270 Mr. Warington on the Action of Animal Charcoal, 



him, which, if successful, he considered might prove of im- 

 portance. The idea had occurred to him in passing one of 

 the large breweries, that, from the greatly increased demand 

 for pale ale, such as is exported to India, as a beverage for 

 home use, it would be practicable to discharge the colour from 

 the ordinary beer by artificial means, and thus obtain the de- 

 sired object. What rendered this, he said, the more import- 

 ant, was the difficulty he had heard expressed by persons in- 

 terested in the matter, in preparing an article sufficiently pale 

 for the purpose of sale, the malt employed requiring to be 

 made expressly for this quality of beer. To effect this deside- 

 ratum, he considered that all that would be required would 

 be to pass the fluid through a medium of animal charcoal, and 

 that the ordinary amber colour of ale would be thus partially 

 removed. I undertook to make his experiment for him, at the 

 same time telling him that I thought the beer would be ren- 

 dered very flat and the flavour much injured, but certainly not 

 anticipating what followed. The method adopted, as pre- 

 senting the least objectionable points to the successful attain- 

 ment of the desired object, was to pass the cold ale through a 

 stratum of animal charcoal placed on a paper filter, and to 

 repass the filtrate through the same medium until the required 

 effect was obtained ; the ale operated upon was high-coloured, 

 and had a bitter taste and the fine aroma of the hop. The 

 colour was rapidly removed, but the ale was found on tasting 

 extremely vapid and flat, and the whole of the bitter flavour 

 was found to have been also abstracted. Not being prepared 

 for this result, I was surprised at the rapidity of the action, 

 and resolved immediately to carry on the investigation by 

 substituting other and stronger bitters in the place of the hop. 

 For this purpose a quantity of the ale which had previously 

 had the flavour of the hop removed by charcoal was prepared, 

 one portion of which was boiled with bruised gentian root 

 and another with the raspings of quassia wood, but on passing 

 these decoctions when cold through the charcoal filter as be- 

 fore, the whole of the intense bitter flavour which they had 

 imbibed rapidly disappeared. 



It now occurred to me that this property of animal char- 

 coal might be made of considerable utility to the chemist, as, 

 from all our information up to the present time, it does not 

 affect the active alkaline organic principles, and therefore 

 should prove the means of separating the bitter of the hop and 

 other materials from that of strychnia or morphia as con- 

 tained in nux vomica or opium, it being frequently stated that 

 some persons, vendors or makers of this common beverage, 

 are in the habit of adding these and other materials in small 



