As the object of all theory, and the aim of all science, is to insure wise practice, the author desires to call special attention to that portion of the work devoted to the chemistry of the excretions, feeling, as he does, that we are entering upon the threshold of an important department of medical inquiry, which, sooner or later, will be followed by valuable practical results. He would also direct the special attention of his readers to the chapter devoted to treatment, being sanguine enough to imagine that the adoption of the principles he has enunciated regarding the mode of action, and administration of the remedies usually employed in hepatic affections, may conduce to a more rational and successful method of treatment than has hitherto been employed. He even goes far enough to hope that the result of the treatment, as shown in the cases cited, will not only justify the adoption of the principles on which it is founded, but also prove a strong incentive to others to follow the line of diagnosis he has striven to inculcate. In some portions of the volume the statements of the author may, perhaps, appear to be rather dogmatic; if so, he would remind his readers that this has arisen from the circumstance of so many old dogmas, and deeply-rooted prejudices having to be combated, for he is quite alive to the fact, that what we regard as scientific truth is in no case incontrovertible certitude, and that the deductions of to-day, in an advancing science like that of medicine, may require material alteration when viewed in the light of the morrow. But he is equally convinced of the fact, that if men fold their arms, and refrain from acting until every link in the chain of knowledge is forged, all progress will be arrested, and the day of certainty still further postponed.