under the same law as the limitations on personal chance and convenience in the previous case.
If there were a space which possessed advantages for any interest of mankind,—being in the sunlight or out of it, in the wind or out of it, near to a spring or remote from a swamp, salubrious, possessing a fine view, or otherwise desirable,—if this space were large and ample in proportion to the number of men who desired to avail themselves of it, no competition or struggle would take place between them for it; but if their number increased, contact and collision would begin. If there should come to be more persons eager for the advantage of situation than could find place under the physical limitations existing, this struggle would go on to any degree of intensity. It would advance under the same law of progression previously stated.
If a number of persons are out in the fields, fresh air is present in immense superfluity. The personal habits of these persons, e.g., cleanliness, would be of little importance; even if some of them had a contagious disease, the danger of infection would be slight. But if they came nearer together, and then nearer, and were finally crowded tightly into some limited and enclosed space, they would consume the air away from each other, they would poison each other; and if there were a disease among them its chances of being transmitted would rise toward certainty.
In the mere matters of space and fresh air and sunlight, therefore, men are under conditions of monotony and exclusion; their spheres of interest and of life-supply collide, and they become noxious to each other, whether they will or not, under a rapidly increasing progression, when their numbers increase with respect to the natural conditions.