95 



genous matters derived from the malt, and which I have every 

 reason to believe, from various tests which I have applied, to be 

 peptone." Unfortunately, HERON does not give the tests which 

 influenced his opinion, so that there is no evidence that such a 

 compound exists. He goes on to say (loc. cit. p. 179) that he has 

 reason to believe that this tanno-peptone is in many cases a cause 

 of turbidity in beer, especially in cold weather, because the haze 

 which will com& on chilling a beer, and which disappears if the 

 temperature is raised, is an extremely characteristic feature of 

 tanno-peptone. If this were so one would expect the tanno-peptone 

 body to be removed on prolonged chilling and filtering, such as 

 takes place in certain modern methods of bottling beer, but it wil 

 be found that these beers, which in some cases have been three 

 weeks in cold store before filtering, still show the tannic acid 

 reaction with ferric chloride. Moreover, the non-alcoholic " hop 

 bitters " and " hop ales," whose basis is usually cane sugar, malt 

 not entering into their composition, generally show the presence of 

 tannic acid when tested. In this case any albuminoid matter 

 present mast have come from the sugars or saccharums employed, 

 if they contain any, so can hardly be of a peptone nature. 



On this point also a communication of MATHIEU to a congress 

 of chemists at Rheims (Annales de la Brasserie, 1904, p. 114) on 

 various turbidities occurring in wine is a propos. In referring to a 

 turbidity due to amorphous particles, he states that these give the 

 reaction for tannoids, and also give off nitrogen by the action of 

 soda-lime, thus indicating the presence of nitrogenous matter, but 

 it does not follow that they are exclusively formed by a combina- 

 tion of tannin and albuminoids, and he thinks the existence of such 

 combination in a chemical sense to be very doubtful. Thus, 

 with aqueous or slightly alcoholic solutions of a tannin extracted 

 from various parts of the grape, which had been purified with 

 alcohol, and in which the absence of nitrogenous compounds had 

 also been verified, deposits of insoluble resinous matter have been 

 obtained (especially in the presence of light and oxygen) which present 

 exactly the reactions obtained with tannoids observed in deposits 

 of white wines obtained under similar conditions ; but in this case 

 there are certainly other substances. The author cites this fact of 



