The testimony taken in the suit of the State of Missouri against the State of Illinois and the sanitary district of Chicago comprises the best symposium on river pollution, its biological and chemical aspects, and its general and special sanitary significance that has ever been assembled. The contentions of both parties to the suit' are supported by the most eminently qualified men in the United States. The evidence presented and the discussions recorded are therefore of unique importance. The final record of testimony occupies 8,000 printed pages, much of which is irrelevant. This digest of testimony is the result of an attempt to recover the valuable material and present it in concise form. A consistent endeavor has been made by the reviewer to eliminate all personal opinions with reference to the issue and to make an impartial presentation of so much of the testimony as in his opinion appears to be relevant and of scientific importance. It will be well to remember in this connection that any digest of so large a volume of testimony must be the result of a final exercise of personal opinion by the reviewer as to those parts which may best be excluded. Naturally opinions will differ on this point; therefore it will be strange if many of those familiar with the case do not find that certain portions of testimony which they consider most important are passed over in this digest without reference. Controversies between counsel, objections to the admission of testimony, legal technicalities and quibbles, badgering cross-examination, and in general all the testimony introduced for purposes of mere corroboration have been disregarded. The object has been to present a faithful statement of the scientific phases of the testimony to the exclusion, if need be, of the legal aspect of the case.
