ORGAN, in anatomy, a member of an organized being through which its func tions are executed. Thus the root, stem, and leaves of a plant are organs.
In music, the most comprehensive and important of all wind instruments. Its history can be traced back to the earliest antiquity. Starting from a small collec tion of pipes, perhaps even from a syrinx, it has gradually grown in size and complexity till, at the present day, one performer has complete control over many thousands of pipes. In its rudi mentary state, the wind was admitted to each pipe at the will of the player by means of a sliding strip of wood, which could be pulled in and out; this mechan ism was the ancestor of our modern key board. The next step was to have more than one series of pipes; strips of wood passing lengthwise under the mouths of each set enabled the player, by pulling a stop, to exercise a choice as to which he used. Afterward, as larger organs were constructed, the smaller were called "por tative," because they could be carried about in processions, etc., and the large ones were called "positive," because they were fixtures. The essential principles of the construction of an organ were thus discovered, and it only remained to ex pand the instruments. In modern in
struments, four, or sometimes even five, rows of keys are found, each represent ing a distinct instrument; these are named after their use br characteristics; as, great organ, that used for grand ef fects, the principal manual; choir organ, that used for the accompaniment of voices; solo organ, that containing stops for solo use; swell organ, pipes placed in a distant box, with shutters opening and closing like Venetian blinds, by means of which a crescendo can be made; pedal organ, the pipes controlled by the pedals. Pipes range from 32 feet to of an inch in length; they are divided into two great classes, flue and reed, names which need no explanation. The title of stops generally intimates their quality of tone, e. Li., flute, violin, oboe, clarinet, trumpet, etc.
In comparative anatomy and physi ology, organ of Bojanus, a double organ with two bilaterally symmetrical halves, one on each side of the body, just below the pericardium. This organ performs the function of a kidney.