The population of each country should be proportionate to its resources. The numerical adjustment should be such that there be no unemployment and that individual productivity be highest without idlers at either end of the social scale. The physical average of the race should be good with no congenital diseases of mind or body and with the minimum of other diseases, and of crime. There should be a high average standard of comfort, self-respect and happiness, and a high moral standard of honesty, tolerance, and kindliness. One would hope for a wide prevalence of that ‘joie de vivre’ and contentment which is doubtless largely temperamental in origin and which contributes more to an individual’s happiness than any number of worldly possessions can ever do. And the social cleavage between classes, and the now stupendous discrepancies between the very rich and the very poor should be reduced to a minimum. Such conditions all would wish generally distributed. It is a question whether a uniformly high degree of intelligence should be equally ubiquitous. In every community, primitive or civilized, an immense amount of crude physical labour has to be done. The soil has to be tilled, someone has to dig coal and iron out of the ground, and endless other kinds of manual work have to be performed. It is doubtful whether the possession of a very high degree of intelligence would make such workers happier or more efficient. But whatever we may individually feel about this point, we would all wish such workers to be healthy, happy, well housed, contented with their lot, fond of their children, and both appreciated by, and on good terms with, the rest of the community. And obviously it is a condition of this sort which an enlightened Birth Control could help to achieve. The above is intended both to be a criterion of biological fitness for the human race, and a more satisfactory standard of national evaluation than the one that is in vogue to-day. It will be noted that there is nothing in it about capacity for wars. If we could substitute some such standard in place of the armament standard by which to grade countries in an order of merit, we should be in a better position to avert the catastrophe of another world war than we are at present. According to such a standard the country most deserving of admiration, respect and imitation to-day would probably be Switzerland. Knowing that she cannot defend herself against her powerful neighbours, she does not aspire to large armies. When other countries can, by a simultaneous control of population, realize a similar security, it will be open to them to follow in her footsteps. The ideal may not appeal to the romantic, but much that passes for romance is frequently pernicious nonsense, like the sentiment by which war is glorified in the eyes of many women and elderly men who have never participated in it.