APPENDIX. 259 



sulphuric acid, repeating the operation three times with 15 cc of the same strength 

 acid, and collect the acid solutions in Another separator. Wash the acid solution with 

 10 cc of ether-chloroform mixture (1 to 3 by volume), discarding the latter, and, if 

 colored, repeat until no more color is acquired. Make the solution alkaline with Am- 

 monia water, and shake out with four successive portions of about 20 cc each of 

 ether-chloroform mixture (1 to 3); collect the latter in a separator, wash with 5 cc of 

 water, transfer the ether-chloroform mixture to a tared flask or beaker, rinsing the 

 separator with a small portion of ether-chloroform, and evaporate the solvent at a 

 temperature not exceeding 70 C. 



(a) Gravimetric. Add 3 cc of ether, evaporate and dry to constant weight at a tem- 

 perature not exceeding 70 C. Report weight of alkaloidal residue. 



(6) Volumetric. Dissolve the residue in about 10 cc of neutral alcohol, add 25 cc 

 of water, 5 to 15 drops of cochineal indicator solution, measure in from a burette a 

 slight excess of N/50 sulphuric acid, mix intimately, and titrate back with N/50 potas- 

 sium hydroxid. Report net amount of N/50 acid required. 



Whenever iodeosin indicator is used, follow the directions of the U. S. Pharma- 

 copoeia VIII, page 542. Solutions standardized by means of cochineal should not 

 be used with iodeosin without running a blank for comparison, as the indicators do 

 not give the same neutral point. 



[These methods and those referred to in the U. S. Pharmacopoeia are applied to Ihe 

 analysis of the following drugs with the modifications noted]: 



ACONITE ROOT. 



Method L U. S. Pharmacopoeia VIII, p. 28. Report the amount of N/10 acid 

 required. 



Method II. Aliquot gravimetric. Use ether instead of ether-chloroform mixture in 

 the final shaking out. 



BELLADONNA LEAVES. 

 



Method I. U. S. Pharmacopoeia VIII, p. 67. Report indicator used and amount 

 of N/10 acid required. 



Method II. Aliquot volumetric. 



BELLADONNA ROOT. 



Method I. U. S. Pharmacopoeia VIII, p. 68. Report indicator used and amount 

 of N/10 acid required. 



Method II. Aliquot volumetric. 



CINCHONA BARK. 



Method I. U. S. Pharmacopoeia VIII, p. 102. Report total and ether-soluble 

 alkaloids. 



Method II. Total extraction, gravimetric. 



COCA LEAVES. 



Method I. U. S. Pharmacopoeia VIII, p. 106. Report indicator used and amount 

 of N/10 acid required. 



Method II. Aliquot gravimetric. Use ether instead of ether-chloroform mixture 

 throughout. 



COLCHICUM CORM. 



Method I. U. S. Pharmacopoeia VIII, p. 111. Report weight of alkaloidal residue. 



Method II. Exhaust 10 grams of the powdered drug by percolation with alcohol, 



add 25 cc of water to the solution and evaporate. Digest and stir the residue for several 



