MALT LIQUORS. 307 



wine to which had been added, respectively, 0.084 and 0.126 grains per 

 liter 0.084 and 0.123 grams. 



M. Reraont l also devised, in 1882, what might be called an empirical 

 method for the estimation of the quantity of salicylic acid added to wine 

 or beer, which would doubtless prove very convenient in case its use 

 were limited by law to a certain definite quantity, as follows : 



In a liquid, similar to that which is to be tested, is dissolved a known 

 quantity of pure salicylic acid; of this standard liquid 50cc. are taken 

 and well shaken with 50cc. of ether, and allowed to separate; 25cc. of 

 the ether are taken iu aflat dish and subjected to evaporation at a 

 temperature below boiling, in the presence of lOcc. of water; when the 

 ether has disappeared, the water is poured into a graduated cylinder 

 and its volume made up to 25cc. with the washings of the dish. This 

 solution contains the same proportion of salicylic acid as the standard ; 

 lOcc. of the liquid to be analyzed are then taken and shaken with lOcc. 

 of ether ; 5cc. of the clear ether are taken, evaporated with 2cc. of 

 water, and the residual liquid made up to 5cc. with the washings of 

 the dish, as above. 



Two tubes, each graduated to 30cc., are taken, and into one is intro- 

 duced 5cc. of the standard aqueous solution as obtained above, and into 

 the other the 5cc. obtained from the sample for analysis. To each tube 

 is added the same quantity of a 1 per cent, solution of ferric chloride, 

 avoiding an excess. The comparison of the two tubes may then be 

 made, and the process can be made quantitative by diluting with water, 

 or other colorimetric methods. 



The author insists upon the necessity of taking, as a means of compar- 

 ison, a liquid of the same nature as the sample for analysis, as the 

 foreign matters which ether dissolves from wine, beer, or cider alter the 

 delicacy of the color test. 



SULPHITES. 



The use of sulphurous acid as a preservative agent in beer and wine, 

 either in the form of soluble sulphites, liquid sulphite of lime, or sulphur 

 fumes, is not at all recent. It is one of the oldest preservatives known. 

 Together with other chemical preservatives its use is forbidden in 

 France, and the German authorities include it with borax as an agent 

 whose physiological effect is still too little known to allow of its indis- 

 criminate use. It is also sometimes introduced into beers by the hops, 

 which are very generally preserved by means of sulphur fumes. The 

 Bavarian authorities allow its use in sulphuring barrels and hops, as 

 will be seen when their method of analysis is described later. Of course 

 the quantities brought into the beer in this way are very small. 



The qualitative test, which is given by many of the books on the sub- 

 ject,* viz, the reduction of the sulphur to hydric sulphide gas by means 

 of nascent hydrogen, is entirely erroneous, as I have proved by experi- 



1 Compt. Reiid. 'Jo, 78(5. -Konig, for instance, p. 410; Dietzsch, p. 123. 



