from which sinapine can be liberated by addition of baryta water. On evaporation, especially when alkaline, the resulting solution decomposes into choline (sincaline, § 525) and the dibasic sinapic acid, C11H12O = C2H100.CO.OH. This latter crystallises in prisms, 12 5 10 cannot be sublimed, and is difficultly soluble in water and alcohol at the ordinary temperature. Sinapine therefore appears to be a saline compound of choline and sinapic acid : 1278. Atropine, C17H23NO3, occurs in the deadly nightshade, (Atropa Belladonna) and in Solanum nigrum. It is prepared from belladonna by heating the freshly expressed and filtered sap to 90°, addition of potash, and shaking with chloroform. It crystallises in prisms of sharp and bitter taste, melts at 90°, is difficultly soluble in cold water, readily in alcohol. Either free or in the form of its salts it causes, even in extremely small quantity, dilatation of the pupil of the eye. On boiling with bases and acids it splits up into tropic acid (§ 1084, 2) and tropine, CH1NO, an alkaloid readily soluble in water, alcohol, and ether, crystallising in tables of m.p. 61°. Hyoscyamine, C17H23NO3, isomeric with the above, occurs in the seeds, &e., of Hyoscyamus niger and H. albus, and appears to be identical with the alkaloid formerly described as daturine (from Datura Stramonium). It crystallises in silky needles; it dilates the pupil, and on heating with baryta is decomposed into tropine and tropic acid. From this the relations of hyoscyamine and atropine must be very close; they are probably physical isomerides. Physostigmine, or eserine, CH2N3O2, is the alkaloid of the Calabar bean (from Physostigma venenosum). It is a yellow, amorphous, strongly alkaline mass, causing contraction of the pupil. It oxidises on exposure to air, as do also the aqueous solution of its salts. 1279. Cocaine, C17H21NO4, the alkaloid of the leaves of Erythroxylon Coca, crystallises in monoclinic prisms and melts at 98°. On heating with hydrochloric acid it splits up into benzoic acid, methylic alcohol, and an alkaloid ecgonine, C,H,NO3. This latter is readily soluble in water, insoluble in ether, and crystallises with one molecule H2O in shining prisms, melting at 198°. 15 Colchicine, C17H1,ÑO,, occurs in all parts of Colchium autumnale; it is amorphous, soluble in water and alcohol, and possesses a sharp and bitter taste. It melts at 140°, is very poisonous, and scarcely possesses basic properties. Solanine, C42H87NO16, occurs in various solonaceous plants, and especially in potatoes that have sprouted in the dark. It is extracted by dilute sulphuric acid, and on quick precipitation of the filtrate with ammonia and recrystallisation of the precipitate from bolling alecici is obtained in silky prisms, melting at 235, of weak basic properties and nearly insoluble in water; its salts are gummy. Even traces of it impart a fine red colour to a warm mixture of alcohol and sulphure acid. Solanine is a glucoside alkaloid, as on boiling with dr mineral acids it takes up water and decomposes into sugar and the more strongly basic solanidine, CH, NO The latter crystallises in fine needles, melts at 200°, and can be sublimed without much decomposition. Its salts crystallise readily. 1280. The seeds of Peganum harmala, a plant growing on the Russian steppes, contain harmaline, C1HNO, crystallising in rhombic pyramids, and harmine, C13H12N2O, crystallising in shining prisms, and which can also be prepared by oxidation of the former. They are both monacid bases. Of other alkaloids there may be mentioned— Aconitine, C30H,,NO,, from monk's hood (Aconitum Napellus). Bebeerine, C,HNO3, in the bark of Nectandra Rodiei. Chelidonine, CH1NO, and chelerythrine, C19H1;N302, in Chelidonium majus. 17 Curarine, contained in the South American arrow poison. Delphinine, C24H35NO2, in Delphinium Staphisagria, and finally caffeine and theobromine, which have been already described (§ 931) BILE DERIVATIVES. 1281. The gall bladder of animals contains a green or brown liquid, of faint alkaline reaction and bitter taste. This has been formed in the liver, and contains, in addition to mucus, choline, lecithine, fatty soaps, and paralactic acid, the sodic, or more rarely the potassic, salts of the bile acids, cholesterine, and the bile pigments. The latter and cholesterine occur at times so richly in the liver that they crystallise out in the gall bladder and form gall stones. Bile Acids. 1282. In the bile of most animals two bile acids are found, which are both monobasic and contain nitrogen, but only one contains sulphur. On boiling with acids or alkalies the two acids from the same animal yield the nitrogen-free acid, cholic acid; in the case of the bile acid free from sulphur, glycocholic acid, glycine (§ 717) is also obtained, whilst from the sulphur-containing acid, taurocholic acid, the second product is taurine (§ 528). All bile acids, even when present in very small quantity, give Pettenkofer's reaction,' i.e. a beautiful purple coloration, on addition of a little sugar and then of concentrated sulphuric acid. This coloration occurs most readily at about 60°. The alkali salts occurring in the bile are readily soluble in water and alcohol, but insoluble in ether. In order to obtain them in a state of purity the bile is mixed with so much animal charcoal that, on evaporating to dryness on the water bath, a dry powder remains, from which absolute alcohol extracts the now colourless salt of the bile acids, together with cholesterine, choline, lactic acid, &c. On addition of ether containing some water, the salts of the bile acids are precipitated as a colourless plaster-like mass, which crystallises on long standing in the liquid and forms the crude material for preparing the acids. The acids of ox gall have been best investigated; they occur also in the bile of man, of the dog, and of most animals that have been investigated as yet, the proportion of the sulphurised acid to that free from sulphur generally differing. They are designated by the name given above. 1283. Glycocholic acid, C26H43NO6. On addition of dilute sulphuric acid to an aqueous solution of the crystallised salts obtained as above described, a colourless precipitate is obtained, which after some time-especially when the water contains some ether-changes into a voluminous magma of fine white needles. Collected on a filter, it contracts on drying to a shining mass of interlaced needles. Glycocholic acid is little soluble in water, more readily in alcohol; it has a faint acid reaction, a bitter-sweet taste, and is dextrorotary ([a] = + 25·7°). It yields salts of neutral reaction, of which the alkali salts are readily soluble in water, those of the other metals mostly difficultly soluble in water, more readily in alcohol. The sodic salt, C26H4NaÑO,, forms fine prisms; addition of plumbic acetate to its aqueous solution precipitates the lead salt, (C26H42NO6)2Pb, as a plaster-like precipitate, soluble in alcohol. 1284. Taurocholic acid, C26H45.NSO7, occurs in ox gall in only small quantity, and cannot be well extracted from it in a state of purity. To prepare it the solution of the salts from ox gall is first treated with normal plumbic acetate to precipitate glycocholic acid, and basic plumbic acetate then added to the filtrate to precipitate taurocholic acid. The latter precipitate is then washed, decomposed with sulphuretted hydrogen under water, and the solution evaporated. The crystallised salts from dog's bile form a better crude material, as they contain only traces of glycocholic acid. The aqueous solution is first mixed with an amount of basic lead acetate by far insufficient for complete precipitation, and the filtrate precipitated with the same reagent. The last precipitate is then decomposed under water with sulphuretted hydrogen, the filtrate highly concentrated and mixed with ether; taurocholic acid then precipitates as a syrup that soon changes into needle-formed crystals. It is readily soluble in water and alcohol, its solutions being dextrorotary ([a]= + 24.5°), and is readily split up, either by boiling with pure water or more readily by acids and alkalies. 1285. Cholic acid, or cholalic acid, C20H4005, is the common decomposition product, together with glycocine or taurine, of both the acids previously mentioned, the splitting up being best effected by boiling for several days with baryta water: C26H13NO6+ H2O = C2H¿NO2 + C24H4005, 5 2 C26H45NSO, + H2O = C2H2NSO3 + C24H4005. The basic salt contained in the still hot liquid is decomposed by addition of hydrochloric acid, and the resulting amorphous precipitate, after washing with water, dissolved in a little sodic hydrate solution, and the liquid, after addition of some ether, again supersaturated with by dilute sulphuric acid, and on quick precipitation of the filtrate with ammonia and recrystallisation of the precipitate from boiling alcohol is obtained in silky prisms, melting at 235°, of weak basic properties and nearly insoluble in water; its salts are gummy. Even traces of it impart a fine red colour to a warm mixture of alcohol and sulphuric acid. Solanine is a glucoside alkaloid, as on boiling with dilute mineral acids it takes up water and decomposes into sugar and the more strongly basic solanidine, C26H1NO2. The latter crystallises in fine needles, melts at 200°, and can be sublimed without much decomposition. Its salts crystallise readily. 41 14 1280. The seeds of Peganum harmala, a plant growing on the Russian steppes, contain harmaline, C13H1Ñ2O, crystallising in rhombic pyramids, and harmine, C13H12N2O, crystallising in shining prisms, and which can also be prepared by oxidation of the former. They are both monacid bases. Of other alkaloids there may be mentioned Aconitine, C30H,,NO,, from monk's hood (Aconitum Napellus). Bebeerine, C19H,NO3, in the bark of Nectandra Rodiei. Chelidonine, C9H17NO4, and chelerythrine, C19H17N3O3, in Chelidonium majus. Curarine, contained in the South American arrow poison. Delphinine, C2H35NO2, in Delphinium Staphisagria, and finally caffeine and theobromine, which have been already described (§ 931). BILE DERIVATIVES. 1281. The gall bladder of animals contains a green or brown liquid, of faint alkaline reaction and bitter taste. This has been formed in the liver, and contains, in addition to mucus, choline, lecithine, fatty soaps, and paralactic acid, the sodic, or more rarely the potassic, salts of the bile acids, cholesterine, and the bile pigments. The latter and cholesterine occur at times so richly in the liver that they crystallise out in the gall bladder and form gall stones. Bile Acids. 1282. In the bile of most animals two bile acids are found, which are both monobasic and contain nitrogen, but only one contains sulphur. On boiling with acids or alkalies the two acids from the same animal yield the nitrogen-free acid, cholic acid; in the case of the bile acid free from sulphur, glycocholic acid, glycine (§ 717) is also obtained, whilst from the sulphur-containing acid, taurocholic acid, the second product is taurine (§ 528). All bile acids, even when present in very small quantity, give 'Pettenkofer's reaction,' i.e. a beautiful purple coloration, on addition of a little sugar and then of concentrated sulphuric acid. This coloration occurs most readily at about 60°. The alkali salts occurring in the bile are readily soluble in water and alcohol, but insoluble in ether. In order to obtain them in a state of purity the bile is mixed with so much animal charcoal that, on evaporating to dryness on the water bath, a dry powder remains, from which absolute alcohol extracts the now colourless salt of the bile acids, together with cholesterine, choline, lactic acid, &c. On addition of ether containing some water, the salts of the bile acids are precipitated as a colourless plaster-like mass, which crystallises on long standing in the liquid and forms the crude material for preparing the acids. The acids of ox gall have been best investigated; they occur also in the bile of man, of the dog, and of most animals that have been investigated as yet, the proportion of the sulphurised acid to that free from sulphur generally differing. They are designated by the name given above. 1283. Glycocholic acid, C2H43NO6. On addition of dilute sulphuric acid to an aqueous solution of the crystallised salts obtained as above described, a colourless precipitate is obtained, which after some time-especially when the water contains some ether-changes into a voluminous magma of fine white needles. Collected on a filter, it contracts on drying to a shining mass of interlaced needles. Glycocholic acid is little soluble in water, more readily in alcohol; it has a faint acid reaction, a bitter-sweet taste, and is dextrorotary ([a] = + 25·7°). It yields salts of neutral reaction, of which the alkali salts are readily soluble in water, those of the other metals mostly difficultly soluble in water, more readily in alcohol. The sodic salt, C26H42NaÑO,, forms fine prisms; addition of plumbic acetate to its aqueous solution precipitates the lead salt, (C26H12NO6)2Pb, as a plaster-like precipitate, soluble in alcohol. 1284. Taurocholic acid, C26H45.NSO7, occurs in ox gall in only small quantity, and cannot be well extracted from it in a state of purity. To prepare it the solution of the salts from ox gall is first treated with normal plumbic acetate to precipitate glycocholic acid, and basic plumbic acetate then added to the filtrate to precipitate taurocholic acid. The latter precipitate is then washed, decomposed with sulphuretted hydrogen under water, and the solution evaporated. The crystallised salts from dog's bile form a better crude material, as they contain only traces of glycocholic acid. The aqueous solution is first mixed with an amount of basic lead acetate by far insufficient for complete precipitation, and the filtrate precipitated with the same. reagent. The last precipitate is then decomposed under water with sulphuretted hydrogen, the filtrate highly concentrated and mixed with ether; taurocholic acid then precipitates as a syrup that soon changes into needle-formed crystals. It is readily soluble in water and alcohol, its solutions being dextrorotary ([a] = + 24.5°), and is readily split up, either by boiling with pure water or more readily by acids and alkalies. 1285. Cholic acid, or cholalic acid, C20H4005, is the common decomposition product, together with glycocine or taurine, of both the acids previously mentioned, the splitting up being best effected by boiling for several days with baryta water: C26H43NO6+ H2O = C2H¿NO2 + C24H40059 C26H45NSO, + H2O = C2H2NSO3 + C24H4005. The basic salt contained in the still hot liquid is decomposed by addition of hydrochloric acid, and the resulting amorphous precipitate, after washing with water, dissolved in a little sodic hydrate solution, and the liquid, after addition of some ether, again supersaturated with |