238 THE FLOATING-MATTER OF THE AIR. 



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 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 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 vicissitudes to which it is subject. 

 Hitherto the art and practice of the brewer have re- 

 sembled those of the physician, both being founded on 

 empirical observation. By this is meant the observa- 

 tion of facts, apart from the principles which explain 

 them, and which give the mind an intelligent mastery 

 over them. The brewer learnt from long experience 

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

 to contend, and has still to contend, against unexplained 

 perplexities. 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 extermination. 



Let us glance for a moment at the outward and 



