38 VINOUS FERMENTATION". 



So that In every It maybe laid down, therefore, as demonftrated, that in 

 mentation an' ^^ery fpirituous fermentation an animal matter is depofited, 

 animal matter is fimilar in all refpefls to that arifing from wort, pofleffing ab- 

 toye^f ^'"^'^^Toiutely the fame properties, and in particular that of decom- 

 pofing fugar, and converting it into carbonic acid and fpirit 

 of wine. This gives rife to a new queftion, that naturally 

 Is this generated prefents itfelf, and ought next to occupy our attention. Is the 

 in theprocefs^of ^g^^ gg,^gj.^tgj| ^^ the procefs of fermentation, or rather was 



it aheady formed, and did ferveasa ferment? 

 No dlrcft proof, I ^"(1 confefs we have yet no experiments, which direftly 

 that nature cm- prove, that nature employs this fubftance exclufively to effedt 

 c!ufi^vely"s a ^^'^ converfion of fugar into alcohol and carbonic acid. For^ 

 ferment. why fliould it be depofited when the fermentation has taken 



place ? It may be faid indeed, that the fugar holds it in folu- 

 tion, that it can diifolve more than is neeelTary for its decora- 

 pofition, and that then the excels is precipitated. But this 

 theory is feebly fupported by experiment. Is this a fufficient 

 reafon, however, to rejedl it altogether ? Have we not feveral 

 iniiances of compounds, that require much time for their for- 

 mation? and this perhaps is what occurs in the juices of fruits, 

 where the ferment and the fugar are long in contad with each 

 If itbeaproduft other. What is certain, or what at leaft appears probable, is, 

 ^^^ToTaW^^'°"' that, if yeaft be a produa of fermentation, as all liquors that 

 comes fiom ferment depofit it, no doubt it owes its origin to one and the 

 fome particular (-^^^g foluble fubflance, from which probably it differs little, and 

 fubftance, httle ,. , , . , - «• .^ r 



changed. which produces it by its reaction on the lugar. 



Yeaft an imme- Whichever of thefe two opinions obtains the preference, 



diate principle of g^^-^gf more numerous trials, as I have no doubt, that yeaft is an 



immediate principle of vegetables, and in confequence a^s an 



important part in the phenomena both of art and of nature; as 



an*d if there be I am likewife perfuaded, that, if any other fubftance capable 



any other fer- ^f exciting fermentation exift, it is in the higheft degree ana- 

 ment, itmuftbe n i • irr r ■ i- i i • • 



fimilar to it, and logous to yealt; that it ditiers from it very little j that it is 



compofedof compofed like it oF azote, oxigen, carbone, and hidrogen; and 



carbone and ' laftly that it has no doubt the fame mode of afting on fugar : 



hidrogen. I fhall proceed to exhibit with the greateft care the properties 



of this matter, which I ihall henceforward term ferment, and 



in particular confider well its adlion on the faccharine principle, ■ 



in order to eftablifli the theory of fermentation. This theory, 



even fuppofing yeaft not to exift already formed, but to be 



produced in fermenting juices, will ftill be of utility, and ca* 



pable of various applications, as will appear below. 



I ftiall 



