DKI'iJS AND MKTIKH>S <>K 1 >K< ' 



In a *2b() cc honker, containing ir>0 cc of wator, dissolve appn>\ 

 imatcly 1 gram (aeeunitoly weighed) of the eyanid. Heat to boil 

 ing, then cautiously add ahout '2 grains of potassium permanganate or 

 such a quantity that the solution after having been heated for one-half 

 hour on (lie steam hath is still distinctly pink. Destroy the e\ce>^ of 

 potassium permanganate with oxalic, acid, heat the mixture a few 

 minutes on the water bath, and the precipitate will subside, leaving a 

 colorless layer of liquid. Filter the solution hot, wash the precipitate 

 on the filter paper with 200 cc of hot water, mix the filtrates, render 

 distinctly acid with nitric aeid, and heat the mixture, to boiling. In 

 this solution the chloride are estimated in the customary manner. 



Mr. J. K. Hay wood, chief of the insecticide and agricultural water 

 laboratory of the Bureau of Chemistry, employs a volumetric, method 

 with satisfactory results. It has been carefully compared with the 

 above gravimetric process and found to accord with it uniformly. 

 The method is as follows: 



Weigh accurately in a weighing bottle about 10 grams of the sub- 

 stance, dissolve in water, and make up accurately to 1 liter. In an 

 aliquot part of this solution estimate the cyanogen by titrating with a 

 decinormal silver nitrate solution. The end reaction is shown by the 

 appearance of a white cloudiness in the solution. Now add potassium 

 chromate, as indicator, and titrate with the standard solution of silver 

 nitrate until the appearance of the usual reddish-brown color of silver 

 chromate. 



The reactions involved in the above method are represented by the 

 following equations: 



(1) AgNO 3 +2KCN=AgCNKCN-f-KNO 3 . 



(2) AgCNKCN+AgNO 8 =2AgCN-fKNO s . 



(3) NaCH-AgNO s =AgCl-fNaN0 3 . 



Representing the number of cubic centimeters of silver nitrate solu- 

 tion used in the first titration b} r A and the number of cubic centi- 

 meters used in the second titration by B, then B A equals the number 

 of cubic centimeters of decinormal silver nitrate solution required to 

 combine with the chlorids present, while the amount of cyanogen can 

 be calculated from A, as indicated by the first equation given. 



INTENTIONAL ADULTERATIONS. 



With very few exceptions the underlying motive of all intentional 

 adulterations is monetary gain. Some of the sophistications conoid - 

 ered above appear to have some superficial excuse for existing, but 

 those here enumerated as intentional are deliberately premeditated 

 misrepresentations, and should be dealt with summarily. In this 

 category comes the potassium cyanid reported above. Other instances 

 are: Borax diluted with sodium bicarbonate; cornstarch delivered when 

 St. Vincent arrowroot is asked for; prime quality drugs mixed with 



