(A lubricitate, from their slipperiness). The lumbricus, which abounds in the intestines of young persons, resembles so nearly, in its general

Appearance, the earth worm, that it has been considered as the same animal. It is, however, distinct, and is the Lumbrici 4784 of the ancient physicians, distinguished from the earth worm by wanting the elevated ring in the middle of its body. The body of the ascaris lum-bricoides, for this is its generic name, is round; its head furnished with three vesicles, placed in a triangular form; generally from twelve to fifteen inches in length, and about the diameter of a goose quill. The head may be distinguished by the three vesicles mentioned, and the triangular space between is the mouth of the animal. The tail terminates suddenly in a very sharp point, and near it the orifice of the anus may be distinctly seen. Near the middle of the body is a circular depression about three lines in extent, in which is an aperture like a small point. This band is most conspicuous when the body of the worm is distended, and it seems wanting when the body is collapsed. Just below the mouth are two small transverse clefts, which Bruguiere calls stigmata, and thinks them the organs of respiration.

Two longitudinal lines extend through the whole body of the worm, which are the tendons to which the semicircular muscles are attached. The animal, however, does not move, like the earth worm, by a vermicular motion, but curls its body in circles, from which it extends the head. A number of vesicles surround the intestinal tube, which proceeds, without any change of direction, from the head to the anus, but they do not extend beyond the depressed band. Below it the connecting medium appears to be a common cellular substance. These vesicles are filled with a mucous, probably a nutritious, fluid. The intestinal canal contains a dark green fluid, resembling the meconium of infants. But even from the lower part of the canal filaments appear to arise, which probably convey a portion of nourishment, though the great reservoirs are in the upper portion. The most singular part of the worm is what may be considered as its uterus. Just below the depressed band a white vessel is seen, which soon divides into two, and after running some way in a cylindrical form, they quickly become smaller, and at last are minutely convoluted, embracing on all sides the intestinal tube. These vessels, forced by the agonies of the worm through the particles of the abdomen, appeared to Mr,. Church the young of the animal, which he, of course, considered as viviparous. It is, however, generally agreed that the lumbricus intestinalis is oviparous.

The lumbricus terrestris has but one vesicle, is flat towards the tail, and has bristles on its under side, which it can erect at pleasure. Its annular muscles are large, and of a dusky red; and on its under surface is a large semilunar fold of the skin, into which the animal can draw its head. It has also three lines on its upper surface.

The intestinal lumbricus is seldom solitary, but in very few instances appears to be injurious. Its source is unknown; for it has not been found in any other situation. When first discharged they are semitrans-parent, and of a dilute red colour, but they soon become yellowish. They are usually found in the jejunum and ileum, rarely in the large intestines, and still more so in the stomach. In each they appear to be escaping from the body, when fever renders their situation uncomfortable, or active anthelmintics force them with the mucus from their seals.

Lamarck Systeme des Animaux sans Vertebres; Histoire Naturelle des Vers, par Deierville, (suite de Buffon); Pallas de intra Viventibus; Hooper's Memoirs of the Medical Society, vol. v. See Vermes. Lumbrioi lati. See TAE niae.. Lumbricorum Semen. See Santonicum. Lumbricus Terrestris. (See Lumbricus intestinalis.) The earth worm is supposed to have an antispasmodic and diuretic virtue. If worms are moistened with vinous spirits to prevent their putrefaction, and placed in a cellar, they deliquesce; and the liquor, when mixed with alkaline salts, is said to yield crystals of nitre. They have been employed for the same purposes as snails.

Lumbricus edulis. A species of lumbricus found on the southern sandy shore of Batavia, is considered as a delicacy; it is described by Pallas, who thinks it the same as the teredo, described in the twenty-sixth volume of the Philosophical Transactions. See Spi-cilegia Zoologica Fasciculus, x. 10. Lumbus, (a lubidine). The loin. Lumbus veneris. See Millefolium. Lumen, (quasi lucimen, a luceo, to shine). The effects of light on the human system have not yet been explained. We have of late only began to perceive with clearness the causes of its influence on vegetables and some chemical preparations. We find, in general, that light separates oxygen; that it changes the nitric into the nitrous acid, and the oxymuriatic to common muriatic acid. We find, also, that it deprives many preparations of their peculiar colour, particularly phosphorus; and it seems greatly to influence the process of crystallization. Some preparations must be exposed to a strong solar light, as carmine; for a cloud, it is said, will spoil the colour, and the argentum fulminans requires to be exposed to the light of the sun for many days. If we ascend to the vegetable kingdom, we shall find that the absence of light deprives the leaves of their colour; and Humboldt, who discovered some vegetables in the deepest shafts of mines, found that the shapes of the leaves were not the same. If plants, then, will grow without light, we must not consider their growth as wholly depending on the decomposition of water, in consequence of light; but we have reason to consider the colour as depending not only on the decomposition of the water, but of the carbonic acid gas also.

Animals confined without light are often of a white colour; but this must be confined to those who usually live in the open air; for the mole, the pangolin, and some others who scarcely ever see the day, are not white. The particular cause of this change has not been examined. It is not apparently from a deficiency of oxygen. Some animals emit light in their motions, and this light is connected with their life and activity, as in the lampyris, the glow worm, the insects in oyster shells, and those which illumine the sea in a storm. In these it seems that light enters into the composition of those fluids to which their activity is owing, and, indeed, every fact now noticed shows that light is a body, and may form a component part of other bodies. We are not acquainted with the effects of light on the human body. We know that the oxygen is a powerful stimulus, and that colour, health, and vigour, are often in excess when this air is breathed; but it seems probable that this is the case when the oxygen is in a loose uncombined state, and that light is salutary in promoting its separation. These speculations are, however, uncertain, and it is still more so, whether light is really a component part of our bodies. When we reflect, however, that the general health is apparently connected with light, that the peculiar acid of the animal system, the phosphoric, has a powerful attraction for this element, and appears to contain it, not only in a chemical combination, but, when in the form of an oxide, unites with, and allows it to separate without decomposition, we may suspect it to be a more powerful agent in the animal economy than has yet been supposed.

For the physical properties of light, see Hauy Traite de la Physique, vol. ii.; Cavallo's Natural Philosophy, vol. iii.; and the article Oculus. For the chemical, see Exeter Essays.