Opium Opoponax Among his works are a poem on Mount customed to it. The habitual consumption Vesuvius, Silva, Epigrams, etc.; but he is of opium by persons otherwise in good more important for the influence of his health is called opium eating, the opium teaching regarding correctness in poetic habit, the morphine habit or morphinism. style than for his own poems. It is taken through the mouth, injected Opium (opi-um), the inspissated under the skin, or (commonly in the juice of a species of poppy Orient) smoked. The pipe, or rather the (Papaver somniferum), cultivated on a stem of the pipe, is about the length and large scale principally in Hindustan and size of an ordinary flute; the bowl is in Asiatic Turkey, but well known in generally made of earthenware. The many places as a garden plant, being an smoker, who is always lying, or at least annual with white, red or violet flowers reclining, takes a small portion of opium and glaucous leaves. The opium is the about the size of a pea on the end of a juice that flows from spoon-headed needle, heats it at a lamp, incisions made in the and then places it in the bowl of the pipe, green heads or seed- the pellet of opium having previously been capsules of the plant perforated with the needle. He then after the fall or re- brings the opium to the flame of the lamp, moval of the petals, inhales the smoke in several inspirations, and the best flows and is then ready to repeat the process from the first incision. with a fresh quantity of opium until the The juice is at first a desired intoxication ensues. Large quanmilky liquid, but soon tities of opium were long consumed in solidifies and turns China, a great part of which formerly came black, and is then from India, though probably as much more scraped off and col- was produced in China itself. The Indian lected. It is one of opium, however, was preferred to their the most energetic of own by the best judges among the narcotics, and at the Chinese. In India it was cultivated (by same time one of the private cultivators) as a government (Papaver somniferum) most precious of all monopoly, and produced a large revenue medicines, and is employed in a great to the government. Opium thus gave variety of cases, but most commonly for rise to the Opium War of 1840-42, bethe purpose of procuring sleep and relief tween England and China, arising from from pain. In medicine it is very com- the destruction by Chinese authorities of monly used in the form of laudanum, a large quantity of opium imported by which is a simple tincture or extract in British merchants. Though defeated, spirits of wine; it is also an ingredient China continued to oppose the introducin various patent and other remedies. tion of opium, and was encouraged to take Another opium preparation is morphine action again when the United States op(q. v.). In its natural state opium posed the introduction of opium into the is heavy, of a dense texture, of a brown- Philippines and finally prohibited it. Folish-yellow color, not perfectly dry, but lowing the agreements of the Internaeasily receiving an impression from the tional Opium Congress held at Shanghai finger; it has a faint smell, and its taste in 1909, the Indo-China opium traffic has is bitter and acrid. The chief active come to an end, India thereby sacrificing principle of opium is morphine, or mor- a sum of $20,000,000 annually. The phine in combination with meconic acid. opium dens of Hongkong were closed by The principle part of our supply of order of the home Government in England, opium is brought from Turkey, whence it and in China itself vast areas under poppy is imported in flat pieces or cakes, cov- cultivation were condemned and replaced ered with leaves. In the case of many tem- by other crops. In both Europe and peraments opium produces such agree- America stringent laws have been passed able effects, whether a delightful dreamy restricting the importation and sale. beatific visions, that numbers of persons calm, a state of pleasant exhilaration, or Opodeldoc (op-o-del'dok), a solution of soap and alcohol, with are led to use it habitually, as others use the addition of camphor and volatile oils. alcohol in some form, though over-indul- It is used externally against rheumatic gence in it is attended with at least as pains, sprains, bruises, and other like evil effects as over-indulgence in the lat- complaints. Also called soap liniment. ter. But like tobacco it is taken by vast (o-pop'ȧ-naks), a fetid numbers without any apparent result one gum-resin of uncertain oriway or other. Some habitual takers of gin and unpleasant odor, occasionally imopium can take as much in a day as ported from Persia, and used in ancient would kill ten or twenty persons unac- times as an antispasmodic. There is Opoponax Oporto a compound perfume which also receives this name. Opposition mæe, and in which they can inclose their young. The best-known species of oposOporto (o-porta; Portuguese, O Porto, sum is the Didelphys virginiana, very the port), a large city and sea- common in the United States. It is alport of Portugal, the second in the coun- most the size of a large cat, the general try, capital of the same province of Entre color whitish-gray, and the whole hair Douro e Minho, on a steep declivity on of a wool-like softness. On the ground the right bank and about 2 miles from the motions of the opossum are awkward the mouth of the Douro, 170 miles north and clumsy, but on the branches of a tree of Lisbon. The river is crossed by two it moves with great celerity and ease, iron bridges of recent construction, one of using the prehensile tail to assist its mothem, the railway bridge, especially bold tions. When caught or threatened with and striking. The appearance of the city danger the opossum counterfeits death, on a first approach is very prepossessing, and playing 'possum' has on this acbut in reality most of the streets are nar- count passed into a proverb as used to row, crooked and dirty, and the houses indicate any deceitful proceeding. The irregularly constructed. Among the chief female has from ten to fifteen young, buildings are the Gothic cathedral, the which are for a long time nourished in church of S. Francisco (Gothic), the the pouch, to which they resort when bishop's palace, an enormous building, the alarmed. The flesh of the animal is English club, the exchange, and the Torre greatly enjoyed by the negro population. dos Clerigos, a granite tower 210 ft. high. Opossum-shrimp, the popular name of several species There are also museums, a large library, medical college, Crystal Palace and fine of Mysis, a genus of small crustaceans. garden, etc. The principal trade is in They receive their name from the females wine, white and red, but chiefly the latter carrying their eggs and young in a pouch (port wine, so named from this town), between the thoracic legs. which is principally exported to Britain. Oppeln (oppeln), a town in Prussian There are some manufactories of hats, Silesia, on the Oder, 53 miles silks, cotton, woolen and linen stuffs, pot- southeast of Breslau. It has an old royal tery, lace, glass, leather and paper, etc. castle, gymnasium, hospital, etc.; tobacco Oporto was at one time the capital of factory, cement and soap works, brewPortugal. In 1809 Wellington drove the eries, limekilns, and some shipping trade. French out of it after the remarkable pas- Pop. (1910) 33,007. sage of the Douro. Pop. (1914) 200,000. Opossum (o-pos'um), the name of several species of Didelphys, a gerus of marsupial mammals, having four hands and a long prehensile tail. They are nocturnal animals, arboreal in their habits, living constantly on trees, Virginian Opossum (Didelphys virginiana) and there pursuing birds, insects, etc., although they do not despise fruit. The females of certain species have an abdominal pouch in which are the mam Oppenheim (open-him), an old town Opposition Optics sun when it passes the meridian at mid- homogeneous, such as air and water, or night. See Conjunction. when rays traverse a medium the density Opposition, in politics, the party who, of which is not uniform, as the atmosunder a constitutional phere. When the ray of light passes from government, are opposed to the existing a rarer into a denser medium, it is bent administration, and who would probably or refracted towards the perpendicular come into power on its displacement. Ops, the Roman female divinity of plenty and fertility. She was regarded as the wife of Saturn, and, accordingly, as the protectress of everything connected with agriculture. Optative (op'ta-tiv), in grammar, that form of the verb in which wish or desire is expressed, existing in the Greek and some other languages, its force being conveyed in English by such circumlocutions as may I,' would that he,' etc. Optics (op'tiks) is the branch of phys Fig. 1.-Refraction, ing figure (fig. 1), the ray RI in the liquid will make a smaller angle with the normal NIN than the ray SI in air, and vice versa. ics which treats of the transmission of light, and its action in connection with the laws of reflection and refraction, including also the phenomena of vision. A ray of light is the smallest con- line drawn through the point of inciceivable portion of light, and is repre- dence, or the angle of refraction is less sented by the straight line along which it than the angle of incidence. On the conis propagated. A pencil of light is a col- trary, when a ray of light passes from a lection of such rays; it is parallel when denser into a rarer medium the refraction all the component rays are parallel to is from the perpendicular, or the angle each other; converging when they all of refraction is greater than the angle proceed to a single point; and diverging of incidence. If one medium is a liquid when they all proceed from a single point. and the other air, as in the accompanyThe focus of the pencil is the point to or from which the rays proceed. Any space or substance which light can traverse is in optics called 'a medium.' When light falls on any surface a cerThe law of reflection is illustrated estain portion of it is reflected or sent back, pecially by the action of mirrors. When and it is owing to this reflected light that a pencil of rays from a luminous point objects are visible. When light falls upon falls on a plane mirror each ray is rethe surface of a solid substance or me- flected according to the law given above, dium that it can traverse (a transpar- and it is easy to show by geometry that ent substance), one portion greater or the pencil which was divergent before inless is directed or reflected back into the cidence has exactly the same divergence medium whence it came; another portion after reflection; but the rays now seem to is transmitted through the solid medium, have proceeded from a point behind the but undergoes a change called refraction; mirror. This point is called the virtual while a third portion is absorbed in the image' of the first point (being not a new medium. When all the minute parts real image of it); the line joining the of a surface give out rays of light in points is at right angles to and is biall directions we call it a luminous sur- sected by the mirror. Now a luminous face, whether it is self-luminous or is object is made up of points, each of which merely reflecting the light from a self- sends a divergent pencil to the mirror, lumincus body such as the sun. The law which seems after reflection to proceed of reflection is that the angle of inci- from a point behind the mirror, and hence dence and that of reflection are in the a luminous object sends rays to a plane same plane, and that the angle of reflec- mirror which after reflection seem to have tion is equal to the angle of incidence, and proceeded from a luminous object behind on the opposite side of the perpendicular. the mirror. An eye receiving a ray (or This law holds true whatever be the na- a small pencil of rays) gets the impresture of the reflecting surface or the origin sion that the luminous point from which of the light which falls upon it. The it was sent is somewhere in the line of law of refraction comes into operation the ray just before reaching the eye, and when a ray of light passes through a hence an eye in such a position as to resmooth surface bounding two media not ceive after reflection a few rays from Optics Optics every point of the object sees the im- of them plain, it is called a plate if they age of the object. (See fig. 2.) Besides are parallel, and a prism if they are not plane mirrors concave and convex mir- parallel. When the faces are curved, or rors are often used in optics. When a one of them curved and the other plain, mirror is not plane the incident rays from it is called a lens. Prisms are the essena luminous point in general neither con- tial parts of the apparatus used for deverge to a single point after reflection nor diverge as if they had come from a virtual image. But when a concave mirror forming a small portion of a spherical surface is used we find that all the rays falling upon it from a luminous point converge so nearly to a luminous point after reflection that their aberration' (as the non-convergence of the rays is called) may be neglected in practice. The line joining the center of the spherical surface with the 'pole' of the mirror (that is, the middle point of the reflecting surface) is called the principal axis. Any bundle of rays parallel to the principal axis converges after reflection to a point in the axis called the principal focus; and any bundle of parallel rays converges Fig. 3.-Reflection (Concave Mirror). composing light and examining the properties of its component parts, as in spectrum analysis. (See Light.) A lens may be regarded as consisting of an unlimited number of prisms, the angles between their faces gradually diminishing the farther away from the axis of the lens. It is the property of convex lenses to diminish the divergency of the pencils of light, of concave lenses to increase that divergency. It is the duty of a convex lens to make rays parallel to the axis falling on one face of it converge accurately to one point after emerging from the other face. This point is called the principal focus, and is the point where a 'real' image would be formed. When rays parallel to the axis pass through a concave lens they diverge, and if produced backwards in the direction from which they come they would meet at one point, which in this case also is called Fig. 2.-Reflection (Plane Mirror). after reflection to a focus which is at the same distance from the mirror as the principal focal distance. When the object from which the rays proceed is at a considerable distance, an inverted image of it will be formed midway between the center of curvature and the mirror. When the object is only at a moderate distance, but exceeding half the radius of curvature, an inverted image is still formed in front of the mirror, being diminished when nearer the mirror than the object is, and magnified when farther away than the object. The image of an object placed nearer a concave mirror than the principal focus is erect and larger than the object, and is 'virtual' as in fig. 3, where A B is the object, ba its image (inverted), F the focus, o the center of the principal focus; but it is only a vircurvature. The image of any object in tual focus, because the rays themselves a convex mirror is also virtual and erect; do not pass through it, but only their it is, however, smaller than the object. backward productions. Thus concave When the two faces of a piece of glass lenses bend rays from the axis, and conthrough which light is refracted are both vex ones bend them towards it. When Fig. 4. Magnification of near Object by Convex Lens. Optimism Optometry we look through a concave lens it makes rate prescription of the glasses required. objects seem smaller whatever their dis- To the optician falls the duty of supplytances are. When we look through a ing the prescribed glasses. The latter convex lens at an object between the lens two functions are lately often fulfilled by and the principal focus it appears larger one and the same individual. History. than it really is, and hence the use of The following chronological sequence of such lenses in magnifying-glasses, micro- enactments of optometrical laws for the scopes and telescopes. The rule as to different states gives a view of the adthe relative size of object and image will vance in the practice throughout the U. be understood from fig. 4, where the small S. A. First to enact an optometrical law arrow A B is the object, and the large was Minnesota (1901), then followed arrow its image, o being the center of the consecutively California (1903), N. Dalens, Ff its foci. Rays from A B are re- kota (same year); Oregon (1905); New fracted towards the axis by the lens, and Mexico (1906); in 1907, Arizona, Monas the visual angle, or angle made by the tana, Idaho, Utah, Tennessee, Indiana, rays at the eyes, is larger than if there Nebraska; New York (1908); in 1909, were no lens, the object appears magni- Vermont, W. Virginia, N. Carolina, Delafied. The length of the object and the ware, Maine, Washington, Iowa, Rhode image will be directly as their distance Island, Kansas, Michigan, Florida; in from o; so that if the image is three 1911, Oklahoma, New Hampshire; Mastimes as far from the lens as the object, sachusetts (1912); in 1913, S. Dakota, it will be three times as long and three Nevada, Colorado, Connecticut; in 1914, times as broad. Convex lenses are used Maryland, New Jersey; 1915, Arkansas, in spectacles for long-sighted (or old- Wisconsin; 1916, Virginia, Georgia; sighted) persons, because the lens of their eye is too much flattened, and does not of itself cause a sufficient convergency of the rays to make an image on the retina, but one that would fall behind it. Concave lenses, again, are used by near sighted persons, because the rays in their case converge so much as to make an image in front of their retina instead of on it. See Eye, Light, Microscope, Telescope, Spectroscope, etc. Optimism (op'tim-izm), that philo sophical doctrine which maintains that this world, in spite of its apparent imperfections, is the best possible. It is an ancient doctrine; among modern philosophers Leibnitz is its principal advocate. 1917, S. Carolina, Wyoming, Pennsyl vania; 1918, Louisiana; 1919, Ohio, Illinois, Alabama; 1920, Mississippi, Kentucky; 1921, Missouri, Texas. Optometry laws have been enacted in 9 provinces of Canada and 3 provinces of Australia. Experts have estimated the present_number of practicing optometrists in the U. S. A. and Canada at about 20,000. Instruction. A course in optometry is taught in Columbia University, New York; Ohio State University, Columbus, O.; and the number of schools of optometry throughout the states are too numerous to mention here; they include such prominent institutions as: Pennsylvania State College of Optometry, Philadelphia; Massachusetts School of Optom Optometry (op-tom'e-tri), the science etry. Boston: Northern Illinois College of examining and meas uring the powers of vision, chiefly with a view to correcting aberrations in refraction, accommodation, etc. (See Eye, Optics.) Although medical science in recent years has shown marvelous advance, no branch of the healing art has progressed more rapidly than optometry. The invention of instruments of precision for the physical investigation of the eye progressed to such perfection by the beginning of the twentieth century that the natural outcome was to introduce a new branch into optical science, giving us the optometrist. Defects of vision may occur from a diseased condition of the eyes or from abnormal formation of these organs. Diseased conditions are referred to the oculist. To the optometrist belongs the discovery of existing defects in refraction and their correction by accu of Ophthalmology, Chicago; Los Angeles (Cal.) School of Optometry; Rochester (N. Y.) School of Optometry, etc. Under the New York law, beginning in 1930, all candidates must take a four-year course in an optometry school connected with a university and leading to degrees. are Technical Equipment. Essentially necessary in every examination room the following instruments: (1) Trial case,' containing plus and minus spheres and plus and minus cylinders, prisms numbered from 4 or 2 to 20 prism diopters; trial frame to hold the lenses. (2) Skiascope or retinoscope for testing the fundus reflex (retina). (3) Ophthalmoscope (q. v.) for studying the media and interior of the eve and estimating its refractions. (4) Ophthalmometer, for measuring the corneal curvature. Of minor apparatus (equally necessary) are |