§ 154. ESTIMATION OF SANTONIN. 141 



the convolvulin of true jalap, which is distinguished by its insohi- 

 biHty in ether, and of tmycthin,'^ which is insohible in ether, but 

 differs in composition from convolvuhn. 



All these glucosidal resins dissolve in cone, sulphuric acid with 

 purple colour. 



§ 154. Estimation of Santonin. — The following method may be 

 adopted for the quantitative estimation of santonin (§ 45) in 

 worm-seed ■? 



15 to 20 grams of the material are digested on a water-bath for 

 2 hours with 15 to 20 cc. of a 10 per cent, caustic soda solution 

 diluted with about 200 cc. of water, filtered and washed. The 

 filtrate and washings are concentrated to .30 or 40 cc, cooled, 

 neutralized with hydrochloric acid, and at once filtered. The pre- 

 cipitate is washed first with 15 to 20 cc. of water, and then with 

 an 8 per cent, soda solution, and any crystals of santonin 

 that may thus be separated subsequently added to the principal 

 portion. The filtrate from the hydrochloric acid precipitate is 

 acidified and shaken with 3 successive portions of 15 to 20 cc. of 

 chloroform. The chloroformic solutions are washed with water 

 and evaporated to dryness ; the residue is dissolved in the smallest 

 jjossible quantity of soda, filtered if necessary (washing the in- 

 soluble portion with a very little water), and acidified Avith 

 hydrochloric acid. After standing for 2 or 3 days in a cool 

 jjlace the santonin is filtered off", washed with 10 to 15 cc. of 

 8 per cent, solution of soda, dried at 110°, and weighed. A cor- 

 rection must be made of 0*002 gram for every 10 cc. of mother- 

 liquor, and 0"003 gram for every 10 cc. of washings. 



Santonin can also be extracted by boiling with milk of lime. 

 15 to 20 grams of worm-seed are digested Avith 200 cc. of milk of 

 lime diluted with 400 cc. of Avater on the Avater-bath for 6 hours, 

 boiled for half an hour and filtered. The residue is again boiled 

 Avith 10 cc. of milk of lime diluted with 200 cc. of water. The 

 filtered decoctions and Avashings are evaporated to about 30 cc, 

 excess of hydrochloric acid added, and at once filtered (the preci- 

 pitate being treated Avith soda as liefere). The filtrate must 

 stand for 5 or 6 days in a cool place, Avhen the santonin may be 

 collected and Avashed Avith soda-solution. The small amount that 



^ N. Repert. f. Pharm, xiii. 97, 1864 (Amer. Journ. Pharm, xxxi. -374). 

 - Compare Archiv d. Pharm. [3], xiii. 306, 1878 (Amer. Journ. Pharm. L 

 296). 



