The widespread evil due to the sickness of one person
You may think that the germs from one person would not make much difference, but that is where you are mistaken. There is a town in Pennsylvania of about eight thousand inhabitants, which gets its water from a stream that flows down from the mountains. One cold winter, while the stream was frozen, a man living on the bank of the stream was taken sick with typhoid fever. His nurse threw the urine and the discharges from his bowels on the ice on the bank of the creek. When the ice melted, the typhoid germs in the discharges found their way to the stream that furnished drinking water to people farther down, and in a very short time there were over one thousand cases of typhoid fever in that town. Before the ice melted there had not been a single case of typhoid, and every one of the thousand cases came from the water into which had been allowed to flow the discharges from one man with typhoid fever. You see what germs from one person may do.
How long typhoid fever germs live in a stream
Sometimes people say that a stream purifies itself every few miles. It does purify itself of some things, but disease germs live from twenty-five to thirty-five days in water, and a stream flows a long way in thirty days.
The pollution of streams with sewage
Sometimes we hear people say that it is safe to put sewage into a certain stream, because no town uses that stream for drinking water. But of this they can never be sure. Not long ago certain people said that the water from the river which flowed through their town was used only by two dairymen and a vegetable gardener, and therefore there was no danger in running sewage into the stream. Yet the dairymen and the gardener sold all their produce in that very town. The townspeople never considered that the water into which they ran their sewage was used by the dairymen for washing their milk vessels (and perhaps for diluting the milk), and by the gardener for washing his lettuce and other vegetables. Thus the germs of disease were brought directly back to the town.
Do not think that you are safe in polluting a stream with sewage because no town uses the water from that stream. The individual on the farm is entitled to protection just as much as the individual in the town. Always remember that when you pollute with disease the water used by the farmer, he may bring that disease back into the town with the produce of his farm.
No sewage, no matter how small the amount, should ever be permitted to go into a stream until all the disease germs it contains have been killed. This can be done, though it will cost something; but we cannot get rid of disease germs without work, and work cannot be done without being paid for.
There are other ways of scattering typhoid germs besides running sewage into streams. Sometimes the nurse does not throw the discharges from a typhoid fever patient into a sewer at all, but into a closet vault. Remember how the material from a closet vault goes through open ground into a well, and you will understand what happens. The germs get into the well, and the whole family may then have typhoid fever.
Let us suppose that the nurse did not throw the discharges either into the closet or into the sewer, but carelessly threw them out on the ground behind the house, where, as it was winter time, they froze as hard as rocks. It does not seem to hurt typhoid germs in the least to be frozen; when they get warm again they are as lively as ever. Let us suppose these particular germs lay there all winter, but in the spring when everything melted the germs were still alive and ready to spread disease. It happened that they did not get into the well or into the milk, but they did get on your food, and made you ill with typhoid fever.