XXrV] SPICES AND OTHER CONDIMENTS 319 



15 TANNIN.— TENTATIVE. 



(For cloves and allspice.) 



Extract 2 grams of the sample for 20 hours with anhydrous ether. Boil the 

 residue for 2 hours with 300 cc. of water, cool, make up to .500 cc. and filter. Measure 

 25 cc. of this infusion into a 1200 cc. flask, add 20 cc. of indigo solution, 7o0 cc. of 

 water and proceed as directed under XVI, 32. One cc. of N/10 oxalic acid is 

 equivalent to 0.006232 gram of quercitannic acid, or 0.0008 gram of oxygen absorbed. 



16 TOTAL SULPHUR.-OFFICIAL. 



(For mustard.) 

 Proceed as directed under III, 17. 



OLIVE OIL, 



(For paprika.) 



17 Qualitative Test. — Tentative. 



Spread 5 grams of the paprika on a watch glass and dry over sulphuric acid for 

 at least 12 hours. Measure 250 cc. of anhydrous, alcohol-free ether [VIII, 9] into a 

 graduated flask on which the mark is situated near the lower end of the neck, and 

 brush the paprika into it. Place a mark on the neck of the flask at the point where 

 the meniscus is, and allow to stand for an hour, shaking at 20 minute intervals 

 during that time. Bring the meniscus back to the mark placed upon the neck, either 

 by cooling the flask and contents if the level has risen, or by adding absolute ether 

 if it has fallen; let the solid particles settle and pipette off 100 cc. of the supernatant 

 liquid, filter through an 11 cm. closely woven paper into a tared, air-dry, 250 cc, 

 glass-stoppered Erlenmeyer flask that has been counterpoised against a similar 

 flask; wash the paper with a little absolute ether. Then distil off the solvent and 

 remove the flask from the bath as soon as the ether ceases to come over. Lay the 

 flask on its side in a water oven and heat for 30 minutes; cool the open flask for at 

 least 30 minutes in the air and weigh. Repeat this heating and weighing until the 

 weight is constant to within 1 mg., 2 heatings usually being sufficient. Note the 

 per cent of ether extract obtained. If more than U hours of heating are required 

 to obtain constant weight, or if the ether extract becomes colorless, reject it and 

 start a new determination with freshly purified ether. 



Dissolve the ether extract in the flask with 10 cc. of chloroform, add 30 cc. of 

 Hanus' solution [XXIII, 17 (a)] and proceed as directed under XXIII, 18, allow- 

 ing 30 minutes for the halogen absorption. Note the iodin number of the ether 

 extract. The iodin number of pure paprika thus obtained should not be less than 

 125. 



MICROSCOPIC EXAMINATION.-TENTATIVE. 



18 GENERAL. 



Adulterants of vegetable origin in spices are detected best by means of the mi- 

 croscope. A general knowledge of vegetable histologj' and the microscopic appear- 

 ance of the spices and spice adulterants is essential. Some of the standard works* 

 on these subjects are listed in the bibUography. 



19 REAGENTS. 



Of the numerous reage'nts employed in histological work the following are the 

 most u.«!eful in spice examinations : — 



(a) Glycerol solution {1 to 1). 



(b) Absolute alcohol. 



