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climate of the district is comparatively cool, owing to the proximity of the hills; and the average annual rainfall is 33 in. The population in 1901 was 877,188, showing an increase of 13.5% in the decade, which was a period of unexampled prosperity. The principal crops are wheat, pulse, cotton and sugar-cane. The district is crossed by the North-Western railway from Delhi to Saharanpur. Hindu tradition represents Muzaffarnagar as having formed a portion of the Pandava kingdom of the Mahābhārata; authentic history, however, dates from the time of the Moslem conquests in the 13th ccntury, from which time it remained a dependency of the various Mahommedan dynasties which ruled at Delhi until the practical downfall of the Mogul Empire in the middle of the 18th century. In 1788 the district fell into the hands of the Mahrattas. After the fall of Aligarh, the whole Doab as far north as the Siwalik hills passed into the hands of the British without a blow, and Muzaffarnagar became part of Saharanpur. It was created a separate jurisdiction in 1824. During the Mutiny there was some disorder, chiefly occasioned by official weakness, but no severe fighting. See Muzaffarnagar District Gazetteer (Allahabad, 1903). MUZAFFARPUR, a town and district of British India, in the Patna division of Bengal. The town is on the right bank of the Little Gandak river, and has a railway station. Pop. (1901), 45,617. The town is well laid out, and is an important centre of trade, being on the direct route from Patna to Nepal. It is the headquarters of the Behar Light Horse volunteer corps and has a college established in 1899. The DISTRict or MUzAFFARPUR has an area of 3035 sq. m. It was formed in January 1875 out of the great district of Tirhoot, which up to that time was the largest and most populous district of Lower Bengal. The district is an alluvial plain between the Ganges and the Great Gandak, the Baghmat and Little Gandak being the principal rivers within it. South of the Little Gandak the land is somewhat elevated, with depressions- containing lakes toward the south-east. North of the Baghmat the land is lower and marshy, but is traversed by elevated dry ridges. The tract between the two rivers is lowest of all and liable to floods. Pop. (1901), 2,754,790, showing an increase of 1.5% in the decade. Average density, 914 per sq. m., being exceeded in all India only by the neighbouring district of Saran. Indigo (superseded to some extent, owing to the fall in price, by sugar) and opium are largely grown. Rice is the chief grain crop, and cloth, carpets and pottery are manufactured. The district is traversed in several directions by the Tirhoot system of the Bengal and North-Western railway. It suffered from drought in 1873-1874, and again in 1897-1898. See Muzaffarpur District Gazetteer (Calcutta, 1907).
MUZIANO, GIROLAM0 (1528–1592), Italian painter, was born at Acquafredda, near Brescia, in 1528. Under Romanino, an imitator of Titian, he studied his art, designing and colouring according to the principles of the Venetian school. But it was not until he had left his native place, still in early youth, and had repaired to Rome about 1550, that he came into notice. There his pictures soon gained for him the surname of Il Giovane de' paesi (the young man of the landscapes); chestnut-trees are"predominant in these works. He next tried the more elevated style of historical painting. He imitated Michelangelo in giving great prominence to the anatomy of his figures, and became fond of painting persons emaciated by abstinence or even disease. His great picture of the “Resurrection of Lazarus” at once established his fame. Michelangelo praised it, and pronounced its author one of the first artists of that age. It was placed in the church of Santa Maria Maggiore, but was afterwards transferred to the Quirinal Palace. Muziano, with dogged perseverance (at one time he shaved his head, so as not to be tempted to go out of doors), continued to proceed in the path on which he had entered. He grew excellent in depicting foreign and military costumes, and in introducing landscapes into his historical pieces after the manner of Titian. Mosaic working also occupied his attention while he was employed as
superintendent at the Vatican; and it became under his hands a perfect imitation of painting. His ability and industry soon gained for him a handsome fortune. Part of this he expended in assisting to found the Academy of St Luke in Rome. He died in 1592, and was buried in the church of Santa Maria Maggiore. Many of Muziano's works are in the churches and palaces of Rome; he also worked in Orvieto and Loreto. In Santa Maria # Angeli, Rome, is one of his chief works, “...St.Jerome preaching to Monks in the Desert"; his “Circumcision" is in the church of the Gesù, his “Ascension" in the Araceli, and his "St Francis receiv. ing the Stigmata" in the church of the Conception. . A picture by him, representing Christ washing the feet of His disciples, is in the cathedral of Reims. MUZZIOLI,. GIOVANNI (1854-1894), Italian painter, was born in Modena, whither his family had removed from Castel
vetro, on the 10th of February 1854. From the time that he
began to attend the local academy at the age of thirteen he was recognized as a prodigy, and four years later, by the unanimous vote of the judges, he gained the Poletti scholarship entitling him to four years' residence in Rome and Florence. After his return to Modena, Muzzioli visited the Paris Exhibition, and there came under the influence of Sir L. Alma Tadema. His first important picture was “In the Temple of Bacchus” (1881); and his masterpiece, “The Funeral of Britannicus,” was one of the chief successes of the Bologna Exhibition of 1888. From 1878 to his death (August 5, 1894) Muzzioli lived in Florence, where he painted the altar-piece for the church of Castelvetro. : History of Modern Italian Art, by A. R. Willard (London, 1898).
MWERU, a large lake of Eastern Central Africa, traversed by the Luapula or upper Congo. It lies 3ooo ft. above the sea, measures about 76 m. in length by some 25 in breadth, and is roughly rectangular, the axis running from S.S.W. to N.N.E. It is cut a little south of its centre by 9° S. and through its N.E. corner passes 29° E. At the south end a shallow bay extends to 9° 31' S. East of this, and some miles further north, the Luapula enters from a vast marsh inundated at high water; it leaves the lake at the north-west corner, making a sharp bend to the west before assuming a northerly direction. Besides the Luapula, the principal influent is the Kalungwizi, from the east. Near the south end of the lake lies the island of Kilwa, about 8 m. in length, rising into plateaus 600 ft. above the lake. Here the air is cool and balmy, the soil dry, with short turf and clumps of shady trees, affording every requirement for a sanatorium. Mweru was reached by David Livingstone in 1867, but its western shore was first explored in 1890 by Sir Alfred Sharpe, who two years later effected its circumnavigation. The eastern shores from the Luapula entrance to its exit. together with Kilwa Island, belong to British Central Africa, the western to the Belgian Congo.
MYAUNGMYA, a district in the Irrawaddy division of lower Burma, formed in 1893 out of a portion of Bassein district, and reconstituted in 1903. It has an area of 2663 sq. m., and a population (1901) of 278,119, showing an increase of 49% in the decade and a density of 104 inhabitants to the square mile. Among the population were about 12,8oo Christians, mostly Karens. The district is a deltaic tract, bordering south on the sea and traversed by many tidal creeks. Rice cultivation and fishing occupy practically all the inhabitants of the district. The town of Myaungmya had 4711 inhabitants in 1901.
MYCENAE, one of the most ancient cities of Greece, was situated on a hill above the northern extremity of the fertile Argive plain—uiz' "Apyeos irroßórowo. Its situation is exceedingly strong, and it commands all the roads leading from Corinth and Achaea into the Argive plain. The walls of Mycenae are the greatest monument that remains of the Heroic age in Greece; part of them is similar in style and doubtless contemporary in date with the walls of the neighbouring town Tiryns. There can therefore be little doubt that the two towns were the strongholds of a single race, Tiryns commanding the sea-coast and Mycenae the inner country. Legend tells of the rivalry between the dynasties of the Pelopidae at Mycenae and of the Proetidae at Argos. In early historic times Argos had obtained the predominance. The Mycenaeans, who had temporarily regained their independence with the help of Sparta, fought on the Greek side at Plataea in 479 B.C. The long warfare between the two cities lasted till 468 B.C., when Mycenae was dismantled and its inhabitants dispersed. The city never revived; Strabo asserts that no trace of it remained in his time, but Pausanias describes the ruins. For the character of Mycenaean art and of the antiquities found at Mycenae see AEGEAN Civilization. The extant remains of the town of Mycenae are spread over the hill between the village of Charvati and the Acropolis. They consist of some traces of town walls and of houses, and of an early bridge over the stream to the east, on the road leading to the Heraeum. The walls of the Acropolis are in
of thin slabs of stone set up on end, with others laid across the top of them; at the part of this enclosure nearest to the Lion Gate is an entrance. Some have supposed the circle of slabs to be the retaining wall of a tumulus; but its structure is not solid enough for such a purpose, and it can hardly be anything but a sacred enclosure. It was within this circle that Dr H. Schliemann found the five graves that contained a marvellous wealth of gold ornaments and other objects; a sixth was subsequently found. Above one of the graves was a small circular altar, and there were also several sculptured slabs set up above them. The graves themselves were mere shafts sunk in the rock. Dr Schliemann identified them with the graves of Agamemnon, Cassandra, and their companions, which were shown to Pausanias within the walls; and there can be little doubt that they are the graves that gave rise to the tradition,
the shape of an irregular triangle, and occupy a position of great natural strength between two valleys. They are preserved to a considerable height on all sides, except where the ravine is precipitous and they have been carried away by a landslip, they are for the most part built of irregular blocks of great size in the so-called “Cyclopian" style, but certain portions, notably that near the chief gate, are built in almost regular courses of squared stones; there are also some later repairs in polygonal masonry. The main entrance is called the Lion Gate, from the famous triangular relief which fills the space above its massive lintel. This represents two lions confronted, resting their front legs on a low altar-like structure on which is a pillar which stands between them. The device is a translation into stone of a type not uncommon in gem-cutter's and goldsmith's work of the “Mycenaean ” age. The gate is approached by a road commanded on one side by the city wall, on the other by a projecting tower. There is also a postern gate on the north side of the wall, and at its eastern extremity are two apertures in the thickness of the wall. One of these leads out on to the rocks above the southern ravine, the other leads to a long staircase, completely concealed in the wall and the rocks, leading down to a subterranean well or spring. Just within the Lion Gate is a projection of the wall surrounding a curious circular enclosure, consisting of two concentric circles
though the historical identity of the persons actually buried in them is a more difficult question. Outside the circle, especially to the south of it, numerous remains of houses of the Mycenaean age have been found, and others, terraced up at various levels, occupy almost the whole of the Acropolis. On the summit, approached by a well-preserved flight of steps, are the remains of a palace of the Mycenaean age, similar to that found at Tiryns, though not so complicated or extensive. Above them are the foundations of a Doric temple, probably dating from the last days of Mycenaean independence in the 5th century. Numerous graves have been found in the slopes of the hills adjoining the town of Mycenae. Most of these consist merely of a chamber, usually square, excavated in the rock, and approached by a “dromos" or horizontal approach in the side of a hill. They are sometimes provided with doorways faced with stucco, and these have painted ornamentation. Many of these tombs have been opened, and their contents are in the Athens museum. Another and much more conspicuous kind of tomb is that known as the beehive tomb. There are eight of them at Mycenae itself, and others in the neighbourhood. Some of them were visible in the time of Pausanias, who calls them the places where Atreus and his sons kept their treasures. There can, however, be no doubt that they were the tombs of princely families. The largest and best preserved of them, now commonly called the Treasury of Atreus, is just outside the Lion Gate. It consists of a circular domed chamber, nearly 50 ft in diameter and in height, a smaller square chamber opens out of it. It is approached by a horizontal avenue 20 ft. wide and 115 ft. long, with side walls of squared stone sloping up to a height of 45 ft. The doorway was flanked with columns of alabaster, with rich spiral ornament, now in the British Museum, and the rest of the façade was very richly decorated, as may be seen from Chipiez's fine restoration The inside of the vault was ornamented with attached bronze ornaments, but not, as is sometimes stated, entirely lined with bronze. It is generally supposed that these tombs, as well as those excavated in the rock, helong to a later date than the shaft-tombs on the Acropdlis. See H Schliemann, Mycenae (1879), C Schuchhardt, Schliemann's Excavations (Eng. trans., 1891), Chr Tsountas, Muxāva sai Mvsnvaxás roxirauðr (1893); Tsountas and Manatt, The Mycenaean Age (1897); Perrot and Chipiez, Histoire de l'art dans l'antiquité, vol. vi., L'art Mycénéenne W' reports in IIoaxrurd rās dox traplas and in "E4nuepis àpxaloMo'yush. (E. G.R.) MYCETOZOA (Myxomycetes, Schleimpilze), in zoology, a group of organisms reproducing themselves by spores. These are produced in or on sporangia which are formed in the air and the spores are distributed by the currents of air They thus differ from other spore-bearing members of the animal kingdom (which produce their spores while immersed in water or, in the case of parasites, within the fluids of their hosts), and resemble the Fungi and many of the lower green plants. In relation with this condition of their fructification the structures formed at the spore-bearing stage to contain or support the spores present a remarkable resemblance to the sporangia of certain groups of Fungi, from which, however, the Mycetozoa are essentially different. Although the sporangial and some other phases have long been known, and Fries had enumerated 192 species in 1829, the main features of their life-history were first worked out in 18591860 by de Bary (1 and 2). He showed that in the Mycetozoa the spore hatches out as a mass of naked protoplasm which almost immediately assumes a free-swimming flagellate form (zoospore), that after multiplying by division this passes into an amoeboid phase, and that from such amoebae the plasmodia arise, though the mode of their origin was not ascertained by him. The plasmodium of the Mycetozoa is a mass of simple protoplasm, without a differentiated envelope and endowed with the power of active locomotion. It penetrates the interstices of decaying vegetable matter, or, in the case of the species Badhamia utricularis, spreads as a film on the surface of living fungi; it may grow almost indefinitely in size, attaining under favourable conditions several feet in extent It constitutes the dominant phase of the life-history From the plasmodium the sporangia take their origin. It was Cienkowski who (in 1863) contributed the important fact that the plasmodia arise by the fusion with one another of numbers of individuals in the amoeboid phase—a mode of origin which is now generally recognized as an essential feature in the conception of a plasmodium, whether as occurring among the Mycetozoa or in other groups (7). De Bary clearly expressed the view that the life-history of the Mycetozoa shows them to belong not to the vegetable but to the animal kingdom. The individual sporangia of the Mycetozoa are, for the most part, minute structures, rarely attaining the size of a mustardseed, though, in the composite form of aethalia, they may form cake-like masscs an inch or more across (fig. 21) They are found, stalked or sessile, in small clusters or distributed by the thousand over a wide area many feet in diameter, on the bark of decaying trees, on dead leaves or sticks, in woods and shrubberies, among the stems of plants on wet moors, and, generally, at the surface in localities where there is a substratum of decaying vegetable matter sufficiently moist to allow the plasmodium to live. Tan-heaps have long been known as a favourite habitat of Fuligo septica, the plasmodia of which, emerging in bright yellow masses at the surface prior to the sporangial (in this case aethalial) phase, are known as “flowers of tan" The
film-like, expanded condition of the plasmodium, varying in colour in different species and traversed by a network of veinlike channels (fig. 5), has long been known. The plasmodial stage was at one time regarded as representing a distinct group of fungi, to which the generic name Mesenterica was applied. The species of Mycetozoa are widely distributed over the world in temperate and tropical latitudes where there is sufficient moisture for them to grow, and they must be regarded as not inconsiderable agents in the disintegrating processes of nature, by which complex organic substances are decomposed into simpler and more stable chemical groups. Classification -The Mycetozoa, as here understood, fall into three main divisions. The Endosporeae, tm which the spores are contained within sporangia, form together with the Exosporeae, which bear their spores on the surface of sporophores, a natural group characterized by forming true plasmodia. They constitute the Euplasmodida. Standing apart from them is the small group of the mould-like Sorophora, in which the amoeboid individuals only come together immediately prior to sporeformation and do not completely fuse with one another A number of other organisms living on vegetable and animal bodies, alive or dead, and leading an entirely aquatic life, are included by Zopf (31) under the Mycetozoa, as the “Monadina,” in distinction from the “Eumycetozoa,” consisting of the three groups above mentioned. The alliance of some of these (e.g. Protomonas) with the Mycetozoa is probable, and was accepted by de Bary, but the relations of other Monadina are obscure, and appear to be at least as close with the Heliozoa (with which many have in fact been classed). The limits here adopted, following de Bary, include a group of organisms which, as shown by their life-history, belong to the animal stock, and yet alone among animals' they have acquired the habit, widely found in the vegetable kingdom, of developing and distributing their spores in air. Class MYCETOZOA. Sub-class 1.-EU plasmodidA.” Division 1.-Endosporeae. Cohort 1.-Amaurosporales. Sub-cohort i.—Calcarineae. Physaraceae. Genera: Badhamia, Physarum, Physarella, richamphora, Erionema, Cienkowskia, Fuligo, Crcterium, Leocarpus, Chondrioderma, Diachaea. Didymiaceae. Genera: Didymium, Spumaria, Lepidoderma. Sub-cohort 2.-Amaurochaetineae. Order 1...Stemonitaceae. Genera: Stemonitis, Comatricha, Enerthenema, Echinostelium, Lamproderma, Clastoderma.
Order 2 Amaurochaetaceae. Genera: Amaurochaete, Brefeldia.
trichia, Listerella. Division 2.-Exosporeae. Order I. Cerationyxaceae. Genus: Ceratiomyxa. Sub-class 2.-Sorophor.A. Order 1. Guttulinaceae. Genera: Copromyxa, Guttulina, Guttulinopsis. Order 2. Dictyosteliaceae.
Genera: Dictyostelium, Acrasis, Polysphondylium.
Bursulla, a member of Zopf's Monadina, likewise forms its spores in air * The classification of the Euplasmodida here given is that of A. and G: Lister (22), the outcome of a careful study of the group extending over more than twenty-five years. The writer of this article desires to express his indebtedness to the opportunities he has had of becoming familiar with the work of his father. Mr A. Lister, F.R.S., whose views on the affinities and life-history of the Mycetozoa he has endeavoured herein to summarize.
We may begin our survey of the life-history at the point where the spores, borne on currents of air, have settled among wet decaying vegetable matter Shrunken when dry, they rapidly absorb water and resume the spherical shape which is found in nearly all species. Each is surrounded by a spore wall, sheltered £y which the protoplasm, though losing moisture by drying, may remain alive for as many as four years. In several cases it has been found to give the chemical reaction of cellulose. It is smooth or variously sculptured according to the species. Within the protoplasm may be seen the nucleus, and one or more contractile vacuoles make their appearance. After the spore has lain in water for a period varying from a few hours to a day or two the wall bursts and the contained rotoplasm slips out and ies free in the water as a minute colourless mass, presenting amoeboid movements (fig. 1, c). It soon assumes an elongated piriform shape, and a flagellum is developed at # £ '. £ - a length equal to the rest f. Amoeboid of the £ The minute
flagellum. zoospore, thus equipped, swims away with a characteristic dancing motion. The protoplasm is granular within but hyaline externally (fig. 1, d). The nucleus, lying at the end of the body where it tapers into the flagellum, is limited by a definite wall and contains a nuclear network and a nucleolus. It often presents the appearance of being drawn out into a point towards the flagellum, and a bell-like structure [first described by Plenge (27)], staining more darkly than the rest of the protoplasm, extends from the base of the flagellum and invests the nucleus (# 2, a and c). The other end of the zoospore may be evenly rounded (fig. 1, d) or it may be produced into short pseudopodia (fig. 1, e). By means of these the zoospore captures bacteria which are drawn into the body and enclosed in digestive vacuoles. A contractile vacuole is also present - - £" near the hind end. Considerable ture investing the nucleus is fnovement may be observed among clearly seen. the granules of the interior, and in the large zoospores of Amaurochaete atra this may amount to an actual streaming, though without the rhythm characteristic of the plasmodial stage.
Other shapes may
After A. Lister Fig. 1 *-Stages in the Hatching of the Spores of Didymium difforme. a. The unruptured spore. b. The protoplasmic contents of the spore emerging. It contains a nucleus with the (light) nucleolus, and a contractile vacuole (shaded) c, The same, free from the spore wall. d, Zoospore, with nucleus at the base of the flagellum, and contractile vacuole. e, Azoospore with pseudopodial processes at the posterior end, to one of which a bacillus adheres. Two digestive vacuoles in the interior contain ingested bacilli.
phase with retracted
panicea, stained. In a and c the bell-like struc
be temporarily, assumed by the zoospore. *> Attaching itself to an object it - may become amoeboid, either with (fig. 1, f) or without (fig. 2, c) the temporary retraction of the flagellum; or it may take an elongated slug-like shape and creep with the flagellum extended in front, with tactile and apparently exploratory movements. That the zoospores of many species of the Endosporeae feed on ris - bacteria has been shown by A. Lister (18). New light has recently been thrown on the matter by Pinoy (26), who has worked chiefly with Sorophora, in which, as shown below, the active phase of the life-history is passed
* Figures 1, 4, and 11-22 are from the British Museum Guide to the British Mycetozoa. The other figures are from Lankester's Treatise on Zoology, part I. Introduction and Protozoa. Fascicle 1. Article Mycetozoa. *
After A. Lister. . -
division of the Zoospore of
- * * * * * *
- - - - - - - - - -
mainly in the state of isolated amoebae. Pinoy finds' that the amoebae of this group live on particular species of bacteria, and that the presence of the latter is a necessary condition for the development of the Sorophora, and even (as has been recognized by other workers) for the hatching of their spores. Pinoy's results indicate, though not so conclusively, that bacteria are likewise the essential food of the Euplasmodida in the £ phases of their life-history. The zoospores do, however, ingest other solid bodies, e.g. carmine granules (Saville Kent, 15). The zoospores multiply by binary fission, the flagellum being withdrawn and the nucleus undergoing mitotic division, with the formation of a well-marked achromatic spindle (fig. 3). It is probable that fission occurs more than once in the zoospore stage; but there is not satisfactory evidence to show how often it may be repeated.” * At this, as at other phases of the life-history, a resting stage may be assumed as the result of drying, but also from other and unknown causes. The flagel
ium is withdrawn and the - - - -
protoplasm, becoming spherical, secretes a cyst wall. The O organism thus passes into the & condition of a microcyst, from ow
which when dry it may be * awakened to renewed activity Q 3'-by wetting. t 'I'At the end of the zoospore v. -- 4: : stage the organism finally 3 9:G withdraws its flagellum and - - assumes the amoeboid shape. It is now known as an amoebula. The amoebulae become endowed, as was first recognized by Cienkowski, wit mutual attraction, and on meeting fuse with one another. Fig. 4 represents a group of such amoebulae. Several have already united to form a common mass, to which others, still free, are converging. The protoplasmic mass thus arising is the plasmodium. The fusion between the protoplasmic bodies of the amoebulae which unite to form it is complete. Their nuclei may be traced for some time in the young plasmodium and no fusion between them has been observed at this stage (20). As the plasmodium increases in size by the addition of amoebulae the task of following the fate of the individual nuclei by direct observation becomes impossible. The appearance of an active plasmodium of Badhamia utricularis, which, as we have seen, lives and feeds on certain fungi, is shown in fig. 5. It consists of a film of protoplasm, of a bright yellow colour, varying in size up to a foot or more in diameter. It is traversed by a network of branching and anastomosing channels, which divide
After A. Lister. , , , ,
Fig. 4.—Amoebulae of Didymium difforme uniting to form a Plasmodium. The common mass contains digestive vacuoles (v). The clear spherical bodies are microcysts and an empty sporeshell is seen to the left." e
FIG. 5-Part of the Plasmodium of Badhama utricularis.
main trunks of the network may lie free with little or no connecting film between them and their neighbours. The plasmodia of other species, which live in the interstices of decaying vegetable matter, are less easily observed, but on emerging on the surface prior to
£ formation they present an essentially similar appearance. here is, however, great variety in the degree of concentration or expansion £f by plasmodia, in relation with food ': moisture and other circumstances. The plasmodia move slowly about over or in the substratum, concentrating in £ where food supply is abundant, and leaving those where it is exhausted. n examining under the microscope a film which has spread over a cover-slip, the channels are scen to be streams of rapidly moving nular protoplasm. This movement is rhythmic in character, ing directed alternately towards the margin of an advancing region of the plasmodium, and away from it. As a channel is watched the stream of granules is seen to become slower, and after a momentary pause to begin in the opposite direction. In an active plasmodium the duration of the flow in either direction varies from a minute and a half to two minutes, though it is always longer when in the direction of the general advance over the substratum. When the flow of the protoplasm is in this latter direction the border becomes turgid, and lobes of hyaline £ are seen (under a high magnification) to start forward, and soon to become filled with granular contents. . When the flow is reversed, the margin becomes thin from the drainage away of its contents. A delicate hyaline layer invests the £ and is apparently less fluid than the material flowing in the channels. The phenomena of the rhythmic movement of the protoplasm are not inconsistent with the yiew that they result from alternating contraction and relaxation of the outer layer in different regions of the plasmodium, but any dogmatic statement as to their causation appears at present inadvisable.
Fig. 6. ta, '' of a stained Plasmodium of Badhamia utricularis. n. Nuclei. b. Nuclei, some in process of simple (amitotic) division. c, Part of a Plasmodium in which the nuclei are in simultaneous mitotic division, . - * d-f. Other stages in this process.
Minute contractile vacuoles may be seen in £ numbers in the thin parts of the plasmodium between the channels. In stained preparations nuclei, varying (in Badhamia utricularis) from 2.5 to 5 micromillimeters in diameter, are found abundantly in the granular protoplasm ' 6, b). They contain a nuclear reticulum and one or more well-marked nucleoli. In any stained plasmodium some nuclei may be found, as shown in the figure b, which appear to be in some stage of simple (amitotic) division, and this is, presumably, the chief mode in which the number of the nuclei keeps pace with the rapidly # plasmodium. There is, however, another mode of nuclear division in, the plasmodium which has hitherto been observed in one recorded instance (19, p. 541), the mitotic (fig. 6, c.f), and this appears to befall all the nuclei of a plasmodium simul. taneously. What the relation of these two modes of nuclear division "## the life-history is obscure. at the amitotic is the usual mode of nuclear division is indicated by the very frequent occurrence of these apparently dividing nuclei and also by the following experiment. A plasmodium of Badhamia utri. spreading over pieces of the fungus Auricularia was observed to increase in size about fourfold in fourteen hours, and during this time a small sample was removed and stained every
Prowazek (28) has recently referred to nuclear stages, similar to those here regarded as of amitotic division, but has interpreted them as nuclear fusions. He does not, however, discuss the mode of multiplication of nuclei in the plasmodium. In the group of the Calcareae, granules of carbonate of lime are abundant in the plasmodia, and in all Mycetozoa other granules of undetermined nature are present... The colour of plasmodia varies in different species, and may be yellow, white, pink, purple or green. The colouring matter is in the form of minute drops, and in the Calcareae these invest the lime granules. Nutrition.-The plasmodium of Badhamia utricularis, advancing over the pilci of suitable fungi, feeds on the superficial layer dissolving the walls of the hyphae (17). The protoplasm may be seen to contain abundant foreign bodies such as spores of fungi or sclerotium cysts (vide infra) which have been taken in and are undergoin digestion... It has been found experimentally (11) that pieces o coagulated proteids are likewise taken in and digested in vacuoles. On the other hand it has been found that plasmodia will live, ultimately producing sporangia, in nutrient solutions (9). It would appear therefore that the nutrition of plasmodia is effected in part # the ingestion of solid foodstuffs, and in part by the absorption of material in solution, and that there is great variety in the complexity of the substances which serve as their food. Sclerolium-As the result of drought, the plasmodium, # become much denser by loss of water, passes into the scleroti condition. Drawing together into a thickish layer, the protoplasm divides up into a number of distinct masses, each containing some io to 20 nuclei, and a cyst wall is excreted round each mass £ 7). The whole has now a hard brittle consistency. In this state the protoplasm will remain alive for two or three years. On the addition of water the cyst walls are ruptured pPio. 7:-Section, of the and in part absorbed, their contents Plasmodium of 'anamta join together, and the active streaming #ricula' when passing into condition of the plasmodium is re- the condition of sclerotium. sumed. It is to be noted, however, ... ", The nuclei contained in that the sclerotial condition may be the young sclerotial cysts. assumed under other conditions than dryness, and sclerotia may even be formed in water. The existence of the sclerotial stage affords a ready means of obtaining the plasmodium for experimental purposes. If a cultivation of the plasmodium of Badhamia utricularis on suitable fungi (Stereum, Auricularia) is allowed to become partially dry the plasmodium draws together and would, if drying were continued, pass into the sclerotial stage on the fungus, If now strips of wet blotting£ are placed so as to touch the plasmodium t e latter, attracted y the moisture, crawls on the blotting-paper. if this is now removed and allowed to dry rapidly, the plasmodium passcs into sclerotium on it.” By this means the plasmodium is removed from the partially disintegrated and decayed fungus on which it has been feeding, and a clean sclerotium is obtained, which, as above stated, remains alive for years (21, p. 7). An easy method for obtaining small plasmodia for microscopic examination is to scatter small fragments, scraped from a piece of the hard sclerotium, over cover-slips wetted with rain-water and kept in a moist atmosphere. In twelve to twentyfour hours small £ will be seen spreading on the cover-slips and these may be mounted for observation. The plasmodial stage ends by the formation of the sporangia. The plasmodium withdraws from the interstices of the material among which it has fed, and emerges on the surface in a diffuse or concentrated mass. In the case of Badhamia utricularis it may withdraw from the fungus on which it has been feeding, or change into £ on it. The mode of formation of the sporangia will be escribed in the case of Badhamia, some of the chief differences in the process and in the structure of the sporangia in other forms being subsequently noticed. When the change to sporangia begins the protoplasm of the plasmodium becomes gradually massed in discrete rounded lo about a half to one millimeter in diameter and scattered in clusters over the area occupied by the plasmodium. The reticulum of channels of the plasmodium becomes meanwhile less and less marked: When the whole of the protoplasm is drawn in to the lobes, the circulation ceases. The lobes are the young sporangia. Meanwhile foreign bodies, taken in with the food, are ejected, and the protoplasm secretes on its outer surface a pellicle of mucoid, transparent substance which dries as the sporangia ripen. is invests the young sporangia, and as they rise above the substratum falls together at their bases forming the stalks; extended over the substratum it forms the £ and in contact with the rounded surface of the sporangium it forms the sporangium-wall. While the sporangium-wall is formed externally a secretion of
uarter of an hour. The later stainings showed no diminution in
e number of nuclei in proportion to £ protoplasm, and yet none of the sample showed any sign of mitotic division (20, p. % It would appear therefore that the mode of increase of the nuclei during this period was amitotic.
* A solution which has thus been found favourable contains the following mineral salts: KH3PO. , K, HPO, MgSO, KNO, CA, (NOx),...a free, acid, and 5% of dextrine.
* If the plasmodium is slowly dried it is very apt to pass into sporangia.