FERMENT A TIO N. 533 



with this exhilarating beverage overcoming all the obstacles 

 which a hot climate threw in the way of its manufacture. 



Our remote ancestors had also learned by experience that 

 wine muketh glad the heart of man. Noah, we are 

 informed, planted a vineyard, drank of the wine, and 

 experienced the consequences. But, though wine and beer 

 possess so old a history, a very few years ago no man knew 

 the secret of their formation. Indeed, it might be said 

 that until the present year no thorough and scientific 

 account Was ever given of the agencies which come into 

 play in the manufacture of beer, of the conditions necessary 

 to its health, and of the maladies and vicissitudes to which 

 it is subject. Hitherto the art and practice of the brewer 

 have resembled those of the physician, both being founded 

 on empirical observation. By this is meant the obser- 

 vation of facts, apart from the principles which explain 

 them, and which give the mind an intelligent mastery 

 over them. The brewer learned from long experience the 

 conditions, not the reasons, of success. But he had to 

 contend, and has still to contend, against unexplained per- 

 plexities. Over and over again his care has been rendered 

 nugatory; his beer has fallen into acidity or rottenness, and 

 disastrous losses have been sustained, of which he has been 

 unable to assign the cause. It is the hidden enemies 

 against which the physician and the brewer have hitherto 

 contended, that recent researches are dragging into the 

 light of day, thus preparing the way for their final exter- 

 mination. 



Let us glance for a moment at the outward and visible 

 signs of fermentation. A few weeks ago I paid a visit to- 

 a private still in a Swiss chalet; and this is what I saw. 

 In the peasant's bedroom was a cask with a very large 

 bunghole carefully closed. The cask contained cherries 

 which had lain in it for fourteen days. It was not entirely 

 filled with the fruit, an air-space being left above the 

 cherries when they were put in. I had the bung removed, 

 and a small lamp dipped into this space. Its flame was 

 instantly extinguished. The oxygen of the air had entirely 

 disappeared, its place being taken by carbonic acid gas.* 



*The gas wliicli is exhaled from the lungs after the oxygen of the 

 air has done its duty in purifying the blood, the same also whick 

 effervesces from soda water and champagne. 



