160 



STUDIES ON FERMENTATION. 



of apparatus for our experiments, which, besides being very 

 convenient, was at the same time sufficiently exact for the 

 object we had in view. 



Into common test-tubes we poured some preserved must ; 

 we then boiled it, with the object of destroying all the germs 

 that it might contain, and then, having passed the flame of a 

 spirit lamp over the upper sides of the tubes, we closed them 

 with corks which had been held in the flame until they began 

 to carbonize (Fig. 32). Having provided ourselves with a 



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Fig. 32. 



series of tubes prepared in this manner, we carried them to a 

 vine, and there dropped into some of them grapes, into others 

 bunches, from which we had taken all the grapes, by cutting 

 their peduncles ; into others, fragments of leaves or the wood 

 of the branches. The corks were again passed through the 

 flame and replaced successively in each tube. Some of the 

 grapes we dropped in whole, some we crushed at the bottom 

 of the tubes with an iron rod that had previously been passed 

 through the flame ; others, again, at the same moment that we 

 introduced them into the tubes, were cut open with scissors, 

 likewise passed previously through the flame, so that a portion 

 of their interior juice might mix with the must in the tube. 

 Our experiments gave the following results : — As long as 

 the grapes were green, about the end of July and during the 

 first fortnight of August, we obtained no fermentation in our 

 must. Between the 20th and 25th of August a few tubes 

 underwent fermentation, by the action of the little apiculated 



