64 ANALYSIS AND ADULTERATIONS OF BUTTER. 



Thus we arrive at the percentage of foreign fat contained 

 in the fat of butter. But as the analyst is required to state 

 the amount of adulteration in the butter as sold by the 

 dealer, a further calculation has to be made, since butter 

 contains on an average 15 per cent, of water, curd, and salt, 

 and 85 per cent, of real butter-fat. Now, since by preparing 

 the fat in its pure state we separate these impurities from it, 

 the percentage of foreign fat is greater in the pure glycerides, 

 as used for analysis, than in the butter vended by the dealer. 



The above formula gives the percentage of foreign fat in the 

 fat analysed. By subtracting this from 100 the proportion of 

 pure butter-fat contained in the mixture is arrived at. If this 

 be called B, then the quantity of real butter corresponding, C, is 



100 B /->, 1 -i^ftKT) 



__ or G = 1'1765 B. 



Then the actual percentage of adulteration in the com- 



100 C 

 mercial butter is = -r p 



Practically, butter never seems to be adulterated with 

 small proportions of foreign fats, but usually the percentage 

 of adulteration is exceedingly large, from 60 to 80 per cent. 

 This may to a large extent be explained by the fact, that 

 it is very difficult to mix, on a small scale, butter with 

 any fat, so that the resulting product still retains its buttery 

 appearance. The dealer, therefore, never, as far as we are 

 aware, adulterates the butter he vends, but it is a special 

 business, a separate branch of manufacture to prepare such 

 mixtures, upon which names like " Butterine," " Oleo- 

 margarine," "Save Butter," etc., have been bestowed, and 

 which are extensively manufactured on the Continent. No 

 objection can of course be raised against such mixtures if 

 they are but sold and acknowledged as such, but frequently, 

 as soon as the article is retailed, it assumes the name of 

 " Butter," to which it has no right. 



