ITS DEFINITION, SCOPE, AND AIMS. 39 e
ancient and modern nations. There is strong reason for believing that national rise and decline is closely connected with this influence. It seems to be the tendency of high civilisation to check fertility in the upper classes, through numerous causes, some of which are well known, others are inferred, and others again are wholly obscure. The latter class are apparently analogous to those which bar the fertility of most species of wild animals in zoological gardens. Out of the hundreds and thousands of species that have been tamed, very few indeed are fertile when their liberty is restricted and their struggles for livelihood are abolished ; those which are so and are otherwise useful to man becoming domesticated. There is perhaps some connection between this obscure action and the disappearance of most savage races when brought into contact with high civilization, though there are other and well-known concomitant causes. But while most barbarous races disappear, some, like the 'riegro, do not. It may therefore be expected that types of our race will be found to exist which can be highly civilised without losing fertility ; nay, they may become more fertile under artificial conditions, as is the case with many domestic animals.
3. Sytematic collection of facts showing the circumstances under which large and thriving families have most frequently originated ; in other words, the conditions of Eugenics. The names of the thriving families