STUDIES ON FERMENTATION. 163 



On October 2nd, 1875, we charged at the vineyard twenty- 

 four tubes, all of which were about a third filled with pure must 

 that had been previously boiled. 



Nos. 1, 2, 3, 4, 5, and 6 tubes containing one crushed grape. 



No. 7 tube containing two crushed grapes. 



No. 8 tube containing one crushed grape. 



Nos 9, 10, 11, and 12 tubes containing some wood of a 

 branch of the vine. 



Nos. 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, and 24 tubes 

 containing a fragment of the wood of a bunch from which the 

 grapes had all been detached and removed. 



In the course of the following days some of these tubes 

 began to ferment ; but in others only fungoid mycelia were 

 visible. 



On October 7th the following tubes were fermenting : the 

 second of the first eight containing whole or crushed grapes; 

 not one of the four that contained wood of the branches ; whilst, 

 on the other hand, of the tubes containing wood of the bunches, 

 15, 17, 20, 21, 22, 23, and 24 were all in full fermentation. 

 In short, fermentation, and therefore germs of yeast, were 

 present in one single tube out of eight containing grapes ; in 

 none of the four tubes containing wood of the vine branch ; but 

 in seven out of the dozen containing wood of the bunches. There 

 was no subsequent change in the number of tubes that fer- 

 mented. 



The same day that we arranged this series of tubes we 

 prepared twenty-four other similar ones, using the wood of 

 bunches preserved from the vintage of the preceding year. Not 

 one of these twenty-four tubes showed the least sign of fer- 

 mentation, although they contained grape juice in presence of 

 the wood of the bunches ; this was a further confirmation of 

 the sterility of the germs of ferment in the case of bunches of 

 grapes preserved for a sufiicient time. 



The next question to be considered was, what length of time 

 after the vintage do the germs on the surface of the woody 

 part of bunches of grapes preserve the faculty of producing 



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