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Farming of Herefordshire. 



The spontaneous fermentation which occurs in the saccharine 

 juices of fruits, such as grapes, pears, apples, &c., is owing to 

 the presence of certain azotised compounds, which have received 

 the name of proteine. Fermentation can onlj be excited in the 

 first instance in the presence of the atmosphere or oxygen ; when 

 once commenced, it will continue until the whole of the sugar 

 present is decomposed, although further admission of the 

 atmosphere is excluded ; alcohol and carbonic acid are formed 

 during the process, yeast or ferment being at the same time pro- 

 duced. The yeasts yielded by the fermentation of beer, wine, 

 perry, cider, &c., if examined under the microscope, and other- 

 wise tested with alkalis and acids, will be found identical. 

 Yeast once produced is not only capable of converting the re- 

 maining saccharine matter into alcohol, but, from its quality of 

 absorbing oxygen, will change the alcohol (spirit) into vinegar. 

 Hence the propriety of fermenting in close vessels, possessing 

 ronly an opening sufficiently large to allow the escape of the car- 

 bonic acid evolved during the process. In "musts" (the juice 

 of grapes, &c.) rich in sugar and proportionally poor in proteine 

 substances, the decomposition of the latter becomes complete, 

 and their separation in an insoluble form is effected by or pre- 

 vious to the conversion of the whole of the sugar into alcohol and 

 carbonic acid. In such a case, if the liquor (now converted into 

 wine) be carefully drawn off or racked from the scum and lees 

 containing the residue of the ferment, and entirely excluded 

 from the atmosphere, it will keep " for ever. Such perfect 

 •exclusion of the atmosphere is, however, impossible ; besides, it 

 ■is known that alcohol is capable of evaporating through the pores 

 of the staves that form the containing vessel. The reason why 

 cider, &c., undergoes so many fermentations, notwithstanding re- 

 peated rackings, arises from the fact of the juice of the apple 

 • and the pear containing a proportion of azotised compounds sus- 

 ceptible of being converted into ferment beyond the quantity 

 required to change the whole of the sugar present into alcohol ; 

 this undue proportion is increased in cold years. From this 

 cause arises the rapid conversion into vinegar of cider and peiTy 

 the produce of such seasons, and the necessity of employing, 

 with proper precautions, saccharine substances from extraneous 

 sources. In the juice obtained from apples and pears the pro- 

 teine sources of ferment are always found in excess (less so, 

 however, in the pear than in the apple) of the saccharine mate- 

 rials ; it consequently becomes an important object, when the 

 whole of the sugar has been converted into alcohol, to free the 

 "liquor from this source of spontaneous fermentation. This can 

 ■generally be best accomplished by employing an infusion of 

 .tannin (the extract of galls, oak bark, &c.), which changes the 



