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M A G M A G 283 Lave public exhibitions of the kind alluded to. The medical profession has always been rightly jealous of the employment of^ hypnotism in the treatment of disease, both from fear of the effects of such operations on the nervous systems of excitable people, and because such practice is in the border land of quackery and of imposture. Still in the hands of skilful men there is no reason why the proper employment of a method influencing the nervous system so powerfully as hypnotism should not be the means of relieving pain or of remedying disease. Literature. A very complete bibliography will bo found ap pended to the article " Mesmerisme," Dictionnaire Encyclopediquc des Sciences Mtdicalcs (deuxieme serie, 1873). In addition, see Braid, Neurypnology, London, 1843 ; Elliotson, Human Physiology, London, 1840 ; Colquhoun, History of Magic, Witchcraft, and Animal Magnetism, London, 1851 ; Mayo, Letters on the Truths contained in Popular Superstitions, with an Account of Mesmerism, Edinburgh, 1851 ; Scoresby, Zoistic Magnetism, London, 1849 j Hughes Bennett, Lecture on the Mesmeric Mania of 1851, Edin burgh, 1851 ; Reichenbach, Researches in Magnetism, Electricity, Heat, Light, Crystallization, and Cliemical Attraction, in their relation to Vital Force, (translated by Dr Gregory, London, 1850 ; in this volume the doctrine of odylic force is set forth); Andrew Buchanan, Darlingism, misnamed Electro-Biology, London, 1851 ; Alexander "Wood, What is Mesmerism ? Edinburgh, 1851 ; "Wein- hold, Seven Lectures on Somnambulism, translated by J. C. Colquhoun, Edinburgh, 1845 ; John Forbes, Illustrations oj Modern Mesmerism, London, 1845. See also Maudsley, Physio logy of Mind, London, 1876 ; and especially Carpenter, Mental Physiology, p. 547 sq. (where the author attempts to account for many of the phenomena by the theory of a dominant idea influencing and governing all other mental operations), London, 1874. The most recent account of these phenomena will be found in Heidenhain s Animal Magnetism, translated by Wooldridge, with a preface by G. J. Romanes, London, 1880. For a short and clear account of hysteria as bearing on the phenomena of hypnotism, see Rosenthal, Clinical Treatise on the Diseases of the Nervous System, vol. ii. p. 29 sq., London, 1881. (J. G. M.) MAGNOLIA, L., the typical genus of the order MagnoliaceaR, named from Pierre Magnol, professor of medicine and botany at Montpellier. It contains about fourteen species, distributed in Japan, China, and the Himalayas, as well as in North America and Mexico (De Candolle, Prod., i. 79 ; Bentham and Hooker, Gen. PL, i. 18; A. Gray, Gen. III., xxiii., xxiv.). Magnolias are trees or shrubs with evergreen or deciduous foliage. They bear conspicuous, and often large, fragrant, white, rose, or purple flowers. The sepals are three in number, the petals six to twelve, in two to four series of three in each, the stamens and carpels being numerous. The fruit consists of a number of follicles which dehisce (contrary to the rule) along the outer edge to allow the scarlet or brown seeds to escape, but which are suspended by a long slender thread. Of the Old-World species, the earliest in cultivation appears to have been M. Yulan, Desf. (conspicua, Salisb.), of China, of which the buds were preserved, as well as used medicinally and to season rice (Pickering, Chron. Hist, of PL, p. GOO). It, together with M. fuscata, Andr., was transported to Europe in 1789 (Paxton s Bot. Die.) and thence to North America, and is now cultivated in the middle States. Of the Japanese magnolias, M. Kobus, DC., and the purple-flowered M. obovata, Thim., were met with by Kaempfer in 1690. They were introduced into England in 1709 and 1804 respect ively. The species M. pumila, Andr., the dwarf magnolia, from the mountains of Amboyna, is nearly evergreen, and bears deliciously scented flowers. It was introduced in 1786. The Indian species are three in number, M. ylobosa, H. f. et T., allied to M. conspicua of Japan; M. sphenocarpa, Roxb., and the most magnificent of all magnolias, M. Campbellii, H. f. et T., which forms a conspicuous feature in the scenery and vegetation of Darjiling. It was discovered by Dr Griffith in Bhutan. It is a large forest tree, abounding on the outer ranges of Sikkim, 80 feet high, and from 6 to 12 feet in girth. The flowers are 6 to 10 inches across, appearing before the leaves. They vary from white to a deep rose colour (Hook, fil., III. Him. PL, pis. iv. and v.). The first of the American species brought to Europe (in 1688, by Banister) was M. glauca, L. It is found in low situations near the sea from Massachusetts to Louisiana, more especially in New Jersey and Carolina. In 1712 Catesby visited Virginia and found M. acuminata, L., the so-called cucumber tree, from the resemblance of the young fruits to small cucumbers. It ranges from Pennsylvania to Carolina. The wood is yellow, and used for bowls; the flowers are rather small. It was introduced into England in 1736. He also found M. umbrella, Lam. (tripetala, L.), called the umbrella tree. The flowers are very large, white, and highly scented. It was brought to England in 1752. M. pyramidata, Bart., discovered by Bartram in 1773, is a native of the western parts of Carolina and Georgia. The most beautiful species of North America is M. grandiflora, L., discovered by Catesby in 1719 in South Carolina and Florida, and introduced into England in 1734. It grows a straight trunk 2 feet in diameter, and upwards of 70 feet high, bearing a profusion of large powerfully lemon-scented creamy-white flowers. In England it is customary to train it against a wall; and the original species is surpassed by the Exmouth varieties, which originated as seedlings at Exeter from the tree first raised in England by Sir John Colliton, and which flower much more freely than the parent plant. The remaining North-American species are M. auriculata, Lam., M. macrophylla, Michx., and M. cordata, Michx. The Mexican species is M. mexicana, DC. The tulip tree, Liriodendron tulipifera, L., frequently cultivated in England, is also a member of the same family. It is the sole species, and is a native of North America. For a description of the principal species of magnolia under cultivation see Hemsley s Handbook of Hardy Trees, <L-c. , p. 24 ; London s Arboretum, vol. i. p. 260. MAGNUS, HEINEICH GUSTAV (1802-1870), an eminent German chemist and physicist, was born at Berlin May 2 f 1802. He early showed a strong scientific bias, which was well fostered and strengthened by his education. Six years of thorough study at Berlin university were supplemented by a year s course at Stockholm in Berzelius s laboratory (1828). After some time spent in Paris under Gay-Lussac and The nard, Magnus settled at Berlin in 1831 as lecturer on technology and physics in the university. In 1834 he was elected extraordinary and in 1845 ordinary professor of these subjects. He died April 4, 1870. His numerous papers, which appeared chiefly in Poggendorff s Annalen and in the publications of the Berlin Academy of Sciences, cover a wide range of chemical and physical subjects. His first memoir, published in 1825, while he was yet a student, was a discussion of the spontaneous inflammability of finely divided iron, nickel, and cobalt. From 1827 to 1833 he was occupied mainly with chemical researches, which resulted in the discovery of sulphovinic, ethionic, and isethionic acids and their salts, and, in conjunction with Ammermuller, of periodic acid. The absorption of gases in blood (1837-45), the expansion of gases by heat (1841-44), the vapour pressures of water and various solutions (1844-54), thermo-electricity (1851), electrolysis (1856), induction of currents (1858-61), conduction of heat in gases (1860), and polarization of heat (1866-68) are some of the many subjects of which he treated. From 1861 onwards he devoted much attention to the still vexed question of diathermancy in gases and vapours, especially to the behaviour in this respect of dry and moist air, and to the thermal effects produced by the condensation of moisture on solid surfaces. Many of his papers were

translated and published in the Philosophical Magazine.