Madden pictures (Figs. 134 and 135) a Swede of forty with congenital absence of osseous structure in the middle line of the sternum, leaving a fissure 5 3/8 X 1 3/16 X 2 inches, the longest diameter being vertical. Madden also mentions several analogous instances on record. Groux's case was in a person of forty-five, and the fissure had the vertical length of four inches. Hodgen of St. Louis reports a case in which there was exstrophy of the heart through the fissure. Slocum reports the occurrence of a sternal fissure 3 X 1 1/2 inches in an Irishman of twenty-five. Madden also cites the case of Abbott in an adult negress and a mother. Obermeier mentions several cases. Gibson and Malet describe a presternal fissure uncovering the base of the heart. Ziemssen, Wrany, and Williams also record congenital fissures of the sternum. Thomson has collected 86 cases of thoracic defects and summarizes his paper by saying that the structures deficient are generally the hair in the mammary and axillary regions, the subcutaneous fat over the muscles, nipples, and breasts, the pectorals and adjacent muscles, the costal cartilages and anterior ends of ribs, the hand and forearm; he also adds that there may be a hernia of the lung, not hereditary, but probably due to the pressure of the arm against the chest. De Marque gives a curious instance in which the chin and chest were congenitally fastened together. Muirhead cites an instance in which a firm, broad strip of cartilage resembling sternomastoid extended from below the left ear to the left upper corner of the sternum, being entirely separate from the jaw. Some preliminary knowledge of embryology is essential to understand the formation of branchial fissures, and we refer the reader to any of the standard works on embryology for this information. Dzondi was one of the first to recognize and classify congenital fistulas of the neck. The proper classification is into lateral and median fissures. In a case studied by Fevrier the exploration of a lateral pharyngeal fistula produced by the introduction of the sound violent reflex phenomena, such as pallor of the face and irregular, violent beating of the heart. The rarest of the lateral class is the preauricular fissure, which has been observed by Fevrier, Le Dentu, Marchand, Peyrot, and Routier. The median congenital fissures of the neck are probably caused by defective union of the branchial arches, although Arndt thinks that he sees in these median fistulas a persistence of the hypobranchial furrow which exists normally in the amphioxus. They are less frequent than the preceding variety.