Page:The New International Encyclopædia 1st ed. v. 11.djvu/882

* LATEX. 798 LATHOM HOUSE. tion of their end walls. A row of cells extend- ing sidewise may fuse with the main line and so form side branches: or, outgrowths may arise from the main tiihe. penetrate between the adja- cent cells, and finally fuse with a neighboring tube. The articulated latex-vessels, therefore, FlO. 2. NON-ABTIOCLATED I/ATEX-VE88ELS. Longitudinal section of the cortex of Euphorbia resiaifera. are distinguished not only by their irregular out- line, in which the mode of origin may be traced, but also by the numerous liranclies connecting with one anollicr. and so forming a network. (Fig. 1.) The non -articulated vessels arise in the very young embryo tluough llio dill'ercntiation of meristem tissue. The cells destined for latex- tulies elongate, grow, and branch as fast as the neighboring tissue grows, and push their way almost independently among the adjacent young Fia. 3. ENniNos op latex-vessels is the leaves of two SPUKGE.S. a. Euphorbia Myrsinites ; h. E. higlnndulosa. In a, the lat«x-ve8Bel is shown lengthwise; in b. it is seen in section. The shaded cells are the palisade parenchyma, which makes food. cells. While they branch abundantly, the branches do not join others and form a network as the articulated tubes do. They are distinguished by their smooth contour, often thick walls, and the absence of anastomosing branches (Fig. 2). The latex-vessels extend through the whole body of the plant, standing in close relation to the nutri- tive tissue of the leaves on the one hand (Fig. .3) and the growing regions on the other. In the older parts of the stem they are most abundant in the cortex and the phloem. They may be con- sidered as a special form of conducting tissue by means of which the various foods contained in (lie latex are readily distributed from regions of manufacture or storage to the regicms of use. When rich in food substances the latex is very opaque, becoming more translucent as the food diminishes. These variations in the food con- tent of the latex are found to be parallel with the nutritive necessities of the plant. The latex-tubes are lined with a delicate layer of protopla.sm, in which are emliediled the various special organs, nuclei of peculiar form, starch- formers ( leucoplasts, q.v.), oil formers (elalo- plasts), etc. The latex itself lies within this protoplasmic body, occupying the same position as the ccU-sap in an ordinary cell. The latex, therefore, may be looked upon as corresponding to the cell-sap which is present in every active cell, from which it didcrs only in the abundance and nature of the dissolved and sus|iended ma- terials. Economically, the most iiiiiiortant sub- stance in the latex is canutihniie, which after manufacture constitutes the rubber of commerce. See KrmtEH. LATH, or LATHE (AS. lce.>. h]>, district; possibly coiuu'cted with Uan. land, levying dis- trict, situation, and with AS. liojiin. Goth, liyan, OUG. (1,901, Ger. lieffen, OChurcli Slav. Iczhati, to lie, Lat. Iccttis, Gk. X^x"'. Icclwx, couch). Formerly a part or division of a cre.sent it consists of fotir or live hundreds and is confined to the County of Kent. Formerly there was a lathe-reeve, or bailill', in each lathe. The same number of hundreds which constitute the Uitlicx of Kent are called the ch/xs of Sussex, In Ireland the lathe is intermediate between the tithing and the hundred, LA'THAM, .John (ITW-l.S.-JT). An English naturalist. Lorn in Eltham. Kent. He pursued medical studies in London: early applied him- self to the study of natural histoi-y. and was one of the founders of the T^innean Society; and be- came associated with other European .societies. An edition of his works, in ten volumes, under the title of dtiifriil Ilintnrii of liirdi. was begun in 1S21 and Mnisbed in 182S, LATHAM, RouEKT Gordon (1812-88), An English ]ilulologist and ethnologist, born at Billingborough, l.incolnsbire. He was educated at Cambridge, and took the degree of il.D., but having made a tour in Denmark and Xorway, he was led to direct his attention particularly to the Scandinavian languages. For several years he was professor of the English language and literature in University College, London, His chief works are: English Lanriiinrie (1841) ; ?Cntiirnl UiifJoni of the VorirfiVs of Manl-hid (London, IRoO)'; Ethnology of thr British Col- onies: llan and Tlis Migrations (London, 1851) ; neseripiire Ethnologii (IS.'iO) : The yniionalHies of Euro))e I 'fiC^^) : Outlines of General or Tie- velopmeutal Philologg (1S7S) ; ffiissian and Turk from n Oeographiral. Ethnnlogienl. and TJistori- enl Point of ViVir (1878). LATHE, l;"iTn, See Metal- Working Machin- ery; Wonn-WORKTXO ^fACIIINERT, LATHOM HOUSE. .An historic mansion in Lancashire, England, some l.*? miles northeast of Liverpool. In tlTe era of the Plantagenets the