f^52 ON feumentation. 



but I cannot say whether it combined with carbon, or with 

 hidrogen. 1 obtained a quantity of carbonic acid gas equal 

 in bulk to a hundred and twenty times the oxigen gas I had 

 added to th>i grape must ; whence it is evident, that, if 

 oxigen be necessary to the commencement of the fermenta- 

 tion, it is not to its continuance; and that the greater part 

 of the carbonic acid produced is the result of the mutual 

 action of the principles of the ferment and those of the sac- 

 charine matter. 



unless the fn another experiment of the same kind as the preceding, 



iraijes were ,, ^ ^. 1,^1 • .• p 



*j • aixd then ^ lermentatjon commenced at the expiration of twenty-one 



slowly, days, but the grapes were in a very advanced stage of ripe- 



ness: and besides, a portion of the same must, placed in 

 excf'pt oxigen contact with a little oxigen, had fermented in six and thirty 

 pfe^ent. hours after it had been prepared. Hence it is farther evi- 

 dent from this experiment, that oxigen gas is singularly 

 favourable to the devtlopement of fermentation. 

 Oxigen equal-i '^^^'^i^ action of oxigen on fermentable juices is observable 

 !y promo'es also in animal substances, I have seen bottles containing 

 lionoranniid ^^ef, mutton, fish even, and mushrooms, prepared at Mr. 

 subitahces. Appert's ; an<^ a month after these different substances were 

 found to be perfectly good. On being exposed to the air, they 

 soon putrefied, as fresh animal substances would have done. 

 On the contrary, if they were replaced in bottles after hav- 

 ing been in contact with the air a few hours only, and were 

 then exposed to the heat of boiling water, they would keep 

 a very long while. If however the bottles were badly 

 corked; and particularly if the heat were not sufficiently 

 prolonged ; and all the oxigen contained in the bottles were 

 not absorbed, putrefaction soon came on. Tn fact, by ana- 

 lysing the air in the bottles in which these substances have 

 l^§en well kept, we may convince ourselves, that it no longer 

 .contains any oxigen ; and that the absence of this gas is 

 ,ronsequei\tly a necessary condition for the preservation of 

 animal and vegetable substances. 

 Vegetable ?.nil On reflecting, that putrefaction and fermentation never 

 s-r.unal sub- develope themselves instantaneously, I conceived, from the 

 Sve,?by^oc- preceding results, that vegetable or animal substances 

 casicnal he;it- mijjht be preserved, without being deprived of the contact 

 »if 'u presenu" **^ **•'» by exposing them occasionally to the heat of boiling 



water 



