4l^> ACIDITN i>V WINlv. 



\'olatiIe Acid 

 Formed, per 

 Alcohol Volatile roo Volume 



Formed Acid per Cent, 



in \^:)lume. Formed, Alcohol 



Veast. per Cent. ])er Mille. Formed. 



Table V: 



1' 11-59 o-sr 4.36 



Q 11.91 0.69 5.79 



R 11.68 i.oi 8.61 



Table VI: 



P 10.09 O-.S-^J .S-30 



Q 10.35 0.72 6.96 



R 9-57 0.99 10.35 



Table VII: ' 



J" .S-3o 0.50 9.38 



Q ^-55 0.61 10.99 



R 4.8S 0.71 14.55 



On comparing tiiej^e results, it will lie seen, considering 

 Tables I. to III. as a group, that the highest amounts of volatile 

 acid were ifound in Table 1. where the sugar concentration was 

 highest. This is in complete agreement with the results above 

 quoted from R. \'on der Heide's experiments on the same subject. 

 Further, we notice that in Table II. the highest amounts of alcohol 

 were formed, whereas in Table III., where a must of practically 

 the same sugar concentration was used, very much less alcohol 

 was formed owing to the ])rcsence of some sulphur dioxide, 

 which, under the conditions of the exi)eriment. prevented the 

 fermentations from going very far. The amotmts of volatile 

 acid here formed do not differ nmch, on the whole, from those 

 given in Table II., l)Ut owing to the nmch smaller amounts of 

 alcohol formed in the former case, the amounts of volatile acid 

 formed in conijiarison with the corresi)on<ling amotmts of alcohol 

 formed are nmch bigger than those given in Taljlc 1 1. Thus the 

 liindering effect oif the sul])hur dio.xide on the alcoliolic fermenta- 

 tion, and the conseqtient increase in the amount of \olatile acid 

 formed, is clearly shown on comi)aring the last vertical column 

 of Tables II. and III. This, again, is in ])erfect agreement with 

 Duclaux's assertion, (|Uoted earh- in lhi^ ])aper. that when yeast 

 grows and lives under adverse circumstances it forms more vola- 

 tile acid than would be the case under more favourable condi- 

 tions. 



Coming to Tables IV. to \'ll., we do not fmd \ery high 

 \olatile acidities, as the 3'east used in these ex])eriments, namely 

 HaB... is not one that tends to form nuich volatile acid. In 

 Table II., where it was compared with 11 other yeasts, it formed 

 the smallest amount of volatile acid, even in comparison with the 

 alcohol formed. Still, on comparing tlie results enumerated in 



