Vein (plant)

“ The ancient mode of shoding for tin-veins, consisted in tracing certain stones, of which tin formed a proportion considerable enough to excite attention, and found at or a little below the surface, to the vein from which they had been accidentally detached, so as to have passed in a sort of succession down the side of a hill. Another mode of seeking tin veins is by sinking pits through the superincumbent earth down to the solid rock, and driving a trench from one to another, north and south, so as to meet with every vein in the track through which it passed. ”

“ The ribs of a butterfly's wings are by some authors described as veins, whilst others style the main ones nervures, and the branches nervules. Fig. 9, B, represents the venation, or neuration of the Black-veined White, and the numeral system [Pg 13] of indicating the veins has been adopted, as it is the most simple. In another method of referring to the venation, and one that has been much in use, vein 12 of the fore wing would be styled the costal nervure, or vein ”

“ Let the pupils compare the distribution of the veins in their specimens. They have already distinguished parallel-veined from netted-veined leaves, and learned that this difference is a secondary distinction between monocotyledons and dicotyledons. [1] The veins in netted-veined leaves are arranged in two ways. The veins start from either side of a single midrib (feather-veined or pinnately-veined) , or they branch from a number of ribs which all start from the top of the petiole, like the fingers from the palm of the hand (palmately-veined) . ”

“ Their downward direction is seldom quite vertical; there is however a species of vein having also an east and west direction which is never metalliferous, but consists generally of clay; this vein is for the most part found to take a course under-ground much less approaching the perpendicular than the metalliferous veins. This variation from the perpendicular in an east and west vein, whether it be towards the north or south, is called the underlie, and when its direction or dip is opposed to that of the metalliferous vein, it mostly, disturbs the direction of the latter. ”

“ It will be readily seen that this is merely a modified form of the ordinary pinnate frond. Throughout the domain of nature there is infinite variety of form and structure, and at the same time unity in plan and conformity to a few generalized types.
25. Venation.— The method of veining admits of great variation, often serving to distinguish species, and more especially the sections of the various genera. In some ferns, like most shield-ferns (Dryopteris) , the veins are free — that is, arising from either side of the midvein they do not unite with any other vein. ”

“ These narrow veins cannot be seen on account of their fineness; but in every stem and in every root things may be discerned which like nerves in animals can be split longitudinally and are called the nerves of the plant, or also certain thicker things, such as those which branch in most leaves and are there called veins. ”

“ The radicles of the inferior vena cava and the left posterior cardinal are formed by the renal veins from the two kidneys, and in their forward course to the heart both veins receive in addition genital and segmental veins. In its course through the liver the inferior vena cava receives several hepatic veins, and finally opens into the sinus venosus, while the left posterior cardinal vein joins the corresponding Cuvierian duct, which also receives anterior cardinal, inferior jugular, and subclavian veins. ”

“ Nor are the veins equally apparent in all animals; but they are more manifest in [Pg 57] those which have most blood, and in the largest creatures; but in those animals which are small, and have not much blood, either by nature or from excess in fat, they are not so easily investigated, for some of the passages are confused, like rivulets that are lost in beds of mud; and there are some animals which have but few, and these fibres instead of veins. The great vein is very conspicuous in all, even the smallest animals. ”

“ Veins are hollow and round, like pipes, arising from the liver, carrying blood and natural spirits; they feed all the parts. Of these there be two chief, Vena porta and Vena cava, from which the rest are corrivated. That Vena porta is a vein coming from the concave of the liver, and receiving those mesaraical veins, by whom he takes the chylus from the stomach and guts, and conveys it to the liver. The other derives blood from the liver to nourish all the other dispersed members. The branches of that Vena porta are the mesaraical and haemorrhoids. ”

“ The body is slender; the head small; the antennæ long, slender, and filiform; the palpi nearly three times as long as the head, compressed, slender, attenuated to the tip, bent downwards; the spiral tongue long; the fore wings large and somewhat triangular, with the apex acute and slightly falcate. The mesial vein of the fore wings emits three branches, the third of which is connected by a slender vein with the inner branch of the postcostal vein, a simple longitudinal vein extending from the
base of the wing to the extremity through the middle of this cross vein ”

“ Even if a vein is a very wide one, as tin veins usually are, miners excavate into the small streaks, and into those hollows they put dry wood and place amongst them at frequent intervals sticks, all sides of which are shaved down fanshaped, which easily take light, and when once they have taken fire communicate it to the other bundles of wood, which easily ignite. ”

“ Blood then ceases to flow along the allantoic vessels; they become obliterated. The vitelline vein, which as the yolk becomes gradually absorbed proportionately diminishes in size and importance, comes to appear as a mere branch of the portal vein. The ductus venosus becomes obliterated; and hence the whole of the blood coming through the portal vein flows into the substance of the liver, and so by the hepatic veins into the vena cava. ”

“ But their disadvantages are numerous; for although the regular metalliferous veins are occasionally found to be but little or not at all disturbed by the passing of the substance of the cross vein through them, except by the mere division of the load, it more often happens that it is as it were broken into small strings or branches. By a careful examination of the nature and direction of these, the miner is indeed sometimes enabled to find pretty readily that part of the load which is on the other side of the cross vein, but he is often baffled. ”

“ In the rabbit a vein is a vessel bringing blood towards the heart, while an artery is a vessel conducting it away. Veins are thin-walled, and therefore flabby, a conspicuous purple when full of blood, and when empty through bleeding and collapsed sometimes difficult to make out in dissection. They are formed by the union of lesser factors. The portal breaks up into lesser branches within the liver. Arteries have thick muscular and elastic walls, thick enough to prevent the blood showing through, and are therefore pale pink or white and keep their round shape. ”

“ The veins, or vascular bundles, act efficiently as strengtheners of the thin surface; to prevent tearing at the leaf-edges the veins are often looped along the margin; while in indented leaves the extremities of the indentations are strengthened with special tissue. When one surface of the leaf faces the sky, as in most cases it does, this surface is strengthened against the weather, and the stomata are arranged mostly on the lower surface. ”

“ Veins free in all our species. (Name from α- privative and σπλήν, the spleen, for supposed remedial properties.)
§ 1. ASPLENIUM proper. Indusium straight or slightly curved, attached to the upper side of the vein, rarely double.
[*] Small evergreen ferns; fronds pinnatifid, or pinnate only near the base.
1. A. pinnatífidum, Nutt. Fronds (3–6 ́ long) lanceolate, pinnatifid, or pinnate below, tapering above into a slender prolongation, "the apex sometimes rooting"; lobes roundish-ovate, obtuse, or the lowest pair long-acuminate ”

“ The vena ischiatica originates by the union of several venous branches which come from the muscles of the pelvis and upper thigh region. The ischiatic vein enters the pelvic cavity along with the ischiatic nerve and artery, and communicates with the vena hypogastrica at about the level of the anterior lobe of the kidney. It is always smaller than the vena cruralis. ”

“ They seldom exceed a few inches in thickness, and are in general much more slender; the same vein which in the middle is an inch or two in thickness, gradually thins away at each extremity, sometimes to a hair's breadth, at other times shooting of like a spreading root of delicate fibres. ”

“ There is in man a vein which feedeth all the other veins. Now water is collected from the three hundred and sixty veins and, in the form of red blood, entereth the left testicle, where it is decocted, by the heat of temperament inherent in the son of Adam, into a thick, white liquid, whose odour is as that of the palm-spathe. ”

“ In the deepest part of the black a white vein is sometimes seen running with a number of small veins attached to it, but care must be taken that these threads are connected with and run, in some degree, in the same direction with the thicker veins. ”

“ Throughout all the classes there occur what are called veins, containing diverse substances. The larking vein is extremely abundant in the superior classes—it is rich in brass knockers, bell handles, and policemen’s rattles; this vein descends through all the lower strata, the specimens in each differing according to the situation in which they are found ”

“ Fig. 88.—A Simple Netted-veined Leaf. Fig. 89.—A Simple Parallel-veined Leaf. Fig. 90.—Compound or Branched Leaf of Brake (a common fern) .
Kinds.—Leaves are simple or unbranched (Figs. 88, 89) , and compound or branched (Fig. 90) . [74] The method of compounding or branching follows the mode of veining. The veining, or venation, is of two general kinds. In some plants the main veins diverge, and there is a conspicuous network of smaller veins; such leaves are netted-veined. They are characteristic of the dicotyledons. ”

“ But so variable is the breadth of veins, that extreme contractions and considerable expansions sometimes confuse all regularity, and render doubtful even the connection of the seemingly disunited parts of such veins. "If we take a vein of 3 or 4 feet to represent a fair average size, it may be only an inch or two wide in one place and 8 or 10 feet in another. Such extremes not infrequently occur within a few fathoms of each other." ”

“ Thus the vegetable circulation, complete in the lungs, but probably in the other part of the system deficient in respect to a system of returning veins, is carried forwards without a heart, like the circulation through the livers of animals where the blood brought from the intestines and mesentery by one vein is dispersed through the liver by the vena portarum, which assumes the office of an artery. ”

“ For example, if a principal vein runs from the east to the west, the rock seams descend in depth likewise from the east toward the west, and the associated vein which joins with the principal vein, whether it runs from the south or the north, has its rock seams extending in the same way as its own, and they do not conform with the seams in the rock of the principal vein which remain the same after the junction unless the associated vein proceeds in the same direction as the principal vein. ”

“ Opinions respecting the functions of the vascular tissues in plants appear to make but little progress towards agreement. The supposition that these vessels and strings of partially-united cells, lined with spiral, annular, reticulated, or other frameworks, are carriers of the plant-juices, is objected to on the ground that they often contain air: as the presence of air arrests the movement of blood through arteries and veins, its presence in the ducts of stems and petioles is assumed to unfit them as channels for sap. ”

“ The commencements of these veins, when they are first of all divided, are called jugular veins; and having branched off in the neck from the great vein, they are continued to the trachea of the lungs. And if these veins are held on the outside, men fall down dead with insensibility, with closed eyes, but without choking. ”

“ A vein may vary in width from less than an inch up to many yards, and the arrangement of its contents is also subject to much variation. Instead of parallel layers of spars and ores, frequently a confused mass of clay and broken rocks, which are often cemented together with sparry matter, chokes up the vein. The ore in a vein may occur in one or more ribs, which often vary in thickness from a mere line up to masses several yards in width. Sometimes the rocks are dislocated along the line of fissure occupied by a great vein; at other times no dislocation can be observed. ”

“ Similarly, we can determine with regard to east and west and the subordinate and their intermediate directions. A vena profunda which descends into the earth may be either vertical, inclined, or crooked the footwall of an inclined vein is easily distinguished from the hangingwall, but it is not so with a vertical vein; and again, the footwall of a crooked vein is inverted and changed into the hangingwall, and contrariwise the hangingwall is twisted into the footwall, but very many of these crooked veins may be turned back to vertical or inclined ones. ”

“ The cutaneous and the muscular veins, lying under the pectoralis muscle, and arising independently from the subclavian vein. They supply the skin and muscles in the region of the arm. There is a second cutaneous vein arising from the abdominal vein and extending on to the skin of the abdomen. Two other small cutaneous veins are seen on the skin of the leg, and another on the skin under the mouth.
[In the Frog a single musculo-cutaneous vein is seen lying under the pectoralis muscle and extends on to the skin.] ”