Some Recent Changes in Illinois River Biology

Abstract

The principal causes of change in the biological environment of the Illinois River which have come in since 1899 are the opening of the drainage canal of the Sanitary District of Chicago in January, 1900, a great increase in the amount of Chicago sewage emptied into the stream, and an extensive reclamation of the river bottoms for agricultural uses ; and it is our present purpose to trace the principal effects of these changes upon the life of the stream.