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ARTHRITIS—ARTHROPODA
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at Pisa, the Campo Santo (early Tuscan schools); at Sant’ Apollinare, Ravenna, primitive Italo-Byzantine mosaics; at Siena, Pinturichio. Examples could be multiplied indefinitely—in Italy alone there are 80,000 churches and chapels, in all of which pictorial art has been employed. In Italy, besides the church “galleries” still used for religious services, there are some which have been secularized and are now used as museums, e.g. Certosa at Pavia, and San Vitale at Ravenna (mosaics); at Florence, the Scalzo (Andrea del Sarto); San Marco (Fra Angelico); the Riccardi and Pazzi chapels (Gozzoli and Perugino); at Milan, in the Santa Maria delle Grazie, the “Last Supper,” by Leonardo, and at Padua, the famous Arena chapel (Giotto).

The Vatican galleries, though best known for their statuary, have fine examples of painting, chiefly of the Italian school; the most famous easel picture is Raphael’s “Transfiguration,” but the Stanze, apartments entirely decorated by painting, are even more famous. In Private and semi-private galleries.England three royal palaces are open to the public—Hampton Court (Mantegna), Windsor (Van Dyck, Zuccarelli), and Kensington (portraits). At Buckingham Palace the Dutch pictures are admirable, and Queen Victoria lent the celebrated Raphael cartoons to the Victoria and Albert Museum. Semi-private collections belong to Dulwich College (Velasquez and Watteau), Oxford University (Italian drawings), the Soane Museum (Hogarth and English school), and the Royal Academy (Leonardo). Among private collections the most important are the Harrach, and Prince Liechtenstein (Vienna), J. Pierpont Morgan (including miniatures), Mrs J. Gardner of Boston (Italian), Prince Corsini (Florence). In Great Britain there are immense riches in private houses, though many collections have been dispersed. The most noteworthy (1909) belong to the dukes of Devonshire and Westminster, Lord Ellesmere, Captain Holford (including the masterpiece of Cuyp), Ludwig Mond, Lord Lansdowne, Miss Rothschild. The finest private collection is at Panshanger, formerly the seat of Lord Cowper, the gallery of Van Dyck’s work being quite the best in the world.

Many galleries are devoted to periodical exhibitions in London; the Royal Academy is the leading agency of this character, having held exhibitions since 1769. Its loan exhibitions of Old Masters are most important. Similar enterprises are the New Gallery, opened in 1888, the Periodical and commercial.Grafton Gallery, and others. There are also old-established societies of etchers, water-colourists, &c. A feature common to these exhibitions is that the public always pays for admission, though they differ from the commercial exhibitions, becoming more common every year, in which the work of a single school or painter is shown for profit. But the annual exhibitions at the Guildhall, under the auspices of the corporation, are free. The great periodical exhibition of French art is known as the Salon, and for some years it has had a rival in the Champ de Mars exhibition. These two societies are now respectively housed in the Grand Palais and Petit Palais, in the Champs Elysées, which were erected in connexion with the Paris Exhibition of 1900, but with the ultimate object of being devoted to the service of the two Salons. Berlin, Rome, Vienna and other Continental towns have regular exhibitions of original work.

The best history of art galleries is found in their official and other catalogues, see article Museums. See also L. Viardot, Les Musées d’Italie, &c. (3 vols., Paris, 1842, 1843, 1844); Annual Reports, official, of National Portrait Gallery, National Galleries of England, Ireland and Scotland; Civil Service Estimates, class iv. official. See also the series edited by Lafenestre and E. Richtenberger: Le Louvre, La Belgique, Le Hollande, Florence, Belgique; A. Lavice, Revue des musées de France,... d’Allemagne,... d’Angleterre,... d’Espagne,... d’Italie,... de Belgique, de Hollande et de Russie (Paris, 1862–1872); E. Michel, Les Musées d’Allemagne (Paris, 1886); Kate Thompson, Public Picture Galleries of Europe (1880); C. L. Eastlake, Notes on Foreign Picture Galleries; Lord Ronald Gower, Pocket Guide to Art Galleries (public and private) of Belgium and Holland (1875); and many works, albums, and so forth, issued mainly for the sake of the illustrations.  (B.) 


ARTHRITIS (from Gr. ἄρθρον, a joint), inflammation of the joints, in various forms of what are generally called gout and rheumatism (q.v.).

ARTHROPODA, a name, denoting the possession by certain animals of jointed limbs, now applied to one of the three sub-phyla into which one of the great phyla (or primary branches) of coelomocoelous animals—the Appendiculata—is divided; the other two being respectively the Chaetopoda and the Rotifera. The word “Arthropoda” was first used in classification by Siebold and Stannius (Lehrbuch der vergleich. Anatomie, Berlin, 1845) as that of a primary division of animals, the others recognized in that treatise being Protozoa, Zoophyta, Vermes, Mollusca and Vertebrata. The names Condylopoda and Gnathopoda have been subsequently proposed for the same group. The word refers to the jointing of the chitinized exo-skeleton of the limbs or lateral appendages of the animals included, which are, roughly speaking, the Crustacea, Arachnida, Hexapoda (so-called “true insects”), Centipedes and Millipedes. This primary group was set up to indicate the residuum of Cuvier’s Articulata when his class Annélides (the modern Chaetopoda) was removed from that embranchement. At the same time C. T. E. von Siebold and H. Stannius renovated the group Vermes of Linnaeus, and placed in it the Chaetopods and the parasitic worms of Cuvier, besides the Rotifers and Turbellarian worms.[1]

The result of the knowledge gained in the last quarter of the 19th century has been to discredit altogether the group Vermes (see Worm), thus set up and so largely accepted by German writers even at the present day. We have, in fact, returned very nearly to Cuvier’s conception of a great division or branch, which he called Articulata, including the Arthropoda and the Chaetopoda (Annélides of Lamarck, a name adopted by Cuvier), and differing from it only by the inclusion of the Rotifera. The name Articulata, introduced by Cuvier, has not been retained by subsequent writers. The same, or nearly the same, assemblage of animals has been called Entomozoaria by de Blainville (1822), Arthrozoa by Burmeister (1843), Entomozoa or Annellata by H. Milne-Edwards (1855), and Annulosa by Alexander M‘Leay (1819), who was followed by Huxley (1856). The character pointed to by all these terms is that of a ring-like segmentation of the body. This, however, is not the character to which we now ascribe the chief weight as evidence of the genetic affinity and monophyletic (uni-ancestral) origin of the Chaetopods, Rotifers and Arthropods. It is the existence in each ring of the body of a pair of hollow lateral appendages or parapodia, moved by intrinsic muscles and penetrated by blood-spaces, which is the leading fact indicating the affinities of these great sub-phyla, and uniting them as blood-relations. The

  1. The group Arthropoda itself, thus constituted, was precisely identical in its area with the Insecta of Linnaeus, the Entoma of Aristotle. But the word “Insect” had become limited since the days of Linnaeus to the Hexapod Pterygote forms, to the exclusion of his Aptera. Lamarck’s penetrating genius is chiefly responsible for the shrinkage of the word Insecta, since it was he who, forty years after Linnaeus’s death, set up and named the two great classes Crustacea and Arachnida (included by Linnaeus under Insecta as the order “Aptera”), assigning to them equal rank with the remaining Insecta of Linnaeus, for which he proposed the very appropriate class-name “Hexapoda.” Lamarck, however, appears not to have insisted on this name Hexapoda, and so the class of Pterygote Hexapods came to retain the group-name Insecta, which is, historically or etymologically, no more appropriate to them than it is to the classes Crustacea and Arachnida. The tendency to retain the original name of an old and comprehensive group for one of the fragments into which such group becomes divided by the advance of knowledge—instead of keeping the name for its logical use as a comprehensive term, including the new divisions, each duly provided with a new name—is most curiously illustrated in the history of the word physiology. Cicero says, “Physiologia naturae ratio,” and such was the meaning of the name Physiologus, given to a cyclopaedia of what was known and imagined about earth, sea, sky, birds, beasts and fishes, which for a thousand years was the authoritative source of information on these matters, and was translated into every European tongue. With the revival of learning, however, first one and then another special study became recognized—anatomy, botany, zoology, mineralogy, until at last the great comprehensive term physiology was bereft of all its once-included subject-matter, excepting the study of vital processes pursued by the more learned members of the medical profession. Professional tradition and an astute perception on their part of the omniscience suggested by the terms, have left the medical men in English-speaking lands in undisturbed but illogical possession of the words physiology, physic and physician.