veins in the leg from the wearing of a tight garter, and of piles as the result of the pressure of an ovarian tumour or a pregnant uterus, or of disease of the liver.
Sometimes the trouble is begun by a direct injury to the vein, which, by setting up an inflammation, weakens the coats of the vein, which then yield under the pressure of the blood-stream. In the case of varicocele, the dilatation of the veins is probably of developmental origin; many other causes are given, but not one of them appears satisfactory. Examination of a varicose vein shows that it is increased in length as well as in capacity. In some parts of its course the vein has its coats much thickened, but at those places where there is dilatation the walls are very thin. Veins thus affected give rise to pains and achings, and they are, moreover, liable to attacks of inflammation which end in clotting of the blood (thrombosis). This is a dangerous condition, as a sudden or violent movement is apt to cause the detachment of a piece of the clot, which, carried up to the brain or the lung, may cause sudden death. Less serious results of varicose veins are swelling of the parts below (oedema), ulceration and abscess.
As regards treatment, the wearing of a well-fitting elastic stocking will prove beneficial in the case of a moderate dilatation of the veins of the leg; the individual must avoid long standing and fatigue. It is well also to have the foot of the bed raised three or four inches, so that during the night the veins may be kept as empty as possible. If the case is more serious, the thinned veins threatening to give way, it will be advisable, provided the dilatations are fairly well localized, and the general condition of the patient permits, to excise the diseased parts, tying the cut ends of the veins, and closing the surface wounds with fine sutures. Should a varicose vein be plugged with clot, it will be advisable to tie it high up where the coats are healthy, and to remove the lower part by dissection. This will render the person safe from the very serious risk of a piece of the clot being carried to the heart, and will also permanently rid him of his trouble. It may be said generally that any operative treatment for varicose veins in the lower extremity is best associated with the application of a ligature upon the large surface vein just before it enters the common femoral vein below the fold of the groin. This operation removes the risk of the downward pressure of blood in the veins whose dilatation has rendered the valves useless.
In the case of a varicose vein being opened by accident or disease, it is quite possible for the individual to bleed to death. The first-aid treatment for the serious haemorrhage should consist in laying the patient on the floor, raising the limb upon the seat of a chair, and fixing a pad over the open vessel by a handkerchief or bandage.
Varicose veins of the spermatic cord (varicocele) of the left side are met with in adolescents. The dilatation is, in all probability, of developmental origin, making its appearance at puberty. It is, as a rule, of no serious moment, and, unless present in an extreme degree, had best be treated merely by a suspension bandage. If, however, it is causing real physical distress, it may be treated by excision of an inch or two of the bunch of dilated veins. The presence of varicocele is apt to cause inconvenience or even discomfort to men living in India or the tropics, but the Englishman who intends spending his life in temperate climes will do well to ignore a varicocele. It will become less and less noticeable as time goes on. (E. O.*)
VARIOLITES (Lat. variola, smallpox), in petrology, a group of
dark green basic igneous rocks which, especially on weathered
surfaces, exhibit pale coloured spots that give them a pockmarked
appearance. In some conditions these spots weather
out prominently; they are grey, pale green, violet or yellowish,
while the matrix of the rock is usually dark green. The variolites
are related most closely to the basalts or diabases. They
are nearly always much decomposed, and, since they are also
fine-grained rocks, their original composition may be much
obscured by secondary changes. The variolitic spots are
rounded in outline and are often about a quarter of an inch in
diameter, but may much exceed this size. They have a radiate
structure and are sometimes, though not generally, zoned with
concentric circles, of different appearance and composition.
Many authors have compared them with the spherulites of the
acid rocks (obsidians and rhyolites), and undoubtedly some
kinds of variolite are merely glassy spherulitic varieties of basalt.
The tachylyte selvages of the dolerite dikes of the west of
Scotland, for example, often contain large brown spherulites
which are easily visible in hand specimens. These spherulites
consist of very thin divergent fibres, and their nature is often
difficult to determine on account of the indefiniteness of the
optical characters of minerals in this state. It seems probable,
however, that they are mostly felspar embedded in dark brown
glass. Small phenocrysts or skeleton crystals of olivine, augite
and plagioclase felspar may occur in these tachylytes.
Other variolites are glassy or partly crystalline facies of olivine-free dolerites, occurring as thin dikes or intrusions, or at the margins of dolerite masses. In these the felspars are well crystallized as thin rods, with square or forked ends, radiating outwards from a centre. They are commonly oligoclase, and sometimes assume branching or feathery forms. Some authors would call these “sphaero-crystals” rather than spherulites; they are an intermediate stage between the latter and the stellate groupings of felspar which occur frequently in igneous rocks. In the same rocks augite spherulites occur also, but this mineral forms plumose growths, branching and curved, which spread through the glassy base and do not interfere with the felspar spherulites. They have much resemblance to the feathery ice crystals which form on window-panes. Occasionally olivine-dolerites have a coarsely spherulitic structure with long rods of plagioclase felspar converging to a point; one example of these rocks from Skye contains variolites over 'three inches in diameter.
Another group of variolites includes the most famous rock of this type, which comes from the Durance, in France. Pebbles of this were well known to collectors for a long time before they were traced to their source at Mont Genevre. They were proved to belong to a diabasic rock which shows well-marked “pillow-structure” or “spheroidal jointing.” Each pillow has a marginal portion which is variolitic, but towards the centre of the block-shaped masses the structure becomes coarse and groups of radiate felspars make their appearance. It is doubtful whether the variolite is an intrusive rock or a lava flow. Many of these pillow lavas (or spilites) occur in the Devonian rocks of Germany, and often they have variolitic facies which seem to belong to the same group as the rock of the Durance. Their spherulites are very often oligoclase felspar or decomposition products after a felspathic mineral. In other cases they consist of chlorite or pale green amphibole, both of which may be secondary after pyroxene. The ground mass is very fine grained and is filled with chlorite, epidote, leucoxene, and other secondary minerals. There is much reason to believe that it was originally in large measure vitreous but has suffered devitrifaction. Sometimes little steam cavities occur and may serve as a nucleus from which the variolite has grown. The radiate structure of the varioles is often nearly obliterated in these much-decomposed rocks, in fact it may never have been very perfect. Variolites are found also in several parts of the Swiss Alps at Jatluga on Lake Onega, in Anglesey, the Lleyn district and Fishguard in Wales, in Cornwall, and in more than one place in Ireland.
Finally, there is a group of spotted rocks formerly known to French petrographers as the variolites du Drac from the locality in which they are found, but they have been proved to be merely vesicular, rotten diabases, with steam cavities filled with white calcite and other secondary minerals. (J. S. F.)
VARISCITE, a native hydrous aluminium phosphate,
AlPO4·2H2O named by A. Breithaupt, in 1837, in consequence
of its occurrence in the Saxon Voigtland (Variscia). It is a green
mineral generally occurring as an incrustation or in nodules.
A compact nodular variety was discovered about 1894 in Cedar
Valley, near Old Camp Floyd, Utah, and was described by Dr
G. F. Kunz as utahlite. Its beautiful apple-green colour has
led to its use, when cut and polished, as an ornamental stone.
The term utahlite must be distinguished from utahite, the name
given by A. Arzruni to a basic ferric sulphate, 3(FeO)2SO4·4H2O,
from Utah.
VARLEY, CORNELIUS (1781–1873), English water-colour painter, a younger brother of John Varley (q.v.), was born at Hackney, London, on the 21st of November 1781. He was educated by his uncle, a philosophical instrument maker, and under him acquired a knowledge of the natural sciences; but about 1800 he joined his brother in a tour through Wales, and began the study of art. He was soon engaged in teaching drawing. From 1803 till 1859 he was an occasional exhibitor in the Royal Academy; and he also contributed regularly to the displays of the Water-Colour Society, of which, in 1803, he was one of the founders, and of which he continued a member till 1821. His works consist mainly of carefully finished classical subjects, with architecture and figures. He published a series of etchings of “Boats and other Craft on the River Thames,” and during his life as an artist he continued deeply interested in scientific pursuits. For his improvements in the camera lucida, the camera obscura and the microscope he received the Isis gold medal of the Society of Arts; and at the International
