22 TWO HISTORICAL FALLACIES: HEATHER BEER AND UISGE BEITHE. 



Samples were got from the central district of Perthshire and from the island of Islay 

 for purposes of analysis. The Islay sending was first to arrive. On drawing one of the 

 bottles and tasting it, it was so entirely free from taste of any sort, and so limpid, that 

 the conclusion was at once formed that rain water had been supplied, and gave the 

 credit to the friend acting as a collector of playing a trick, but on inquiry the forester 

 who had gathered it, a thoroughly reliable man, described precautions to prevent any 

 dilution by rain, and was prepared to guarantee that the sap was free from mixture of 

 any kind. An analysis was then made in the Public Health Laboratory in the 

 University, reported as follows : — 



" It was slightly opalescent, with a faint acid reaction. Its specific gravity was 1002, 

 water 1000. It contained no sugar, its total solids being 0*302 per cent. The solid 

 matter was almost entirely vegetable albumen, and contained neither starch nor dextrine." 



The Perthshire sample arrived in Edinburgh in the beginning of April, which 

 accurately corresponds with the time of the year mentioned by Lightfoot as the best in 

 which to gather it. It was very carefully analysed at Granton. It was also slightly 

 opalescent, and it was impossible to filter it clear. At 59° Fahr. it had a specific 

 gravity of 1003*09. It yielded on evaporation over the water bath 0*6910 solid 

 matter per cent. On examination this was found to consist of extractive matter 5 420 

 per 1000 grammes (or grammes per litre) ; fermentable sugar, 0*440 per 1000 ; tartaric 

 acid, 0*455 ; ash, lime, magnesia, and alkalies, 0*290. 



In addition to the solid matter there was a small quantity of alcohol present, 0*244 

 per 1000; carbonic acid, 0*293 per 1000. 



This alcohol must have been the result of a natural fermentation of the sugar in the 

 sap, and allowing for this, the amount per cent, of sugar in the sap, including what had 

 been fermented naturally, and what was fermentable, was 0*680 grammes per litre, or 

 0*0680 per cent. 



The determination of the sugar was made by fermentation with dry German yeast ; 

 the tartaric acid by the silver mirror. The extractive matter was found to reduce 

 copper, but only being fermentable to the small extent mentioned, we may conclude 

 that the most of it was dextrine ; this, however, does not agree with the first analysis, 

 which gave no sugar, nor starch, nor dextrine, and consequently the whole was supposed 

 to be vegetable albumen. 



From a practical point of view, and granting what is possible, that samples of birch 

 sap may vary in the richness of their contents, it never could of itself yield anything 

 active either as a drink or as a medicine. Lightfoot's recipe would come out probably 

 quite the same if so much water were used in place of the sap. 



In fact, the conclusions reached are, that though heather flowers, if infused in malt, 

 or added to a fermentable syrup, may give a flavour to the product, it is in itself of no 

 value as a source of ale or beer. 



Birch sap is equally useless, and can only give satisfaction as a drink or a medicine 

 from an imaginative point of view. 



