Diaphanoscope

[Gr. diaphanes, transparent, skopeo, I see.] A dark box, suitably constructed for exhibiting transparent photographs or other pictures. It may or may not be furnished with a lens. over and decu ating to surround the œsophagal opening; but all of them ultimately uniting with the central tendon, and thus making but one muscular partition. The D. is convex superiorly, and concave inferiorly, and is covered on the upper side by the pleura, and on the lower by the peritoneum. In form it is nearly circular, and is fleshy at the edges, but becomes tendinous towards the centre. It presents three large openings and several smaller ones. The opening of the vena cava is quadrangular in form, and is situated in the tendinous centre. The œsophagal opening is posterior to that of the vena cava, and is of an elliptic form. The aortic opening is the most posterior, triangular, and between the crura. This muscle is the principal agent in respiration; for by contracting, it enlarges the cavity of the chest, and allows the lungs to receive the air in inspiration; while, by being relaxed, the cavity of the chest is again diminished, and the air suddenly expelled. The contracting and relaxing of this muscle must likewise, it is evident, have a similar effect in increasing and diminishing the size of the abdominal cavity; and hence, by its action upon the stomach and intestines, it aids in the expulsion of the fæces and urine. The D. is largely engaged in laughing, sneezing, sighing, sobbing, and other affections of the respiratory organs. Whatever occasions stoppage of the action of this muscle speedily proves fatal. It is subject to inflammation, called diaphragmatitis ; but as this is rarely confined to the organ itself, but communicated either to the pleura or peritoneum, its symptoms and mode of treatment correspond with inflammation of these parts. It is also the part chiefly involved in the spasmodic affection called hiccough. - See HICCOUGH, PLEURITIS, and PERITONITIS. ( Zool .) The septa by which the chambers of multilocular and other shells are divided from each other. ( Optics .) A circular ring used in some optical instruments. ( Mach .) A partition or dividing wall of a compartment. Diaphanous, ( di - afan - us,) a. [Gr. diaphanes , from dia, and phaino, to shine.] A term applied to bodies which, like porcelain, permit the light to pa through Diaphragmatic, a. ( Anat . ) Pertaining or relating their substances. It is the synonym of translucent. A body which allows the distinct forms of objects to be seen through, is transparent. - In common language D. is frequently, though improperly, used as synonymous with transparent; as, "a crystal river, diapha nous." Words worth. ( Bot .) Semi-transparent, like horn. Diaphanously, adv. In a diaphanous manner; clearly; transparently.