EXTENT OF ADULTERATION. 



From 25 to 41 per cent of the invoices of Sicilian sumac imported 

 into the country are adulterated, and this adulteration is effected 

 almost exclusively with lentiscus. These adulterated shipments are, 

 as a rule, so labeled as to convey the impression that they are pure 

 Sicilian sumac. It is sometimes claimed that shipments of sumac 

 are mixed with lentiscus in accordance with the order of the importer. 

 In such cases the consignment should be properly labeled indicating 

 the amount of lentiscus used. The tannin content is from 2 to 7 per 

 cent lower in the adulterated samples than in the pure sumacs, averag- 

 ing about 4.5 per cent lower, and the color of the extract prepared 

 from them is much darker than that of pure sumac extracts. While 

 to the experienced analyst the color of the extract or of the dried 

 material is generally indicative of the purity of the sample, only 

 microscopical examination can definitely determine this question. 



The adulteration of Sicilian sumac is of more importance than is 

 indicated merely by a lower tannin content, otherwise American 

 sumac could be used at a much smaller cost. When high-grade, 

 light-colored leathers or durable sumac-tanned leathers are required, 

 as for instance in bookbinding, adulteration results in discoloration 

 and destruction of the leather in a much shorter time than when pure 

 sumac is employed in tanning, and the money loss thus occasioned 

 is many times the difference in cost between a pure and an adulterated 

 sumac. 



Aside from any ethical consideration, there is absolutely no advan- 

 tage to the tanner in the purchase of adulterated sumac because, as a 

 matter of fact, the tannin in such sumac costs more for a given amount 

 than when bought in pure sumac. Thus taking the current quota- 

 tions of from $71 to $72 per ton for sumac containing 29 per cent of 

 tannin, $70 to $71 for 28 per cent, and $69 to $70 for 27 per cent, the 

 tannin costs from 12.2 to 12.4 cents, from 12.5 to 12.7 cents, and from 

 12.7 to 13 cents per pound, respectively. That is, the tanner is mak- 

 ing a lower grade leather at a greater cost when using adulterated 

 sumac. Finally, as there may be a variation of as much as 10 per 

 cent in the tannin content of pure sumac, it should always be bought 

 on the basis of its tannin content, and if adulterated should be so 

 labeled. 



117 (32) 



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