SINCE the publication of Rivers's “Essays on the Depopulation of Melanesia” in 1922, much attention has been given to the population problem in the Pacific and the causes of the decrease in numbers of the natives. A discussion at the Sydney meeting of the Australian and New Zealand Association for the Advancement of Science afforded a welcome opportunity for taking stock of the advance that has been made in the interval towards a real understanding of the factors involved. So far as it is possible to draw any general conclusions from the observations which were reported in the discussion and the inferences drawn from them, it would appear that while the psychological factor, on which Rivers laid so much stress, is still regarded as of importance, there is a tendency to attach greater significance to food arid the need for medical attention. On the other hand, it is evident that there has been some change—perhaps even in a considerable degree—in conditions since the time when Rivers's observations were made. Some of the populations appear to be approaching, or even to have attained, a state of equilibrium in their contact with Europeans. Where this is occurring, credit must undoubtedly be given to wise methods of administration.