Page:The New International Encyclopædia 1st ed. v. 14.djvu/251

* MYXCEDEMA. 213 MYZONTES. cot), cachexia thyroidca (Koclier), and hydro- paresie (Feris). ilyxa'deinu is caused by de- struction of the tissue of Hue tliyioid gland by disease, or as a result of removal of it by opera- tion. It occurs priuci])ally in women, and is in fact an acquired cretinism in ;ulull life. Jiy far the greater number of eases occur between the aj;es of thirty-tive and forty-five. In some fami- lies there is a distinct inheritance of a predisposi- tion to disease of the thyroid gland. The disease occurs most frequently in cold climates, and is perhaps most frequent in Eurojie. The symptoms of the disease develop gradually, in most cases nearly a year elapsing before the disease becomes distinct. Among the principal sj'mptoms are languor; sensibility to cold; ab.seiice of perspira- tion; loss of hair; decay of nails and teeth; pallor; subnormal temperature; hallucinations of sight and hearing, and even actual insanity; an;e- mia ; indigestion; and enlargement of l.vni])hatic glands. The treatment is to feed the patient with thyroid gland extract or dr,v thyroid, together with tonics, such as phosphoric acid and iron. Thyroid grafting has proved ellicacious in many cases. The partial or entire thyroid of an ani- mal is transplanted into the peritoneal cavity or into the subcutaneous tissue of the patient, to whom thyroid has been administered for a con- siderable time previously to the grafting, as sug- gested by Victor Horslev. Treatment bv the ad- ministration of thyroid extract has been largely employed since it was first used in 1891 bv Mur- ra.v of England. The extract is made by macerat- ing sheep's thj-roids in gl.ycerine. It must be ailministered with great care, degeneration of tlie heart or of the great vessels being an indi- cation for very small initial dosage. In some pa- tients profuse diarrhoea results, in others vom- iting, sweating, headache, swelling of the glands about the jaw, and prostration. The remedv may be used hypoderraicallv. After the symptoms of the disease have disappeared, the patient must take a small quantity of the th.vroid extract at regular intervals as long as she lives, to maintain the improved condition. See Cretinlsm. Con- sult: Gull, "On a Cretinoid State Supervening in Adult Life in Women," in Clinical Socicti/'s Transactions (London, 1874) ; Murray, in Brit- ish Medical Journal (London, ISni); Virchow, in Berliner klinische Wochcnschrift (1887); Horsle,v, in Brotrn Lectures (London, 1884) ; Osier, in American Journal of the iledical Sciences (Philadelphia, 1893); Gindette, Mi/x- cedema and the Thi/roid Gland (London, 1895). MYXOMYCETES, mik'sfl-mi-se'tez ( Neo-Lat. nom.]il.,from Gk./nuJa./H.V-''". uuicus -]- ixmrrs^mykcs, fungus). A group of organisms commonly called slime molds. Certain phases of their life history are very animal-like, but the final fructification has man.v plant characteristics, and as the forms are described and classified b.v the fructification the work has naturall,v fallen within the province of botany. They are here treated as one of the great groups of the fungi (q.v.) . The purpose of the fructification is the production of multitudes of very minute spores. The spores germinate in moist situations on the soil and in humus, giv- ing rise each to a motile protoplasmic body pro- vided with a cilium (Figs. 6.7.8). These swarm cells swim around in the moisture, increasing in nunilier by division (fission). After an active period they become more quiet and creep around like amcebae (Figs. 1,2,3), finally approaching one another and fusing in pairs, or jierhaps sev- eral together. Such fused groups become centres of attraction to nuuiy hundreds of swarmers, which contribute their substances to the common mass. The result is a large protoplasmic bod,y, called a plasnioduim (Fig. 9), which moves over the surface of the humus and into crevices like a gigantic amicba. Its food is largely bacteria and other fungi, which are taken directly into the pro- toplasmic body and digested, the luird and wortli- less portions being discarded. Vegetating plasmodia shun the light and seek moisture. But these habits are reversed when the fructification is to be formed ; the plasmodia then come to the light and take position in the driest situations that the.v can find. This is the time when plasmodia are most conspicuous and are frequently found on stumps, Iiark, and hu- mus. The largest plasmodia may cover several square inches, but most of them are niucli small- er, and some are no larger than a pin-head. MYXOMVCETE8. Chondrioderma : 1, 2. 3, amoeboid stage ; ^. 5. re8ting stage ; 6, 7. 8, motile stage ; 9, Plasmodium stemouites ; 10, sporangia. The form of the fructifications is exceedingly various, some being large and irregular, and others with an extraordinary delicacy and com- plexity of structure, but the general history of spore formation is much the same. The Plasmo- dium e.xcretes a great deal of nuiterial (and fre- quently mineral matter) which forms the wall of the spore-case (sporangium) and its stalk if present (Fig. 10). A filamentous network called the eapillitium may also be di'velojied inside the spore-case, its function lieing to distribute the spores. The protoplasm which remains after these activities divides up into minute rounded bodies which, investing themselves with walls, become the spores. The plasmodia of slime molds have been favorite subjects of observation by physi- ologists, who find here the largest masses of pro- toplasm that can be studied. For a general account consult: Engler and Prantl, Die natiirliehen I'ltanzenfamilicn (Leip- zig, 1887) ; and for special descriptive treatment. Lister, A Monofpytpli of the Myeeto:oa (London, 1894) ; McBride. The orth American Slime ilouldx (New York, 1809). MYZONTES, mi-Eon'tez. Same as Cyclos- tomi (q.v.).