RECENT articles published on congenital cystic disease of the lungs have apphed a new name to a well known and long established clinical and pathologic entity. True, x-rays have permitted the visualization of the cysts in the living subject, but they have added nothing to the excellent clinical description of the disease given by Laënnec (26) under the heading “Symptoms and Signs of Vesicular Emphysema” and also by Sir Thomas Watson (48) and others. A study of emphysema reveals that large cysts were reported by Matthew Baillie (2), Theophile Bonet (6), Giovanni Battista Morgagni (34), Van Swiéten (46), Sir John Floyer (16), Ruisch (Friederich Ruysch), 40, and Antonio Maria Valsalva (45). Jean Baptiste Bouillaud (7) mentioned a case in which the bladder or pouch was equal to the size of a stomach of ordinary dimensions. More recently Charles Hilton Fagge (14), James Copland (11), Rindfleisch (37), Rokitansky (39), and Virchow (47), have reported interesting observations. For example, Fagge (14) writes: “There is an enormous destruction of capillaries when the affection is at all extensive. Rindfleisch speaks of the vessels as collapsing until ‘only a narrow ribbon-like band is left, which may be recognized as an obliterated vessel by its greater transparency amid a dark, often pigmented, parenchyma, and by its uniting with other bands like itself to form the usual anastomotic network.’” He goes on to say that— “Some relatively wide communications are opened up between the pulmonary artery on the one hand, and the pulmonary and bronchial veins on the other hand. These anastomoses appear in well injected lungs as peculiar elongated, unbranched, vascular arches of the same diameter throughout, contrasting very strikingly with a far more numerous assemblage of extremely tortuous and dilated arteries, for whose contents no such supplemental mode of escape has been provided.” Is this not an earlier description, and a satisfactory explanation, of the “fine curvilinear shadows characteristic of a multilocular cyst,” described by Kirklin (24) and by Schenck (41), and visible in the case reported herewith? As to autopsy findings, the description given by Laënnec (26) of one of his own cases is as fine a description as one is likely to find on this subject. Watson (48) gives a generalized description which agrees in many features with that of Koontz (25), as reported by Kirklin (24), and also with the description given by Schenck (41). The congenital origin of the anomaly did not escape the observation of these men, and there are arguments for and against it by some of the authors mentioned in the bibliography. For example, Sir William Osler (36) wrote: