1 62 "DISEASES OF BEER, 



tation was caused by the activity of microscopic organisms 

 that the explanation was forthcoming. 



Thus, long before anything was known as to the causes 

 which bring about the diseases of fermented liquids, a method 

 had been found for their prevention, which, in fact, is the best 

 that we have at the present day. What has been added later 

 by various technologists, consists only of small improve- 

 ments ; in all essentials we employ the method of heating 

 elaborated by Scheele and Appert. There is, however, no 

 rule of universal application. If a satisfactory result is to 

 be attained, the heating process must be arranged to suit 

 the character of the different liquids under treatment. What 

 will suit one kind of beer or wine will not always prove 

 satisfactory with another. 



Appert's method of preserving wine and beer does not 

 appear to have found any general application until Pasteur 

 took the matter in hand. Pasteur made great efforts to 

 bring about the general application of this method of treat- 

 ment to wine. His associate, Velten, carried out some 

 experiments with beer. At the present time, the method 

 is known all the world over under the name Pasteurisation. 



Scheele's name has been completely forgotten in con- 

 nection with this, and there are not many who know that 

 we are indebted to a Scandinavian for this beatttiful and 

 practical discovery. 



Spallanzani's experiments and results were received favour- 

 ably only by the few, and in particular it was argued against 

 them that the air enclosed in his hermetically closed flasks 

 was changed by the boiling, and also that it was present in 

 too small a quantity to enable spontaneous generation to 

 take place. 



In 1836-1837 a number of experiments were carried out 

 by Franz Schulze and Theodor Schwann separately, which 

 proved that various readily fermentable and decomposable 

 substances could be preserved unchanged if they were boiled 



