EPODE  , in

verse, the third part in an ode, which followed the strophe and the antistrophe, and completed the movement; it was called Eacgbbs srepio3os by the Greeks . At a certain moment the choirs, which had chanted to right of the altar or stage and then to left of it, combined and sang in unison, or permitted the coryphaeus to sing for them all, standing in the centre . When, with the appearance of Stesichorus and the evolution of choral lyric, a learned and artificial kind of poetry began to be cultivated in Greece, a new form, the stbos Eir w uc6v, or epode-song, came into existence . It consisted of a verse of trimeter iambic, followed by a dimeter iambic, and it is reported that, although the epode was carried to its highest perfection by Stesichorus, an earlier poet, Archilochus, was really the inventor of this form . The epode soon took a firm place in choral poetry, which it lost when that branch of literature declined . But it extended beyond the ode, and in the early dramatists we find numerous examples of monologues and dialogues framed on the epodical system . In Latin poetry the epode was cultivated, in conscious archaism, both as a part of the ode and as an independent branch of poetry . Of the former class, the epithalamia of Catullus, founded on an imitation of Pindar, present us with examples of strophe, antistrophe and epode; and it has been observed that the celebrated ode of Horace, beginning Quem virum aut heron lyra vel acri, possesses this triple character . But the word is now mainly familiar from an experiment of Horace in the second class, for he entitled his fifth book of odes Epodon fiber or the Book of Epodes . He says in the course of these poems, that in composing them he was introducing a new form, at least in Latin literature, and that he was imitating the effect of the iambic distichs invented by Archilochus . Accordingly we find the first ten of these epodes terminal portions of the ramifications and extend upwards to varying degrees . Thus in a typical acinous gland the cells are restricted to the final alveoli .

The remaining tubes are to be considered mainly as ducts . In tubulo-alveolar glands the secreting epithelium lines the alveus as well as the terminal tubule . The gland cells are all placed upon a

basement membrane . In many instances this membrane is formed of very thin flattened cells, in other instances it is apparently a homogeneous membrane, and according to some observers is simply a modified part of the basal surface of the cell, while according to others it is a definite structure distinct from the epithelium . In the secretory portion of the gland and in the smaller ducts the epithelial layer is one cell thick only . In the larger ducts there are two layers of cells, but even here the surface cell usually extends by a thinned-out stalk down to the basement membrane . The detailed characters of the epithelium of the different glands of the body are given in separate articles (see ALIMENTARY CANAL, &c.) . It will be sufficent here to give the more general characters possessed by these cells . They are cubical or conical cells with distinct oval nuclei and granular protoplasm . Within the protoplasm is accumulated a large number of spherical granules arranged in diverse manners in different cells . The granules vary much in size in different glands, and in chemical composition, but in all cases represent a store of material ready to be discharged from the cell as its secretion . Hence the general appearance of the cell is found to vary according to the previous degree of activity of the cell .

If it has been at

rest for some time the cell contains very many granules which swell it out and increase its size . The nucleus is then largely hidden by the granules . ,In the opposite condition, i.e. when the cell has been actively secreting, the protoplasm is much clearer, the nucleus obvious and the cell shrunken in size, all these changes being due to the extrusion of the granules . Endothelium and Mesothelium.—Lining the blood vessels, lymph vessels and lymph spaces are found flattened cells apposed Endothel- to one another by their edges to form an extremely tun and thin membrane . These cells are developed from the mesothel- middle embryonic layer and are termed endothelium. turn . A very similar type of cells is also found, formed into a very thin continuous sheet, lining the body-cavity, i.e. pleural pericardial. and peritoneal cavities . These cells develop from that portion of the mesoderm known as the mesothelium, and are therefore frequently termed mesothelial, though by many they are also included as endothelial cells . A mesothelial cell is very flattened, thus resembling a squamous epithelial cell . It possesses a protoplasm with faint granules and an oval or round nucleus (fig . 12) . The outline of the cell is irregularly polyhedral, and the borders may be finely serrated . The cells are united to one another by an intercellular cement substance which, however, is very scanty in amount, but can be made apparent by staining with silver nitrate when the appearance reproduced in the figure is seen .

By being thus united together, the cells form a continuous layer . This layer is pierced by a number of small openings, known as stomata, which bring the cavity into

direct communication with lymph spaces or vessels lying beneath the membrane . The stomata are surrounded by a special layer of cubical and granular cells . Through these stomata fluids and other materials present in the body-cavity can be removed into the lymph spaces . Endothelial membranes (fig . 13) are quite similar in structure to mesothelial . They are usually elongated cells of irregular outline and serrated borders . By means of endothelial or surfaces of the parts covered by them are rendered very smooth, mesothelial membranes the composed in alternate verses of iambic trimeter and iambic dimeter, thus: " At o Deorum quicquid in coelo regit Terras et humanum genus," In the seven remaining epodes Horace has diversified the measures, while retaining the general character of the distich . This group of poems belongs in the main to the early youth of the poet, and displays a truculence and a controversial heat which are absent from his more mature writings . As he was imitating Archilochus in form, he believed himself justified, no doubt, in repeating the sarcastic violence of his fierce model . The curious thing is that these particular poems of Horace, which are really short lyrical satires, have appropriated almost exclusively the name of epodes, although they bear little enough resemblance to the genuine epode of early Greek literature .