ORGAN (AS'. oryttne,orattna. from La t. orfmn et, 11'0111 Gk. 4-yattott, argil non, i rtunent organ ; connected with 4)yer, croon, work, Av. rarez, to work, Goth. 01-1O. wereh, weralt, Ger. 11"(r1:. AS. to ore, Eng. work). In biology, any part of a plant or , al that has a definite work to perfot in for the good of the whole being. In the possession of organs living creatures differ from mineral substances; consequently the former are called 'organisms,' and are said to be composed of organic matter, whereas the latter• are inorganic. Even in the lowliest one-celled creatures organs make their appearance. The timbals may be regarded as the first or oldest organ in organisms. The cytoplasm as well as micleoplasm must, however, be regarded as com posed of a complex of primitive organs which we cannot indeed see, hut with whose behavior we a re acquainted. These are the 'biophores' or inicrosonies. In sonic of these organs. also called 'orgauwids,' seems to reside the control of the nutrition; in others that of locomotion; in others that of sensation. Visible structures are also developed, such as a loamwork and often cilia. Thus even in its most primitive form protoplasm is already possessed of many organs; it, is m-yanizl.d. Of the origin of the most primitive organism. of the source of this for
tunate concurrence of mutually operating or gans, we are totally ignorant.
Although even the simplest protoplasm is organized, organization becomes more complex in the higher forms. The organs become niere numerous and have different ranks. There are the organs of gross anatomy, such as the eye, the stoumeh, heart, and the limbs, tissues, etc., which are complexes of organs of a lower rank, and are in turn made up of the unit organs—the cells. All yells have the organized structure of protoplasm. The essence of organization is division of labor. In a great factory each worker does 0 single stage of the work, so that if one drops out the work of the others is stopped. In such a factory, therefore, extreme division of labor is found. on the whole, to be ad vantageous to the amount and quality of the work done; so in the organism. Important is the fact that, despite the extreme division of labor in the organism, the whole rules over the parts. So that even if an o•gaun fails to perform its function completely, the Organism may still survive through a regulative capacity in the rest of the organism.