VINOUS FERMENTATION, 3^9 



I fhall not recapitulate the phyfical qualities of ferment, as 

 1 have mentioned them feveral times already; but I fliall con- ' 



fine mjfelf to its chemical properties, which alone are of ef- 

 fential import. It has no tafte. It neither reddens infufion of Chemical pro- 

 litmus, nor changes fyrup of violets green. The putrid f•s^-^7f7^"° 

 mentation, which in time it undergoes, is in. every refpe|5l 

 iimilar to that of animal fubflances. By deficcation it lofes 

 three fourths of its weight, and this lofs confifls entirely of 

 water. Thus dried it is ftill capable of exciting fermentation ; 

 it is by no means decompofe^, and may be preferved in this May be prc- 



flate without alteration for an indefinite time. We may avail f^''^^^ ^"y . 



r ^ r , • i i-n length of time 



ourielves of this property, to convey it to places at a diltance ^^^q^ dried. 



from any brewery, or with which it is fo difficult to keep up an 

 intercourfe, that frefh yeaft could not be fent to them, parti- 

 cularly in furamer, without becoming putrid. Diftilled in a Analyfis. 

 fmall retort, and urging the iire fo far as this would bear, eight 

 parts of ferment left a refiduum of 2.83 of coal; and I obtained 

 1.61 of water, 1.31 of oil, and 1.46 of muriate of ammonia 

 on adding muriatic acid. Finally, I colleded 0.33 of gas, 

 containing a fifth of its bulk of carbonic acid, and which, 

 when this was feparated from it by potafii, burnt like carbo- 

 nated hidrogen, and required 1.5 of oxigen for its combuftion. 

 From this experiment we fee, that ferment contains in parti- 

 cular a great quantity of carbon. 



Water at the temperature of 12? or 15^ does not diflblve Infoluble In 

 ^^ of ferment: indeed it diffblves fo little, that after (landing ^v^^^*"* 

 upon it feveral hours, and being well filtered, it has fcarcely 

 any a6lion upon fugar. Boiling water occafions it to undergo Boiling water 

 a decompofition, which I fliall examine in another memoir. °""P° ** *'* 



Nitric acid, even diluted with water, at eighteen degrees. Nitric acid con- 

 decompofes it alfo: it converts it into greafe; and there ••'^ f^tt" J^at^er- 

 evolved from it at firfl: azot mingled with carbonic acid, and and azot with 

 afterward nitrous gas at the fame time. carbonic acid, 



, . r 1 n • r ^"^ nitrous gas 



Potafii a6ls upon this lubftance in the fame manner as upon are given out. 

 animal matters, and the phenomena in both cafes are perfe<5lly J^'^^ potafli ic 

 the fame: with each it forms a faponaceous fubftance, and a ammonia is ex- 

 great quantity of ammonia, that is volatilized. . tricated. 



But of all the properties of ferment, no one is fo remarkable, ^" aftion upon 

 and at the fame time fo ufeful, confequently no one fo much 

 deferves to be ftudied, as its action upon fugar : this is inte- 

 refling to men in every clafs of fociety, from the mechanic to 



the 



