Page:The New International Encyclopædia 1st ed. v. 14.djvu/78

MOTOR ORGAN. of the main leafstalk anil of the stalks of the leatlets (Fig. 1). When the latter are short the motor organ may constitute the whole stalk. The motor organ is a cushion (pulvinus) of thin- walled tissue (parenchyma) whose centre is oc- cupied by a strand of libro-vaseular and mechan- ical tissue (Fig. 2). This is in sharp contrast with the structure of the stalk elsewhere. There the out- er parenchyma forms the usual cortex, the vascu- lar and mechanical strands are distinct and often numerous, and the centre is occupied by a pith (parenchyma) of considerable volume. The central position of the strands in the motor 62 MOTT. other plants variations in the intensity of light cause similar but slow curvatures in the motor organs. Exactly how the exudation of water from the cells of the motor organ is brought FlO. 1. MOTOB OI10AN8 OF LEAF OF IIKAN. The primary organ at the tuwe of main petiole; Becond- ary ones at the baae of ett<'h leaflet ; the lower flfirures show the curvature of these orwanaafter HtiinulatioD (l>ladMs cut away to show more clearly). organ obviously permits freer bending. The cells of the parenchyma are normally turgid, and by mutual pressure the organ is kept rigid, support- ing the leaf or the leaflet. The action of an appropriate stimulus on the plant results in the exuilation of water from the cells on one side of the i)ulvinu3. This water passes into the inter- cellular spaces of the organ and the cells of course lose their turgor. Owing to the now un- opposed pressure of the still turgid colls on one side of the organ, it bends more or less, the flaccid side becoming concave, and the leaf-blade is car- ried through a considerable arc. In the sensi- tive plants (Mimosa) of the tropics, contact is the usual stimulus. The whole reaction takes place very rapidly, the time from shock to re- spon.se being only a fraction of a second. In FlS. 2. LONGITrOISAL SECTION THROrOH MOTOR ORGAX OF SENSITIVE PLANT {Mimusa pudicai. about is not known. It is probable that the stimulus in some way alters the physical struc- ture of the protoplasm within the affected cells so that the contained solution is allowed to filter out. See MovEiiEXT. MOTRIL, niu-trel'. A city and port of entiy in Siiutliern Spain, in the Province of Granada, situated on the Mediterranean coast, 32 miles south by east of Granada (Map: Spain. D 4). There are ruins of old Moorish fortifications, but thcgreater part is well built with modern houses. Motril is chiefly an industrial town, has iron foundries, and manufactures sugar, spirits, choco- late, tlour, soap, paper, cotton textiles, and pot- tery. The harbor is an exposed roadstead. Popu- lation, in 1000, 18,508. MOTT, ,T.MEs (1788-18G8). An American abolitionist, born at Cowneck. Long Island. Soon after completing his education he became a teach- er in a Friends' boarding-school in Dutchess Coimty. N. Y., where he met Lucretia Coffin (see MoTT, Lucbeti.), whom he afterwards mar- ried. In 1810 he removed to Philadelphia and became a merchant. He early manifested his svmpathy with the anti-slavery movement and was one of the first supporters of William Lloyd (iarrison. He was one of the organizers of the Philadelphia National . liSlavery So- ciety in 18.'i3. and in 1840 he was a delegate to the World's Anti-Slavery Convention in London. There lie took a prominent part in the agitation to admit women delegates, and eight years later presided over the first national convention held in support of the woman's rights movement. In 1848 he joined in calling the Anti-Sabbath Con- vention, and after the war was actively interested in the establishment of Swarthmore College by the Philadelphia Yearly Meeting, of which he was a member. MOTT, I.tcFiETiA (Corny) (170.1-1880). An American abolitionist and woman's rights advo- cate, boni on Nantucket Island. She was edu- cated in the Friends' School at Xine Partners, near Poughke<'psie, N. Y., where she met .Tames Mott Iq.v.K whom in 1818 she married. She became ]irominent as a preacher in the Society of Friends and was chosen a minister. .s a result of a vi«it to Virginia in 181S she became an ar- ilent advocate of emancipation. .t the 'Separa- tion' of 1827 which divided the Society of Friends