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 devoured by Polyphemus) made his escape by clinging to the bellies of the sheep let out to pasture. Euripides in the Cyclops essentially follows the Homeric account. A later story associates Polyphemus with Galatea (see ).

 POLYPODIUM, in botany, a large genus of true (q.v.), Widely distributed throughout the world, but specially developed in the tropics. The name is derived from Gr. , many, and, a little foot, on account of the foot-like appearance of the rhizome and its branches. The species differ greatly in size and general appearance and in the character of the frond; the sori or groups of spore-cases (sporangia) are borne on the back of the leaf, are globose and naked, that is, are not covered with a membrane (indusium) (see fig. 1). The common polypody (fig. 2) (P. vulgare) is widely diffused in the British Isles, where it is found on walls, banks, trees, &c.; the creeping, densely-scaly rootstock bears deeply pinnately cut fronds, the fertile ones bearing on the back the bright yellow naked groups of sporangia (sori). It is also known as adder's foot, golden maidenhair and wood-fern, and is the oakfern of the old herbals.

There are a large number of varieties, differing chiefly in the form and division of the pinnae; var. cambricum (originally found in Wales) has the pinnae themselves deeply cut into narrow segments; var. cornubiense is a very elegant plant with finely-divided fronds; var. cristatum is a handsome variety with fronds forking at the apex and the tips of all the pinnae crested and curled. P. dryopteris, generally known as oakfern, is a very graceful plant with delicate fronds, 6 to 12 in. long, the three main branches of which are themselves pinnately divided; it is found in dry, shady places in mountain districts in Great Britain, but is very rare in Ireland. P. phegopteris (beechfern) is a graceful species with a black, slender root-stock, from which the pinnate fronds rise on long stalks, generally about 12 in. long, including the stalk; it is characterized by having the lower pinnae of the frond deflexed; it is generally distributed in Britain, though not common. Many other species from different parts of the world are known in greenhouse cultivation.  POLYPUS, a term signifying a tumour which is attached by a narrow neck to the walls of a cavity lined with mucous

membrane. A polypus or polypoid tumour may belong to any variety of tumour, either simple or malignant. The most common variety is a polypus of the nose of simple character and easily removed. Polypi are also met with in the ear, larynx, uterus, bladder, vagina, and rectum. (See .)  POLYTECHNIC (Gr., many, and , an art), a term which may be held to designate any institution formed with a view to encourage or to illustrate various arts and sciences. It has, however, been used with different applications in several European countries. In France the first école polytechnique was founded by the National Convention at the end of the 18th century, as a practical protest against the almost exclusive devotion to literary and abstract studies in the places of higher learning. The institution is described as one “où l'on instruit les jeunes gens, destinés à entrer dans les écoles spéciales d'artillerie, du génie, des mines, des ponts et chaussées, créé en 1794 sous le nom d'école centrale des travaux publiques, et en 1795 sous celui qu'elle porte aujourd'hui” (Littré). In Germany there are nine technical colleges which, in like manner, have a special and industrial rather than a general educational purpose. In Switzerland, the principal educational institution, which is not maintained or administered by the communal authorities, but is non-local and provided by the Federal government, is the Polytechnikum at Zurich. In all the important towns of the Federation there are trade and technical schools of a more or less special character, adapted to the local industries; e.g. schools for silk-weaving, wood-carving, watchmaking, or agriculture. But the Zurich Polytechnikum has a wider and more comprehensive range of work. It is a college designed to give instruction and practical training in those sciences which stand in the closest relation to manufactures and commerce and to skilled industry in general and its work is of university rank.

To the English public the word polytechnic has only recently become familiar, in connexion with some London institutions of

an exceptional character. In the reign of William IV. there was an institution in London called after the name of his consort—“The Adelaide Gallery”—and devoted rather to the display of new scientific inventions and curiosities than to research or to the teaching of science. It enjoyed an ephemeral popularity, and was soon imitated by an institution called the Polytechnic in Regent Street, with a somewhat more pretentious programme, a diving-bell, electrical and mechanical apparatus, besides occasional illustrated lectures of a popular and more or less recreative character. In the popular mind this institution is inseparably associated with “Professor” Pepper, the author of The Boy's Playbook of Science and of Pepper's Ghost. Both of these institutions, after a few years of success, failed financially; and in 1880 Mr Quintin Hogg, an active and generous philanthropist, purchased the disused building in Regent Street, and reopened it on an altered basis, though still retaining the name of Polytechnic, to which, however, he gave a new significance. He had during sixteen years been singularly successful in gathering together young shopmen and artisans in London in the evenings and on Sunday for religious and social intercourse, and in acquiring their confidence. But by rapid degrees his enterprise, which began as an evangelistic effort, developed into an educational institution of a novel and comprehensive character, with classes for the serious study of science, art, and literature, a gymnasium, library, reading circles, laboratories for physics and chemistry, conversation and debating clubs, organized country excursions, swimming, rowing, and natural history societies, a savings bank, and choral singing, besides religious services, open to all the members, though not obligatory for any. The founder, who from the first took the closest personal interest in the students, well describes his own aims: “What we wanted to develop our institute into was a place which should recognize that God had given man more than one side to his character, and where we could gratify any reasonable taste, whether athletic, intellectual, spiritual or social. The success of this effort was remarkable. In the first winter