122 TECHNICAL ANALYSIS OF 



be expected, but in no case was beer attacked by them. 

 Bacteria which are able to attack beer would appear to be but 

 very rarely present in water. 



When, however, these liquids (wort and beer) were much 

 diluted, the micro-organisms with which they were infected 

 developed, as a rule, very freely. This was shown both in 

 the case of the mixtures in the flasks and of the drop 

 cultures on the gelatine plates, and still more distinctly by 

 means of some special experiments which were made in this 

 direction. Not only wort, but also beer, lost its original 

 resistive power under these conditions. In this state of 

 dilution, however, they are no longer what is understood in 

 the brewery as wort and beer. In examining the flasks the 

 fact must not be overlooked that there are bacteria which 

 can grow in wort, and especially in beer, without producing 

 cloudiness ; amongst these are, e. g. the acetic acid bacteria 

 described by myself a few years ago. 



In order to gain further information with regard to the 

 antiseptic power of the above-mentioned liquids, some special 

 experiments were undertaken. Some of the wort and beer 

 mixtures teeming with bacteria were introduced into a flask 

 containing sterilised distilled water in sufficient quantity to 

 render the latter cloudy. Single drops of this new mixture 

 were then introduced into a number of flasks containing beer 

 and wort. These were vigorously agitated, and consequently 

 became aerated, and they were then set aside at a temperature 

 of 24-25 C. In a short time the liquid in all the flasks 

 became as bright as before infection ; but after two days 

 almost all those containing wort became cloudy, owing to 

 very vigorous growths of bacteria. Those containing beer, on 

 the other hand, were still bright after sixteen days, and did not 

 show a trace of any growth, although they had been infected 

 with a great number at least, hundreds of living bacteria, 

 exactly as in the case of the wort flasks. 



Identical results were obtained from similar experiments 



