ii2 TECHNICAL ANALYSIS OF 



but in a still higher degree to the fact that the air of this room 

 is cooled by means of an ice-machine, and that it is sub- 

 mitted to a special purifying treatment by means of a 

 shower of salt water. The air of the fermenting cellar of 

 Old Carlsberg contained, on the average, 0*0006 ^erm in 

 i cc. or i germ in 1591 cc. These numbers are given on 

 the assumption that they may serve as a kind of standard 

 in such analysis at least, until we obtain a better one. 



Similar analyses were likewise made in the fermenting 

 rooms of other breweries in which no purification of the 

 atmosphere had been attempted, and the difference was most 

 marked ; the air not infrequently contained more than four 

 times the number of germs that were found in the case 

 mentioned above. Bacteria Sarcina amongst others were 

 also frequently found in the latter case, and also wild yeasts, 

 which proved to be disease-producing yeasts. It was during 

 these studies that the idea first occurred to me that some 

 of the most common and most dangerous diseases of beer 

 were caused not by bacteria, but by certain of the Saccharo- 

 mycetes, and this idea was the starting point of my investi- 

 gations in this direction. 



The experiments naturally hold strictly good only for 

 those places where they were made, and under the conditions 

 there obtaining. Generally speaking, however, they will also 

 hold good for other similar districts and for other breweries. 

 Although carried out in 1878-80, they are still the most 

 comprehensive experiments which we have in this field, and 

 the results obtained have lost nothing as regards their validity. 

 With regard to the technique of these old experiments, it 

 may likewise still be affirmed that the principle was correct. 

 The only objection that can be raised from our present stand- 

 point is that the same result can be attained in a more ready 

 manner. In conducting such experiments on the micro- 

 organisms of the air, I should now employ a similar method to 

 that described in the following section on the analysis of water. 



