OI J I 



OPI 



mis with the Orchis. Linnaeus distin- 

 guished this natural order into genera 

 from the nectarium, which in Orchis 

 forms a horn or spur at the back of the 

 flower, whereas the lip of it in this is a 

 petal, hanging- down, with a ridge or keel 

 running along the back. O. nidis avis, 

 bird's nest Ophrys, has the root compos- 

 ed of many strong fibres, from which 

 arise two oval veined leaves, jointed at 

 their base ; between these spring up a 

 naked stalk, about eight inches in height, 

 terminated by a loose spike of herbace- 

 ous flowers, resembling gnats, composed 

 of five petals, with a long bifid lip to the 

 nectarium, a crest or standard above, and 

 two wings on the side ; capsule angular, 

 opening in six parts, filled with small 

 seeds like dust. Native of several parts 

 of Europe. 



OPHTHALMIA, in medicine, an in- 

 flammation of the membranes which in- 

 vest the eye. 



OPIUM, in chemistry and medicine., 

 an inspissated gummy juice, which is ob- 

 tained from the head of the " papaper 

 somniferum." It is imported from Per- 

 sia, Arabia, and other warm parts of Asia, 

 in flat cakes, covered with leaves to pre- 

 vent their sticking together. It has a 

 reddish brown colour, and strong pecu- 

 liar smell : its taste at first is nauseous 

 and bitter ; but this soon becomes acrid, 

 and produces a slight warmth in the 

 mouth. A peculiar substance has been 

 detected in opium, to which it is suppos- 

 ed the properties it possesses of pro- 

 ducing sleep are owing. On account of 

 this property, this substance has receiy- 

 cd the name of narcotic matter. It is 

 obtained from the milky juices of some 

 plants, as those of the poppy, lettuce, 

 and some others. Opium, which is ex- 

 tracted from the poppy, is prepared by 

 the following process. The heads of the 

 white poppy, which is cultivated in dif- 

 ferent countries of the east for this pur- 

 pose, are wounded with a sharp instru- 

 ment; a milky juice flows out, which 

 concretes, and is collected and formed in- 

 to cakes. In this state opium is a tenacious 

 substance, of a brownish colour; has a pe- 

 culiar srnell, and a disagreeable bitter 

 taste. It becomes soft with a moderate 

 heat. It readily takes fire, and burns rapid- 

 ly. By the analysis of opium, it appears to 

 be composed of the sulphates of lime and 

 of potash, extractive matter, gluten, mu- 

 cilage, resinous matter, and an oil, be- 

 sides the narcotic matter, to which its pe- 

 culiar properties are owing. By digest- 

 ing opium in water, part of it is dissolv- 



ed, and by evaporating the solution to the 

 consistence of syrup, a gritty precipitate 

 appears, which becomes more copious 

 with the addition of water. This preci- 

 pitate is composed of resinous and ex- 

 tractive matter, besides the peculiar nar- 

 cotic matter which is crystallized. When 

 alcohol is digested on this precipitate, the 

 resinous and narcotic matters are dissolv- 

 ed, and the extractive matter remains 

 behind. As the solution cools, the nar- 

 cotic matter crystallizes ; but the crystals 

 are coloured with a portion of resin. By 

 repeated solutions and crystallizations it 

 may be obtained tolerably pure. If alco- 

 hol be digested on the residuum, it be- 

 comes of a deep red colour, the same 

 crystals are deposited on cooling, and 

 may be purified in the same way from 

 the resinous matter with which they are 

 contaminated. The narcotic matter, when 

 properly purified, is of a white colour ; 

 crystallizes in right-angled prisms, with 

 a rhomboidal base ; and has neither taste 

 nor smell. It is insoluble in cold water, 

 and requires 400 parts of boiling water 

 for its solution, from which it is precipi- 

 tated by cooling. The solution does not 

 redden the tincture of turnsole. It is 

 soluble in 24 parts of boiling alcohol, and 

 requires about 100 parts when it is cold. 

 When water is added to the solution in 

 alcohol, it is precipitated in the form of a 

 white opaque matter. One of the most 

 decided characters of this substance is its 

 easy solubility in all the acids, and without 

 the aid of heat. It is precipitated from 

 these solutions by means of an alkali, in 

 the form of white powder. Pure alkalies 

 increase the power of its solubility in wa- 

 ter, and the acids, when not added in ex- 

 cess, occasion a precipitate. When nitric 

 acid is poured on the crystals reduced to 

 a coarse powder, it communicates to 

 them a red colour, and readily dissolves 

 them. When the solution is heated and 

 evaporated, it yields crystals of oxalic 

 acid in considerable quantity. The resi- 

 duum has a very bitter taste. From the 

 effects of heat and of nitric acid on this 

 substance, it appears to be composed of 

 oxygen, hydrogen, carbon, and azote. 

 This narcotic substance is also found in 

 the milky juice, and in the extracts 

 which are obtained from several other 

 plants, as from different species of lac- 

 tuca, or lettuce ; hyoscyamus niger, or 

 henbane. The leaves of some" plants 

 also produce similar effects, as those of 

 the deadly night-shade, fox-glove, and 

 conium, maculatum, or hemlock. Seie 



POPPT, 



