Published online by Cambridge University Press: 17 January 2008
* This article was originally read as a paper, in substantially the same form in which it is now printed, at a joint meeting of the Institute of Advanced Legal Studies, University of London, and the Section of International and Comparative Law of the American Bar Association, held at the Senate House, University of London, on July 25, 1957. The permission of the Institute of Advanced Legal Studies and of the Section of International and Comparative Law to reprint this paper is gratefully acknowledged.