DETECTION OF ADULTERATION. 



NOTES ON THE MICROSCOPICAL EXAMINATION OF SICILIAN 

 SUMAC AND ITS ADULTERANTS. 



By B. J. HOWARD, Chief, Microchemical Laboratory. 



The differentiation of pure and adulterated sumac by means of 

 the microscope is not at all a new procedure, but it does not appear 

 to be generally employed by the trade in this country. The work 

 done in this laboratory indicates that this is a convenient and quick 

 method of identifying certain of the common adulterants in Italian 

 sumac leaves, and that in the detection of the most common adulter- 

 ant, Pistacia lentiscus, no great experience is necessary to obtain 

 reliable results. The examinations here reported include only com- 

 mercial samples, most of which were in a powdered form, and hence 

 no studies of sections were made. The investigations have been in 

 progress since 1903. The paper by Priestman a will be found very 

 useful to beginners along this line, but the technique of the method 

 as there described seems to leave something to be desired in the way 

 of simplification. As will be shown, the technique adopted in this 

 laboratory is quite different, and, it is believed, has some advantages 

 over Priestman's. 



APPARATUS AND REAGENTS. 



The most important apparatus required is a good compound micro- 

 scope giving a range of magnification of from about 75 to 200 diame- 

 ters. Magnifications of 90 and 180 were actually used in the work 

 here reported, but if approximately these powers are used, giving 

 good definition, no trouble should be experienced. The instrument 

 should have fine and coarse adjustments and a substage condenser 

 with iris diaphragm. A mechanical stage with wide range of move- 

 ment (about 2.5 cm or more) will be found very convenient, though 

 it is not really n'ecessary. 



Microscope slides 25 by 75 mm (1 by 3 inches) and cover-glasses, 

 round or square, are required, round covers of 0.75 inch diameter and 

 from 0.17 to 0.25 mm in thickness, listed by some dealers in micro- 

 scopical apparatus as No 2, are preferred. Some device for produc- 

 ing a small flame, such as a micro-bunsen burner or small alcohol 



a J. Soc. Chem. Ind., 1905, 24: 231. 



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