose to deal with them very briefly. I begin with the question whether the classificatory system of relationship provides us with any evidence that mankind once possessed a form of social organisation, or rather such an absence of social organisation, as would accompany a condition of general promiscuity in which, if one can speak of marriage at all, marriage was practised between all and any members of the community, including brothers and sisters. I can deal with this subject very briefly because I hope to have succeeded elsewhere in knocking away the support on which the whole of Morgan’s own construction rested.