i/o "DISEASES" OF BEER, 



my earlier treatises, my investigations have shown that this 

 view is quite incorrect. One and the same species may occur 

 with cells which might be taken as belonging to all the fonns 

 classed by Reess as distinct species. Associated with the 

 conception of different species, there is naturally also the con- 

 ception of a difference in the activity ; both these views were 

 expressed by Reess. On p. 21 he suggests that the reason 

 for the custom, then prevalent in all breweries, of getting a 

 change of yeast, is, possibly, that the yeast becomes con- 

 taminated by the various fungi occurring in the brewery 

 premises, and that during their growth these have an injurious 

 effect on the activity of the yeast. On p. 40 he also expresses 

 the opinion that besides Sacch. cerevisice, other alcoholic fer- 

 ments can also occur, which are capable of exciting injurious 

 fermentations. 



In the following year two communications appeared on 

 diseases in beer produced by alcoholic ferments, one by 

 Holzner, the other by Lintner, sen.* As both these investiga- 

 tions led to the same result, they may here be discussed 

 together. A dangerous disease is described in them, which 

 was at that time prevalent in low-fermentation breweries. 

 This disease manifested itself in such a manner that the beer 

 fined in the lager casks only with very great difficulty, and 

 when this finally occurred it became thick again when tapped, 

 the turbidity being caused by the presence of numerous small 

 yeast cells. A microscopic examination led to the belief 

 that this yeast was the species described by Reess under the 

 name Sacch. exiguus. No experiments were made, and at 

 that time it was assumed that the species described by 

 Reess were true species. Since this, as we have seen, is 

 not the case, these investigations were unable to throw any 

 certain light on the question. However, they are at any rate 

 deserving of credit, since they, for the first time, called the 

 attention of zymotechnologists to the small light yeast cells 



* ' Der Bayerische Bierbrauer,' Munich, 1871, pp. 14 and 64. 



