STUDIES ON FERMENTATION. 



but which had not been brought into contact with the air, has 

 presented no signs of fermentation, although placed under 

 conditions most favourable to its development." 



The result of this experiment, when roughly made, is cor- 

 rectly described by Gay-Lussac ; in other words, it may be 

 proved that if, at the time of vintage, we prepare some bottles 

 of must, after Appert's process, and, in the course of time, open 

 them and decant their contents into other bottles, we shall 

 soon see the must ferment and deposit yeast. It is, neverthe- 

 less, equally certain that the inferences which have been 

 drawn from this celebrated experiment have been founded 

 on error, and that the germs of yeast are very rarely 

 derived from the particles of dust floating in the air with 

 which the must comes in contact. The germs in question are, 

 in our opinion, generally derived, not from the air, but from the 

 sides of the bottles, from corks, from the string employed in 

 corking, from corkscrews, and from a variety of other things. 

 The reason for this is that any room, vault, cellar, or labora- 

 tory where the grapes, or must, or vintage, are handled — 

 unless special precautions, of which Appert and Gay-Lussac 

 certainly never thought, are taken — all the utensils, as well as 

 all articles of clothing, and all the sides of the bottles which 

 the hands have touched, are contaminated by cells of ferment 

 derived from must that has fermented, or by germs from 

 the surface of grapes and clusters. Thus, at the moment of 

 decanting the must, a thousand accidental circumstances may 

 lead to the introduction of those germs, the origin of which, 

 as we have seen, may be actually traced to the very grapes 

 which served for the manufacture of the must. In other words, 

 we believe the inference that the germs of yeast which cause 

 the experiment to succeed, are derived from particles of dust 

 floating in the air of the place where we decant the contents 

 of our bottles, to be altogether an erroneous one. 



Since the preceding remarks were written, we have endea- 

 voured to repeat this experiment of Gay-Lussac's in such a 

 manner as we believed would confirm our views, by varying the 



