SPINDLE TREE. 447 SPINELLO ARETINO. epiNDLE THEE (EuoByuius Europseus). SPINE, CuEVATUKE OF THE. There arc two distinct foniis of curvature, lateral curvature, arising from weakness of the bones, ligaments, and muscles, and angular curvature, which re- sults from carious disease of the vertebrae. Lateral curvature of the spine, or scoliosis, ia not simply a bending of the spine laterally. In addition there is also considerable rotation or twisting of the vertebral bodies which normally are held in their proper relation and position by the ligaments and muscles. Muscular action is necessary for the maintenance of the erect pose ; and if, through fatigue and exhaustion or through muscular weakness, from disease, such as rickets {q.v. ), the muscle^ fail to act, a temporary deformity is brought about. If this is not remedied the ligaments become relaxed, the bones which are not yet fully developed adopt their growth to conform to the new relations, and the deformity persists. Postural habits, such as standing on one leg or sitting incorrectly at a desk, tend to distort the spine and to stretch certain ligaments, and often result in perma- nent deformity. Lateral curvature is more frequent among girls than among boys, for their muscles are less de- veloped by physical exercise and their general strength is often imequal to the strain put upon them in their school life. In lateral curvature the bodies of the vertebrse rotate toward the con- vexity and the spines toward the concavity of the curve. In the dorsal region the ribs are car- ried with the vertebrae in their rotation, and therefore the chest becomes deformed and the fimctions of heart and lungs are seriously in- terfered with. In order to maintain the erect position a compensatory curve develops. In the dorsal region the tendency is to the right, while in the lumbar region it is to the left. The subjects of this afTection do not usually complain of pain and often nothing wrong is noticed except an awkwardness in gait or a ten- dency to carry one shoulder higher than the other. An examination will sliow the prominent spinal processes and the abnormal curve of the spine. Spinal supports and plaster jackets are not to be u.scd. The whole treatment should be directed to strengthening the muscles by exeixise and massage. Exercise, liowevcr, must not be carried to excess, for this will only aggravate the existing conditions. Angular curvature of the spine, commonly known as Pott's disease, is the result of caries of the vertebra', a disease essentially tubercular in character. It occurs most frequently in chil- dren between the ages of three and twelve years, but is also met with in babes and in adults. An injury such as a blow or a fall often acts as an important factor, but at times we can trace no existing cau.se whatever. The most conunon seat of disease is in the dorsal vertebrae. The inflammation begins in the bodies of the vertebr;p, and as they become softened or de- stroyed the spinal column above settles down upon the healthy portion below and the spines of the diseased vertebra? are pushed backward, producing a deformity more or less marked. The symptoms are rigidity of the spine with tenderness and a deformity of varying degree. Sometimes abscesses form and pus and bony debris are evacuated (especially lumbar and psoas abscesses). The pain is frequently marked and in some cases pressure upon the spinal cord or nerves gives symptoms of an aggravated type. The disease is slow, with a poor prognosis," al- though the chances are vastly improved if treat- ment is begun early. The best we can hope for is an arrest of the disease and an ankylosis at the site of the trouble. Eest of the spine is the essential factor in treatment, and is obtained bj; a plaster-of-Paris jacket or some one of the surgical appliances especially adapted to special regions. General treatment and hygiene are of course necessary. SPINEL (OF. spinelle, cspineUe. Fr. spinelle, spinel, from Lat. spina, thorn, spine). A mineral magnesium aluminate crystallized in the ortho- rhombic system. It has a vitreous lustre and is found in various shades of red, passing into blue, green, yellow, brown, black, and occasionally nearly white. It is highly prized as a gem, and the transparent red colored crystals are called spinel rubies; wdiile the violet' and purple ones are known as almandine ; the rose-red to pink colored varieties as balas rubies; the black varieties as pleonasle; the yellow or orange spinels are called rubicelle, and the pale to sap- phire-blue kinds are known as sapphiriue. The gem varieties are found for the most part in Ceylon. Siam, and other Eastern countries, and near Franklin, N. .T., crystals occur that occa- sionally atTord small gems. SPINELLO ARETINO, spenel'lo a'ra-te'no, properly LucA Spikello (c. 1.33.3-1410) . A Flor- entine painter, a prominent representative of the declining school of Giotto. He was born in Flor- ence, of a family of Aretine goldsmiths settled there, and probably was a pupil of .Jacopo di Casentino. He was employed upon the chief decorative tasks of JTiddle Italy, in the churches of Florence, in the Campo Santo of Pisa, where he painted scenes from the lives nf Saints Eiihe=us and Hippolytus, and in the Palazzo Pnbblico of Siena, decorating the Sala di Badia with subjects from the life of
