548 FRAGMENTS OF SCIENCE. 
and a flavor peculiar to itself. Keep them out of your 
beer and it remains forever unaltered. Never without 
them will your beer contract disease. But their germs are 
in the air, in the vessels employed in the brewery; even in 
the yeast used to impregnate the wort. Consciously or 
unconsciously, the art of the brewer is directed against 
them. His aim is to paralyze, if he cannot annihilate 
them. 
For beer, moreover, the question of temperature is one 
of supreme importance; indeed, the recognized influence 
of temperature is causing on the continent of Europe a 
complete revolution in the manufacture of beer. When I 
was a student in Berlin, in 1851, there were certain places 
specially devoted to the sale of Bavarian beer, which was 
then making its way into public favor. This beer is pre- 
pared by what is called the process of low fermentation; 
the name being given partly because the yeast of the beer; 
instead of rising to the top and issuing through the bung- 
hole, falls to the bottom of the cask; but partly, also, 
because it is produced at a low temperature. The other 
and older process, called high fermentation, is far more 
handy, expeditious, and cheap. .In high fermentation 
eight days suffice for the production of the beer; in low 
fermentation, ten, fifteen, even twenty days are found 
necessary. Vast quantities of ice, moreover, are consumed 
in the process of low fermentation. In the single brewery 
of Dreher, of Vienna, a hundred million pounds of ice are 
consumed annually in cooling the wort and beer. Not- 
withstanding these obvious and weighty drawbacks, the 
low fermentation is rapidly displacing the high upon the 
Continent. Here are some statistics which show the 
number of breweries of both kinds existing in Bohemia 
in 1860, 1865, and 1870: 
I860. 1865. 1870. 
High Fermentation . . 281 81 18 
Low Fermentation . . 135 459 831 
Thus in ten years the number of high-fermentation 
breweries fell from 281 to 18, while the number of low- 
fermentation breweries rose from 135 to 831. The sole 
reason for this vast change a change which involves a 
great expenditure of time, labor, and money is the 
additional command which it gives the brewer over the 
