To whatever degree, however, it may have been potent in causing war in the past, it is certain that the pressure of population as a cause of war will be eliminated in the future. The only nations nowadays that can afford to make war on the grand scale are the wealthy and civilized nations. But civilization excludes a high birth-rate: there has never been any exception to that law, nor can we conceive any exceptions, for it is more than a social law; it is a biological law. Russia, a still imperfectly civilized country, stands apart in having a very high birth-rate, but it also has a very high death-rate, and even should it happen that in Russia improved social conditions lower the death-rate before affecting the birth-rate, there is still ample room within Russian territory for the consequent increase of population. Among all the other nations which are considered to threaten the world's peace, the birth-rate is rapidly falling. This is so, for instance, as regards England and Germany. Germany, especially, it was once thought--though in actual fact Germany has not fought for over forty years--had an interest in going to war in order to find an outlet for her surplus population, compelled, in the absence of suitable German colonies, to sacrifice its patriotism and lose its nationality by emigrating to foreign countries. But the German birth-rate is falling, German emigration is decreasing, and the immense growth of German industry is easily able to absorb the new generation. Thus the declining birth-rate of civilized lands will alone largely serve in the end to eliminate warfare, partly by removing one of its causes, partly because the increased value of human life will make war too costly.