304 FOOD AND FOOD ADULTERANTS. 



amyl alcohol as a solvent, as follows : "50cc. wine 1 (or beer) are shaken 

 up with 5cc. amyl alcohol in a small flask for a few minutes and allowed 

 to separate. The clear amyl alcohol is then drawn off and an equal 

 quantity of alcohol added, with which it makes a colorless solution. To 

 this solution is added a few drops of dilute solution of chloride of iron, 

 which produces the violet color." 



The use of chloroform as a solvent is recommended by the German 

 Imperial Commission for the establishment of methods for wine analy- 

 sis. 2 



The Paris Municipal Laboratory allows the choice of four different 

 methods for applying the test in case the ether extract does not afford 

 satisfactory results: 



(1) By adding a small quantity of a dilute solution of chloride of iron to precipitate 



the tannin, and subsequent extraction with ether. 



(2) By precipitation of the tannin with gelatine or albumen. 



(3) By treatment with ether in the ordinary way and after the ether is evaporated 



the residue is again treated with a few cubic centimeters of perfectly pure 

 benzine, the solution evaporated, and the residue from this evaporation sub- 

 jected to the test. 



(4) By treatment with pure chloroform. 



The union of Bavarian chemists has 3 adopted the method of Bb'se 4 

 who uses a mixture of equal parts of ethyl ic and petroleum ether for 

 extracting the beer or wine, as follows : u 50cc. of the beer are shaken up 

 in a separatory funnel with equal parts of ether and petroleum ether, 

 after acidulating with 5cc. of dilute sulphuric acid. The separation 

 follows very quickly, when the watery part is allowed to flow through 

 the stop cock and the ethereal. is poured out through the neck into a 

 small dish. After the ether has been evaporated, and also the greater 

 part of the petroleum ether except a few cubic centimeters, 3-4 cc. of 

 water are brought into the still warm dish. This is well stirred, a few 

 drops of a very dilute solution of chloride of iron added, and the whole 

 filtered through a moistened filter, which allows of the passage only of 

 the watery part of the solution. On the addition of the chloride of iron 

 the petroleum ether solution assumes a deep yellow color, due to cer- 

 tain compounds of the iron with the resin of the hops. In the absence 

 of salicylic acid the filtrate is nearly water-clear with a slight tinge of 

 yellow ; if present, even in traces, the solution takes on the well known 

 violet color. 5 



To test the efficiency of these various methods two samples of a very 

 dark beer known to be free from salicylic acid were taken, and to one 

 was added salicylic acid in the proportion of .05 grams to the liter, and 



I Some, of the processes given are intended for wine, but arc equally applicable to 

 beer, milk, fruit juices, &c. 



- Die Woinanalyso, Kommentar, u. s. \v. 



II Op. eit. 



Areli. f. llyg'u-u. Analyst. 1.;. i: 1 . :. 



''The same test is given by If. Tall'e, Hull, de la Soe. deCliim.de Paris, .Id. No. 1'J. 



