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On the Ttemoval of the Bitter Taste and Lichenous Odour of 

 Iceland Moss, ^c* William Davidson, M.D. Com- 

 municated by tlie Society of Arts of Scotland. 



Iceland moss (Cetraria Icelandica) is used, in some north- 

 ern countries, in the formation of bread ; but its extremely 

 bitter taste has always been found a very great objection to 

 it, as a general article of diet. M. Westring proposed the 

 subcarbonate of potass as an agent capable of removing the 

 bitter principle. He states that 32 grammes of the subcar- 

 bonate of potass suffice to produce the effect on 500 grammes 

 of the lichen, steeped for tv^^enty-four hours, in a quantity of 

 water sufficient to cover it ; or about one part of the alkali to 

 sixteen of the lichen. 



The time, however, which he directs for maceration does 

 not appear to be sufficient to extract the whole of the bitter 

 principle, and in order to ensure this (even with this propor- 

 tion of potass) two or three days must be allowed. Accord- 

 ing to Berzelius, Iceland moss is composed of the following 

 substances, in 100, viz. chloraphylle 1.6, bitter principle 3.0,+ 

 uncrystallizable sugar 3.6, gum 3.7, apothem of extractive 7.0, 

 starch 44.6, bilichenates of potass and lime, &c. 1.9, amylace- 

 ous tibrin 36.2. 



From this composition of the lichen, it is probable that the 

 alkaline solution Mill take up the sugar, gum, and a portion 

 of the extractive, but the starch and starchy fibrinous princi- 

 ple constituting about 81 per cent., will not be dissolved. 



It therefore appears that a prolonged maceration of the 

 lichen, in the solution of potass, will not cause a much great- 



=* Head before the Society of Arts for Scotland, 20th June 1838. The 

 Honorary Silver Medal awarded 18th December 1839. 



t M. Herberger Pharmacian of Kaiserslautem, has lately obtained the 

 bitter principle in a state of purity, which he has named Cetrarin. Accord- 

 ing to this chemist, it is white like magnesia, but he has not been able to 

 procure it in a crystalline form. It has no odoui- but an intensely bitter 

 taste. Alkaline solutions dissolve it very readily, but tliese combinations 

 have a great tendency to bo transformed into ulmates. — Journal de Pliar- 

 macie, October 1837. 



