The sewage of Baltimore, formerly, was poured into the Chesapeake Bay, polluting the waters almost beyond the state of toleration in the vicinity of the city, destroying the fishing interests and polluting the oyster beds throughout the whole length of the Chesapeake Bay. The sewage of Baltimore is now carried to large areas of filter beds, distributed over them in a fine spray in the most convenient form to be acted upon by the organisms which grow in the purifying receptacles. Only the clear, purified, effluent water is allowed to enter the Bay.

The city of New York has already taken steps toward conducting the immense sewage of that great metropolis under the East River and onto the sandy plains of Long Island, where it may undergo a similar purification. The State of Ohio has enacted legislation looking to the speedy prohibition of pouring the sewage of Cleveland and Cincinnati into Lake Erie and the Ohio River respectively. The States of Indiana and Illinois particularly have undertaken local surveys of their own waters and have prosecuted them with fine results. The citizens of those two states will soon be able to learn from official sources what streams carry water suitable for potable purposes and what do not. This problem is of supreme importance to the people from the aspect of sanitation and health.