The popularity of this article was such that its republication was considered desirable, so as to place it in permanent form as a monograph on this subject. The author of the term, indurative mediastino-pericarditis,is Kussmaul, whose original article appeared in the Berliner Klinische Wochenschrift, for 1873. These cases are those in which great difficulty of diagnosis is presented clinically and "where at the autopsy there is found an adherent pericardium with an increase of fibrous tissue in the mediastinum. The increased mediastinal tissue is united to the external surface of the pericardium, and both it and the pericardium are united to the left and, may also be to the right lung." The author has appended an extended bibliography to the monograph and has made a collection of twenty-five cases.