The distinguished chairman of the committee of arrangements informed me that a short address of some kind would be required of me at this meeting, and that as the audience would not be confined to members of the Mississippi Valley Medical Association, some topic connected with public hygiene should be selected.Being sincerely desirous to please my amiable friend, Dr. Love, I thought it might not be inappropriate to briefly consider a topic of interest to all the members of the Association, namely, the Drainage of Chicago.There are some side questions connected with this subject that are of very great interest, and I shall refer to them, but the limitation of time will only afford opportunity for a statement of the sanitary problem, and of the manner in which those in authority propose to solve it.TOPOGRAPHY AND CLIMATOLGY.Let us glance at the topography of Chicago as it