FERMENTATION AND DISEASE. 131 



was practised, and its produce relished, more than two thousand years 

 ago. Theophrastus, who was born nearly four hundred years before 

 Christ, described beer as the wine of barley. It is extremely difficult to 

 preserve beer in a hot country ; still, Egypt was the land in which it 

 was first brewed, the desire of man to quench his thirst with this ex- 

 hilarating 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 

 maketh 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 vicis- 

 situdes to which it is subject. Hitherto, indeed, the art and practice 

 of the brewer have resembled those of the physician, both being 

 founded on empirical observation. By this is meant the observation 

 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 suc- 

 cess. But he had to contend, and he has still to contend, against un- 

 explained perplexities. Over and over again his care has been ren- 

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

 disastrous losses have been sustained of which lie has been unable 

 to assign the cause. It is the hidden enemies against which the phy- 

 sician and the brewer have hitherto contended that recent researches 

 are dragging into the light of day, thus preparing the way for their 

 final extermination. 



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 bung-hole carefully closed. The cask con- 

 tained cherries which had lain in it for fourteen days. It was not en- 

 tirely 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. 1 I tasted the cherries ; they were very sour, though 

 when put into the cask they were sweet. The cherries and the liquid 

 associated with them were then placed in a copper boiler, to which a 

 copper head was closely fitted. From the head proceeded a copper 

 tube which passed straight through a vessel of cold water, and issued 

 at the other side. Under the open end of the tube was placed a bottle 



1 The gas which is exhaled from the lungs after the oxygen of the air has done its duty 

 in purifying the blood, the same also which effervesces from soda-water and champagne. 



