124 TECHNICAL ANALYSIS OF 



In those cases where a trial was made, it was found that 

 when i cc. of water was added to 10 cc. of beer, no 

 growth occurred other than mould and Pasteur's so-called 

 Torula, and not infrequently no growth of any kind developed. 

 In other words, this shows, then, that the addition of I cc. 

 of water to 10 cc. of beer was not sufficient to destroy the 

 antiseptic power of the beer as regards resistance to the action 

 of the bacteria present in the water, for none of the latter 

 developed in the beer which was thus diluted. 



It is self-evident that a microscopic examination should be 

 made of each growth in the flasks, and in many cases it will 

 also be advisable to make special cultivation experiments in 

 order to ascertain to what extent the different species are 

 dangerous. 



All the experiments have shown that the gelatine method 

 gives miich higher numbers than the technical brewery method, 

 and this applies to both wort-gelatine and meat decoction 

 peptone gelatine. We have also seen that there is no fixed 

 ratio between the numbers obtained by means of the two methods, 

 and therefore any conclusions drawn from the one cannot be 

 applied to the other. And with regard to these numerous 

 colonies which develop in the gelatine, we stand face to face 

 with the sad fact that even when we submit each of them to 

 a thorough microscopic examination, we are still unable to 

 decide whether they contain growths which are able to attack 

 wort and beer. In order to arrive at an answer to this ques- 

 tion and this is really the whole point it is necessary to make 

 cultivation experiments in these liquids. A further important 

 objection to the use of gelatine is that some of the micro-organ- 

 isms, which are of the greatest practical importance as regards 

 the analysis, often do not develop in this medium. This 

 applies, for instance, to acetic acid bacteria, Saccharomycetes 

 and other alcoholic ferments. I have found by means of direct 

 experiments with several such species that in the enfeebled 

 condition in which they are present in atmospheric dust, in 



