of micrantha, or provinciana fina, on a diameter of 24 inches has not more than the thickness of half a line of bark. In consequence probably of this circumstance the micrantha wrinkles longitudinally much more in drying than the nitida. 3. The external colour of the derm of the nitida varies from maroon colour to that of rust, and that of the periderm (where not covered with lichens) is brown of deeper or lighter shade; the superficial colour of the micrantha is as to its prevailing hue glaucous green, and this observation has reference both to the derm and epiderm. The substance of the bark may be considered red in the nitida, and rusty yellow (“ d'un jaune orangé clair et grisâtre," Weddell) in the micrantha. In some species of this latter bark the tone is much richer and deeper, but still different from that of the nitida. In the Bolivian micrantha the bark, according to Dr. Weddell, takes, as soon as it is stripped from the tree, a bright blood red colour, and in fact it is not difficult to trace a peculiarly persistent colouring matter in the examination of both the Peruvian and Bolivian kinds of micrantha. 4. The appellation grey refers in both these species to the striking effect of the overspreading thallus of various graphideæ, &c., forming sometimes very pretty groups when carefully examined. It is scarcely needful to say that this circumstance shows nothing as to the kind or quality of the bark, further than as an indication that the tree has grown in an open situation exposed to rain and sunshine. §§ Other kinds are occasionally quite as much adorned with this bright clothing, especially the calisaya quill, and Goebel has figured together, in plate vii, the quill of grey bark (C. nitida) and that of China regia (apparently Calisaya pallida) as thus resembling each other. 5. The characteristic appearance of the outer coat of the C. micrantha (which however varies much) is attempted to be given by the same writer under plate vi., fig. 6-8, as Lima or Huanuco barks, and this contrasted with plate vii. above referred to, is the only available representation I can refer to for illustration of this point. The resinous character of the bark of C. nitida appears to be described in the Quinologia among the characteristics of the finest bark, as follows:-" The gum-resinous sap must be found in abundance inspissated between the outer coat and the bark, and show itself on the fracture of the bark, forming a somewhat dark circle in which (as Bergius says) may be seen some shining points 99 This distinct resinous circle is connected with when it is held against the sun.' the constitution of the bark, as indicated by various chemical re-agents, which, so far as I have made experiments, concur in showing that it is rich in all the usual constituents of the sap of the cinchonæ, whilst the predominant feature is the abundance of tannin. This must, I conclude, be of importance in a medicinal point of view. The simple decoction of the two barks presents a remarkable point of contrast, for whilst the decoction of the nitida is brown, becomes speedily troubled, and deposits an abundant sediment on cooling, that of the micrantha is pale yellow, remains clear for a time, and then gives a small and flocculent deposit. The predominant feature of the micrantha is to be found in its general woody texture, a feature which is very noticeable in reducing it to powder, whilst the only hard portion of the nitida is its resinous circle. I cannot but suppose the "fine grey" bark (the nitida bark) would act much more powerfully on the human system than the inferior grey (the produce of C. micrantha), but no corresponding or at least no adequate distinction appears to be made in commerce. (To be continued.) SS QUINOLOGIA, UNDER C. OFFICINALIS. "These trees grow on the high mountains, where it is cold at night, but sunny and mild by day, and where also other different trees, shrubs, and smaller plants cover the rocks and cliffs. They like a free air, cold, water, and sunshine. Shady and close situations are injurious to the full perfection of the bark." ON YELLOW BARK. BY ROBERT SCHWARTZ. YELLOW BARK (Königs-Chinarinde), which is said to be obtained from Cinchona lancifolia, Mutis*, contains two bases, viz., cinchonine and quinine, and three acids, kinic, cincho-tannic, and kinovic acids. It owes its peculiar reddish-yellow colour to red cinchonic, a product of the decomposition of the cincho-tannic acid. Cinchonine and quinine, as well as kinic acid, have often been analyzed, but nothing is at present known respecting the composition of cincho-tannic acid and red cinchonic. When the bruised bark is boiled with water, the above-mentioned substances may be detected in the watery extract. By repeatedly boiling with water, the kinic and cincho-tannic acids can be completely removed from the bark, but of the red cinchonic and of the kinovic acid, the greater proportion remains undissolved in it. When the bark, after being exhausted with water, is boiled with diluted milk of lime, it yields all the kinovic acid contained in it, but retains the red cinchonic. When, however, the bark previously exhausted by water is treated with spirit of wine mixed with muriatic acid, the whole of the kinovic acid is dissolved, whilst the red cinchonic, liberated from its combinations by the muriatic acid, dissolves in the spirit of wine, which acquires thereby a deep-red colour. Kinovic acid is contained only in a small proportion in the aqueous decoction of the bark, the greater portion being retained by the latter, which shows that the greater portion at least of the kinovic acid is contained in the bark in a free state, as it is almost entirely insoluble in water. By boiling the bark, deprived of all soluble substances, by diluted milk of lime, and filtering the decoction, a yellowish liquid is obtained, which, upon the addition of muriatic acid, lets fall an abundant precipitate of kinovic acid in the form of gelatinous flakes. In this way, a quantity of kinovic acid is obtained from the genuine cinchona barks, which is as large as that obtained by the same method from the bark of cinchona nova. In order to obtain the kinovic acid in a pure state, its calcareous salt, dissolved in water, is treated with animal charcoal, and the decolourized filtered liquid decomposed by muriatic acid. The gelatinous precipitate is treated with water as long as wash-water is rendered cloudy by a solution of nitrate of silver. The acid dried at 212° F., was analyzed, and yielded : All the properties of this substance, and also its composition, sufficiently prove the identity of this bitter matter with kinovic acid or the so-called kinova bitter, which exists ready formed in the bark, and can be artificially obtained from caincic acid (from the bark of the root of Chiococca racemosa). The statements of Winckler with regard to the presence of kinovic acid in the genuine cinchona barks are thus corroborated. Cincho-tannic acid.-Berzelius was the first who tried to obtain this acid in a pure state. The author has repeated these experiments, and found it advisable no to employ magnesia: the properties of the acid he found to be exactly the same as mentioned by Berzelius. The greatest difficulty in examining this acid, is offered by its tendency to absorb oxygen, so that it is scarcely possible to obtain an acid which has not absorbed a certain quantity of this element. There exists hardly any substance which so readily combines with the oxygen of the air, as the tannic acid of cinchona barks. This tendency is possessed in a still higher degree by the compounds of tannic acid with alkalies and alkaline earths, in a moist state, so that the alkaline cincho-tannates might be employed for eudiometrical experiments, like pyrogallic acid. The cincho-tannic acid is contained in the bark in small quantities only; the author was obliged to employ forty-eight pounds of the bark to obtain a quantity of acid sufficient for his experiments. The bruised bark was boiled with water, the decoction strained through linen, and mixed with a small quantity of magnesia, which took up some of the red * This is a mistake; yellow bark is the produce of Cinchona Calisaya (Weddell).—Ev. PH. J. cinchonic and became brownish-red. The filtered liquid, treated with acetate of lead, yielded an abundant brownish-red precipitate, which was decomposed under water by sulphuretted hydrogen. From the liquid filtered from the sulphuret of lead, tribasic acetate of lead threw down a brownish-red substance, which was partially soluble in acetic acid. By this method kinovic acid and a small quantity of red cinchonic remain behind with the sulphuret of lead. The greater portion of the red cinchonic, combined with a small quantity of oxide of lead, remains undissolved by the acetic acid. The acetic solution, if treated with ammonia, yields a beautiful light-yellow precipitate, which was washed with water and decomposed by a current of sulphuretted hydrogen. The liquid, filtered from the sulphuret of lead, which is now perfectly free from gum, was deprived of sulphuretted hydrogen by a small quantity of an alcoholic solution of sugar of lead, and filtered to get rid of sulphuret of lead. By a further addition of an alcoholic solution of sugar of lead, a light-yellow precipitate is formed, which was separated by filtration, treated with alcohol, and placed in a vacuum over sulphuric acid. In order to prevent oxidization by some atmospheric air, which might possibly have remained behind, a paste-like mixture of protosulphate of iron and hydrate of potash was placed into the receiver. The analysis of this salt showed: Carbon ..... 55.70 ... 28 168... 55.81 The formula for this salt of lead is pretty nearly C28 H13 O15+3 Pb O, which may be considered as composed of (C14 He O7, 2 Pb O)+(C14 He O7, PbO HO). Supposing the oxide of lead in this salt to be replaced by equivalent quantities of water, the formula of the hydrate of the cincho-tannic acid would be C11 H. O,+ 2 HO=C11 H3 09. In order to obtain the hydrate of the cincho-tannic acid, pure cincho-tannate of lead is decomposed under water by sulphuretted hydrogen. The liquid filtered from the sulphuret of lead was allowed to evaporate over sulphuric acid, near a moistened mixture of protosulphate of iron and hydrate of potash, after which an inflated, brittle, yellow, strongly hygroscopic substance remained behind, which became electric on friction, and had an astringent acidulous taste. As will be seen from analysis, the acid had imbibed a certain quantity of oxygen during the short time it was in contact with the air, while the sulphuric acid in the receiver was being renewed, whilst another portion of it remained in an unaltered condition: 44.75 ... 42 = 252 Carbon ... 100.00 ... 862 The formula C42 H30 O35 can be reduced to 2 (C1 H10 O12)+C14 H10 Ou. Two-thirds of the tannic acid have accordingly imbibed oxygen, whilst one-third has remained unaltered. The formula C14 H10 011 is C1 H6 O:+2 HO+2 aq. These last two equivalents of water, which could not be removed from the hydrate of the cinchotannic acid in the vacuum, were tried to be expelled by heating the acid at 212° Fah. in a current of carbonic acid gas. The deep-red colour which the substance assumed, showed that decomposition had taken place, which was further proved by the fact, that this acid, when brought in contact with water, was but partially soluble, and remained behind in the shape of a reddish-brown resinous mass. If an aqueous solution of cincho-tannic acid be mixed with sulphuric acid, a precipitate appears, as was observed by Berzelius. If a concentrated aqueous solution of the acid be mixed with a small quantity of muriatic acid, and heated to the boiling point, the tannic acid is completely decomposed, and beautiful red flakes are formed, which dissolve in alkaline liquids with a leek-green colour. Subjected to dry distillation the cincho-tannic acid evolves a very slight odour of carbolic acid.-The distillates diluted with water, produces all those reactions by which R. Wagner characterises phenylic acid, a diluted solution of perchloride of iron produces a green colour without any precipitate, and on the addition of ammonia this changes into red. This aqueous solution also absorbs oxygen with great avidity from the air, on the addition of an alkali. If it should be proved by additional experiments, that by the dry distillation of cincho-tannic acid, phenylic acid is actually generated, it would indicate a close relation between the constitution of this acid and kinovic acid, which latter acid yields, according to Wöhler, besides other products, carbolic acid. A combination of pure cincho-tannic acid with oxide of lead, dried in a vacuum at 212° Fah., gave the following numbers : An aqueous solution of pure cincho-tannic acid exposed to the air, became turbid on the addition of water, and a reddish-brown substance was precipitated, which, washed with water and dried at 212° Fah., had the following composition : The formula C36 H22 019, can be reduced to 3 (C12 H; O6) + HO. By the addition of sulphuric acid to the aqueous solution after filtration from the substance described above, a reddish precipitate was thrown down, very similar to the former, and which dissolved readily in alcohol, but much less so in water. It consisted of: Carbon......... 38.87 ... 12 = 72 . . . 38.91 This substance may be regarded as a hydrate, C12 H, O13-С12 H, O11+2 HO. According to this view there existed three compounds, which contained for 7 equivs. of carbon and 7 equivs. of hydrogen, 6.9, and 11 equivs. of oxygen. 3 (C12 H7 O6) + HO. C12 HT 09 C12 HT O11+2 HO. If the composition of hydrate of cincho-tannic acid be expressed by the formula C14 Hs O, and the formula of that product of oxidation containing the least proportion of oxygen-C12 H, O, be deducted from this, the formula of the anhydrous formic acid C2 HO2 is left. If, therefore, two equivs. of oxygen are added to the equiv. of cincho-tannic acid, the latter forms 1 equiv. water, 2 equivs. carbonic acid, and 1 equiv. oxygen in the above-described substance, C12 H; Os, which by further addition of oxygen may form C12 H; O11. The generation of carbonic acid simultaneously with red cinchonic has been already proved by Berzelius. Red Cinchonic, or Cinchona Red.--Powdered cinchona bark, deprived by boiling of all substances soluble in water, was exhausted by diluted ammonia; and the intensely reddish-brown liquid let fall, when treated with an excess of muriatic acid, kinovic acid and red cinchonic in the shape of voluminous reddish-brown flakes. These were collected on a filter, washed with water, and boiled with diluted milk of lime; the red cinchonic forms thus with the lime a combination, insoluble in water, whilst the kinovate of lime is dissolved by water. The compound of red cinchonic with lime washed with water was heated with diluted muriatic acid, placed upon a filter, and washed with water, till the filtered liquid was no longer clouded by nitrate of silver. The red cinchonic, which had thus been freed from lime, was re-dissolved in diluted ammonia and precipitated by muriatic acid, perfectly exhausted with water, dissolved in spirit of wine, and the liquid filtered from the flakes, and evaporated in the water-bath to dryness. The red cinchonic thus obtained formed a chocolate-brown mass, nearly insoluble in water, which dissolved with greatest facility in alcohol, ether, and alkalies, with an intensely red colour. Dried at 212° F., the analytical result was: The cincho-tannic acid (C1, H, O,) must absorb 3 eq. of oxygen in order to be able to form 1 eq. of this red cinchonic, 2 eq. carbonic acid, and 1 eq. of water. When a solution of cincho-tannic acid, mixed with a few drops of liquid ammonia, is brought in contact with atmospheric air in a glass-tube, the volume of the air is rapidly lessened by the absorption of oxygen. When the absorption has ceased, carbonic acid gas is developed upon the application of a few drops of sulphuric acid, which, with regard to the volume, amounts to much less than the quantity of the absorbed oxygen; at the same time flakes of a reddish-brown substance, enclosing red cinchonic, separate from the liquid. The tendency of the tannic acid, when combined with a base, to absorb oxygen, is the reason why so small a proportion of cincho-tannic acid is contained in bark, whilst that of the red cinchonic is much larger; and even of this small quantity a large portion is lost by its being changed into red cinchonic during the preparation, which requires a number of operations in order to remove all other substances. All these experiments were performed in the laboratory of Prof. Roehleder.-Central Blatt., 1852, No. xiii., p. 194. DESCRIPTION OF THE GENUINE QUINA-TREE OF LOXA. BY J. J. CALDAS. THE genuine quina of Loxa is a tree of from ten to sixteen Spanish ells (five to eight fathoms) high. The trunk is seldom single, two or three or more commonly growing from the same root. In the first case the trunk is quite perpendicular, in the latter case it is somewhat inclined horizontally, circular, about one-half ell in diameter, and the accessory trunks from four to eight inches in diameter. The upper surface of the bark is very variable. According to age, temperature, and locality, it varies from a light brownish colour to black. If the trunk and the branches are much exposed to the sun and wind, the bark becomes black, and if the tree is closely surrounded by other trees, it assumes a brownish colour, which varies to a light yellowish grey. A large quantity of lichens grow on the whole of the surface On the epidermis, whatever its colour may be, annular impressions or furrows are always perceptible, although sometimes but slightly impressed. They are the traces of the places where the stipules were situated. Immediately beneath each ring are two almost circular cicatrices, formed by the petiole after the fall of the leaves. Between the rings many other transverse furrows and cracks, varying in length, depth, and distance from each other, are perceived mostly parallel to the rings, but never extending entirely round the trunk. All these characteristics of the surface are also found on other species of Cinchona, and are, therefore, insufficient by themselves to distinguish any species. On the inner smooth surface, which is formed of fine, parallel, longitudinal fibres, we perceive numerous whitish spots, some of which are shining, but most of them dull. The colour of this surface is similar to that of dry cinnamon, passing rather into yellow when the bark is fresh. The edges of the fractured surface of the bark are sharp, like glass, and only here and there a small point is perceptible on the inner edge. Under a magnifier the epidermis appears attached [gebunden], blackish, and shining; the subjacent parenchyma, which forms a concentric ring, is thicker than the epidermis, sometimes blackish, sometimes brownish-yellow with many shining spots. Next follow the layers formed of parallel fibres, between which we observe shining points, which proceed from the gummy resinous juice diffused through the entire bark. The branches are at the lower part terete, towards the extremities quadrangular, compressed, with two longitudinal furrows opposite the insertion of the leaves, covered with a white very short tomentum, standing crosswise, perpendicular, rarely horizontal. They divide into others, which are arranged in like manner, with a reddish bark. The crown of the tree is oval and very leafy. The leaves are opposite, between oblong and lanceolate, quite entire, the circumference undulating, anteriorly somewhat contracted, and terminating in an obtuse point; flat, shining on both surfaces, beautifully green on the upper surface, somewhat pale on the under one; the nerve and veins rose-coloured. The leaves at the ends of the branches four to eight inches long, two to four broad. When young and delicate they are covered on the under surface with a short delicate down; when full grown they are of a bright red colour. The petiole is terete, above somewhat flattened, reddish, shining, one to two inches |