158 "DISEASES" OF BEER, 



Closely connected with the investigations on the diseases of 

 fermented liquids is, as mentioned above, the important 

 question of spontaneous generation (generatio cequivoca). By 

 spontaneous generation is itnderstood the development of living 

 organisms from dead matter, especially from shapeless organic 

 I matter without eggs, seeds or germs. 



There have been naturalists at all times who embraced this 

 view. In the years 1745-1756 it was revived by the writings 

 of Needham. One of Needham's experiments consisted in 

 strongly heating meat extract in closed flasks, and since 

 organisms developed in these flasks, he considered that they 

 must have been produced by spontaneous generation. Buffon 

 and a large number of other savants adopted his doctrine. 



There were, however, also opponents to this view, the 

 most famous of whom was Spallanzani. In 1765 he com- 

 menced the publication of a series of experiments against 

 the view upheld by Needham. The flasks with which he 

 made his experiments were closed hermetically and placed 

 in a vessel of boiling water, and the high temperature main- 

 tained for about an hour. No micro-organisms appeared in 

 the flasks after this treatment, not even after they had been 

 cooled ; this occurred, however, at once when air was allowed 

 to enter. Spallanzani concluded from his experiments that 

 spontaneous generation did not take place, and that the germs, 

 or, as he called them, the eggs for the development of micro- 

 organisms were present in the air. When these gained access 

 to the dococtions with which he and Needham experimented, 

 their further development took place. 



It would lead us too far from our subject to discuss the 

 history of this remarkable doctrine, and we will therefore only 

 mention those points which are of special importance in rela- 

 tion to the investigations on the diseases of fermented liquids. 

 Consequently, only that portion of the literature will be 

 quoted which has a direct bearing on this question. 



As long ago as 1782, the famous Swedish chemist Scheele 



