MUSCOVITE 



MUSHROOM 



355 



this arrangement a contraction of a single inch in 

 the muscle moves the hand (f), in the same time, 

 through the extent of alxmt 12 inches, but then the 

 hand moves througli every inch with only about 

 the twelfth part of the power exerted by the 

 muscle. By the junction ot two or more levers in 

 one direction, as in the different segments of the 

 extremities, the extent and velocity of their united 

 actions are communicated to the extreme one. 



Tiin-i. a blow of the Fist may lie made to include 

 the force of all the muscles engaged in extending 

 tin- shoulder, elbow, and wrist. 



The great and characteristic property of muscular 

 tissue that of shortening itself in a particular 

 direction when stimulated is called contractility. 

 The stimulus may be direct irritation by mechanical 

 means, or by galvanism, or by some chemical sub- 

 stance, but in the living body the muscular filires 

 are, in most cases, made to contract by the inime- 

 diate intluence of the nerves distributed among 

 them, which are consequently termed motor nerves 

 (gee NERVOUS SYSTEM), and are under the intlu- 

 ence of the will. By an exertion of volition, we 

 can contract more or fewer muscles at once, and to 

 any degree, within certain limits ; and, as a matter 

 of fact, there is hardly any ordinary movement 

 ]! formed in which several muscles are not called 

 into play. But every voluntary muscle is also 

 subject to other influences more powerful in their 

 operation than the will. The movement of the 

 features under the impulses of passion and emotion 

 are more or less involuntary, as is shown by the 

 very partial power the will has of restraining 

 them, and the extreme difficulty of imitating them. 

 Many movements ensue involuntarily when certain 

 impressions, which need not necessarily 1* attended 

 with consciousness, are made on the surface of the 

 body, or on any part of its interior, either by 

 external or internal causes. Such movements are 

 termed reflex, and are noticed in the article NERVOUS 

 SYSTEM. For various important groups of muscles, 

 see ARM, EYE, FOOT, HANK, KNEE, LEO, &c. ; 

 and for the source of muscular force, see DIET, 

 DIGESTION. 



Muscovite. See MICA. 



Muscovy. See RUSSIA. 



Mliscs. in tin; (Jreek Mythology, divinities 

 originally included amongst the Nymphs, but 

 afterwards regarded as quite distinct from them. 

 To them was ascribed the power of inspiring song, 

 and poets and ir.usicians were therefore regarded 

 as their pupils and favourites. They were first 

 honoured amongst the Thracians, and, as 1'irria. 

 around Olympus was the original seat of that 

 people, it came to he considered as the native 

 country of the Muses, who were therefore called 

 Pieridei. In the earliest period their number was 

 three, though Homer sometimes speaks of a single 

 HIM-'-, and once, at least, allude* to nine. This last 

 U the number given by Hesiod in hU Tkeogony, who 



also mentions their names Clio, the muse of his- 

 tory ; Kuterpe, of lyric poetry ; Thalia, of comedy ; 

 Melpomene, of tragedy; Terpsichore, of choral dance 

 and song; Erato, of erotic poetry; Polyhymnia, of 

 the sulilime hymn ; Urania, of astronomy ; and 

 Calliope, of epic poetry. Their origin is differ- 

 ently given, but the most widely-spread account 

 represented them as the daughters of Zeus and 

 Mnemosyne. Homer speaks of them as the 

 goddesses of song, and as dwelling on the summit 

 of Olympus. They are also often represented as 

 the companions of Apollo, and as singing while he 

 played upon the lyre at the banquets of the Immor- 

 tals. Various legends ascribed to them victories in 

 musical competitions, particularly over the Sirens. 

 In the later classic times particular provinces were 

 assigned to them in connection with different 

 departments of literature, science, and the line 

 arts ; but the invocations addressed to them appear 

 to have l>een, as in the case of modern writers, 

 merely formal imitations of the early poets. 

 Their worship amongst the Romans was a mere 

 imitation of the Greeks, and never l>ecame truly 

 national or popular. Among the places sacred to 

 them were the fountains of Aganippe and Hippo- 

 crene on Mount Helicon, and the Castalian spring 

 on Mount Parnassus. 



Museum (Or. mouseion), originally the name 

 giveji by the ancient* to a temple of the Muses, 

 and afterwards to a building devoted to science, 

 learning, and the fine arts. The first museum of 

 thi* kind was the celebrated Alexandrian Museum 

 a meeting-place for learned men and a library, 

 founded alxmt 2HO B.C. in the palace. After the 

 revival of learning in Europe the term museum 

 came to be applied to collections of antiquities, 

 and sculptures, and paintings. Collections illus- 

 trative of natural history and other sciences now 

 form a chief part of the treasures of many of the 

 greatest museums, and there are museums devoted 

 to particular branches of science, and to illustrating 

 the industrial arts. Of the museums of Britain, 

 the British Museum (q.v. ) and that of South 

 Kensington (see KENSINGTON) are the most im- 

 portant. The museums of the Vatican in Rome, 

 of the Louvre in Paris, of St Petersburg, Dresden, 

 Vienna, Munich, and Berlin, and the National 

 Museum at Washington also are among the 

 greatest in the world. See the Address of the 

 President of the British Association, 1889. 



iMusliu Islands. See OBOCK. 



Mushroom, or AGARIC, the popular name of 

 ;i somewhat diverse group of genera and species of 

 fungi belonging to the sub-order Hymenomycetes, 

 of the great class Cryptogams. The best known of 

 the true mushrooms to English readers is the 

 Common Mushroom (Agaricus camjtestris), and it 

 is the type of the sub-order named. In Britain 

 it is the most esteemed of its trilie, though little 

 valued in countries where fungi more generally 

 form an article of diet of the people ; in Italy 

 it is disapproved. It should be noted that some 

 of the forms common to Europe and North 

 America are esteemed in England, but found un- 

 palatable in the United States. The Common 

 Mushroom varies considerably in appearance accord- 

 ing to soil and locality, but presents in all its 

 variation* the same essential characters. It has 

 a ileshy head or jnleus, smooth or scaly on the 

 upper surface, varying in colour from white to 

 different shades of tawny or fuliginous brown. 

 The gills (kymenitim) on the under side of the 

 head are free, at first pallid, changing by grada- 

 tions in age to pink, purple, and brown-black. 

 The stem is white, varied in shape, full, firm, 

 furnished towards the top with a white persist- 

 ent ring. The Common Mushroom is widely 



