As we shall see later on, civilization obscures and even opposes this struggle for existence, but it is in progress all the same, at all times and under all conditions. Every one knows, for instance, that one-third of the human beings born into the world every year die before they are five years old. The reason for this lies in the fact that they are, in some way or other, less fitted to meet the conditions of life on earth than the other two-thirds. The germ of cholera infantum is an enemy to the human race, and so long as it continues to exist upon earth it will devote all of its activity to attacking human infants and seeking to destroy them. It happens that some babies recover from cholera infantum, while others die of it. This is merely another way of saying that the former, having been born with a capacity for resisting the attack of the germ, or having been given the capacity artificially, are better fitted to survive, and that the latter, being incapable of making this resistance, are unfit. All life upon earth is nothing more than a battle with the enemies of life. A germ is such an enemy, cold is such an enemy, lack of food is such an enemy, and others that may be mentioned are lack of water, ignorance of natural laws, armed foes and deficient physical strength. The man who is able to get all of the food he wants, and so can nourish his body until it becomes strong enough to combat the germs of disease; who gets enough to drink, who has shelter from the elements, who has devised means for protecting himself against the desires of other men--who yearn, perhaps, who take for themselves some of the things that he has acquired--such a man, it is obvious, is far better fitted to live than a man who has none of these things. He is far better fitted to survive, in a purely physical sense, because his body is nourished and protected, and he is far better fitted to attain happiness, because most of his powerful wants are satisfied.