Page:The New International Encyclopædia 1st ed. v. 14.djvu/234

* MUT. 196 MTJTATION THEORY. mural docoiiilioiis she is more commonly (hpitlpil ill liuman form wearing the vulture head-dress and other sjmljols of a queen of Egypt. Consult: W iedeniaiin. Riiiijion of the Ancient Kiiyiitiuns (Xew York, 1897) ; Benson and GourUiy, The Temiilc (if Mi'il in Asher (London, 1898). MUTANABBI, nioo'td-nii'bii (Ar. Ahii al- Taijyib Aliinnil ihn ul-Jlundin al-M iitannhbi (90.5- SMi.j). One of the most noted of the Arahie poets of the period of decline. He was born in f^yria, the son of a water-carrier, and spent several years in the desert alSaniuica (Meso])otamia ). lie was not a fervid Moslem, and at one time even juit him- self forward as a propliet (whence liis name, Mtitdnabbi, 'the one claiming to be a propliet"). He was taken prisoner by Lulu, the Iklisliid Kiiiir of Einesa. After being set at lil)erty he lived ill great poverty and neglect, but in 94S became attached to the Court of Saif al-Dawlah at Aleppo, whom he accompanied on his raids, and whose praises he sang. He left Saif al-Dawlah in 957, going over to his enemy the Ikhshid Kafur of Egypt. In 961 he went to Bagdad, and at last to Shiraz, where the Hujide Adud al- Dnwlah became his patron. He was murdered in 91J.5 on the road from Sliiraz to Kufa. His Diiiiin, containing 281) poems, has been very widely read in the East, where he is considered the last great Arabic poet, perliaps because of his intense national feeling. Xo less than forty commentaries have Ijeen written on his Diaiin. Mutanabbi is the type of the Court singer, his theme the battle and the heroic deeds of his patrons. His songs lack the fire of the earlier Bedouin poetry and are artificial, but their tech- nical excellence cannot be denied. They have been edited by Dieterici, with the coiiimeiilarv of (il-M'i-iliiili (Berlin, lStil),and published at Bulak (ISIini and Cairo (1870 and 1890) with that of al--Vhb(iii. Other editions are: Calcutta (1S1.5), Beirut ( 1800), Bombay (1892). The /Jnr.iii has been completely translated by Hammer-Purg- stall. Molrnrbbi drr r/rosste nriibiftrhr Dirhler (Vienna. 1S24) : extracts may be found in Kiick- ert's llamn.ia (Stuttgart. 1840), and in Ouseley, The Oriental Collection, vol. i. (London. 1797). Consult: Bohlen, Commentntio dr Miitrinabbio, (Bonn, 1824) : Dieterici, Mutanabbi und Seifud- dnnhi (T>eipzig, 1847). MUTATION. See r>rL.UT. MUTATION THEORY (Lat. miitatio, change, from niiitnrc, to change, for moiitare, frei|iientative of moierr, to move, Skt. mil-, to push). The hypothesis that evcdution (c|.v.) takes place by means of sudilcn clmngi's rather than through slow and almost imperceptible transformations. This idea, though not new. has been called into great prominence by the publica- tion in 1901 of Die Mutntinnxtheoric by Prof. Hugo de N'ries, professor of botany at Amster- dam. Darwin himself, os|)ecinlly in his earlier works, recognized that 'single variations' or sports are to he reckoned willi as well as natural selection. Through the influence of Wallace and others, natural selection had eome to be the rul- ing tlicorv, and it is only in recent years that the significance of sports in evolution has had much place. However, as long ago as lSfi4 Kiilliker made nn appeal for heterogenesis (which is identical with the mutation of De Vries) as a factor in the evolution of species. Professor Scott of Princeton has used the word mutation for gradual modifications. Still other writers have referred to the sudden origin of species as saltatory evcdution. But De Vries is the tirst autlior who has performed ex])eriiiu'nts and worked out a theory to fit the facts which they have yielded. Before taking up the experiments it may be said that mutation involves no necessary aban- donment of natural .selection, except in .so far as it may have been held to account for the actual origination of new characters. Darwin recognized that natural selection improves but cannot originate anything new; mutation, on the other hand, is a means for the devclopiiieiit of new characters, and even a new assemblage of characters, i.e. a new species. It should he stated, however, that DeVries gives but little place to natural selection, even as a means of imjiroving something already present. His experiments show that there is a definite and rather narrow limit to individual variation, and the full ad- vantage of artificial scdection along any given line can usually l)e olitained within a few genera- tions, as in the parsnip or carrot. He claims also that natural selection never fixes a character, but that reversion to the original may occur after many generations. Mutation, on the other hand, is believed to bring into existence some- thing wholly new, without any transitions or con- necting links. The new form. i.e. the mutant, remains (axed from the outset, and if it is fit, it will remain as a new species. In ISSO De 'ries observed a colony of evening primrose {Oenothera Laniarekiana) in which were two forms difl'cring strikingly from the com- mon type. Feeling that these aberrant forms doubtless came from the same parentage as the more common forms, he made artificial cultures to see if further aberrant forms would develop. He found such to be the case to an asfonisliing degree. Out of .'iO.OOO seedlings of (Knolhfra Lamarelciana in the various years of study, 800. or about l..! |)er cent., were mutants, while 98. 5 per cent, came true to seed, ilore than one- fourth of the SOO mutants were of one type, which De Vries named (Knolhern lata, i.e. this form appeared anew in cultures more than 200 times. A form which he called fEnothera r]i(tas a|)pcared but once. When cultures are made from these new forms they are found to come true to seed except for occasional mutations; nor was any tendency to reversion observed. To these new forms, as to the two aberrant types observed in 1880. De Vries has given names which imply that these forms arc actually new species. They have, he says, all the characteristics of species, differing not in one. but in several characters, and rcnniining cimstant in all cultures. He shows that they are as much entitled to be considered separate species as are the various members of the natural group to which the parent (F.nothera T.iimarehiana belongs. Indeed, it is possilile to identify most of the new species even while yet seedlings. There are no transitions between ])arcnt and ofTsiu-ing. or between one new s)iccie9 and another. There is no slow and gradual fixa- tion of characters by natural selection. Imt the new species is complete from the outset. ^lost of these new forms would doubtless disappear in a natural state, for they would be obliged to en- gage in a keen stnmsle with species already pres- ent, or would giadually suffer the loss of their specific characters through hybridization. How-