62 STUDIES ON FKRMENTATION. 



forming germs — that is to say, to those germs which exist in a 

 state of suspension in the air. 



In our Memoir of 1862, which we have quoted several times, 

 we have explained that it is almost impossible to draw any 

 serious conclusions from experiments made in a basin of 

 mercury, because of the organic particles of dust which always 

 exifjt in that metal, and which, without the knowledge of 

 the operator, pass into the interior of the vessel, where they 

 produce certain changes which one is tempted to impute to 

 heterogenesis. 



In all classical works an experiment of Appert's, reproduced 

 by Gay-Lussac, is given. This, through a faulty interpretation, 

 led to the hypothesis of the continuity of the causes of fer- 

 mentation, if we may use such a term, in the atmospheric 

 air.* 



When we decant bottles of must, which has been preserved 

 by Appert's method, into other bottles, all the latter soon set 

 up a fermentation : this constitutes the experiment. If it were 

 proved that the must, whilst being decanted, came in contact 

 with atmospheric air alone, as Gay-Lussac believed, we should 

 be compelled to admit, according to the theory of germs, that 

 the must had come in contact with some particles of ferment 

 in the air during decanting. And again, if it were shown that 

 the experiment could succeed in any place whatsoever, we must 

 come to the conclusion that germs of ferment exist everywhere 

 in a state of suspension in the air. 



" I have taken,"" writes Gay-Lussac, " a bottle of must that 

 had been preserved for a year and was perfectly transparent, 

 and have decanted the must into another bottle, which I then 

 carefully corked and exposed to a temperature of 15° C. to 

 30° C. (59° F. to 86° F.). Eight days afterwards the must has 

 lost its transparency ; fermentation has taken place in it, and 

 soon my must has become transformed into a vinous liquor, 

 sparkling like the best champagne. A second bottle of must 

 that had been preserved for a year, like the preceding one, 



* Gay-Lussac, Annaks deChimic, t. Ixxvi. p. 247, Mcmoire citt', 1810. 



