06 STUDIES ON FERMENTATION. 



transformed into active bacteria. Nothinj^ can be easier than to 

 prove this fact, by taking some of our two-necked flasks (Fig. 

 4) and preparing pure wort in them, by boiling, and then 

 leaving it to cool and undergo the process of oxidation. In 

 wort thus exposed to the air — the air being pure and free from 

 germs — there will be formed a granular deposit, which will never 

 become active or transform itself into any kind of organism 

 whatever. 



"We may also remark that whilst M. Trecul used wort in his 

 experiments, he does not tell us if it was hopped or not. Had 

 M. Trecul informed us that the facts which he described applied 

 to unhopped wort, we should reply that a temperature of 60° C. 

 or 70° C. (140° F. or 160° F.) is quite insufficient to kill the 

 germs of bacteria existing in such a wort. Hopped wort 

 should be heated to 70° 0. or 75° C. (160° F. to 170° F.), that 

 it may remain inert after having cooled down in contact 

 with pure air ; unhopped wort must be heated to about 90° C. 

 (194° F.). 



In short, whatever may be the case, it must be evident to 

 our readers that the active bacteria observed by M. Trecul existed 

 in the form of germs in the wort that he used, and that what 

 he observed was nothing more than the development of these 

 germs when brought into contact with the air held in solution 

 in the liquid. 



As for the success of M. Trecul's experiments on the 

 penicillimn, we have no doubt that that gentleman has sown 

 germs of yeast or tonilce, which bear so striking a resemblance 

 to yeast, at the same time that he sowed spores, since he took 

 his spores from sporangia of penicilUum that had been exposed 

 to contact with ordinary air. The conditions under which M. 

 Trecul conducted his experiment rendered it difficult for the 

 spores — although, relatively, much more numerous than the 

 contaminating germs of ferment with which they happened to 

 be associated — to make way against these latter, since the spores 

 were unable to continue their development in a medium that 

 was deprived of oxygen. On the other hand, the cells of 



