FER 



FER 



is called fermentation. The product 

 of fermentation is various : when alco- 

 hol is formed it is called vinous ; when 

 starch is converted into sugar, as in 

 bread-making, saccharine. Lactic acid 

 fermentation is when that substance j 

 is produced from sugar ; -putrefactive 

 fermentation, which occurs in dung- 

 hills, takes place when nitrogen is an 

 ingredient in the decaying matter. 



Fermentation is a chemical change, 

 whereby complex organic bodies are 

 converted into more simple forms ; 

 thus, sugar is changed into carbonic 

 acid and alcohol. It differs from 

 eremacausis, in the circumstance that 

 oxygen is only absorbed in the begin- 

 ning, and that the changes take place 

 in an abundance of water. The prin- 

 cipal products of fermentation are 

 water, carbonic acid, alcohol, and car- 

 buret of hydrogen. When nitrogen 

 is present, ammonia, with fetid gass- 

 es, containing sulpliur and phospho- 

 rus, are also exhaled. The heat is 

 a result of these changes. The de- 

 cay is hastened by w-armth and an 

 abundance of yeast ; it is retarded by 

 excessive moisture, and so high a 

 temperature as to coagulate the fer- 

 ments. Those bodies which absorb 

 oxygen rapidly, as green vitriol, hin- 

 der fermentation by intercepting the 

 first change : these are called anti- 

 septics. Mineral acids also destroy 

 the activity of ferments. 



Sugar, starch, woody fibre, &c., 

 cannot ferment spontaneously, for 

 they contain no nitrogen ; they are, 

 however, caWeA fermentable. The jui- 

 ces of fruits, trees, canes, &c., rapidly 

 ferment, because, besides sugar, they 

 contain albuinen, casein, or fibrin, 

 which, decaying easily, conveys the 

 change to the fermentable matter 

 present ; but their fermentation may 

 be hindered by adding a little lime, 

 boiling down to a sirup, or otherwise 

 coagulating or solidifying the de- 

 structive nitrogen principles. 



In consequence of the continuance 

 of fermentation, irrespective of ac- 

 cess of air, fluids in this state must 

 not be barrelled up tightly, or the car- 

 bonic acid gas may burst the vessel ; 

 but by lowering the temperature to 

 280 



45° Fahrenheit (by placing in a cel- 

 lar), separating all the yeast, or fu- 

 migating the cask with vapour of sul- 

 phur, it may be considerably or alto- 

 gether arrested. The vinous fer- 

 mentation runs into the acetous if 

 the substances are freely exposed to 

 air, as cider or beer in an open cask. 

 See Beer, Cider. 



FERNS, FILICES. Flowerless 

 plants, with beautifully -developed 

 leaves, bearing their seed-vessels on 

 the lower side. They are crypto- 

 gamia in the system of Linnaeus, and 

 acotyledonous in that of Jussieu. 

 They have little economical value, 

 grow in wet or rocky situations, and 

 serve well enough for packing, in the 

 place of straw, or to increase the 

 amount of yard manure. 



FERROCYANATE OF POT- 

 ASH. A yellow, crystalline salt, also 

 called Prussiate of potash, the solu- 

 tion of which is used as a test for pe- 

 roxide of iron in solution, with which 

 it strikes a beautiful blue, being, in- 

 deed, Prussian blue. It is also used 

 in the laboratory as a test for copper 

 and other metals, and to form various 

 compounds of cyanogen from. 



FERRUGINOUS {(xom ferrum, 

 iron). Containing iron, or of the col- 

 our of rust. Ferruginous waters are 

 also called chalybeates, and much es- 

 teemed as tonics. Ferruginous soils, 

 when friable, are frequently ver}' fer- 

 tile and improveable. 



FERRUGO. Also Ruhigo, Rust : 

 it is a species of urcdo. 



FERRET. A useful animal of the 

 weasel kind ; the Mustclafuro (Fig.) 

 of naturalists. It is domesticated in 







Europe for the destruction of rats, 

 rabbits, and other small vermin, and 

 might be usefully employed in the 

 United States in granaries. 



" It procreates twice a year, and 

 brings from six to eight young ; smells 

 very fetid. The ferret is very sus 

 ceptible of cold, and must be kept % 



