September i, 1882.] THE TROPICAL AGRICULTURIST. 



187 



form free from alcohol (see page 430) but in presence of 

 sulphate of cinchonine or quinidiiie, sensible quantities 

 pass into solution. OrystitUizatiou of the quinine sulphate 

 from water affords a simple and fairly accurate mode of 

 separation, which has the advantage that is is similar to 

 the process employed by the manufacturer. 



The tabulated scheme for the separation of the principal 

 cinchona bases on next page is founded on a method de- 

 scribed by De Vrij. * The process requires a considerable 

 weight of alkaloids, and does not yield strictly accurate 

 results. Traces of quinidine and cinchonidine are dissolved 

 by the ether, and are only recovered on treatment, of the 

 amorphous alkaloids with a limited quantity of ether as 

 directed. In presence of much quinine the solubility ot 

 cinchonidine in ether is notably increased. The best i>art 

 of the process is the accm-ate estimation of the crystalliz- 

 able quinine, and this determination may be stiil fuitber 

 improved by substituting iodosulphate of qninoiiUne for the 

 tincture of iodine, as described on page 421 ; f but this mode 

 of operating sacrifices the possibility of investigating the 

 nature of the amorphous alkaloids. 



A weight of not less thau 2, and preferably 5, grammes 

 of the mixed alkaloids in a free state is finely powdered, 

 and treated in a closed tube with ten times its weight 

 of ether (free from alcohol). The mixture is well shaken 

 and left at rest for twelve hours, when it is fidtered, 

 and the residue washed with a small quantity of ether. 



A. The residue is ih-ied and weighed? It may contain 

 cinchonine, cinclionidine and quinidine. It is dissolved in 

 a slight excess of dilute bytlrochloric acid, and the solu- 



■ tion rendered neutral by cautious addition of soda. The 

 cinchonidine is then precipitated as tartrate, the quin- 

 idine as hydriodide, and the cinchonine as hydrate, the 

 operations being conducted exactly as described on page 

 454, with the exception that quinine and amorphous 

 alkaloids having been previously removed, the processes 

 and calculations necessitated by their presence may be 

 omitted. 



B, The ethereal solution is evaporated to dryness, and 

 the residue weighed. It consists of quinine, amoiylious 

 alkaloiih, and quinaitfine, with traces of quinidine and 

 cinchonidine. It is dissolved in 10 parts of proof spirit, 

 acidulated with l-20th of sulphuric acid. To this solu- 

 tion an alcohoHc .solution of iodine is grailually added 

 as long as a precipitate is produced. Excess of iodine 

 must be carefiilly avoided. In presence of much quinine, 

 a black precipitate of herepathite is immediately pro- 

 duced, but, if the quantity is small, some time is required 

 for its appearance. In such a case only a small quant- 

 ity of iodine solution must be added, and the liquid 

 well stirred, and left twelve hours. The precipitate is 

 filtered off, and washed with strong alcohol. 



The precipitate consists of herepathite. It is dried at 

 100 ^ C, weighed. The weight, multiplied by '55055, gives 

 the quantity of quinine in the mixed alkaloids operated 

 upon. The precipitate may also be treated as suggested 

 iu the note on page 451. 

 The solution is treated with sulphurous acid till colourless, 

 and theti carefully neutrahzed with caustic soda. The 

 alcohol is evaporated oS", and the liquid treated with ex- 

 cess of soda or ammonia, and agitattd with chloroform. 

 The residue left on evaporating the cldoroform consists of 

 amorphous alkidoiels, witl) traces of quinidine. The two 

 latter vvill remain undissolved on treatment with a limited 

 quantity ot ether, an ) the amorphous alkaloids may be 

 distinguished as described on pag^ 444. 

 In some cases it is desirable to separate the quinine in 

 the actual form of crystallised sulphate, ' his being regarded 

 by many as tlie best proof of tlie proportion obtainable by 

 t e manufacturer. The following method de-cribed by 

 Muter is the most accurate mole ot proceeiling : — 



Treat the total alkaloids or the ether-residue from 20 

 grammes of b.irk with warm distilled water slightly acidul.at- 

 ed with dilu e sulphuric acid, till the mixture is [erceptibly 

 acid. Add water t. make VOc.c. for each 1 gramme of 

 a'kaluids taken, and then very di'ute soda >vith constant 

 stirring till the iquid is exactly neutral, with a faint tentl- 



* Pharm. Journ [3], ii. 642. 



t If desired, the b'-repatbit- may be converted into crystal- 

 lized quinine sulphate by heating it/ with alcohol and suipb- 

 urous acid till colourless, and then neutralizing with soda 

 ani)pruceeding as described on page 453. 



ency to acidity. Uige-t the liquid at 85" C. for five 

 mi.,utes; then cool, and leave at looC.fi.r one hour. Filter 

 the liquid through a small d<iuble filter (2J inches diameter), 

 the two filters being previously trimmed to equal \vei»ht, 

 and receive the filtrate i a graduated cylinder. Wash 

 carefuUv mth water at 15 "= C. till the filtrate and washinga 

 measure 90 c.c. tor each 1 gramme of the mixed alkaloids. 

 The fi ter and contents are now oumplotely dried at 100^ 0., 

 and weighed, the second filter being used .^s a counterpoise. 

 To the weight in grammes add OUOSl/ gramme for each 

 c.c. of filtrate and wisliings. The sum divided by 0855 

 gives the corresponding amount of crystallised sulphate, and 

 tliis number multiplied by 5 gives the cr^staIlised quinine 

 suljjhaie obtainable from 100 grammes of dried bark. 



Tlie quinine sulphate so obtained is apt to contain 

 cinchonidine sulphate (.see page 435). 



The foregoing method may be applied with advantage 

 to the residue obtained by evaporatmg lo dryness the 

 ethereal solution B. of Do Vrij's process (page 452), and 

 for many practical purposes is even preferahle to pre- 

 eipitation aa herepathite. The remaining alkaloids may be 

 recovered from the filtrate from the quinine sulphate by 

 concentrating the liquid somewhat, adding soda in excess, and 

 agitating with chloroform. On evaporating the chloroform 

 the bases will be obtained in a solid state, and may be 

 separatecl in the following manner. The method may 

 also be applied to the total mixed alkaloids exiracted 

 from a sample of bark, in which case it may be carried 

 on simultaneously with the treatment for crystallised 

 quinine sulphate described above. 



The mixed alkaloids extracted from the bark or the filtrate 

 from quinine sulphate by treatment with soda and 

 chloroform, or the residual alkaloids left on treat- 

 ing the total alkaloids wiih ether (see page 452), 

 ate dissolved in strong alcohol. The solution ia 

 rendered laintly acid by hydrochloric acid, and evaporated 

 to dryness at 100'' C. The residue is dissolved in the 

 least possible bulk of water at 40''^ C, and the trace of 

 free acid neutralised by soda. A saturated solution of 

 Kochelle salt is next added in excess, the liquid cooled to 

 15" C, and re()eatedly stirred during o e hour. Crystal- 

 line streaks in the track of the glass rodoonsistof tartrate 

 of cinchonidine (irquiiiiae). The precipitate is cdlected 

 on a double tared filter, and waslied cautiously with cold 

 water, the filtrate andwasliings being coUectedin a graduat- 

 ed cylinder. 

 The precipitate is dried at 100° to 105'" C. and weighed, 

 the ouier fillerbeing used as a counlerpoi-e The amount 

 found is corrected by adding -00083 gramme for .ach 

 1 c.(\ measured by the filtrate and wash-water. The sum 

 multiplied by -804 gives the weight oi cinchonidiu,. If 

 quinine has not previously been separated, the amriint of 

 crystallised sulphate lound must be multiplied by -^lii. and 

 the product substracted from the weight of the tartrate 

 before calculating it to cinchonidine, 

 A The filtrate is cmceiitrated to its original bulk, cooled, 

 a drop ot dilute acetic acid added, und then excess of a 

 Batur.ited solution ot potassium iodide (free from auy 

 alkaline reactionj. The liquid is left tor two hour at 

 15° C, 1 eing frequently stirred. y^ ny streaks in the 

 track ot the gla^s rod are produced hj quinidine hydr- 

 iodide. The liqui'i is filtered on a double counterpoised 

 filler, and the precipitate cautiously washed with cold 

 water. 

 Tlte precipitate is dried at 100" and weighed. Its weight 

 is corrected by the addition of •IX)07r gramme for each 1 

 c.c. of filtrate and washinga (B). The sum, multiplied 

 by '7168, gives the quinidine. 

 B, filtrate is measured and made distinct by alkahne 

 with caustic soda. The precipitated ciHcAowiHe is filtered 

 off. Washed, dried, and weighed, or else extracted by 

 agitation with chloroform. The weight found is cor- 

 rected by deductin!! .00052 for each 1 c.c. measured by 

 tU'rate A., and -000(6 tor each c.c. of filirate B. Any 

 amorphous alkaloid may be dissolved out by spirit of -94 

 sq. grr,\-ity. 



The foregoing process, -with experience, gives very good 

 re:oIis. the sum of the separated alkaloids frequently . 

 amouLti ig to 99 per cent of the mixed bases operated on. 

 It is well suited for Indian harks. The most defective part 

 of the process is the separation of the cinchonine from 

 the amorphous bases by lUlute spirit. A cautious employ- 

 ment of ether is, perhaps, preferable. If the process of 



