26 THE INVISIBLE WORLD 



time immemorial the wort carried by the brewer 

 from brewing to brewing has been a culture for the 

 microbes of beer. 



Until recently all such work was done un- 

 wittingly. The baker did not know that the yeast 

 which he used was literally alive with the invisi- 

 ble beings which we now call microbes, and that 

 to the work of these beings he was indebted for the 

 fine qualities of his bread ; nor did the brewer know 

 that the wort which he carried from brewing to 

 brewing was likewise filled with similar beings, 

 and that to them he owed the fine flavors of his 

 beer. But by the recent invention and use of the 

 microscope, and other means, all is now plain ; and 

 such work is done intelligently. 



Originally, therefore, the first brewings of beer 

 could have been made only by the aid of wild mi- 

 crobes which came into the wort from the atmos- 

 phere. How long this continued we know not. 

 But at length, either by accident or experiment, 

 wort from one brewing must have been transferred 

 to the next, and from this to the next, repeating the 

 process many times. When it was found that bet- 

 ter results were obtained, this method finally be- 

 came habitual. The microbes were at first wild. 

 They then became domesticated. Then by long 

 processes of culture they became greatly improved, 

 and now do their excellent work for the world. 



A similar history must of course be supposed to 

 be traced in the development of breadmaking. The 

 microbes causing the first ferments were wild. At 



