Habitat: Damp places.
Features ? One or more erect stems, branched at top. Leaves opposite, lanceolate, four to six inches long, united at base, crenate edges, tiny, yellow resin dots beneath. Flowers August to October. Persistently bitter taste.Part used ? Herb.Action: Diaphoretic, febrifuge, tonic, laxative, expectorant.
Influenza and feverish conditions generally, for which purpose it is very successfully used by the American negroes. Also used in catarrhs. The infusion of 1 ounce to 1 pint boiling water may be given in wineglassful doses frequently, hot as a diaphoretic and febrifuge, cold as a tonic.F. H. England, of the College of Medicine and Surgery, Chicago (Physio- Medical) says ? "It is a pure relaxant to the liver. It acts slowly and persistently. Its greatest power is manifested upon the stomach, liver, bowels and uterus."... bonesetHabitat: Hedgerows.
Features ? Square, grey, hairy stem, up to two feet high. Leaves stalked, cordate-ovate, serrate, whitish down beneath. Flowers white, crimson dots, two-lipped, in short, dense spikes. Characteristic mint-like scent.Part used ? Herbs, leaves.Action: Carminative, tonic, diaphoretic, anti-spasmodic.
Especially used for flatulence and digestive pains in children, and for production of perspiration in both children and adults. For diaphoreticpurposes in adults, 2-tablespoonful doses of the 1 ounce to 1 pint infusion thrice daily, with a cupful at bedtime; proportionate doses in children's complaints.American physio-medical practice recommends blood-warm bowel injections of the infusion for babies with intestinal flatulence.... catnepHabitat: Cornfields, waste places and in gardens.
Features ? Stem square, weak, much branched, trailing with tendency to ascend, between six inches and one foot long. Leaves small, opposite, ovoid, sessile, entire at edges, black dots underneath. Flowers scarlet, corolla rotate, on long, slender, axillary stalk.Part used ? Leaves.Action: Diuretic, hepatic, diaphoretic.
The properties of this herb, although very active, are not yet fully known, and care should be exercised in using it. It has been successful in the treatment of liver irregularities, forms of rheumatism and dropsy. The pulverised leaves are administered in doses of from 15 to 60 grains.... pimpernel, scarletHabitat: Hedges and woods.
Features ? The upright, woody but slender stem, branching from the upper part only, attains a height of between one and two feet. The leaves are stalkless and elliptical in shape, about half an inch long, grow in pairs on opposite sides of the stem and branches and, in addition to the transparent dots noticed above, are sometimes marked with black spots on the under side. Numerous bright yellow flowers, dotted and streaked with dark purple, cluster, in June and July, at the ends of side branches and stem. A bitter, astringent taste is remarked.Action: Expectorant, diuretic and astringent.
Indicated in coughs, colds, and disorders of the urinary system. It was prescribed more often by the English herbal school of a hundred years ago than it is to-day, and was noticed as far back as Culpeper for "wounds, hurts and bruises." Indeed, an infusion of the fresh flowers in Olive oil, to make the "Oil of St. John's Wort," is still used as an application to wounds, swellings, and ulcers. Internally, the infusion of 1 ounce of the herb to 1 pint of boiling water is taken in wineglass doses.In America St. John's Wort grows freely in the cornfields, which proximity was held by Tilke to operate beneficially upon both herb and grain. Discussing American wheat which has grown among quantities of St. John's Wort he tells us ? "It is well known, by almost every baker who works in his business, that this flour improves the quality of the bread, byhaving a small quantity of it in every batch, particularly in seasons when the English flour is of inferior quality. A clever author informs us that it contains one-fourth more gluten than our famous wheats grown in Gloucestershire, known by the name of 'rivets.' " Tilke was himself a baker in his early days.... st. john's wortPathway of light from the eye to the brain Light enters the EYE by passing through the transparent cornea, then through the aqueous humour ?lling the anterior chamber. It then passes through the pupil, through the lens and the vitreous to reach the retina. In the retina, the rod and cone photoreceptors detect light and relay messages in the form of electrochemical impulses through the various layers of the retina to the nerve ?bres. The nerve ?bres carry messages via the optic nerve, optic chiasma, optic tract, lateral geniculate body and ?nally the optic radiations to the visual cortex.
Here in the visual cortex these messages are interpreted. It is therefore the visual cortex of the BRAIN that ‘sees’.
Visual acuity Two points will not be seen as two unless they are separated by a minimum distance. This distance is such that the objects are so far apart that the lines joining them to the eye enclose between them (subtend) an angle of at least one minute of a degree. This amount of separation allows the images of the two points to fall on two separate cones (if the light from two points falls on one cone, the two points would be seen as a single point). There are many tests of visual acuity. One of the more common is the Snellen test type. This is made up of many letters of di?erent size. By conventions the chart is placed 6 metres away from the patient. Someone able to see the lowest line at this distance has a visual acuity of 6/4. If they are only able to see the top letter they have 6/60 vision. ‘Normal’ vision is 6/6.
Colour vision ‘White light’ is made up of component colours. These can be separated by a prism, thereby producing a spectrum. The three cardinal colours are red, green, and blue; all other colours can be produced by a varying mixture of these three. Colour vision is a complex subject. The trichromat theory of colour vision suggests that there are three types of cones, each type sensitive to one of the cardinal colours. Colour perception is based on di?erential stimulation of these cone types. The opponent colour theory suggests that each cone type can generate signals of the opposite kind. Output from some cones can collaborate with the output from others or can inhibit the action of other cones. Colour perception results from these various complex interactions.
Defective colour vision may be hereditary or acquired, and can occur in the presence of normal visual acuity. HEREDITARY DEFECTIVE COLOUR VISION is more common in men (7 per cent of males) than women (0·5 per cent of females). Men are affected, but women convey the abnormal gene (see GENES) to their children. It occurs because one or more of the photopigments of the retina are abnormal, or the cones are damaged. Red-green colour defect is the most common. ACQUIRED DEFECTIVE COLOUR VISION is the result of disease of the cones or their connections in the retina, optic nerve or brain – for example, macular disease, optic neuritis. Col-our vision can be impaired but not lost as a result of corneal opaci?cation or cataract formation (see under EYE, DISORDERS OF).
TESTS OF COLOUR VISION These use specially designed numbers made of coloured dots surrounded by dots of confusing colour (e.g. plates).... vision
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